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Why oddball screws on guns?
Posted: Fri Feb 21, 2020 5:32 pm
by fortyshooter
Coming from a machinist point of view...why 8-40 screws for the sight mount screws on the rifle receivers instead of common 8-32??
Yes I know more threads per inch for better strength...but a sight mount??
So much for a quick little project. 8-40's hard to come by at typical walk in stores!
Re: Why oddball screws on guns?
Posted: Fri Feb 21, 2020 5:35 pm
by BigAl52
I know its not a local store 40 but have you thought about Brownells?
Re: Why oddball screws on guns?
Posted: Fri Feb 21, 2020 5:52 pm
by JEBar
Re: Why oddball screws on guns?
Posted: Fri Feb 21, 2020 7:25 pm
by Sir Henry
You’ll understand when you are a little older
Re: Why oddball screws on guns?
Posted: Fri Feb 21, 2020 9:32 pm
by Mags
.
8-40 is very common here. Not so much 8/32.
fortyshooter wrote: ↑Fri Feb 21, 2020 5:32 pm
Coming from a machinist point of view...why 8-40 screws for the sight mount screws on the rifle receivers instead of common 8-32??
Yes I know more threads per inch for better strength...but a sight mount??
So much for a quick little project. 8-40's hard to come by at typical walk in stores!
Re: Why oddball screws on guns?
Posted: Sat Feb 22, 2020 10:35 am
by North Country Gal
Actually, 6-48 is the standard size used by the vast majority of brands for the thread size on scope mounts, even brands made outside the U.S. Marlin was always the oddball with it's 8-40. If you need 8-40, check mounts for Marlins.
Re: Why oddball screws on guns?
Posted: Sat Feb 22, 2020 11:33 am
by Grunt67
fortyshooter wrote: ↑Fri Feb 21, 2020 5:32 pm
Coming from a machinist point of view...why 8-40 screws for the sight mount screws on the rifle receivers instead of common 8-32??
Yes I know more threads per inch for better strength...but a sight mount??
So much for a quick little project. 8-40's hard to come by at typical walk in stores!
Another former machinist here. You might find a 8-40 at Lowes or Home Depot, if you have one handy, but likely they would be a socket screw head. Never had a need to check, but might be worth a look if you're close. Other than that, Brownells, etc. as someone else said. Good luck........
Re: Why oddball screws on guns?
Posted: Sun Feb 23, 2020 9:19 am
by Rifletom
forty, I might have some 8-40 screws. I'll check today when we get back from church and breakfast. Pretty sure I do, but, will check.
Edit: Dang, 6-40x3/8" and 6-48x1/4". Well, we tried. About 10 each.
