AmericanLongRifles Forums
General discussion => Gun Building => Topic started by: James Wilson Everett on November 18, 2011, 03:35:34 PM
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Guys,
The topic on making 18th c breech threads wandered off into the use of a screw plate. It is great how one discussion leads to another. Here is an introduction on how 18th c gunsmiths made the screws for the lockplate & other machine screws. Making wood screws is in a seperate tutorial.
Here is a photo of a typical screw plate that would have been used by our 18th c gunsmith. It makes 10 different sizes of machine screws and taps. You can see the paired holes, the lower holes make a thread that is identical to the upper holes but is a few thousanth of an inch larger. The larger holes make the tap, the smaller holes make the screw.
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4877a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/217fa38d-f198-4333-b5cb-544cfef6cc65/p/1e277ef7-3d83-43a5-9d72-8eddc669f526)
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4905a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/217fa38d-f198-4333-b5cb-544cfef6cc65/p/32417913-43dd-4cc1-9256-6c0d791f5e0f)
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4907a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/217fa38d-f198-4333-b5cb-544cfef6cc65/p/c1ff4be0-6445-4d2d-9690-87d35c986d6a)
The screws I use to make the hand made locks is a 0.174 - 30 thread and one can be seen in the second screw plate photo. The screw plate swages or forms the threads, they are not cut as in modern dies. To make these lock threads I form a pin using a screw grinder with a shaft diameter of 0.157. The screw plate swages this out to the 0.174 thread. The threads look a lot like lightbulb threads, and they are very smooth.
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4904a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/217fa38d-f198-4333-b5cb-544cfef6cc65/p/8c0782d7-7ff1-4bd6-9d5c-521cc77dce81)
Jim Everett
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Thanks, Jim. So when threading the screw one simply screws the stock in, as opposed to the back and forth action one would use with a modern die? And do you use any lubricant?
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Rich,
I normally hold the iron rod in a vise and turn the screw plate onto the rod. The photos show a finished screw just for a show-n-tell. Actually, the iron rod for that screw was a blacksmith tong handle originally. I do not cut the screw from the rod until after the thread is completed and even after it is installed in the threaded hole. Then I cut it from the rod and finish the head & slot. You do not need the keep reversing the screw plate as you do with a modern die as there is no chip breaking required. You actually can turn the screw plate onto the rod as quickly as you wish. The tool is very easy to start and to keep square, unlike modern dies that seem to be nearly impossible to start square by hand (at least for me). Of course a good lubricant helps I use any oil or grease or soap. Thanks a lot for the question, I can tell that you have used a die a lot.
Jim Everett
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Thank you for posting your excellent information and photos. This is very interesting to me. Have you ever used a screw plate with modern mild steels? If so what was the result?
Bruce Robb
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The $64.00 question: Where can one purchase one of these screw plates?
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I got 2 off evil-bay over the years. But I search there weekly with several key words.
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Guys,
Here are some answers to your questions. I am glad to see the inerest in actually using the old tools & techniques to make the guns.
Bruce, Yes the screw plate works very well with modern mild steel. Go to mcmaster.com for the McMaster-Carr supply company. Order some 12L14 carbon steel rods to make the screws. 1/4 dia. works great for the lock screws and 1/2 dia. is for the hammer screw and for the sideplate screws. I also use high carbon steel to make the taps and also the frizzen screw if the flashpan does not have the screw support arm. You can get W-1 drill rod from McMaster Carr that acts very close to 1095 steel.
Dr. Tim, These are available and not too expensive on E-Bay. I have bought several from E-Bay. Sometimes they are listed by names other than screw plate - thread plate - threader, and others. Try to get one with the two little side holes as these are usually very well made tools. Here are photos of another screw plate.
Jim Everett
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4892a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/217fa38d-f198-4333-b5cb-544cfef6cc65/p/80496f24-6342-4027-b46d-2afc4911af93)
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4893a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/217fa38d-f198-4333-b5cb-544cfef6cc65/p/f39af56d-5180-4e69-90b7-b0ecb3d386ff)
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The $64.00 question: Where can one purchase one of these screw plates?
Jim, apparently feeling sorry for me since I had no shoes, gave me a screwplate after we met, three years ago! ;)
I've been putting that screwplate to good use too. Thanks Jim. :)
All of these show-and-tell posts should go in the tutorial section. Looks like I'm not the only one trying to learn how to use the old tools.
Andy
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No, you're not the only person trying to learn how to use the old tools. I'm following along in total bewilderment and awe. I've always wondered how they made things like screws and such back in the old days before modern lathes and tools came along. I really do appreciate all this information being so painstakingly shared here. ;D
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A lot of what y'all are interested in in terms of using period tools to make screws, etc. is addressed in Volume I of The Journal of Historical Armsmaking Technology, NMLRA, 1985. Out of print but often available through EBay or used book stores on line for 25-40 dollars.
As a side note --- the screw plates with the two holes flanking the threaded hole are usually later in the 19th century. Those holes were added so a broken screw could be removed by splitting it with a jewler's saw.
