On Fri, 01 Oct 2004 10:57:31 +0100, Andy Dingley
wrote:
On Fri, 01 Oct 2004 06:54:24 +0100, Mike Halmarack
wrote:
But I think you're exaggerating the lack of tolerance between the 2
for practical purposes.
You haven't seen this done, have you ?
Do you mean I haven't seen a 1/4"shank fitted into a 6mm collet?
If that's what you mean, then your right again, I've neither done it
nor seen it but I have read quite a lot about it and this is what
I've understood so far:
Some manufacturers/users rightly or wrongly make no practical
distinction between 6mm and 1/4" shank/collet fitting. They then go
ahead and use the combination without a problem.
Others have fitted 1/4" shanks into 1/4" collets and had the cutter
fly out in use. Discussion has then moved to the micrometer
measurement level in an attempt to explain and understand the event.
The problem is that collets are hardened and relatively stiff. They'll
tighten down to any size, but they then form a cone that's only
gripping over a short ring, not the full length.
The cutters ran off
axis and if 1/4" is forced into 6mm they form an open-mouthed cone
that's just asking for a flyer.
There are variations. some collets will behave in this way, some will
distort/conform to the shank depending on their structure.
In order to make and validate a point some people refer to levels of
precision that often don't exist in practical reality.
It's a bit like the discussion of who's holier, the one who goes to
church on Sunday only, or the one who goes to church every day.
Remember the old Bosch routers, where they were supplied with a 6.4mm
collet, a couple of 6mm cutters and an adapter shim that most people
ignored. They'd hold reasonably well (any cutter slip didn't cause it
to work much looser) , but the 6mm cutter ran well out of true.
Degrees of precision again and who can argue against more precision as
opposed to less?
There is also the possibly more relevant matter of context. This
thread is about an alternative source of d-i-y tools that have
generally proved to be dependable and inexpensive. Such a thread will
inevitably attract brand zealots, who will use both rational argument
and hocus pocus to denigrate the competition. The router table for
sale at Aldi is at least as good as other inexpensive tables. The
router in question has both 6mm and 8mm collets and while 6mm shanked
bits may be most easily acquired by purchasing the accompanying bit
sets, 8mm shanked cutters can be had from numerous sources including
Trend.
The argument against metric sized router bit shanks is turning into a
bit of an anachronism, especially when you have people talking up the
merits of imperial shanks on bits with metric cutter profiles.
--
Mike Halmarack
Drop the EGG to mail me.
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