cut open-ended slot with ironworker

I cant quite tell from your drawing, but I am guessing you want an oval punch in the punch station to do this. This is a rounded end slotting punch. Long ovals are available in a bunch of standard sizes- I have 1/4" x

1" and 1/4" x 1 1/2" for mine, for example. Or somebody like Cleveland punch will make you any size you want. if you are only punching with one end of the punch, you will get uneven wear, and may go thru punches faster than normal, but it should work fine.

Ries

This is what I was wondering - using the rounded-end slotting punch in the punching station. So you are allowed to use it with part of the length of the punch "passing through air" while the rest of the punch takes out metal?

(I've used the slotting punch for openings in the middle of plates already)

Is there a restriction - like say 2/3rds of the length of the punch must meet the metal?

'nother thing I was wondering - could you punch first with a round punch, then land a square punch centred on the metal "bridge" you would then need to take out to leave an open-ended slot - or am I getting way ahead of the complexity needed?

Richard Smith

You for sure can't do the latter without a train wreck. Ries's advice is as usual very good - call Cleveland Steel Tool and talk to them. Or see if there is a special punching attachment for your machine which does open ended slots.

GWE

If you have a slotting punch 1 by 1.5 punch a series of slotted holes at 1.5 inch centers then go back and clean out the little scallops afterward. In most cases it is a good idea to use this method. If you punch using only part of the punch often the point will push the plate or your punch to one side. Another ploy for nibbling with a round punch is to grind the center point off so that the punch doesn't shift the plate. Set up a straight edge on one side and a series of soapstone marks on the support table 1.5 inches apart. If your plate tends to warp use a hand held stripper and insert that under the stripper on the machine to offer more support as you lift up. Randy

I have punched partial holes before without the punch being pushed off center- but I am sure it could happen. I think its a lot easier to punch one hole, rather than nibble. One thing you could do is punch two plates at a time- make a stop that holds them together, in the right spot, and punch one half of your punch in each plate, so the load is even on the punch, and you get two parts with each operation.

Relatively speaking, 1/8" and 1/4" steel is so thin, I dont think you would have much punch movement anyway.

Thanks to you Ries and all the respondees - appreciated very much, as always is the help I get here on SEJW.

"> One thing you could do is punch two plates at a time- make a stop that > holds them together, in the right spot, and punch ..."

I feel interest in this idea - I'll punch out a closed rectangular opening 100mm x 50mm from a plate of steel which holds side-by-side two strips and see how this goes.

Richard S.