Gary
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Would the gunsmith back then have bought these plates via a company making them here or were they imported?
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Guys,
My understanding is that such tools were imported from England, I believe Birmingham was the tool making center. However, I am a tool user and not a collector. Maybe someone who collects tools can have a more definitive input here. Thanks for the interest and for the question.
Andy, Good to hear from you and I am glad that you are putting the screwplate to good use.
Jim Everett
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Jim, were tapped holes done the same way, basically formed not cut, and how would that affect the size hole one needs to drill?
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Interesting thread!
And I have a question too.
I have a hand forged/made screw plate, and tried to make a screw with it once, but with no luck. But, I used a slightly larger diameter piece of metal than the thread size in the screw plate, like you'd do when you cut threads. However you're saying you use a smaller diameter than the thread size to form the threads? I was thinking the plate would swedge the threads down to size, and you indicate that the plate will swedge the threads out to a larger size? In your example, a .157 blank out to a .174 screw.
John
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To put some more light on the subject read this: One Good Turn: A Natural History of the Screwdriver and the Screw by Witold Rybczynski. The screwdriver was the only tool that was not around a thousand years ago. This book goes through the progression of everything that was made possible as screws got better.
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Guys,
During the swage process, either for machine screws in this posting, or for the wood screws in the tutorial section, the threads will expand outwards from the original shaft diameter. A good approximation is the distance that the thread valley is pressed into the metal is the same distance that the thread crest grows outwards. You have to arrive at the optimum diameter for the original shaft by trial & error. For the lock screws that I make from the first posted photos - the final thread diameter is 0.174 - the original shaft diameter is 0.157 - the hole in the screw plate will pass a 0.136 drill but will not pass a 0.140 drill, so the plate hole diameter is about 0.138. I know this sounds weird when compared to the way we use a modern die, but it is the way screws were made in the period.
Jim Everett
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I see a couple on ebay now. They are in England. They are listed as watch maker screw plates but the largest size is 2mm. Interesting. Danny
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Danny,
Try for some larger sizes unless the plates would be for making those amazing miniature guns. The sizes I normally use from my "working" screwplate is:
1. 0.156-30 for the thin screw used for a sling swivel.
2. 0.174-30 for the lock screws, the sideplate screws and for the tang screw.
3. 0.216-23 for the lock top jaw screw.
4. 0.268-19 for - I can't remember, but I did use it somewhere because I have the tap. I guess my mind is like a collander - only lumpy things stay in.
I plan to post a topic on making and using the 18th c taps sometime soon.
Jim Everett
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I've been reading this thread with great interest. Thanks, Jim, for the information and pictures. I continue to be impressed and intrigued with the tools used by 18th & 19th century gunsmiths.
Bill
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Guys,
Here are some photos of the taps that must be made from the screwplate. Making the screws is only half of the job. Since these screws predate the standard sizes we must also make the taps for the threaded holes. The screw plate has two nearly identical holes. One hole being a few thousanth of an inch larger and is used to make the tap. As I am sure you understand, the tap must be slightly larger than the screw for everything to go together. These are made from W-1 tool steel and are heated to 1500F and brine quenched - yep fully hard.
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Taps/100_4879a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/58119844-6f1c-4015-a428-cc9647fedbc1/p/a0da96d5-d894-40f5-a1a6-d2963e7caf55)
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Taps/100_4880a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/58119844-6f1c-4015-a428-cc9647fedbc1/p/3b95627c-8fe0-42ca-a993-8b7c650bb5d3)
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Taps/100_4881a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/58119844-6f1c-4015-a428-cc9647fedbc1/p/9909b424-f2d3-4ad5-a4ea-a98fe19d581f)
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Taps/100_4882a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/58119844-6f1c-4015-a428-cc9647fedbc1/p/e98ccde0-9027-464c-b155-f373b770166a)
These are the four taps described in the posting of this morning. Bad news - the size of the hole in the lockplate is only determined by trial & error. There is no reference to tell you this since every screw palte is different. When you get it figured out - only tell your apprentice not to reveal it on pain of death!!
Jim Everett
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Guys,
Here are some photos of the taps that must be made from the screwplate. Making the screws is only half of the job. Since these screws predate the standard sizes we must also make the taps for the threaded holes. The screw plate has two nearly identical holes. One hole being a few thousanth of an inch larger and is used to make the tap. As I am sure you understand, the tap must be slightly larger than the screw for everything to go together. These are made from W-1 tool steel and are heated to 1500F and brine quenched - yep fully hard.
(https://i1137.photobucket.com/albums/n514/JamesEverett/Tools/Taps/100_4879a.jpg)
(https://i1137.photobucket.com/albums/n514/JamesEverett/Tools/Taps/100_4880a.jpg)
(https://i1137.photobucket.com/albums/n514/JamesEverett/Tools/Taps/100_4881a.jpg)
(https://i1137.photobucket.com/albums/n514/JamesEverett/Tools/Taps/100_4882a.jpg)
These are the four taps described in the posting of this morning. Bad news - the size of the hole in the lockplate is only determined by trial & error. There is no reference to tell you this since every screw palte is different. When you get it figured out - only tell your apprentice not to reveal it on pain of death!!Jim Everett
Just for clarification, the pieces used to be threaded as taps need to be softer at first than the screw plate, correct? I'm thinking the stock that accepts the threads must first be annealed, then after threading re-hardened ... ???
