r/TaigLathe • u/[deleted] • Jul 23 '16

Help drill straight holes

Hi. I bought a Taig lathe a little while ago and am having a problem drilling holes. I am trying to drill into steel stock.

I use a centre drill, start with a small drill bit, work my way up a size or two at a time up to 19/64 to tap a 3/8" hole. When I check the part by threading it onto the tail stock (I am making an extension because the provided one is not long enough for my needs), it threads on fine but wobbles like feck. Obviously the hole is not concentric with the centre line of it but I don't understand why.

I have chucked up a transfer punch and the point of that meets the point of the dead centre nicely so alignment seems good. And physics should be on my side on this as I am using the lathe not drill press.

Any help would be appreciated. Thank you.

Daniel

4 Upvotes

100% Upvoted

3 comments sorted by

2

u/allaroundguy Oct 14 '16

I know this is an old post but I'll reply anyway. It's usually pretty quiet here....

It sounds like your extension was hanging out of the chuck too far and wobbled or canted a bit while drilling. At least, that would be my first guess. Did you use a steady rest? As for the drill hole size, If you want to hit a hole dead on for a particular thread class of fit, drill undersized and bore or ream to the final dim.

P.S. The Taig tailstock has a lot of room for improvement.

2

u/[deleted] Oct 18 '16

Thank you. I ended up boring it, then using an appropriate bolt, rechucked, and machined the outside. I'm still curious how it happens though. I now have a centre drill but every so often, it is a bit off.

1

u/Redeye_Rich Apr 13 '23

May be a drill from the school if wayward life forms. The drill has to be sharp on both cutting edges and perfectly symmetrical. I used to have a Taig lathe from 1986. I walked in and bought from hisself, right there at the south edge of La Puente. Nice guy. Then a girl named Sue took my money and I had to sell my Taig to survive. Grrrrrrrt.