Using Machine Screws Instead of Wood Screws

[BrianR]

I know this was posted before, but I can't find it because the "Search" thingy isn't working. I want to use a machine screw to connect some hardware to wood (a 10-24 screw). Anyone know what size drill bit is recommended for this? Thanks all.

[ 06-10-2005, 09:09 PM: Message edited by: BrianR ]

[Dave R]

If you are using #10 machine screws, the clearance hole for a close fit would be drilled with a #9 drill (0.1920"). You could go with the next closer size if you don't have numbered drills.

By the way, if you wanted to use #10 sheet metal screws, the charts show the pilot hole as 9/64" but I believe that is in metal. I would go slightly smaller for hardwood and a bit smaller yet in softwood.

[ 06-10-2005, 09:29 PM: Message edited by: Dave R ]

[JimConlin]

If the hardware is to be heavily loaded, consider this-
Drill as above and counterbore 2/3 of the depth to 2x the screw's dia. and fill that volume with epoxy and cabosil or West #403. Then, screw your part down. If you must, lube the part with Pam or wd40 to ease release.
The idea is to cast a plug of a strong material which has lots of area for transferring load from the fastening to less strong material.
See the Gougeon book for more detail.

[ 06-10-2005, 09:49 PM: Message edited by: JimConlin ]

[Gary E]

I want to use a machine screw to connect some hardware to wood (a 10-24 screw). Anyone know what size drill bit is recommended for this? What you want is the best fiting tap hole so that the screw fits as tight as possible.

10-24 UNC 3B
Minor Dia 0.1450 - 0.1555

to produce that hole use a
No 27 drill 0.144
up to a No 23 drill 0.154

Are you planning to tap the hole? or just screw it in? if a brass or bronze screw it may break, run in first with a hard socket head cap screw.

[BrianR]

Awesome! You guys are the absolute best. So quick too! Many many thanks.

[shellback]

The sise of the pilot hole depends on what wood you're putting the screw into.

[kc8pql]

Or you could use a threaded insert and not have any worries about stripping the screw out.

[G. Schollmeier]

It would be time well spent reading the Advance fastener bonding section in the West System user manual. http://www.westsystem.com/frames/tier1/usingepoxy.htm They have testing to back up their methods.

Gary