Ian White wrote:
John Rumm wrote:

TMH:
Why would you want to remove the thread off an auger bit? Just
stick it in a suitably powerful mains drill and it will go straight
through. Plaster might dull it a bit, but who cares?

Cash:
The problem is that the thread will tend to 'pull' the auger in the
direction that you don't want it to go - taking the thread off resolves

I think that's slightly missing the, er, point.

The screw point on the traditional auger is a primitive form of
auto-feed, intended to pull the bit through the wood without the user
having to lean hard on the brace-and-bit (much though that tones up the
stomach muscles).

The main problem is that it never worked all that well, because the
optimum feed rates for hard wood or soft, close grained or open, are all
different. Sometimes it's necessary to haul back on the brace to prevent
it smashing through the wood.

To be fair it works well in some cases, and poorly in others. It much
depends on the wood type and direction of cut. Drilling into end grain
on soft wood (say a 50mm hole in a newel post), you want all the pull
you can get.

And that's the second problem: put the same tool in "a suitably powerful
mains drill" and it *will* smash straight through the wood - always at
its own chosen feed rate.

That is the problem the hole solves for you. If you pre drill a small
hole (say 5mm) it will greatly reduce the pull from the worm. 8mm will
probably eliminate it altogether, 3mm will leave you a fair bit etc.

At least that way you have the choice of retaining the pull for when you
do want it.

Just pre drill a small hole in the timber to allow clearance around
most of the worm thread - that will reduce (or eliminate if you
prefer) the pull from the thread without trashing a perfectly good auger.


"Trashing" is far too strong a word. If the threaded point is regularly
forcing you to do two drilling operations instead of one, then grinding
the thread off is a perfectly reasonable modification.

No need to force it using the technique described. If you were drilling
100's of holes in the same timber and situation etc, then it might be
worth modding the bit - but its not a general solution since the problem
is a moving target.


--
Cheers,

John.

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