tumbler mill

[Mark Elliott]

Jim,

I am using 12" bastard files for my mills; cut in half, of course.   

[shortbarrel]

Think it would be good, if someone would post how you anneal and re-harden the file for making the tumbler mill. What kind of drills and reamers were used in making the holes in the mill. Also what kind of drill was used to drill the hammer screw in the tumbler and what kind of tap was used to thread the blind hole . Give me some answers here folks. I got my ways,lets here yours

[Acer Saccharum]

Give me some answers here folks. I got my ways,lets here yours

Uh, we're all volunteers here.

[James Wilson Everett]

Guys,

When I made the tumbler mill I started with a new file, next time I will get one with  more coarse cut.  I did not anneal the file, I stress relieved it.  You can do this by heating to a temperature just beyond the temper color blue or maybe just until it shows red in a dark room.  Now the file is soft enough to cut & drill without the risk of warping, loss of carbon and other things that can happen with a full anneal (heating to a bright orange).  If memory serves, I just tossed the file into my charcoal grill after the burgers were off and let it sit until morning - very sophisticated!

Cut the file in two and mark each piece so they can always be reassembled in the same configuration.  Glue the two sides together with Elmer's glue and drill the small tumbler pin holes through.  I used three different sizes as you can see, the smallest is about the same as a large Siler tumbler.  Also drill the through holes for the threaded studs.  Now take apart the two sides, hot water works.  Using the existing small tumbler pin holes as the centers, drill the larger diameter tumbler shaft holes.  On my tool I just knocked off a corner on each half to remind me to reassemble the halves in the proper configuration.  I just used standard number & letter twist drills for the holes, no reamers were used.  In addition I added a variety of holes for the purpose of making screw shanks in the field.  I made several sizes, but now I wish that I had made several more in the assorted sizes.  Re-harden by heating to orange hot, about 1500F, a bit hotter than when a magnet will no longer stick to the part.  Quench vertically in room temp brine and you are done. 

I made the threaded studs with the 18th c screw plate so they are an odd size, but close to 1/4"  The brass spacers are the same thickness, I think about 0.265"  and the odd looking "nut" I made for easy hand adjustment.  I end up tightening the nuts a smidgen about every 10 seconds when using the tool.  I have to disassemble and clear chips about once a minute which makes me think that there is an advantage to the coarser cut file used by Steve B.

Jim 

[rich pierce]

I am posting for Hank Elwood, to load photos for him.  Hopefully Hank will chime in more about how to prep the rough forging, how to load it into the tumbler mill, and how to “crank it”.

“My name is Hank Elwood and I have been reading the ALR's discussion on tumbler mills.  I made one about 15 years ago.  Gary Brumfield was kind enough to bring the one in the JHAT book from CW to Bowling Green KY to class.  I spent several hours along with others in class studying the mill.  Then after I returned home I proceeded to make one.  The photo I am trying to send has a brass tumbler in the posision of a steel one.  It's easier to see and you can see the teeth in the brass shank that is held in the vice as you rotate the mill around the tumbler.  I made this mill by hand except for the two posts that seperate the top from the bottom.  The rest I cut out with hacksaw and files.  The teeth I cut with a file then case hardened the teeth.  My neighbor welded the lower cutting plate to the shank of the handle, then I turned the curly maple handle on my wood lathe.  It works great and can be used from rough forging." 

As you can see Hank is a fine craftsman.

[Mark Elliott]

In looking at the last tumbler mill posted,  I am not real clear about how the screw is adjusted.   Could a sketch be posted showing the parts in the top section of the mill where the long bent handle is attached?

[James Wilson Everett]

Wow!  There goes the 10th commandment again!  You guys are really getting my interest up to make a better mill.

Jim

[Sawatis]

Super nice work there Hank!

[helwood]

First I want to thank Rich for helping me post these photos of the tumbler mill.  I would also like to thank Gary Brumfield for bringing the tumbler mill from C.W. to class seen in the JHAT Vol.I book.  We were allowed to stare at it as long as we wanted but couldn't take it apart, which is totally understandable.  The good thing about going to Bowling Green is that the students all bring experiences with them and even tho you are signed up for one class you learn from everyone.  The magic is in the upper two pieces  of the mill in what I call the "Top Hat".  It is the nut that allows you to drive the top cutter down onto the tumbler while rotating the wooden handle in the opposit direction thereby cutting the two shafts and cutting parelell sides on the tumbler.  The other things pointed out while we were studying the piece is that the cutter teeth are not like spokes on a wheel they are off set so the swarf doesn't get driven into the shafts and result in undercutting the shaft.  The modeling color on the cutter and body is from casinite, heat treating, the cutting and bearing surfaces.  Mark I have sent more photos to Rich and I think it will clear up any questions.  James thank you for your kind words, it's nice to know people are interested in what you're doing. Hank

[rich pierce]

More pictures of the tumbler mill, disassembled.







 

[Mark Elliott]

Thanks for the photos and the explanation.    I am now confident that I can build one.   However,  I think I will stick with the file based one for the time being.    It is still quicker and easier to make. 

