Hi Bill. Got my bearings from here **LINK** although I did mine in metric. The springs I got from the show at Harrogate.Bought a length to cut up…Sorry can't remember which stand it was from. John

These people do springs the choice seems to be endless and they will sell you one at a sensible price. **LINK**

Olly

Bill,

You need to enable compatability mode on you Laptop's IE.

Dave

Hi Bill ,

If its an ordinary HSS centre drill then no easy way of softening it en situ . Easy removal needs spark erosion equipment or similar .

Best thing to do is to drill from the back on the original alignment as near as you can judge and then punch the broken bit of centre drill out . If you can't drill on the original alignment because its a blind bore in thick metal then come in sideways or at a steep angle and use a taper drift to knock the bit out and then plug the access hole afterwards .

If you've got a bit of patience you can also gring the broken bit out using a fine point on a hand held mini grinder or using an aluminium lap and grinding paste .

There are special drills and milling cutters hard enough to cut HSS but probably not worth buying any just for this .

MikeW

Edited By MICHAEL WILLIAMS on 24/07/2013 19:55:26

Motto of the story is use a spotting drill and save the ctr drill for when you actually want to run a ctr in the hole.