Thread: Lathe tailstock repair (retapping grub screw)

Hi,

Ive got to repair my tailstock and need some advice...

I haven't pulled apart a tailstock before so bare with me if this is common knowledge or if I'm using the incorrect terminology. In my tailstock there is a threaded brass section that friction fits into the back end of the tailstock spindle. This threaded brass section screws onto the threaded rod attached to the tailstock's hand wheel.

As well as being a friction fit, the brass is held in place with a grub screw that's tapped into the join line between the brass section and iron spindle (parallel to the axis of the lathe, not across it).

Anyway, what's happened is, through winding the tailstock right back to pop out the live centre, this grub screw has actually compressed, distorted and sheared the thread away from the iron side of the tapped hole. The brass and iron have then separated and the spindle no longer winds in if you where to pull on it.

I have to retap this hole and insert a new grub screw.

Here's my question....

Would you suggest retapping the existing hole wih a larger thread or start again somewhere else on the join?

I do not have a vice on my drill press so would have to rig something up. I'm also afraid that the drill bit might wander into the softer brass.

Does anyone have any advice as to how to drill this hole accurately enough to tap it out and insert a screw?

Thanks,

John.