Dimple dies

I want some dimple dies, and I'd prefer to to home brew them because I went from busy as hell to nada. Got the material (4140ph), time and tools.

Flare looks about 30 degrees but I think that varies to achieve a consistent dimple depth. The corners have a generous radius. The rest looks like the dims could be adjusted to suit whatever.

Am I missing anything?

Sent via CNC 88HS

Mild steel or whatever steel you got laying around should work fine.

Never made any dimple dies, but made many press forming tools from mild steel and usually does better than I expect it to.

If you're making dimples in mild steel there's not a ton of springback. The angle you machine is probably what you'll get (or very close to it)

Garwood said:

Mild steel or whatever steel you got laying around should work fine.

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I've got a whole pile of stressproof bar ends that'd be perfect.

Cole2534 said:

I want some dimple dies, and I'd prefer to to home brew them because I went from busy as hell to nada. Got the material (4140ph), time and tools.

Flare looks about 30 degrees but I think that varies to achieve a consistent dimple depth. The corners have a generous radius. The rest looks like the dims could be adjusted to suit whatever.

Am I missing anything?

Sent via CNC 88HS

Click to expand...

This will give you some more ideas?

Metal Punches, Flares & Die Sets for Automotive & Aircraft Fabrication

Kevin

I've made several dimple dies, mostly out of mild steel bar. I used 35 degrees for the flare angle (just copied from the Mittler Bros. "aircraft" style dies). I made the OD 50% larger than the starting hole diameter (so a 3/4" hole is 1-1/8" OD, 1" hole is 1-1/2" and so on). I didn't care about the height of the flare being consistent, I just assumed they would get taller as the holes got bigger.

The thing to pay attention to is the clearance between the male and female die. The OD of the male flare should be smaller than the OD of the female flare so you're not excessively pinching the material at the edge of the dimple. The amount of clearance is based on the thickness of material you intend to flare...I did either 0.090" or 0.120" for mine, I don't remember offhand. The dies I made work fine on thinner material as well as what I calculated my clearance around.

Here are a couple example photos. I left the centers of the male dies solid since I was using them with a press, but you could drill a hole to allow using a bolt to squeeze them.

Graham Gott said:

The thing to pay attention to is the clearance between the male and female die. The OD of the male flare should be smaller than the OD of the female flare so you're not excessively pinching the material at the edge of the dimple. The amount of clearance is based on the thickness of material you intend to flare...I did either 0.090" or 0.120" for mine, I don't remember offhand. The dies I made work fine on thinner material as well as what I calculated my clearance around.

Click to expand...

Great info, thanks!