What's the thread size on UZI handguard screws?

[cvasqu03]

I've been planning out some holiday projects including some silicone molding and using a recently acquired 3D printer and scanner. I recently noticed how mini-UZI handguards seem to have disappeared and thought that might be a good place to start. I was able to get one side of the handguard so I'll probably have to 3D scan it and flip the image, then 3D print it before making silicone molds for it. I'm not planning to sell these, just wanted to see what my new equipment is capable of. That being said, I did notice that the handguard panel I got seemed to have the threaded insert molded into the plastic itself and I'd like to try making it the same way. So, what's the threading size on the screws for mini-UZI handguards? Does anyone know how long the threading is? Also, I assume it's the same for full size handguards and pistol grips too right?

 

[Villafuego]

Pretty sure Uzi handguard screws are 1/8"-40 tpi BSW (British Standard Whitworth)

 

[Fatboy148]

You are correct Villafuego. Then there is a practical application that may be easier to find......

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In Richards Uzi info thread he answers this question. (I will cut and paste with my reply)

Uzi Model A rear sight screw threads are 1/8" BSW (British Standard Whitworth). The grip and forend screws use the same thread.

Thanks for that tidbit and now it makes sense to me.

Wanting some spares, a few weeks ago, I looked and couldn't find machine screws ANYWHERE locally that would match up to the grip threads on my Model B.

In defeat, I came back home to lick my wounds and research it.

At Shadeone's site: (http://www.shadeone.com/guns/parts.html) I found this in reference to the screws... "A few aftermarket companies use Allen bolts with an ugly bright gold/brass color to them so be careful. Thread size 5-40".

I went and looked in my own shop at my containers of screws and found that not only did I have them but the UNC 5-40 screws really did fit the nuts in the grip. After doing research today and comparing the two different thread designs, I found that while they are not the same, they are pretty close to being the same spec.


UNC - Unified National Coarse Thread - 60° Thread Angle ANSI B1.1

VS

BSW (British Standard Whitworth) Coarse Pitch - 55° Thread Angle BS84



Nominal - TPI - Pitch mm

5-40 UNC - 40 - 0.635

1/8" BSW - 40 - 0.635

UNC has a thread angle of 60 degrees and Whitworth has 55 degrees. A quote from a model train forum I found today... "mismatched nuts and bolts will mate up, so it is not uncommon to find UNC bolts or studs where BSW should have been or vice versa".

Glad it was rainy here today. I found yet another thing that I never would have known.

Thanks again for sharing your tidbits of knowledge with us Richard.

 

[cvasqu03]

Thank you both, this is great information.