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Back when I was flying FB-111s out of Plattburgh, NY in the '70s I bought an old farm in the Adirondacks. Had several out buildings including a shop with all the equipment a blacksmith would need. Too darn cold to retire there so I regretfully sold the place as is in the '80s. Did take this screw plate with me, though. It appears to be quite hard. No holes for chip removal but I assume that one could use the plate as described in this discussion. I have been hesitant to do so. Should I start with brass rod to check it out?
(http://i1207.photobucket.com/albums/bb471/eddillon/19th%20century%20screw%20plate/IMG_2821.jpg)
(http://i1207.photobucket.com/albums/bb471/eddillon/19th%20century%20screw%20plate/IMG_2817.jpg)
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You can try brass rod, but be sure to anneal it first as usually brass rod is work hardened. Heat it to a dull red and quench in water. Yes, I know this sounds like it will harden the brass like it does with carbon steel, but this is the way to soften brass. Actually leaded steel rod 12L14 rod will work better. Use a good thick grease or soap as a lube. Give the rod a little taper to help start the thread.
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Ya got to love it... 18th century roll taps... I keep telling people they wern't dumb.. Couple of great threads James.. Thanks much...
Regards
Dave
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Glen,
You are right! I should have said that the taps were formed from annealed, soft W-1 tool steel first, and when completely formed and finished, then they were hardened. I guess this does make more sense.
Jim
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I was told that in flyers jargon,"Buying the Farm" referred to a departure stall at the end of the runway that lands in a housing development. I lost my doctor like that when his V tailed doctor killer crapped out taking him and a daughter with it.
No homes involved but still tragic enough.
Bob Roller
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Bob, you are right about the jargon. Happy to report that I purchased the farm and that I did not "buy the farm".
Did some unauthorized high speed passes over the farm a couple of time. Too tempting. My barn had a shiny metal roof that could be seen from miles away. Managed to cause the early demise of two my neighbor's turkeys. Costly lighting of afterburners. Statisicallyy more doctors "buy the farm" in private aircraft than any other profession. ;)
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Guys,
As noted by Riflesmith's comment on 18 Nov., the two side holes seem to be a slightly later development in the manufacture of screwplates. Please note that I am a tool user, not necessarily a collector and expert on them. Anyway, here is a screw plate without the side holes, marked P S STUBS and the number 16. Peter Stubs was a noted English tool maker 1756-1806 although his name was marked on the firm's tools long after his death. I must assume that this screwplate dates earlier than those shown with the side holes. By the way, the side holes are used to allow access of a jewler's saw blade to cut through a broken screw shank and to remove it when that oops happens.
Jim Everett
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4914a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/217fa38d-f198-4333-b5cb-544cfef6cc65/p/1971a389-fb64-4162-bb16-749812776b7b)
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4915a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/217fa38d-f198-4333-b5cb-544cfef6cc65/p/e5ee8937-c018-428e-8018-561dd8883118)
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What are those little stamped diagonal line, James? is that the sequence you follow to make the screw smaller and smaller?
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Jim,
Just for reference, roughly how long are the screw plates you've been posting? Or, what range of lengths? Just trying to get an idea of size.
Thanks,
Bill
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Guys,
The little scribed line on the screwplates align the two holes that are for the same thread. Each of the two holes will make the identical threads with the exception that one thread will be very slightly smaller, usually by about 0.002 inches on the diameter. The larger thread is for making the tap and the smaller thread is for making the screw. Really, for everything to fit together properly the tap thread must be a little larger than the screw thread.
The sizes of the screwplates posted are as follows.
The large brown screwplate with the tiny side holes posted first - blade length 6.5 in. and LOA 10.4 in. It is marked Lewis & Griffith.
The small shiny screwplate with the tiny side holes posted second - blade length 4.3 in. and LOA 7.5 in. It is marked CB.
The large brown screwplate without side holes posted last - blade length 6.8 in. and LOA 10.7 in. It is marked Stubs
Jim Everett
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James that is great show and tell now for wood screws how where those baby made
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Guys,
For the wood screws, look in the tutorial section of the forums under the title "Making 18th c Wood Screws".
Jim
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thanks James
this is very interesting something to look for you never know maybe old garage sales
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Guys,
Here are some photos of another screwplate that was not made by a professional tool maker. The local smith probably borrowed as many taps as he could from his neighbors and made this screwplate from an old file (notice the file handle tang). Also, to find a screwplate with some of the original mating taps is very unusual. I don't know the trade of the smith who used this tool, but it looks like he had the screw sizes to make anything from a wagon to a watch.
