Threaded Transfer Punches

[Shox Dr]

Needed 4xM8 transfer screws tonight, so made them out of M8 rub screws, bored the middle to 2.4mm, found a Tungsten that would just fit. Then using a centre punch, gave the end sharp rap, so as to preen the hole a little. Ground the tungsten and pushed it in from the broached end, [after hitting the preened end it required tapping down] so it was just proud. Cut the excess off and there you have it. Well not quite I needed a hole in the end of a 6mm Hex. Luckily I had some made from cheese, so didn't need to temper it,

OK for M8+ any smaller and you would have to drop down to 1.2mm.

 

[PSweeney]

I sharpen the end on an old Allen key to a point, that way I can set the grub to the required depth and still get it out.

 

[Kram]

Looks good! might borrow that idea.

I tried doing a similar thing. I want to drill a 6 hole PCD to be tapped with better accuracy than I can mark out - tried this first attempt was rubbish... after drilling it was way off !! Second attempt I turned down some silver steel to 6.7mm (failed to get a tight fit but close enough) and was going to hold it in lathe collet. With the PCD part clamped against the work I should be able to line it up, change tool and drill. Plan to use a 4mm slot drill as it should ignore the badly located pilots, where a normal drill might move to the old hole.
Got a few spare hex keys, thought one might be good as a carbide tool holder. Milled the end to fit with a carbide end mill cut very nice.. then realised its too hard for normal taps so ill find some more bar for a holder or use a nut underneath.

 

[Wallace]

Looks good! might borrow that idea.

I tried doing a similar thing. I want to drill a 6 hole PCD to be tapped with better accuracy than I can mark out

Could you use an optical centre punch? Wanted one for years and decide that my 50th present to me would be a gold plated one. Wish I had done it for my 21st.......