5-40 unc machine screws

Porthandbuoy

Well-Known Member
Joined
27 Apr 2003
Messages
5,862
Location
The Gareloch
www.backbearing.com
Does anyone know where I can get 5-40 x 1/2" machine screws? Google, Amazon and eBay have not been much help tonight.

I'm renovating an antique boat compass where one of the fastening had sheared. I've got the remnants out and I'd prefer to replace with the same size rather than drill and tap 8 to have them match.
 
Thanks guys. Stainless no good, has to be brass. Neither Westfield nor Namrick have anything suitable on their website. I'll try calling them, and others, tomorrow to see if they do 'specials'.
 
1/8" Whitworth will fit ......... perhaps thats not very helpful but I quickly found a source of 1/8 W round headed and countersunk ones

My Dad would have made one!
Don't you know anyone with a small lathe who could make you one?

Or pop round here one day and make one yourself Dad's lathe is still in the garage( Only 960 miles for the round trip!)
 
Last edited:
1/8" Whitworth will fit

After I'd posted re 5-40 screws, I did wonder if the thread required isn't actually 1/8" Whitworth. I feel that a unified thread would be very unlikely on an antique marine instrument, unless it was possibly American, whitworth would be much more likely this side of the Atlantic. It's still used, sometimes designated as a Model Engineer, ME, thread.
 
After I'd posted re 5-40 screws, I did wonder if the thread required isn't actually 1/8" Whitworth. I feel that a unified thread would be very unlikely on an antique marine instrument, unless it was possibly American, whitworth would be much more likely this side of the Atlantic. It's still used, sometimes designated as a Model Engineer, ME, thread.

I wondered how the OP had identified them as UNC. Difficult to distinguish from Whitworth on such a small size I'd think. I assumed it's because it's American made


He does not say what head he requires. Cheese head, round head, raised head or countersunk. I guess slotted though.
 
I wondered how the OP had identified them as UNC. Difficult to distinguish from Whitworth on such a small size I'd think. I assumed it's because it's American made


He does not say what head he requires. Cheese head, round head, raised head or countersunk. I guess slotted though.

Under a strong magnifying glass the threads appear to be flattened at the crests, not rounded = unc, not Whitworth.

Original heads are fillister, but would replace with pan, cheese or round; countersunk no good. Agree whitworth with the correct head would do, and I'd follow that route before drilling and tapping, probably for BA.
 
Top