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4918a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/217fa38d-f198-4333-b5cb-544cfef6cc65/p/cb9f5bdb-37a4-4610-a5fd-7f974f69cdea)
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4916a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/217fa38d-f198-4333-b5cb-544cfef6cc65/p/0011b1c4-53bb-4f36-9e1f-904fd93b1b08)
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4920a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/217fa38d-f198-4333-b5cb-544cfef6cc65/p/95d29c3d-3ba3-49eb-b1e4-629d78973e79)
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4919a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/217fa38d-f198-4333-b5cb-544cfef6cc65/p/ac6bb3e6-25ed-4532-bf50-cb124cea85b4)
I do not actually use this one, but it is interesting.
Jim Everett
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I was told that in flyers jargon,"Buying the Farm" referred to a departure stall at the end of the runway that lands in a housing development. I lost my doctor like that when his V tailed doctor killer crapped out taking him and a daughter with it.
No homes involved but still tragic enough.
Bob Roller
When I was learning to fly a guy stuck one of these into the plowed field one IFR night while trying to get in on a VOR approach without an instrument rating. 4 on board. His wife crawled from the wreck to a farm house, only survivor. Don't think he was a doctor though. I had not thought about V tails and doctors in years.... Last one I remember before I quit flying a doc hit Mt McKinley with one.
I don't know where "buying the farm" came from but I always heard it as an aviation term referring to someone who made a "bad landing".
Dan
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Guys, Another tool used to make a machine screw prior to threading with the screwplate is a tool called a screw grinder. This is the tool used to bring the iron to the proper diameter and cylindrical shape. The screw grinder has a through hole of the proper diameter for the shaft of the screw before threading. In this case to make a 0.174 - 30 screw thread the shaft starts at 0.157 diameter. This is not a typo - the threads grow outwards from 0.157 to 0.174 during the thread swage process. The cutting teeth form both the shaft diameter and the square surface under the screw head. You clamp the grinder in a vice and twist the iron rod through it allowing the finished shaft to pass into the hole. It saves time to rough form the shaft using a file until you have an octagon type shape about 0.16 across the flats before using the grinder.
Jim Everett
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4873a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/217fa38d-f198-4333-b5cb-544cfef6cc65/p/f3369700-d159-4b6c-9e36-b0bee42feead)
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4874a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/217fa38d-f198-4333-b5cb-544cfef6cc65/p/77a9d79a-c97e-468d-a652-2c575c56cd50)
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4876a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/217fa38d-f198-4333-b5cb-544cfef6cc65/p/45637ed8-8b20-4054-9f0b-209d7a2f9537)
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Guys,
Here is a page from the mid 18th c tool catalog by John Wyke showing the array of different size screw plates that were available from England. Normally the gunsmith would make his own taps from the larger of the mated thread holes in the plate as the taps were an expendable item - just like today, but in the 18th c the gunsmith could not buy a replacement tap that matches the screwplate he has. Original screw plates that look just like those illustrated are readily available on e-bay or in antique shops.
Jim Everett
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Wyke/ScrewPlatea.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/59f48ff2-b870-451b-9b32-0808e0f04812/p/6c0e84d6-ac65-4333-879a-4b6cd0be8013)
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Notice that the #345 is also the tap wrench? That slot near where the handle joins the flat part fits the period taps below.
Gary
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Guys, Another tool used to make a machine screw prior to threading with the screwplate is a tool called a screw grinder. This is the tool used to bring the iron to the proper diameter and cylindrical shape. The screw grinder has a through hole of the proper diameter for the shaft of the screw before threading. In this case to make a 0.174 - 30 screw thread the shaft starts at 0.157 diameter. This is not a typo - the threads grow outwards from 0.157 to 0.174 during the thread swage process. The cutting teeth form both the shaft diameter and the square surface under the screw head. You clamp the grinder in a vice and twist the iron rod through it allowing the finished shaft to pass into the hole. It saves time to rough form the shaft using a file until you have an octagon type shape about 0.16 across the flats before using the grinder.
Jim Everett
Jim,
When looking at original screws on 17th and 18th century locks I've not noticed the threads being larger than than the screw shaft diameter. Perhaps it's just that I've not payed enough attention. I did take a minute to examine screws on a Andrew Dolep lock from the late 17th century and measured no appreciable difference between thread and shank diameter. Any thoughts? I'll look at some other examples I have when I get a chance.
Thanks,
Jim
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Jim,
Now this is getting somewhat advanced, thanks for the comment. This does require more explanation. My screws do not show the threads larger than the shaft, like on the sear screw where the sear pivots on the unthreasded shaft like an axle. Here the screw blank is formed with two different diameters before threading. A 0.174 shaft near the head and a 0.157 shaft for the thread. When the thread is formed and the diameter becomes 0.174 the whole screw is of the same diameter. Now the sear hole fit will not be sloppy and will not be pivoting on the thresded portion, either.
Jim
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Thanks for the explanation, Jim. Makes perfect sense.
Jim
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I suppose you could use a 'thread diameter' screw grinder to cut a nice shoulder on the shank just past the thread. And another size grinder to trim under the head of the screw.