[Curtis]

That is just awesome Hank.  I think I could maybe even make one of those!  Thanks for sharing the information.  It would be really cool if you could bring it to Bowling Green next year.  It would be great to see it in person.

Curtis

[helwood]

I forgot to comment on the rough forging except to say they are in JHAT, sorry.  James' rough forging isn't bad but the large shaft could be longer to be secured  it in the vice and the tip is tapered a bit to start it into the lower cutter as you bring the top cutter down.  The top cutter is driven down by rotating the wrench on top clockwise.  That's the direction of a regular thread but as you're closing the top down you need to power the cutting and so the direction of the cutting teeth are counter-clockwise by turning with the large wooden handle.  It's really pretty easy.  I think easier than computers, my last post took my almost 3 hrs and lost it twice.  Hank

[David R. Pennington]

Hank, I'm with you. I can build something quicker than I can do some of this computer stuff. I am getting better though. I'll have to learn when my kids all move out I guess.
Beautiful tumbler mill. Thanks for sharing. I'll print the pictures and save them for reference in case I ever get to making one.

[Acer Saccharum]

It's really pretty easy.  I think easier than computers, my last post took my almost 3 hrs and lost it twice.  Hank

Hahahaha, it's a matter of perspective! 

[Steve Bookout]

Wonderful thread and great photos, guys.  I have really enjoyed this exchange of information.

[James Wilson Everett]

Guys,

Now for the next step in making the tumbler.

With the "blob" clamped in a vise with the shaft pointing up, use one half of the mill to finish the shaft diameter and start cutting the tumbler surface.  The picture shows the tumbler blob with about 1/2 of the surface cut and smooth.



Now assemble the whole mill together and start cutting the tumbler small shaft.  At this point we are not trying to completely cut smooth the surfaces, just to start them and locate the shafts on the "blob".



Here is what it looks like now, with the surfaces partially done.



There is no need to waste time in smoothing both surfaces of the "blob".  Now we cut/file/grind the "blob" to a much closer shape of the final tumbler.





As you can see, now there is a much smaller surface area to be smoothed.  The finished tumbler is from a Chambers lock and only costs about $20, no wonder a hand made gun is expensive!  Sometimes I think I must have hit my head since I enjoy making gunlocks the old way.

Also, the absolutely beautiful tumbler mills shown above have made me feel so poorly about my ugly one, that my plan is to make a nice one a lot like Hank's mill.  Remember, a gun is only a byproduct of really nice tools!!!

Jim

[Sawatis]

Hey Jim
When you are milling "the blob" to locate the bridle axle, are you using any lube or are you turning it dry?

[Sawatis]

So...back to Hank....It looks like the milling cutter (on the bottom at least) is interchangeable and held by a set screw...is it also keyed or something to prevent rotation of the cutter?  What about the upper cutter..is is fixed?  Sooo many questions!  

[James Wilson Everett]

John,

I use a little motor oil on where the large shaft passes through the cutter hole as the fit here is very tight.  Of course, the oil does eventually get all over.

Hank,

I probably have even more questions than John!  Is there a photo you could post showing the detail of how the cutting edges intersect with the central hole?  I think I understand, but a photo would surely help.  When making my screw grinders, a very similar cutting tool, my cutting edges are just like wheel spokes, directly to the hole center.  And, yes, I do notice that the cutting chips do get down into the hole where they can scratch the shaft.  Maybe I have the cutting edges in an improper orientation.

Jim

[Sawatis]

Ha Jim...beat me to it...I was going to ask Hank the same thing!
John

[Mark Elliott]

I agree with Steve, this is a great thread with lots of good information.

[David R. Pennington]

Dittos Mark. This stuff is why I like ALR so much. Jim don't worry about ugly if ugly works.

[helwood]

Greetings, With the questions I started back looking at the mill again and must correct an earlier process.  The mill is turned clockwise and the top cutter is driven down counterclockwise.  The cutters have square shanks that are then held in with a setscrew.  I have sent Jim 3 additional photos of the mill, one of it apart showing the tophat and how it is sandwiched in the top, second of the square shank comming through the bottom, and a third of the way the cutting teeth are oriented.  The bottom cutter is the best example but it doesn't take alot to keep the swaf/chip from scaring the shaft. I am more than happy to try to explain I'm not a machinist so I may not have the exact vocabulary to say it correctly but I'll give it my best shot.  Hank

[David R. Pennington]

Hank, I think I have this figured out now. When the mill, (via the wood handle) is rotated clockwise with tumbler shaft extended below and held stationary in the vise, the bottom surface of the tumbler (lock plate side) is cut. Pressure is exerted to force tumbler against cutter by rotating wrench handle counter clockwise. This rotates the captivated nut (top hat) which forces central section to slide down on the two guide shafts. If I am seeing this correctly the top cutter will not cut in this direction. When the mill rotation is reversed then the top cutter would cut and the bottom cutter would not cut. This would be an ingenious part of the design which would allow control of how much each face is milled instead of cutting both simultaneously!
I see how the cutter teeth are sloped downward to the outer edge of the circle to guide swarf away from center.
Am I on track?
Beautiful machine!