Guns - desperately need a screw

[Trenchard]

Ha, thought that'd get you looking.
The latest fun and games are fitting a steel dovetail rail to a gun to carry a telescopic sight.
The gun is a .22 calibre BSA Martini International Mk.II, which is effectively an approx half-size
version of the famous Martini Henry rifles used in the defence of Rorke's Drift in 1979 (see the
film 'Zulu').

The BSA version was originally invented by one Al Freeland, of Rock Island Illinois and BSA made
the design under license in the late 1950s. This explains why the pre-tapped holes I need to use
have an American thread and this is what's causing problems.

The screw needed is a 6 - 48, a number 5 screw with 48 threads per inch. The specs are...

Diameter: 9/64 inch (to nearest fraction), 0.135 inch, 3.3 mm.
Tapping drill: No. 31
Material: blued steel

Here's the rub. The screw holes were used to fit two steel blocks that took a spindly tube scope.
The steel blocks, ufortunately named the front and rear sight stools took very short screw. So
I can get any number of screws in 1/4, 3/8 ot 1/2 inch but I need eight 3/4 inch screws at least.

I also need countersunk screws and the drive type doesn't matter, I could use slotted, Allen hex or Torx.
Thing is, the 3/4" ones I'm chasing come from the US and have been missing from the suppliers for two months so the seller (Brownell's) won't take an order.

So, the right screws are in the rocking horse teeth/hen sh*t category and I need at least eight of them.

I know everyone (like me) who went through the Meccano/Hornby Dublo rite of passage has a bits box.
If anyone can help, I'll gladly pay.

Yours hopefully...

[mikey_b]

I suppose drilling the thread out, and re-tapping to a more easily obtainable thread is out of the question?

[pequod]

I have an assortment of old screws in various old 'baccy tins inherited from a relative who had a machining business, which may provide the parts you need? They can't be uncommon for that era?

I'll have a look tomorrow and let you know.

P

[Trenchard]

mikey_b

Thanks. Retapping is an option but not yet having a gun licence means I can't bring the barrel and receiver home or take it anywhere else. There's no kit at the club.

[Trenchard]

pequod said:

I have an assortment of old screws in various old 'baccy tins inherited from a relative who had a machining business, which may provide the parts you need? They can't be uncommon for that era?

I'll have a look tomorrow and let you know.

P

Thanks pequod, this is the kind of thing I'm hoping for. The gun's serial number dates it to 1957 and I understand 6-48s were often used in the States. However, , according to their gun forums, even they are struggling at present.

[InitialDave]

Would these suit if you took the length down slightly?

May not be the same countersink angle you need though?

https://www.kenfarrell.com/index.php?route=product...

Edit: nope, reading fail, you need 3/4", not 3/8"

Edited by InitialDave on Thursday 5th May 19:27

[MKnight702]

Have you thought of looking on Ebay. I usually find them great for sourcing a few odd size screws etc.

I also have a BSA Model 12/15, oh, and I did have a Mk IV Martini Henry in 577/450 but I sold that.

[Trenchard]

InitialDave said:

Would these suit if you took the length down slightly?

May not be the same countersink angle you need though?

https://www.kenfarrell.com/index.php?route=product...

Edit: nope, reading fail, you need 3/4", not 3/8"

Edited by InitialDave on Thursday 5th May 19:27

Thanks, InitialDave. Been there, I'm afraid but thanks for looking.

[Trenchard]

MKnight702 said:

Have you thought of looking on Ebay. I usually find them great for sourcing a few odd size screws etc.

I also have a BSA Model 12/15, oh, and I did have a Mk IV Martini Henry in 577/450 but I sold that.

Thanks, MKnight702,

eBay is the place for any number of screws uo to 3/8" long. They almost all in America and costly but too short for my task.

I've fired a 12/15 and a Mk.3 SA at the old club. I was fancying a Mk.3 but the alloy foreend hanger worries me. The one I'm working on and going to buy is a heavy barrel Mk.2 - I do benchrest shooting. I'm a big fan of the Martini action...looked afterr, they're practically bomb proof.

[sociopath]

Don't know if these guys will be able to help, but they're very friendly and have often sold me individual bolts when I've been stuck.

Even if they don't have any they may have an idea where you could get them

https://leytonfasteners.co.uk/

[biggiles]

I was about to say I'd found them on Brownells: https://www.brownells.co.uk/LONG-6-48-8-40-SCREWS-... but you say they don't actually have stock (though the website says they do).

Seems they are only used in the gun world these days: https://www.northwestfirearms.com/threads/help-i-n... Some possible suppliers in the US, and a suggestion to use a tap if desperate.

[Trenchard]

sociopath said:

Don't know if these guys will be able to help, but they're very friendly and have often sold me individual bolts when I've been stuck.

Even if they don't have any they may have an idea where you could get them

https://leytonfasteners.co.uk/

Thank you, sociopath. I've emailed them with my question.

[No ideas for a name]

You could try Non Standard Socket Screw Limited (yes, it really exists)

https://www.nssocketscrews.com/standard-products

Oddly enought they have 'standard products'???

[smifffymoto]

You could also try Threadfast in Congleton.

[Simpo Two]

Trenchard said:

version of the famous Martini Henry rifles used in the defence of Rorke's Drift in 1979

History appears to have changed!

[Trenchard]

Simpo Two said:

History appears to have changed!

Pedants' revolt? 'tis but a century out! Just wait 'til you mistype something.

[dhutch]

As another option, can you counter bore the new rail to a depth to allow use of shorter/existing screws?

[Trenchard]

No ideas for a name said:

You could try Non Standard Socket Screw Limited (yes, it really exists)

https://www.nssocketscrews.com/standard-products

Oddly enought they have 'standard products'???

Thanks, mate. E-mail sent to them.

[Trenchard]

smifffymoto said:

You could also try Threadfast in Congleton.

Thanks, smifffymoto,

Email sent to them.

[thebraketester]

"Desperately need a lathe"

Isn't that what the thread should be called? :-)