tumbler mill

[James Wilson Everett]

Hank,

The photos of the last two tumbler mills were found as photos only.  I think I found them on BING by searching for 18th c tools.  So, I have not been able to inspect the actual pieces.  I surmise that the second tool will cut the two shafts, but I do not know for sure.  Thanks for the question, sorry I don't have a definitive answer.

Jim

[Mark Elliott]

I use a file and diamond hones, but I try to make the full cock notch rather neutral.    I want the sear to just stay in place.   For set triggers,  I use a flat flat sear fit to the full cock notch and for single triggers,  I round the nose of the sear.   Should I be dong something different?    You are the expert,  Bob.   How do you cut a full cock notch?    Actually,  I find cutting a half cock notch much more troublesome with just a file.    I have to use a knife edge jewelers file for that and it still isn't ideal.   

Round the sear nose may increase wear since the PSI at the contact points skyrockets. Try just stoning the upper edge slightly at an angle to let the sear come out of the notch easier.

Dan

Dan,  That makes perfect sense.

[Bob Roller]

I use a file and diamond hones, but I try to make the full cock notch rather neutral.    I want the sear to just stay in place.   For set triggers,  I use a flat flat sear fit to the full cock notch and for single triggers,  I round the nose of the sear.   Should I be dong something different?    You are the expert,  Bob.   How do you cut a full cock notch?    Actually,  I find cutting a half cock notch much more troublesome with just a file.    I have to use a knife edge jewelers file for that and it still isn't ideal.   

Round the sear nose may increase wear since the PSI at the contact points skyrockets. Try just stoning the upper edge slightly at an angle to let the sear come out of the notch easier.

Dan

Dan,  That makes perfect sense.

 I cut the full cock notch with a milling machine using a 3/16"carbide end mill with 3 flutes
turning 1000RPM according to the belt chart.The cut is .080 deep and then I angle the tumbler
and under cut the full cock and finish the half cock with a file ground for the job.The tumbler is the
last thing to be hardened.I harden the sear and fly and the springs are tempered but not detailed
and the lock is assembled with the soft tumbler.If it is a flintlock I will fire it to develop a wear
pattern on the full cock notch and when it feels "right",I take the lock apart and harden and temper the tumbler.
The same is done with a caplock by snapping the hammer against a piece of hard wood.

Bob Roller

(Acer: Bob, I edited your statement above.)

[James Wilson Everett]

Guys,

Here are some more photos of a really nice original tumbler mill.  Looking at the last three photo sets of the original mills, it seems to me that the same person has "restored" these old tools.  They have the same looking degree of patina and the same color and gloss finish on the wood handles. 

This tool is very similar to the mill that I made much earlier in this topic.  It has cylindrical cutters that cut in only one direction, you turn the tool clockwise to cut.  Also, the two screw adjustments also act to align the two cutters.  A feature that I do prefer on mine is the two opposing handles.  These allow the rotational torque force to be applied without an overturning moment.  This way the tool does not tend to wobble left-right in the vise as it would when using only one handle.  A very nice looking old tool that certainly does show the "There is nothing new under the sun".  Ecclesiastes 1:9.

Jim

[rich pierce]

Jim, thanks.  I have so little understanding of how these work that I will ask a question that seems silly.  How are they employed?  It sounds like the shaft of the forging is held in a vise and then the tool is rotated above the vise.  Is this correct?  It seems likely the shaft of the forging would want to twist in the vise.  Is this a problem?

[James Wilson Everett]

Rich,

Thanks for the question.  You are entirely correct.  The long shaft of the tumbler forging must be held rather firmly in the jaws of a post vise.  The torque on the tool will try to twist the tumbler shank from the vise jaws.  It does help to make the tumbler shaft of the forging to protrude about an inch below the bottom of the mill so that the vise can get a good "bite".  Look at the photos on page 4 of this topic.  The mill used there is only about 1/4 inch above the top of the vise jaws.

The use of the tool is a lot like a modern die stock, but you do not have to reverse the tool to break the chip as with the die stock.  After a few revolutions of the tool, the two wing nuts are tightened a tiny bit, then the cut is continued.  With the earlier pictured tumbler mills made from a file, the entire tool must be disassembled often to clear the chips from the file teeth.  The latest tool shown, and the tool I made, clear the chips automatically and do not need to be disassembled to clear the chips.  Thanks to Hank for the cutter design!

