Sovereign_13
Senior Member
- Messages
- 311
After reading this over and over again and trying to figure out how fair.child plans to "start" with a bit that is larger than 1/4" and then use a 1/4" bit, I wonder if the 17/64 bit being referenced is not a Forstner, and the plan is to use a 17/64" bit to drill the hole and then flatten the bottom with the 1/4" Forstner.
In which case, I'd probably say to just use the 1/4" Forstner. The extra 1/128" of clearance a 17/64" hole will give you between the sides of the hole and the shaft of the insert is probably just a precaution to prevent binding.
Here, it recommends the hole size be 1/4" for the 4-40 and 6-32 fasteners, depending on tools and materials.
https://www.ezlok.com/download/DimDwg_KnifeThread.pdf
In this case, I think you could also drill a 5/16" hole and epoxy the inserts into place, but I defer to the vastly superior knowledge of the forum.
In which case, I'd probably say to just use the 1/4" Forstner. The extra 1/128" of clearance a 17/64" hole will give you between the sides of the hole and the shaft of the insert is probably just a precaution to prevent binding.
Here, it recommends the hole size be 1/4" for the 4-40 and 6-32 fasteners, depending on tools and materials.
https://www.ezlok.com/download/DimDwg_KnifeThread.pdf
In this case, I think you could also drill a 5/16" hole and epoxy the inserts into place, but I defer to the vastly superior knowledge of the forum.
