View Full Version : Square 5C collet block and 4 jaw for radially offset holes?

06-30-2007, 11:40 PM
Will your typical 5C collet block stand up to the jaws of a 4 jaw chuck? I'm thinking about using that arrangement to drill radially located holes on small round parts up to the 5C limit.

Would I be better off building a custom holder with micrometer (or at least screw) smooth adjustment of the offset?

Hey! A boring head could do it for smaller parts, perhaps larger with a holder for each part ... except I don't have a boring head :(


07-01-2007, 12:21 AM
Why not just use the 4-jaw to hold the part? Unless you have to use a collet block and collets (trying to justify the expense), you won't get any more of an off-set. The hardest part will be indexing each hole.

07-01-2007, 02:43 AM
I just did a job like that....The 1/4 rod would not chuck in big 4 Jaw, they don't close that tight..... I did use some brass packing between jaws and collet block. Worked fine, was for an eccentric adustable front sight...

John Stevenson
07-01-2007, 05:31 AM
No reason why not to at all.
I did the same as BGUNS and used brass packing as my 4 jaw has wicked grooves in the teeth and easily marks smooth material.

I set mine up this way to purposely bore a blank 5C collet to 6mm but off center by 10 thou.
The maximum eccentric has been marked on the face and it's used to regrind engraving cutters so the material behind the cutting edge is in relief.
Saves a lot of time.