if the crosshead is non ferrous use alum mixture you will get it at an asian spice shop if you keep it warm it will speed the process up.

On 22 December 2024 at 13:27 michael howarth 1 Said:

A carbide drill, say 2mm, should shift it. A carbide end mill probably better.

mick

+1 on the carbide drill.

I had to drill out a 3mm tap yesterday.

Luckily I’ve got a good stock of carby drills from work……..

Jimb

I’ve used a diamond burr in a Dremel to level up a broken tap for drilling with a solid carbide drill. A ball-type will leave a concave surface that helps the drill to centre better. I have some cheap sets from a tool stall at a market. They don’t last five minutes but are useful for this type of thing if the break isn’t too far below the surface.

There are Carbide drills made specifically for this task and they do work well, providing the whole drilling setup is rigid. E.g. in a vertical mill, with the workpiece clamped to the machine table.

An example of the drill:-

https://www.drill-service.co.uk/products/drills/spade-and-tap-removing-drill/dctrd-carbide-drill-tap-removing-spade-type/