This reminds me, I have some watchmaker taps and dies from the 19th Cent. This topic will get me to dig those out and take a fresh look. And a photo if useful here.
Vewwy twicky business, Mr. Wabbit.
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Guys,
Actually in making the screws there are several different size grinders for the thread shaft, for the shaft without threads and for the head. You can thread the shaft for the 0.174 - 30 threads (the ones I use for gunlocks) starting with the shaft at 0.174. This is just the same way we do the modern die cut threads today. However, the force required is much higher and the result is often a twisted off shank. It is much easier to put the 0.174 threads on a 0.157 shaft. When the threads run to the point where the shaft increases diameter to 0.174 there is often a build up or raised ridge as the swaged material has nowhere to go at this point. This ridge at the intersection must be filed away for something like the sear or the frizzen hole to fit over the new thread. I know that this sounds complicated and it is certainly much easier to use the modern Siler style lock kits. But when you actually make a lock in the 18th c style it give us so much more respect for those period craftsmen.
Jim Everett
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Gary,
I guess that the black oblong in the #345 may indeed be used for a tap wrench. It really would make a lot of sense to include such a feature. However, I have never seen a screwplate with such a tap wrench feature included. Maybe someone out there has seen one, if so, please let us all know about it. Here are some photos of a small 18th c tap wrench that was forged from wrought iron. It is about 8" long. The tap wrenches that tighten on the tap square by a screw are a lot more easy to use, this one has a lot of slop between the tap and the wrench square. I am sure you can envision how much more difficult such a tool is to use. I do not know when the screw adjustable type of wrenches started to be used.
Jim Everett
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Taps/100_4924a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/58119844-6f1c-4015-a428-cc9647fedbc1/p/7b6879db-7cd6-4113-a3c0-10eb1c482c19)
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Taps/100_4925a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/58119844-6f1c-4015-a428-cc9647fedbc1/p/d1343dd4-ae4d-43d3-a863-911d5c8826ee)
(https://hosting.photobucket.com/albums/n514/JamesEverett/Tools/Taps/100_4926a.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/58119844-6f1c-4015-a428-cc9647fedbc1/p/cf6fda26-c3d3-4ef0-a4cd-14c8b7709ec4)
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He made that one quick, with a little time and some well made drifts, he would have had some tighter holes.
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Danny,
Of course your observation is true. But, I really enjoy looking at some 18th c things that are not exactly perfect. It helps me to realize that this things were made by a guy who was in many ways just like me, that is imperfect. Check this out - the copy of the page from the John Wyke catalog was engraved by hand on a copper plate. Look at the perfection of the straight lines. If we ever feel proud of our work - try to engrave a truly straight and uniform line as in this example. I am afraid mine would look a lot like a snake trail. Boy, did this ever wander off subject!
Happy New Year
Jim Everett
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And he had to engrave it in reverse! I bet he charged a few shillings for that work.
HAPPY NEW YEARS y'all.
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Love this stuff! Love being educated on these old tools. This is a large part of the enjoyment for me in building is learning history in a hands-on practical way you can't get any other way. My most recent project hasn't seen a power tool nor will it (except for when Dunlap band sawed out the blank).
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Love this stuff! Love being educated on these old tools. This is a large part of the enjoyment for me in building is learning history in a hands-on practical way you can't get any other way. My most recent project hasn't seen a power tool nor will it (except for when Dunlap band sawed out the blank).
I couldn't agree more; this has got to be one of the best threads I've found on this site to date. THANKS !!! ;D
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I couldn't agree more; this has got to be one of the best threads I've found on this site to date. THANKS !!! ;D
Pun unintentional? ;D
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Jim, How is your forge set up? Side draught, RR Pot, Champion blower or Great bellows?
Danny
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Danny,
You obviously know a lot more than me about the different forges, because I must admit some ignorance of the terms in your question. For forging the flintlock mechanism and almost all of the small parts I simply clamp an oxy-acetylene torch in my vice with the flame pointing up. With my anvil within inches of this it is easier to forge the very small parts without burning my knuckles. I actually do the forging sitting down in a chair. I can forge a few strokes and reheat several times in a minute quite easily. For bigger stuff I borrow a neighbor's forge that uses one of those hand crank things. The draft blows upwards through what I think is a truck wheel. Also, some of my pistol barrels are forged by a dear friend, Jymm Hoffman, who uses a trip hammer to forge barrel blanks that are 1,000 times better looking than mine.
Jim Everett
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Wow! I thought that you would have a Spreading Chestnut tree and everything. My forge is made out of sawmill pine nailed into the form of a 2 foot cube with a 1/8 " sheet iron top. My air comes in from the side through a freight wagon wheel bearing, a side draught forge. The blower is a 19th century Champion Climax, 100 bucks at the flea market and my anvil is a little 100 lb London job, same price. The iron plate is so burned through that I had to fill the holes with concrete but it still works fine.
