Adjustable Centre Bit.

[Boringgeoff]

Well done Andy! Righto, come along now chaps, two down one to go!
Eric, I've had mine sitting in a pot of wood shavings (Jarrah and Wattle) in a dry cool spot to encourage it to sprout a new spur but no luck so far.
Cheers,
Geoff.

 

[AndyT]

I recently noticed another one of these on eBay - the middle size, 9/16". There are plenty of nice clear pictures while the original listing is still visible, here.
http://www.ebay.co.uk/itm/Adjustable-ex ... 2666030569

I didn't buy it, a) because the starting price was £39.99 + p&p (!) and
(b) because the spur was broken off - AGAIN! Honestly, these old tools are a load of junk. :wink:

 

[Phil Pascoe]

Phill, that looks like an example of the Clark's patent design - much more common and more robust.

The (perfectly ordinary looking to me) square taper shank is what fits into a brace.
Do you mean to imply that you don't have one?

Thanks. I was given this and a collection of drill/auger bits but no brace, by a friend clearing a workshop. No drilling machine of mine would accept the tapered shank so I sort of forgot about them until this thread. (There were a lot of chisels, gouges and very useful stuff so do not think for a moment that I am complaining).

Some of the auger bits are quite large - surely they would not have been used in a hand driven tool?

Sorry to OP if I have hijacked the thread.....

A brace? If you are happy to pay the postage, I'll send you one.

 

[Eric The Viking]

I bet it's just me , but I often used to end up cutting large spirals with my expansive bit, when the adjustable part came loose. Very frustrating.

Also, they do wander rather a lot in softwood, as there's only the leadscrew to pull a rather cumbersome cutter arrangement with it. It never seemed to matter how sharp I managed to get the spur, either.

But I'm heavier now than when I last made a lot of use of it ( :-( ) Perhaps I ought to give it another try, for several reasons!

E.

PS @ the good doctor: don't ever believe the diameter scale. Try it on scrap and AOT.

 

[Boringgeoff]

Reviving this Anderson Expansive bit thread to inform you that an Auger bit enthusiast, Eric Brown, has sent me Anderson's patent and here it is with his permission.

Cheers,
Geoff.