Making punch tools for our hand press

Posted: March 28, 2010 in Uncategorized
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Just finished a small metalworking project to make a heavy-duty hole-punching machine.  This is needed as we have been bending the handles of even the heaviest hand-punches that we can find, trying to go thru multiple layers of fire hose and webbing.

Aunt Betsy got us an arbor press for Christmas that uses snap and grommet-setting dies with a 3/8″ shaft, so we have been able to use 3/8″ bolts to fabricate new attachments for it.  This post walks thru the process of using nuts, bolts, and brass to make a hole-punching tool for use on the press. 

Hand-punch
The problem – I keep bending the handles of these hand-punches trying to go thru thick materials.  Note – the punch tubes themselves are threaded. 

Press
This is the arbor press – in this photo, it is set up rivet setting dies made from 3/8″ bolts capped with brass.

Workbench
The workbench       

Brassing_a_bolt
First off, I needed to make the bottom ‘anvil’ – This is basically a flat surface covered in soft brass, so your punch tips won’t get smashed by pushing down on a hard surface.  To make it, I cut a small tab of brass from a door kickplate that I found at the ReStore, placed a 3/8″ bolt on top of it, got both pieces cherry red (not melting) and melted brass onto their junction.

                               

Brassing_a_bolt2
Next I took the fused bolt+brass, put it in a cordless drill, and used the drill as a lathe, rounding and polishing it on the grinder and wire wheel.  This will be the bottom 1/2 of our punch press.

                               

Punchmaking1
The top 1/2 of the punch press needs to be a 3/8″ shaft that is tapped with 5/16″ fine-threads – the size of the threads on the tubular punches that come on our hand punch.  I didn’t have a 5/16″ tap, so I decided to braze a nut with the proper thread onto a 3/8″ bolt.  The 5/16″ bolt on top is just to keep the brazing from getting into the threads, and came out after the brass was set.  It was really hot, and when my glove started smoking I just dropped it on the concrete. 

                               

Punchmaking-assembled
Here is what the piece looks like with the punch tip screwed into it.

                               

Punchmaking-hogged
I forgot that we needed a way for the punched material to get out of the inside of the punch tube.  I clamped the piece in the drill press and tried to drill at an angle.  Not ideal or pretty, but it worked out.

                               

Punchmaking-hogged-assembled
Final piece, filed, and cleaned up – some brass had dripped on the shaft, so I put it back in the drill and spun it while I held a file on it to clean it up.

                               

Punching
The final product – it works well!  The only concern is that since the press generates about 1,000 lbs of pressure, the pressure on the tip is probably about 3,000 psi, so we’ll need to be careful not to pull too hard, lest we punch all the way thru the brass cap on the bottom piece.  
I can make these on a custom basis if you have a hand press and want to be able to punch with it.

                          

Hot_shoe
Remember the hot bolt that I dropped on the concrete?  After a while of tapping around the shop, I was wondering if I had a rock stuck in my shoe.  
We’ll use this new tool to punch leather for bookbag sides, punch the corners of messenger bags, and just about any other rivet setting that we do in the shop.

                               

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