What I would like to have is a 200 lb Fisher Norris, a square Rail Road Tuyere in a 3 foot square, bricked in forge with a 6 in deep box full of coal and a 4 foot Great Bellows in an enclosed shop, 5 tons of coal and a ton of steel, like I used to have at the Museum, but i can do all of the work that I require.
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Guys,
This reply is simply to bring this topic back to life!
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James: 40 years ago I got into making a jam tap to make the jam die. If you take a knife blade and a piece of wood dowel and turn the knife blade a few degrees and rotate, you are making a screw. Used this method to make a threaded high carbon (fully annealed) screw thread in a jig I clamped in the vise. Made two sizes. From here it gets kind of deep. If anyone has any questions post them and I,ll try to answer. James THANKS for your time and effort here.
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Ever since this thread started I've been looking for original die plates but so far all the ones I have found were unusable or out of my financial reach.
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Jim, I don't think this post ever died!
Do have a question I've been pondering while I've been forging things...tapered reamers...I have a few both 4-square and half round for use in a brace...but their sizes are considerably larger than the screws we use in locks etc. Do you have any examples of some that fit in the lock-screw size range..I'm wonder how long, how much taper, how many sizes...it would see that the tapers would have to be less steep with the small diameter holes in thinner metals, otherwise you'd be from good to too large in a hurry across the thickness of the piece...rendering the taps (and screw) useless. Thoughts?
John
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Here is a photo of the small tapered reamer that I use for the lock plate screw holes. I made this one to have about the same taper as the larger originals that I have. I mounted this reamer in a small wood handle and I simply turn it like a screw driver. I believe that the survival rate of the really small 18th c tools is very low.
(https://i1137.photobucket.com/albums/n514/JamesEverett/Tools/drills/100_4887a.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/Tools/drills/100_4887a.jpg.html)
To determine when the hole reaches the correct size, I use a go - no go gauge. When the hole is the proper size, the gauge will pass into the hole up to the tiny step you see about half way on the pin.
[U(https://i1137.photobucket.com/albums/n514/JamesEverett/Tools/drills/100_4883a.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/Tools/drills/100_4883a.jpg.html)
Here is what the gauge looks like when in a hole of the proper size.
(https://i1137.photobucket.com/albums/n514/JamesEverett/Tools/drills/100_4885a.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/Tools/drills/100_4885a.jpg.html)
All of these sizes are determined by trial & error, there is no manual to find the proper size.
Jim
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Just love this topic.
I have some screw plates and also a couple that are adjustable.
There is no doubt in my mind that the old screw threads and holes were tapered. I have, for instance, an English 1810 f/l fowler and needed a replacement top jaw and screw. My engineering friend turned up a perfect screw but with a parallel thread. Sloppy fit, so made a larger one. Couldn't make it tight. Tapered female thread. One day I will have one turned up with a taper.
All male and female screw threads on the fowler are likewise tapered. And I discovered that the taper has been matched to the hole such that the thread wedges in at just the point the head also tightens against the body. I assume it must be a careful trial and error process to achieve that fit. It does mean, however, that the threads on the screw also press outwards against the female threads and hole making for a stronger connection? I can see how this would make a better interference fit on such as a breech plug.
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OK, thanks for the pics Jim. Based on these and Mr Hammer's post, it raises another question...screws, taps, reamers all tapered... so how was a hole, like the tumbler shaft hole that should be a precision fit to reduce play handles...are they tapered in the originals? This would make me think that if the shaft ...which would be concentric based on our tumbler mill discussions, would be rotating in a tapered hole. If so was the large end of the taper on the cock side or tumbler side?? Either way there would be a narrow contact surface where the hole was "just right" and this would undoubtable result in rapid wear...even on a cased lock plate. Is this evidenced in well worn locks...might be why they are well worn?
John
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I had the opportunity to study an early Dutch musket lock, very large, with a very curved banana lock plate. The frizzen was wide as a child's hand. Ok, about 1.5". Anyway I was very surprised to see the tumbler axle was quite noticeably tapered as was the hole in the lock plate.
I have no idea if this was a common feature on very early locks.
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Guys,
Very good questions, but the answers are elusive indeed. From all of the 18th c tooling that I have seen, the only way to achieve a tightly controlled diameter small hole is to use an undersized fishtail bit followed by a tapered reamer. This always results in a very slight or very tiny taper to the hole, probably one or two thousandths of an inch taper in the thickness of a lock plate. An unknown tool is the "false drill" as used at the Harpers Ferry arsenal. This tool apparently did result in a cylindrical hole of a controlled diameter. Unfortunately, I have not been able to discover what a "false drill" looked like or how it was used. See this topic: http://americanlongrifles.org/forum/index.php?topic=36020.msg345643#msg345643.
This is now called "primary research" as there is no book or other publication where a researcher can find the answer. So, anybody out there have any idea what an 18th or19th c "false drill" is?
