Milling arbor - how to drill and tap it

[AlasdairM]

I need a 2MT B16 arbor with 3/8 BSW for drawbar for a keyless chuck for my milling machine. I already happen to have a 2MT B16 arbor which has a tang on (for a drill press).

The arbor I am trying to adapt is from Warco - their item no. 8139A as shown at http://www.warco.co.uk/productimages/documents/P103.pdf.

I have tried to drill a 4mm hole in the end of the arbor through the tang before cutting the tang off. so that I can then drill a larger hole to tap it for the drawbar, but it is extremely hard and none of my tooling seems to make any inroads. The drill bits I have used made a lot of smoke and have been blunted - I have tried various speeds and use cutting oil.

If I attack it with my angle grinder to remove the tang, will it be "softer" under the tang for me to drill and tap it?

Anyone have any bright ideas please?!

Regards, A

 

[bentprop]

Hi,Alisdair,I had the same problem,trying to cut the tang off a reducing sleeve.
They must be hardened to some degree,so I asked a friend to chuck it in his open fire, and let it cool with the ashes overnight.This worked very well.I was able to remove the tang with a hacksaw without a problem.In other words,it needs to be annealed before you can work it.

 

[AlasdairM]

BP - many thanks for this. Will anneal it and see if drilling it becomes any easier

Regards, A