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Pinning tongs

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So I'm having a bit of trouble and not sure if it has been addressed, but pinning tongs isn't quite working out as well as I think it should. I've made a few pair, but after those 3, I just haven't been able to get it right.

The trouble I'm having is as I punch the hole, the boss caves into the pritchet and it may crack. I don't beat too thin but it still may be. Thickness suggestions? I read about using a nut underneath the boss as I punch.

Using 1/2 in rebar, heating to a orange/yellow, moving it down to just over 1/4 inch.

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You should be able to do the punching over the face and only use the pritchel for ejecting the slug.

Also Rebar is it's own punishment.

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Like Thomas said. Unless you are using a pointed punch. Then that would be bad for the face of your anvil. 

Also the nut under the boss is just a spacer for when you are riveting the first head of the rivet so that you will have the length you need for the other sides head.  

Might help to include some pictures, or to be more descriptive of what you are doing and using to do it. 

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12 minutes ago, ThomasPowers said:

You should be able to do the punching over the face and only use the pritchel for ejecting the slug.

Also Rebar is it's own punishment.

That's for sure.

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Make a bolster plate with a series of hole diameters to suit the size of punch and support the sides of the hole.

If you are knocking out a Ø6mm (1/4") slug and your finished drifted hole is an Ø8mm (Ø5/16") hole...don't use a Ø20mm (Ø3/4") pritchel hole as a bolster....do the maths as they say....or math as you say :)

I have seen the guy at Vaughan's making tongs on a little 1cwt Alldays hammer, he just used a hex nut as a bolster to take the slug. 

The advantage of a circular or hex bolster block over a bolster plate with a lot of holes, is that it is easy to centre it under the hole....especially when punching little holes for things like tong rivets.

Alan

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I have punched a zillion holes and never use a bolster. If I'm punching a 1/2 inch hole I use the appropriate size punch, hit it until I feel anvil resistance.flip it over, look for the telltale spot that indicates the location of the soon-to be slug and hit that. slug drops out on face of the anvil. Punching holes is not hard-just relax and do it.  Also- as Thomas said, using rebar is its own punishment. I have been in a pinch and made horseshoes out of the stuff. Sometimes it is great and sometimes it is not worth the price of scrap.

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Well I have punched two zillion holes and always use a bolster.:) Either a fixed or sliding bolster under the press....actually it is true I am usually using a slot punch and drift rather than a round punch for a rivet. But the process does depend on drifting through over an appropriate sized hole for the size of the punch/drift in order to prevent the problem the OP has of dragging the sides into the pritchel hole.

I agree when you are using a punch that is the same size as the required hole and the material is thick enough to shear the slug clean working over the face of the anvil is fine, you are supporting the sides of the hole. I am mostly trying to get more spread so slot and drift.

With offset jaw tongs I usually do them under the power hammer so they are punched on their backs and then flipped over onto a bolster which raises the offset jaw above the bottom pallet.

Alan

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Thanks yall. The bolster plate would greatly suit the need. Was thinking of a spring fuller idea with the punch on top and a nut on bottom, but I might be getting ahead of myself. 

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