Jim
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Jim, I suspect it is a drill with a false edge on the v bit and sharpened sides like reamer. It could start in the tapered hole and ream it straight
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Danny,
You obviously know a lot more than me about the different forges, because I must admit some ignorance of the terms in your question. For forging the flintlock mechanism and almost all of the small parts I simply clamp an oxy-acetylene torch in my vice with the flame pointing up. With my anvil within inches of this it is easier to forge the very small parts without burning my knuckles. I actually do the forging sitting down in a chair. I can forge a few strokes and reheat several times in a minute quite easily. For bigger stuff I borrow a neighbor's forge that uses one of those hand crank things. The draft blows upwards through what I think is a truck wheel. Also, some of my pistol barrels are forged by a dear friend, Jymm Hoffman, who uses a trip hammer to forge barrel blanks that are 1,000 times better looking than mine.
Jim Everett
Doh! Why didn't I think of putting the torch in the vise???
Interested to see if one of these threading devices can be made out of modern materials/tools.
BTW on the V tail/buying the farm--flew one quite a bit in the 1970s. Didn't kill myself but I wasn't a Dr (& I understood variable pitch props)
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Danny,
You obviously know a lot more than me about the different forges, because I must admit some ignorance of the terms in your question. For forging the flintlock mechanism and almost all of the small parts I simply clamp an oxy-acetylene torch in my vice with the flame pointing up. With my anvil within inches of this it is easier to forge the very small parts without burning my knuckles. I actually do the forging sitting down in a chair. I can forge a few strokes and reheat several times in a minute quite easily. For bigger stuff I borrow a neighbor's forge that uses one of those hand crank things. The draft blows upwards through what I think is a truck wheel. Also, some of my pistol barrels are forged by a dear friend, Jymm Hoffman, who uses a trip hammer to forge barrel blanks that are 1,000 times better looking than mine.
Jim Everett
Doh! Why didn't I think of putting the torch in the vise???
Interested to see if one of these threading devices can be made out of modern materials/tools.
BTW on the V tail/buying the farm--flew one quite a bit in the 1970s. Didn't kill myself but I wasn't a Dr (& I understood variable pitch props)
I have a propane forge and all the accessories capable of doing good size work. However, for making springs, final bends in a trigger guard, and similar small bits of work; I use a rosebud tip on my Smith Little Torch on its magnetic mount. It puts the flame out horizontally. That rosebud make more than enough heat for working anything from a mainspring on down. It is much better than any plain propane or MAPP torch I ever used. It is one of the best purchases I ever made. I use it with Propane and it is very clean for indoor use.
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Danny,
You obviously know a lot more than me about the different forges, because I must admit some ignorance of the terms in your question. For forging the flintlock mechanism and almost all of the small parts I simply clamp an oxy-acetylene torch in my vice with the flame pointing up. With my anvil within inches of this it is easier to forge the very small parts without burning my knuckles. I actually do the forging sitting down in a chair. I can forge a few strokes and reheat several times in a minute quite easily. For bigger stuff I borrow a neighbor's forge that uses one of those hand crank things. The draft blows upwards through what I think is a truck wheel. Also, some of my pistol barrels are forged by a dear friend, Jymm Hoffman, who uses a trip hammer to forge barrel blanks that are 1,000 times better looking than mine.
Jim Everett
Doh! Why didn't I think of putting the torch in the vise???
Interested to see if one of these threading devices can be made out of modern materials/tools.
BTW on the V tail/buying the farm--flew one quite a bit in the 1970s. Didn't kill myself but I wasn't a Dr (& I understood variable pitch props)
I lost my doctor in one of the V tailed Beeches.It also took his beautiful daughter and her fiancé as well.
I have a wee bit of time in one but that was playing around many years ago.
Bob Roller
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Guys,
In reply to a question from ShutEyeHunter: Yes, I have made a screwplate that looks a bit like the originals, but has many of the modern screw threads that I would likely encounter when at Show-N-Tells doing 18th c gunsmithing. With this tool I can make a replacement screw for a modern reproduction just sitting under a shade tree. Sometimes the re-enactors are rather surprised that a person can actually do an 18th c skill! The complete discussion of this stuff is found on an old topic "Articifer's Box" http://americanlongrifles.org/forum/index.php?topic=22390.msg214020#msg214020
Here are some photos of the "modern" screw plate. It is made from 1095 carbon steel, I don't remember the temper.
(https://i1137.photobucket.com/albums/n514/JamesEverett/Box/Box5.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/Box/Box5.jpg.html)
(https://i1137.photobucket.com/albums/n514/JamesEverett/Box/Box6.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/Box/Box6.jpg.html)
(https://hosting.photobucket.com/albums/n514/JamesEverett/Box/Box4.jpg?width=1920&height=1080&fit=bounds) (https://photobucket.com/u/JamesEverett/a/2cfc1283-c82f-445a-a448-aeece9448ced/p/9c716907-4aa3-4fe4-b06b-c3299436cfde)
Jim
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I am late to this discussion, but it is very good.
In a modern machine shop the thread grinders would be called hollow mills, they are fairly specialized and a lot of machinists would have never used one.
The movement of metal in thread forming is interesting. The diameter of stock for a male thread, or the hole for a female thread is close to the pitch diameter of the thread being made. However if one changes the stock diameter by .001", the diameter of the thread will change by .003" because of the geometric nature of the material flow.
