On Mon, 7 Nov 2005 22:31:07 +0100, (Nick
Müller) wrote:

John Martin wrote:

You're right, Nick - it's a key slot and has nothing to do with
expansion or contraction.

It's not that I want to be right, I want to understand why it is the way
it is. For that application, the key slot is quite odd, so I think the
usage is something different.


I tried to fool you, but couldn't.

Or maybe I'm still fooling you? :-)))


You're probably also right about broaching the slot. If I had to make
them, though, I think I'd just run the slitting cutter a little deeper
to cut the through slot and the shallow slot on the far side in one
pass.

ACK, that's what I meant.


But there is undoubtedly a good reason for a separate broaching
operation.

That's what I would like to know.


Maybe they slit it before they bore it and cut to length.

Slitting before boring would not be very clever.


Enjoy,

Hi Nick,

I think the slot is just to facilitate clamping around the
flutes on a drill bit. They stick out a bit more on their
leading edge. Most common drill bits are of a two flute
design. The slots would create a better clamping surface to
the bit when used over the flutes. I suspect that it would
thread on to the bit when it is almost tight.

--
Leon Fisk
Grand Rapids MI/Zone 5b
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