Cutting washers from shim stock???

[deadin]

I need to fabricate a couple of app 3/8ths OD, 3/16ths ID washers from .004 shim stock and don't have the foggiest idea on how to go about it. Any suggestions????? I have some brass stock and probably could find some steel. Which one doesn't really matter, but they need to be flat with clean edges.

 

[kd7fhg]

I have use double back tape to hold the stock down to a piece of scrap and used a circle cuter on my mill (Use Slow Speed), You could also do it on a lathe, make a jig that bolts to your lathe face plate, drill the center hole on the washer that you are making, bolt that to the jig and use a slow speed and trim the outside, you don't want it to go flying off.
Rex

 

[Bill Gruby]

A precision Punch set wll work well here. Harbor Freight has one for around $30.00. Punch the ID first then the OD.

"Bill Gruby"



http://www.harborfreight.com/9-piece-punch-and-die-set-95547.html

 

[steamer]

Well...the first thing I'd try ......
Make up a punch from some mild steel...I wouldn't even harden it.

Little to loose..

Dave

 

[Metal Butcher]

You could use regular hole punchs. After punching it out, hammer the shim stock flat between two pieces of steel (filed flat) and sand the edges with 600 grit, or finer sand paper.

Standard punch set.

http://www.harborfreight.com/9-piec...ferralID=64350ce0-4155-11e0-9f53-001b2166becc

If you need to make a lot of them you could invest is this high quality set.

http://www.bettymills.com/shop/prod...utm_keyword=PRB605-40105&utm_content=Facility

-MB

 

[Stan]

I won't offer any suggestion because I can't think of any way that would guarantee no rough or rolled edge. .004" material is very difficult to machine cleanly and it is easy to have a few tenths or even a thou of irregularity.

I have made lots of washers out of .025" brass shim stock and that is fairly easy to chamfer the edges but .004" is a whole different world. Can you concentrate on a clean center hole and make the washer oversize so that outside edge is not in compression?

 

[Noitoen]

If they were many, I would etch them in ferric chloride solution.

 

[deadin]

If I can get a reasonably clean center hole, I was thinking of clamping the shim stock between a couple of pieces of thicker stock (.25 or so) by using a center bolt and nut, and then just turning/filing the whole assembly down to the desired OD. (The outside diameter is critical in that it can't be oversized.)

I would like to try the hollow punch idea and I've got a set....somewhere.... Now all I have to do is find them. ;D
(Haven't seen them in several years.)

 

[Dave G]

A standard rule of thumb for punch and die clearance is 5% of stock thickness per side. For .004 thick stock, the proper clearance would be .0002 per side and if the part is round that would be .0004 difference between the punch and die on diameter. If the clearance is correct there will be very little burr on the edge. Softer materials can use less clearance than this to reduce the burr. It would probably be easier to turn them on a lathe if only a few were needed. Maybe punch the small hole then mount on an arbor in the lathe to turn the od. Use a thicker backer on each end of the .004 thick blanks to reduce defection and provide support. Hope this helps, Dave

 

[krv3000]

HI wot i have dun in the past is to mack up a ply system ie sum thicker steel stock then the shim stock then a nuther Peace of steel stock and so on you can ether yous super glue for ache lamanet or doubled sided gum tape drill out the center od thenbolt it all together and mashen up on your lathe regards bob

 

[Twmaster]

As thin as that stuff is you could punch a clean hole in the center then cut the OD with a pair of tin snips. Then sand or file the edges.

 

[Omnimill]

If I can get a reasonably clean center hole, I was thinking of clamping the shim stock between a couple of pieces of thicker stock (.25 or so) by using a center bolt and nut, and then just turning/filing the whole assembly down to the desired OD.

Thats the way I would do it.

Vic.

 

[Mainer]

I'd probably try the sandwich approach as well. You could even do it on the mill to cut the center hole. Clamp the shim stock firmly between two solid and really, really flat plates (so the shim stock doesn't get pulled), and drill your hole. It might be better to drill a bit undersize then plunge a 3/16" 4-flute end mill to get the final i.d.

Remove, cut roughly to size with snips, then do the sandwich thing on the lathe, as you proposed. If you make the center bolt a close fit in the hole, you should get very good concentricity. I'd probably turn a stub arbor in place to be sure it ran true, thread the end #10-32 (#10 is only 0.003" larger than 3/16"), then assemble the sandwich on the arbor and crank down a nut.

 

[n4zou]

Drill your holes in the shim stock clamped between some scrap wood.
Then rough cut around the holes making sure to leave some extra material for turning to size.
Drill a hole the same ID in hardwood dowel slightly larger than the desired OD of your washers.
Cut the wood dowel in sections and sandwich your washers between them using a screw the same ID as the washers and wood dowel sections. Turn the wood dowel and washers in your lathe to the desired OD. I would suggest using hardwood dowel so the washers are property supported while turning to size.

 

[mrfixitat]

hi, the way i done it was to take 2 aluminum plates 3"x3"x1/2" and clamp them together then in the corners opposite each other drill thru both pieces and install 1/8 or 3/16's roll pin then drill the 2 holes 3/8ths and 3/16's be shure to leave room between the holes, then use drill rod 2" long of each size and square the one end,u may want to ream the holes so the drill rod just slides thru,then loosen the plates and slide shim stock between the plates and install the 3/16 drill rod and hit it real hard and it will cut a perfect hole then take plates apart and center the the hole in the bigger hole then put plates back together and whack the bigger drill rod and u will have a nice washer,u may have to put some grease on shim stock to keep it where you want it before putting plates back together. i used this method to make shims for my lathe head stock bearings. my 2 cents worth jack