As to "bought the farm", I was given to understand that the phrase started in World War One. A soldier leaving for the war would buy a life insurance policy and the amount was often equal the the family mortgage. If he did not return....
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Guys,
Recently there have been a couple of mentions of screw plate use. This comment just resurrects this old topic.
Jim
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Yes I re read all this the other night. I managed to find one old screw plate, (a smaller one) and an adjustable one. Now to make a screw grinder I guess?
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Guys,
Another update on the use of an 18th c screwplate. A question often asked is "what is the proper diameter for the shaft prior to forming the threads?" The answer up to now was to just do a trial & error type of figuring until, at long last, the proper diameter is found. A much easier, and ingenious, way has been re-discovered. The proper shaft diameter is that size that will just barely pass through the next larger hole in the screwplate. It really does seem to work well. Look at the photo to see what I mean. This surely does make this tool a lot easier to use and a lot more sophisticated in design.
(https://i1137.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4877b_zpsidzcvs8v.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/Tools/Screw%20Plate/100_4877b_zpsidzcvs8v.jpg.html)
This information was re-discovered by our own master screwmaker, Mark Elliot, so all thanks go to him alone. This is another example of the answer being right before our eyes, yet we don't see it. Thanks again to Mark!
Jim
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James, would it make sense, if I was a maker (or user) of screw plates, to make all the screw holes the SAME PITCH?
If I were making screws, I can take a blank from one hole to the next to form the threads completely, like move down the plate from a starter size down to a finish size?
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James, would it make sense, if I was a maker (or user) of screw plates, to make all the screw holes the SAME PITCH?
If I were making screws, I can take a blank from one hole to the next to form the threads completely, like move down the plate from a starter size down to a finish size?
The screw plate that I have (18th century) seems to have a couple groups of four holes that have the same pitch with increasingly smaller holes. The pitches of the eight groups (A-H) are 24, 32, 40, and 48 TPI. Four of the groups are approxomately 32 TPI and two groups are approximately 24 TPI.
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Guys,
Another update on the use of an 18th c screwplate. A question often asked is "what is the proper diameter for the shaft prior to forming the threads?" The answer up to now was to just do a trial & error type of figuring until, at long last, the proper diameter is found. A much easier, and ingenious, way has been re-discovered. The proper shaft diameter is that size that will just barely pass through the next larger hole in the screwplate. It really does seem to work well. Look at the photo to see what I mean. This surely does make this tool a lot easier to use and a lot more sophisticated in design.
(http://i1137.photobucket.com/albums/n514/JamesEverett/Tools/Screw%20Plate/100_4877b_zpsidzcvs8v.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/Tools/Screw%20Plate/100_4877b_zpsidzcvs8v.jpg.html)
This information was re-discovered by our own master screwmaker, Mark Elliot, so all thanks go to him alone. This is another example of the answer being right before our eyes, yet we don't see it. Thanks again to Mark!
Jim
The relationship also appears to apply to tap drill/reamer size.
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Guys,
Just a note to bring this topic back to the top.
Jim
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Guys,
To bring this topic back to life.
Jim
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Looking at the taps, do they also swage female threads? I see some with a gouge parallel to the shaft filed in and some without.
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This has been a remarkable education in early screw threading. I have run across a few screw plates over the years but all have been for the tiniest of screws. The largest perhaps a no. 4. Im will keep looking as I would like try what I’ve learned here.
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Guys,
Yes the 18th c. taps do not cut the threads, they swage them. The little grooved capture the small amount of swag dust, tiny metal chips, that you get in the process. For the female threads the I.D. of the hole is much smaller after the threads are swaged.
Jim
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I've just spent a few hours on the trial and error process of determining the proper rod size for the screws. It is not an easy task! Once that's done I'm starting on the various screw mills. Any tips on making them?
For your plate that uses modern threads, did you just drill and tap it as you normally would? And if so are you still swaging or does the modern version cut threads like a modern die?
Thank you again for once again sharing your wealth of knowledge here!
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Jim, is the screw plate used to swage the tap? I have thought about making a tp by swaging an annealed section of drill rod.
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Guys,
Great questions here, I will attempt to provide answers.
Heinz: Yes the screwplate is used to swage the tap. With the paired holes, one is slightly larger but with the same pitch. The larger hole is for the tap and the smaller hole is for the thread. The tap must be very slightly larger than the thread to provide a bit of clearance, otherwise the male screw will be quite difficult to install in a tapped hole without this clearance.
Bubblehead: Check out the posting in this topic for January 13, 2016. This shows an easier way to determine the correct diameter for the blank shaft before swaging the threads.
Jim
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This has been a very enlightening thread, James!
I have a screw plate that has lived with the family forever, but was unaware of how the holes ran, for making the taps.
Thank you!
Richard.
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Thanks James, that simple pairing had never occurred to me. I had thought it was two stages of swaging the screw, I get to laugh at myself on that one :-)