More punching on the Hydraulic press...

[Stumptown Forge]

Wow great set up Larry those dovetails are sweet. I have had to resort to using hold downs due to my presses design. Great write up on your punching.

[JNewman]

Has anyone gone anywhere with the cotter crank punch retainer? I have to make a punch holder and die holder for my new press over the next couple of weeks. I am planning on drilling a 1" hole into a block of 4140 and running a 1/2 or even 5/8 hole through the side of the 1" hole and I had been thinking of a nut on a modified grade 8 bolt.

The die end will have to mount to a heavy block that will mount onto the table with 2 pins. I may go with a dovetail like Larry has but I am leaning towards just a slot 60mm wide which is the same as the mount on the ram, so tools are interchangeable. I with then either just bolt it on with holes tapped in the sides or face. Or I can bolt cap pieces over the slot turning it into a sort of t slot.

[Randy Calhoun]

I did some playing today and built a table with a through hole for the press.... I wanted to see if I could do a pretty big hole .... 1 5/8" was the largest round alloy bar I had so I made a 1 5/8 punch and drift..



In the press




And the hole..... 1 5/8 through 1 3/4 thick by 2 1/2 wide.... Not quite in the center but not bad for a first go....

I did learn I need a more secure way to hold the tooling... my 1/2" set screw is not cutting it.. I need to figure out a quick change bolster set up as well...

Larry,
Did you punch and drift that hole with that one tool? Was there a plug that popped out or was it more of a slitting action? Sorry for all the questions. Just trying to make some decisions for my own tooling. Thanks a lot.

[Larry L]

That was pretty much punch and drift in one tool... I did take a second heat and clean the hole up on just a chunk of shaft used as a mandrel. Since doing some of these tests I have found that a straight sided tool really seems to work as well if you are punching, if its more of a slit/drift thing then a thin tapered punch and drift.... Ive never had any luck with a big hydraulic slitting tool as the edge just goes away to fast to do any work. I do know there are a few guys doing it with high performance steels but I have never had any luck..

[Randy Calhoun]

That was pretty much punch and drift in one tool... I did take a second heat and clean the hole up on just a chunk of shaft used as a mandrel. Since doing some of these tests I have found that a straight sided tool really seems to work as well if you are punching, if its more of a slit/drift thing then a thin tapered punch and drift.... Ive never had any luck with a big hydraulic slitting tool as the edge just goes away to fast to do any work. I do know there are a few guys doing it with high performance steels but I have never had any luck..

Was there a plug that came out? I'm asking because your punch is well rounded on the end and seems like it might just tear through instead of shearing the plug out? Thanks for the info!

[Larry L]

Yep, you get a plug, just like you would get with a flat face tool under a powerhammer.... Under the press though if you have any sharp edges they very well could roll when the tool gets hot and glue the punch in the part.... the very soft and tapered punch acts much flatter than it looks

[Randy Calhoun]

Yep, you get a plug, just like you would get with a flat face tool under a powerhammer.... Under the press though if you have any sharp edges they very well could roll when the tool gets hot and glue the punch in the part.... the very soft and tapered punch acts much flatter than it looks

Thanks a lot Larry

[Danger]

I cheated and cut the slot with a track torch

The stripper is a bit in the moment also but I only had a couple to do.


http://dillonsculpture.tumblr.com/day/2012/03/04

[Larry L]

Nice Dillon.... Thats fine hole