Parker Hale threads

[ovenpaa]

Does anyone know what the thread of the screws used to hold the PH17 sight in place on a BSA might be, yes I know it is piece of string type question however I am at a bit of a loss as to what it might be. It appears to be 48TPI and the major diameter of the screw is around 0.136"

[TomH]

I would think it's a specific gunmaking thread used by BSA/Parker Hale before the adoption of British Standard threads and used thereafter on the "if it aint broke" principle.

[North Star]

Check this out. It looks like it could be an obsolete thread?

http://www.practicalmachinist.com/vb/ge ... ad-223456/

[Alpha1]

4BA

[Doz]

4BA

4BA is only about 38.5TPI

[Alpha1]

Hmm.

Enfield threads.docx

(36.64 KiB) Downloaded 57 times

[dromia]

Ask at Norman Clark's, surely they will know.

[ovenpaa]

Dromia, good point as they certainly should know. I have to move the little P17 sight from one rifle to another and it would be nice to duplicate the fixings 1:1 however by the sound of it the chances of finding a suitable tap as opposed to having one made are not good.

[bigfathairybiker]

Try http://www.tap-die.com

Mark


Edit: Just an idea, are shotgun beads.136x48tpi?

[Alpha1]

I asked the clever guy at work he thinks It must be a odd one.
The nearest is M3 but considering its age may be not.
M3 48tpi x .13