trlvn
Ultra Member
I'm not sure I should be let out of the house unsupervised...
So, I made a cross-drilling jig last year. It is a simple thing: inexpensive spindle from Banggood with a couple of pieces of steel so it can be mounted in a quick change tool post holder.
https://www.banggood.com/No-Power-S...html?rmmds=myorder&ID=41528&cur_warehouse=USA
I tried it out when I got it done and it was well off centre. I got back to it yesterday and eventually thought up a way to hopefully get the drill point really close to the centre line of the lathe. I faced the end of a piece of stock and it helpfully left a tiny nub at the center. Like, hair thin. So I got my magnifiers and adjusted so that a point in the cross-drill jig was in line with the little nub.
And did another test. And it was off. Not a lot but at least 5 thous. Whaaat?? Did another test and it was off about the same amount but...the other side of centre??
Ran out of time yesterday and was just about to go back to it today when I realized that the problem is my old 3-jaw chuck. It can be way off (10+ thous in some cases) and I hadn't turned the diameter of the stock so of course I was going to get wonky results. The cross-drilling jig may still be out by a little but it was brain-dead to test without a diameter that was concentric to the centre line.
Duh.
I think I'll just go have a nap. I think I can do that without screwing up. Maybe.
Craig
So, I made a cross-drilling jig last year. It is a simple thing: inexpensive spindle from Banggood with a couple of pieces of steel so it can be mounted in a quick change tool post holder.
https://www.banggood.com/No-Power-S...html?rmmds=myorder&ID=41528&cur_warehouse=USA
I tried it out when I got it done and it was well off centre. I got back to it yesterday and eventually thought up a way to hopefully get the drill point really close to the centre line of the lathe. I faced the end of a piece of stock and it helpfully left a tiny nub at the center. Like, hair thin. So I got my magnifiers and adjusted so that a point in the cross-drill jig was in line with the little nub.
And did another test. And it was off. Not a lot but at least 5 thous. Whaaat?? Did another test and it was off about the same amount but...the other side of centre??
Ran out of time yesterday and was just about to go back to it today when I realized that the problem is my old 3-jaw chuck. It can be way off (10+ thous in some cases) and I hadn't turned the diameter of the stock so of course I was going to get wonky results. The cross-drilling jig may still be out by a little but it was brain-dead to test without a diameter that was concentric to the centre line.
Duh.
I think I'll just go have a nap. I think I can do that without screwing up. Maybe.
Craig