I needed a 4mm hole punch for a project. So, I made one;
It's made from 7mm dia. silver steel, 60mm long. The business end was drilled 3.7mm and reamed to 4mm, only about 10mm deep. A 60 degree taper was turned, using my compound slide, leaving a nice sharp edge. Then I heated it to bright red to harden it and followed that with a couple of hours in the oven at 200 degrees to temper the steel.
It's been tested, on leather and thin plastic glazing material, and it works well enough. It could do with a slot behind the cutting edge to eject the punchings, which I could have milled, but I didn't fancy the extra work. Punches are of course available to buy, in fact I have a set (which doesn't go down to 4mm) but I wanted to make one for a couple of reasons.
Making my own means that I can make punches to any size that I want (within reason), handy if I want to cut out glazing for loco spectacle plates. And some ready made punches are of variable quality, if mine are rubbish then I only have myself to blame.
Paul.
No comments:
Post a Comment
Feel free to leave comments but please note that due to spam issues they are subject to moderation and therefore unlikely to appear immediately. Don't let that put you off though.
Spam never gets published but does make me laugh! Anonymous comments don't get published either.
If you're an engineering company trying to use this blog for free advertising, ask yourself this. What have you got to offer me in return for having your website link published?
And whilst your reading this, everything I post is subject to copyright.