--- Thomas Conroy <booktoolcutter@y...> wrote:
> Galoots:
> With a big bit, having a
> coarse lead screw 
> means it takes a lot more force to turn the brace;
> putting a 1 1/4" 
> hole through hard maple, or even cherry, with a
> coarse bit is a 
> pain, 

Now, that I can understand. I did my experiment with a
tiny #4 (1/4") bit so I didn't have that problem. 

> I had always assumed that the fine screw would pull
> the bit through 
> faster, but today I put two 1"  and two 1 1/4" holes
> through 1 3/4" 
> teak, and counted the turns. They both took 25-30
> turns for the lead 
> screw to stick out of the other side although the
> bigger bit looked 
> to have one turn in the lead screw for every turn in
> the lead screw 
> of the smaller bit. Don't have an explanation for
> this one, and it 
> doesn't accord with my memory of previous
> experience.
> 

So, are you saying that you used one course and one
fine of each size and they took the same number of
turns?  When I tried it with my #4, the fine thread
took 90 turns to go as deep as the other did in 25 or
so turns. (can't remember the exact numbers this
morning)

So, to sum up, so far it seems that with large bits a
fine thread might help make the boring easier as
you're not trying to hog out a lot of wood with each
turn, but still no reason to use fine threads on the
smaller bits. 

AAAndrew
Slipping and sliding away in Durham, North Carolina

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