antique screw plate info

[jluke]

good morning all ,ive only been working on building flintlocks for a year ,and I have a fair amount of tools ,and I try and pick up old woodworking too or blacksmithing stuff when I come across it ,ive found an old English made screw plate ,would it be worth my money to pick it up not something im to familiar with but I love learning with the old stuff,its a fairly big plate .any help would be appreciated .thanks again

[PPatch]

Hello Luke;

Welcome to the forums.  I would say snap it up, you may end up using it and liking it down the road a bit, plus if you don't want it someone here might. There was a discussion about screw plates not too long ago, I believe it was in the Gun Building forum but don't hold me to that, could have been in another forum. You can go through the posts and find it.

dave

[Shreckmeister]

I picked one Up in a box lot at an auction for next to nothing if you're patient you'll find one cheap somewhere.

[Bob Roller]

good morning all ,ive only been working on building flintlocks for a year ,and I have a fair amount of tools ,and I try and pick up old woodworking too or blacksmithing stuff when I come across it ,ive found an old English made screw plate ,would it be worth my money to pick it up not something im to familiar with but I love learning with the old stuff,its a fairly big plate .any help would be appreciated .thanks again

Luke,
Is the screw plate marked as to thread sizes and is it a plate to check threads with or one to cut them.
If it's English it may be for Whitworth threads or some proprietary threads unique to one particular gunmaker.

Bob Roller

[jluke]

its a HUGHES WARRINGTON STEEL TAP AND DIE screw plate

[Shreckmeister]

I have an old one made from a repurposed file that I got from Frank Kobilis A couple years ago

https://www.facebook.com/photo.php?fbid=10206289402131860&set=a.10206092078598895.1073741827.1170330961&type=3&theater

[James Wilson Everett]

Luke,

Here is a screw plate marked "T Lewis & Griffith" and "Warrington", probably late 18th c/early 19th c.  It is a very nice one that I use in gunmaking.  Does yours look similar to this one?

[Bob Roller]

Luke,

Here is a screw plate marked "T Lewis & Griffith" and "Warrington", probably late 18th c/early 19th c.  It is a very nice one that I use in gunmaking.  Does yours look similar to this one?

This screw plate looks like it is used for actual threading of a blank or restoring an existing screw or for checking to see what thread is on any particular screw. I have a screw plate and it's marked as to the threads at each hole but will not cut a thread like a die will. The one in the picture shows relief cuts at each hole for chip clearance.

Bob Roller

[James Wilson Everett]

Guys,

These original screwplates do not cut threads as modern dies do.  They swage or form the threads without cutting, so there are no metal chips formed as the screw threads are swaged.  The little side holes are used to allow access of a jeweler's saw blade in order to cut across and remove a broken off thread that gets stuck.  The side holes are not for cutting chip clearance, although they do certainly look like they serve that purpose.  Apparently, earlier screwplates did not have these side holes as in this picture, below.  The side holes serve no purpose unless you get that dratted OOPS, then they are really handy.

Jim

[jluke]

james it looks like the first one you displayed,

[wet willy]

Making a screw using a screw plate is a very time-consuming process. Specialty screw-making machines have been around for hundreds of years, and I suspect Colonial 'smiths bought their screws.

As a watch restorer, I have several Swiss-made screw plates used to fabricate screws from the late 18th century and mid 19th. They cut threads with major diameters, the largest being about 0.18 down to 0.08, so probably not a gunsmith tool. The edge slots, I was taught, were to present a sharp cutting edge to cut the thread. As a student, we made screws by turning blanks from the head diameter to the shaft, then chucked the blank in a watchmakers lathe and cut the threads on a screw plate with the screw held in a chuck and the plate hand-held.

The plates I have are the same tpi for a several positions, just a different diameter. They are all numbered in some sequence, some are 1 thru 15, and not related to any thread size.

Working on 19th century watches, I know many screws were replaced as they cross-threaded/forced screws into a too small hole, resulting in the need to make a larger screw (screws were steel, the watch plates were brass, so it was the plate that sufferred). I have several plates similar to the one above that don't have slots, gauges to help determine the OD of a rod and are so marked.

A gunsmith would need a larger diameter screw and I wonder how they used the screwplate? How did they hold the stock to be threaded and how did they determine the shaft diameter? Did they make a tap from stock turned in a screw plate?

[Jerry V Lape]

Might be interesting if one of the machinist on this board made a few plates with the common sizes used in gun building and brought back another skill among us in making the screws we need for each build in PC thread and shape.  One more item we could learn to complete our building skills. 

[Bob Roller]

Might be interesting if one of the machinist on this board made a few plates with the common sizes used in gun building and brought back another skill among us in making the screws we need for each build in PC thread and shape.  One more item we could learn to complete our building skills. 

I have made several screw plates in years past. Some of these PC threads are nearly impossible to identify and to duplicate them would be costly. I have a small number of odd taps and dies that were purpose bought and have yet to be used. The 1/4x80 mentioned earlier was for a Billinghurst bench gun that was never used and the owner of the gun has passed away. I am always looking for odd tools from the past but from the view of an accumulator only.

Bob Roller

[horologist]

I buy antique screwplates whenever I can do so reasonably.  I also purchase old, odd sizes of taps and dies.
Such things are handy when restoring antique clocks. My rule is the replacement part should be made to fit the clock, not the other way around. Some of them swage the threads and take a bit of experimenting to get the correct diameter, others cut the threads much like a modern die.

If anyone is curious, the link below is where I make something as simple as making a screw seem an impossible task. There are screwplates involved along with some other odd tools. It took about 20 minutes to find the correct screwplate and about 15 minutes to fabricate the screw.

http://www.livingstonstandardtime.com/screwplate/screwplate.htm

If you are restoring an antique rifle then the antique screwplates may well be of use but for building a modern gun they won't be much help. The threads are not going to match modern standards. Far be it for me to discourage the purchase and use of old tools but it is hard to beat a good modern die and die holder for this purpose.

Troy

[wet willy]

Horologist: Same setup I have, probably same cross slide version.  Screw making process is about the same as I was taught. Screw plates may be important for certain kinds of work, but I maintain even 18th century gunsmiths bought screws but tapped their own lock plates, etc. Maybe shaped screw heads on purchased  blanks, perhaps on some high-grade arms polished and blued them.

If I was making a living as a gunsmith in the 18th or 19th century, I'd sure have a supply of ready-made screws to be cut-to-length and finished. Hand-cranked screw-cutting lathes were available in the mid-1700's, and I suspect most, after being set up by the Master, were operated for hours on end by 12 year old boys.

[Mark Elliott]

Below is a link to a blog post of mine about a screw plate I purchased.   You might find the analysis interesting.

http://www.markelliottva.com/wordpress/2015/06/tools-toys-june-15/