Thumbnail Shinking Dies for a homebuilt P-Hammer

Kent White has a set of round shrinking dies for the air planishing hammer. They aren't thumbnail. In fact I'm not sure how they actually work. They aren't held in any particular orientation, they rotate freely. But I've seen them first hand, and they do in fact shrink. I think has to do with the material used in the face of the die.

[CCWKen]

I've been playing with srinking dies for P-hammer. I got started but haven't finished yet. I'm using the Needle Scaler hammer that has (uses) the square shank dies. I got the dies to make a tuck, capture it and hammer it down. After I worked on the dies to clean them up and polish, they didn't work any longer. I think I opened up the clearance too much.

When I get a chance to make another upper die, I'll give it shot. The pics below show the rough upper die and the first trial.

[tdoty]

Well, I made a set of thumbnail dies :roll: . Don't know how they'll work in the P-hammer, but they do work using a ball pein hammer .

I'll offer up more info, and maybe some pics when I get a chance to try them out. My main goal is shrinking aluminum, but I'll see if I can give a go at some steel too - without my neighbors shooting at me :shock: 8) . Gonna test 'em out after work tonight :shock: .

Tim D.

Why not drill a hole in the shank area of the hammer, and tap it for a set screw.... broaching a slot in the hammer and making a keyed shank upper -

I suspect the parts are much too hard to be easily machined.

[jlrussell4]

Hey guys,

John "the Tinman" Tuto shrinks with his planishing hammer. No special dies other than the wheel style lower. John's explaination to me at MM04 makes me think it's more in the technique than the tooling.
A few years back someone explained how Kent White wanted the user of his shrinking dies to use them. He seemed to think one could shrink with any planishing hammer if the proper method was used.
Just some food for thought

Jim

[dauer]

Hey;

I too have seen Kent White shrink without thumbnail dies and I have pictures I am going to try to post. of the upper die in action. It was really amazing as I watched him flatten a high crown he had made in a peice of 3003 half hard al. then put the crown back in and flatten it back out without any annealing! I also recieved a flyer from TM Technologies offering a DVD 2 hours long on "Air Hammer Operations" though it's a bit pricy and guaranteed to be a big sales pitch for their plannishing hammer....


Dave
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[dauer]

Well tried to upload the pictures, surprise.... didn't work.

Dave

[tdoty]

Originally Posted by Sam Lee

I suspect the parts are much too hard to be easily machined.

I'm doubting that too - but I shall find out! Why? Because my dies work nicely. Rotation of the dies IS an issue though. Banged up my lower die when the upper turned :shock: .

The lower die is made from a 1" Grade 8 bolt shank, with the shank from a 1/4-20 TIGged in place for the "thumbnail". The upper is a flush rivet set I had - a heavy one, almost like a "bumping hammer". The notch was carved out with a die grinder, which explains the nasty nicks!



Here's the first shrink done on a piece of .063" aluminum:


And, here are the shrinking results on 18 gauge steel:


Just to explain the origin of the steel - it's a chunk trimmed from a project I brought home from MM04. 18 gauge from Frigo Design.

So, the results:

1. Yes, an air chisel/muffler gun/ air hammer and likely a riveter are capable of shrinking 18 gauge steel with thumbnail dies.

2. Yes, rotation of the dies is an issue!

3. Thumnail dies aren't that hard to make. Good ones are likely much more difficult than just making ones that work .

Gonna have to try these on an actual part, not just a piece of metal! Might have to make a new lower first though .


Other things:

I, for one, would like to hear (read ) more about John Tuto's shrinking method. I think it would be quite interesting. There just wasn't enough week at MM04 to talk to everybody about everything - know what I mean?

Kent White's dies are also interesting - and they're $235. That's $235 I'm not likely to spend for a while - too many other things in line first.

I've crushed hand tucks with my P-hammer before. Setup and air pressure are important, as well as technique. The problem is, it's easy to stretch them back out too!

Just thought I'd share - stay tuned for the next step!

Tim D.

All;
Seems to me, thumnail dies can be free floating, they will find thier own centers. I think I saw it on Kents video, when he was forming a bead on a Pulmax. Makes sence. The dies were'nt thumbnail, but similar, & were'nt keyed.

Cheers

[mr.c]

Tim, from what I see in your photo, you are stretching the metal. See how it "flows" off of the straight edge of the panel. I experienced similar stretching with the first dies that I made for the trace-a-punch. I had to do some tweaking on the dies before they started to shrink the metal.
Someone mentioned floating dies. The upper die in the trace-a-punch would eventually vibrate loose and become free floating. (Generally when I was back at the motel catching some zee's while you guys worked past midnite.) The out of alignment of the dies beat up the upper die with the tip of the lower. Probably marked up someones panel severely. Actually that all worked out good for me in that grinding out the marks after I got home gave me the effect that I had been working for. No marks on aluminum panels. I had tweaked the dies several times at MM trying to sneak up on the right shape. They don't shrink as aggressively but don't mark the panel. I have a suspicion that you can't get aggressive shrink without marking the panel.