hex socket bolts

[Ron Nossaman]

> As far as I know the only tests done on this subject were by Lee Valley 
> tools and WoodenBoat magazine. In general they found that withdrawal 
> strength was moderately higher with untapped holes.
>  
> Del

I'd think that would be dependent on the compliance of the material 
the bolt is going into, and the diameter and thread pitch (read 
thread depth and interference fit) of same. Pressing relatively 
smaller diameter capstans into sugar pine, basswood, or spruce in 
keys, and pressing relatively larger diameter plate support bolts 
with considerably deeper threads into hard maple aren't going to 
realistically equate. I'd much prefer drilling a smaller diameter 
pilot and tapping with either a real tap, or a modified all-thread 
substitute and getting a high degree of thread contact in the rim, 
than drilling a pilot big enough to press or drive the bolt straight 
in and sacrificing much of that thread contact. Realistically, those 
plate screws aren't under a lot of stress, so I  guess it's more a 
matter of a belt and suspenders overbuilding security thing, but 
that's my call.

Ron N