Failed Shim Punch Project

YYCHM

YYCHM

(Craig)
Premium Member
kylemp said:
If you're intent on trying to do this as a punch die you're going to have to get into grinding probably or it might work for a little while and then stop working.
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I dare say you may have hit the nail on the head here. A few successes has kept me poking at it. I've gone full circle at least 5 times now. She ain't gonna fly with the skill sets, material and equip I have. I'll scrap the punch set idea and study the lathe solutions now.

Thanks
 
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K

kylemp

Well-Known Member
YYCHobbyMachinist said:
I dare say you may have hit the nail on the head here. A few successes has kept me poking at it. I've gone full circle at least 5 times now. She ain't gonna fly with the skill sets and equip I have. I'll scrap the punch set idea and study the lathe solutions now.

Thanks
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If you want to keep trying I think the other portion that you're likely missing is alignment on the punch. If you can find a way to steady the punch in relation to the die and lock them both down and ensure that it move perpendicular to the die you'll likely have better success. Reamers are your friend in this case, if you have a reamer or can cut a good fi ish accurate bore with your mill or lathe you may be able to weld up a fixture for an arbour press or something similar that would keep the punch constrained to move straight up and down in relation to the die and still have room to cut some relief in the punch and die. You might also get away with just cutting relief in the die.. But cutting a taper on a mill correctly isn't easy. At the very least - is your stock all ground? This isn't going to work with her tolled or probably even cold roll steel for the punch and die. If you want to learn more about it I'd suggest finding some information on ironworker dies probably.

Also check out
 
YYCHM

YYCHM

(Craig)
Premium Member
"her tolled"? Do you mean "hot rolled"?

I've been using mild steel, nothing special, and couldn't tell you what it is actually. The punches started from PA cylinder pins. The die plates were scrap sourced from MSM.
 
P

PeterT

Ultra Member
Premium Member
The Stefan video is very informative. Notice a few key elements:
- brass shim stock washer material = relatively soft compared to mild steel & particularly anything approaching spring steel shim stock if that was ever the goal
- 0.2mm thick (= less that 0.008") so again easier to shear than maybe what you are trying?
- pins are HSS & dowel pin = very hard. I'd guess 62-65 Rockwell C. This ties in with what I was suggesting about heat treating is very likely a pre-requisite
- block was D2 tool steel. This is an air hardening tool steel, although I believe he said he did not harden. In its annealed state, still pretty tough stuff. He mentioned nice bore & relief (not taper) which I think has more to do with parts fall-through clearance.

Even with this relatively thin/weak/small material you could hear the 'thwunk' as the pin sheared through. It makes me cringe a bit seeing his mill spindle in this manner bearings wise, but anyway. So reflecting on your project, hopefully you can see the differences. More cutting area, stronger, thicker stock, softer shearing tools & a different recipe of clearances involved.
 
YYCHM

YYCHM

(Craig)
Premium Member
After reviewing the lathe turning option(s), I have concluded that it demands too much sacrificial material.

Looks like this project has me beat. I hate admitting defeat, but that's how it goes sometimes.
 
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Dabbler

Dabbler

ersatz engineer
YYC Janger already gave you a great solution to your feet issue. Ask him to send you a photo of his vise knobs. They are very impressive.
 
YYCHM

YYCHM

(Craig)
Premium Member
Dabbler said:
YYC Janger already gave you a great solution to your feet issue. Ask him to send you a photo of his vise knobs. They are very impressive.
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Wrong forum thread. This thread has nothing to do with feet or vise knobs. I assume your talking about the guy looking for custom brass speaker tower bases/feet.
 
Dabbler

Dabbler

ersatz engineer
oops. sorry. I was just reading the other thread and got cross wired..... -- How worn out is that pulley?
 
F

Former Member

Guest
Sorry I wasn't on the site back then, the solution is drill (or punch) medallions of shim stock to ID, place a bunch on a mandrel clamp tight, throw on lathe turn OD.

Works with any material that can't be held but can be compressed without deformation.

I do this for plastic nylon washers for one of my products.
 
Janger

Janger

(John)
Administrator
Vendor
Degen said:
Sorry I wasn't on the site back then, the solution is drill (or punch) medallions of shim stock to ID, place a bunch on a mandrel clamp tight, throw on lathe turn OD.

Works with any material that can't be held but can be compressed without deformation.

I do this for plastic nylon washers for one of my products.
Click to expand...
Products? You make products? Let’s hear about that!
 
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