drill bit to binding mounting screw diameter ratio

[Spiny Norman]

I'm about to mount some telemark and some AT bindings. I don't have mounting info for either.

Is there a generally accepted ratio bw the width of the mounting screw and the width of the drill bit to be used?

For instance, when i am putting decking on a metal pallet I use a bit that is 1/32" smaller than the shaft of the bolt. I can measure the screws with a caliper.

Thanks

[Stephen]

The presence of carbon fiber or metal would make a difference.
Not a direct answer, but maybe this will help?
https://www.slidewright.com/measuring-f ... bits-taps/

[fledersau]

Hi, i work as a tech in a ski shop and i mount bindings all day long.
For AT and tele bindings for downhill usually you use 9 to 9.5mm length drill bits. For XC or BC XC bindings the length can go up to 15mm. check the length that the screw that goes out of the bottom of the binding.

For drill bit diameter, usually it's 3.5-3.6mm, but when there is a bigger carbon topsheet or a metal plate, it's 4.1mm and a tool to make a thread is best.

[Spiny Norman]

Thanks

[Jurassien]

Hi, i work as a tech in a ski shop and i mount bindings all day long.
For AT and tele bindings for downhill usually you use 9 to 9.5mm length drill bits. For XC or BC XC bindings the length can go up to 15mm. check the length that the screw that goes out of the bottom of the binding.

For drill bit diameter, usually it's 3.5-3.6mm, but when there is a bigger carbon topsheet or a metal plate, it's 4.1mm and a tool to make a thread is best.

Perfect answer, to which I can only add that special drill-bits, with depth-stop, are available which are intended specifically for mounting ski-bindings:

https://www.tognar.com/mounting-drill-b ... -bindings/

[phoenix]

It's worth it to get the proper bits from Tognar. Skis often have the recommended drill bit size printed on the top sheet, or you could call the company, if you're unsure.

[JohnSKepler]

Kind of a dead thread, and my knowledge doesn't stem from ski experience but from a lifetime of woodworking, though, if I had no other information this is what I would do and I'd bet my pink-slip it would work fine.

Generally I'll drill the pilot hole the same size as the minor diameter of the screw. The minor diameter is a width of the central shank without the threads. I generally work in the English system with my drill bits so they are measured in 64ths of an inch. If the threads are really wide, like a binding screw, I'll go up 1/64 to allow a bit of expansion from the threads cutting into the wood. Also, if the wood is very hard like oak or maple I'll go up 1/64 since it may crack if there's nowhere for it to go. This has never failed me in wood working but most of the stuff I build isn't under the dynamic stresses of a ski.

[Spiny Norman]

Thanks guys.