How do a drill a hole?

[John Hill]

I want to drill a hole accurately in the end of a shaft so that I can clamp a tool in the manner of a collet.

This is a simple job to fit a centre drill to a Morse taper blank but every attempt so far has come out crooked.

Here is a sketch, of course the male bit has a saw cut so that it can compress somewhat as it is screwed into the shaft.



I drilled the hole with the two bits screwed together and mounted in the lathe spindle taper.

[Bernd]

I drilled the hole with the two bits screwed together and mounted in the lathe spindle taper.

Did you cut the slot before you drilled the hole?

Bernd

[John Hill]

No, drilled then cut.

[No1_sonuk]

How many cuts?

Could it be that the hole is accurately concentric, but that the grip isn't.

[John Hill]

I have only one cut in the 'collet'.

[sbwhart]

Try putting the cut part way through, or two cut part way through from opposite ends 90 deg to each other.

Hope this helps

Stew

[John Hill]

Thanks for all the comments and advice guys!  I am home now and just about to go down and try to check if the thread is true to the spindle axis.  The main part of this tool is stainless and I had a hard time cutting the internal thread.