Jim 

[Curtis]

Hank Elwood was kind enough to bring his tumbler mill to the MNLRA Gunsmithing Seminar last month, and I took a quite a few photos.  It is a real nice piece of handiwork!  Hank gave his blessing for me to share the photos here, hopefully they will help anyone interested in building or studying such a device.  These should supplement the pics previously posted.

Here are the pics:




























































Thanks for looking!  And thank you Hank for bringing it to the seminar!

[Bob Roller]

 A superb piece of work and looking at it from the view of a machinist and sometimes tool maker
I get tired just thinking of the work it took to make it. If such a tool is to be used to copy earlier work on
locks I would recommend 1144 Stressproof as a material for tumblers. It machines,using a lathe like 12L14 and is easy to file and shape and will oil harden like drill rod.
Congratulations on a fine bit of recreating an ancient tool.

Bob Roller

[helwood]

Thanks Bob for your comments.  Most of it I made with hacksaw and files.  Never had shop, still trying to figure out lathe and milling machine I bought.  Milling machine I use more frequently for a really good drill press.  So I usually go back to my files. I was wondering if I go to a great metal store in Burbank CA and ask for 1144 Stressproof stock will they know what I'm asking for, OK?
Hank

[Bob Roller]

Thanks Bob for your comments.  Most of it I made with hacksaw and files.  Never had shop, still trying to figure out lathe and milling machine I bought.  Milling machine I use more frequently for a really good drill press.  So I usually go back to my files. I was wondering if I go to a great metal store in Burbank CA and ask for 1144 Stressproof stock will they know what I'm asking for, OK?
Hank

Hank,
If you go on line you'll find a number of places to get 1144 Stressproof.
I use Southern Tool Steel Supply but there are many others and most will sell
small quantities. Some industrial supply catalogs have it listed. If I wasn't
down to my last 10" I'd send you a piece.I use 1-1/4" for ALL my tumblers and
make discs that all have 5/16x3/8 stems with a 6x40 thread for the hammer screw
and are .230 to.235 thick with a .140 stem to go thru the bridle. These are then
altered to suit whatever lock I am making.
What problems are you having with the lathe and mill? I have 4 lathes and 40 years
ago I made a 6" Atlas into a machine used mostly for screws and last week did a rebuild
and found the counter shaft bushings worn and from new had NO oil holes.I am
thinking "Oilite" bushings because I bought this lathe new in September of 1964
and paid for it with the only $500 bill I ever saw or owned.
Keep up the good work and post often.

Bob Roller

[helwood]

Bob,  Thanks for the info. my problem with the equipment is more of a general one.  I have purchased videos on how to operate them but more practice and someone to ask questions like in class would be better.  Calif. doesn't have adult education programs like friends tell me they have in the Midwest.  The funny thing about the tumbler mill is that after I had help posting the pictures of the mill I started on a project I wanted to make for over 18 years.  A brace of Miquelet, c1730 Dragoon pistols.  You can see them in the photos that Curtis posted of the NMLRA class this year.  They are technically a snaphaunce.  NO Tumbler.  I started the project with a link of anchor chain, a high quality source of wrought iron.  The springs were made from W1 drill stock.  The only thing I didn't make were the frizzens.  I made the lock first in wood,clay, and copper to mock it up first, only had a photo to work from.  So as I carved, the more it looked like a large Siler frizzen. Figured I already had enough on my plate.
Fun project, learned a lot.  Hank

[ddoyle]

Huge thanks to everyone who has contributed to this thread. And a thanks to Mr Glazner for creating the venue.

If any one out there is a technical writer and wants a project they could create a legacy synthesizing the knowledge that is being shared on lock building  in these threads. We are talking 10-15 lifetimes of hard earned knowledge floating around here!

I for one am taking notes on water proof field paper and guarding them close.

[FDR]

I sure hope this ends up under "tutorials" so we can  actually find it later.  Yes I know about "search" just seen the result of too many  computer/server upgrades and the information is just too good to loose.