Where to source 1/8" 40tps faceplate screws for old style MK grid switch banks?

[Kitchen10]

Hi All,

I'm doing a job at the moment where there is an old style MK metalclad grid 12 switch bank which has the cover held with one screw and duct tape(!). It needs three more screws for the faceplate but they're imperial and I can't find any. The dimensions are:

-1/8" diameter
-5/16" long exc. head
-40 threads per inch
-Countersunk head (slotted)

I think it's ridiculous to change an entire bank of perfectly good switches because there's three screws missing! Any help is much appreciated!

Many thanks,
Henry

 

[Leesparkykent]

http://www.builderdepot.co.uk/mk-sc...m_term=1100908924678&utm_content=All products

 

[SparkyChick]

I was going to suggest a 3.5mm re-threader/tap and a box of M3.5 countersunk machine screws.

 

[FatAlan]

If my dad had been spark he'd have a tobacco tin in the garage somewhere full of the things. Even though he's not a spark he may still have. I bet some of the dinosaurs on here have some

 

[PEG]

Sounds like 5 BA,but could be a BSF size,just depends on your measuring accuracy...

...That big meteorite is making it darker...i think i'll have a lie down...

 

[LeeH]

Re tap it to metric M3.5 or M4 if there is enough meat on the box.

 

[Kitchen10]

http://www.builderdepot.co.uk/mk-screw-for-mk-face-plates.html?utm_source=bing&utm_medium=cpc&utm_campaign=All Products&utm_term=1100908924678&utm_content=All products

Thanks! Good to know someone still sells 'em.

I was going to suggest a 3.5mm re-threader/tap and a box of M3.5 countersunk machine screws.

Re tap it to metric M3.5 or M4 if there is enough meat on the box.

I had considered that, but I don't have the right tap. Might go out and buy one.

If my dad had been spark he'd have a tobacco tin in the garage somewhere full of the things. Even though he's not a spark he may still have. I bet some of the dinosaurs on here have some

I asked my grandad, but no cigar!

 

[rsgaz]

-5/16" long exc. head

Countersunk screws are measured including the head. So I'd guess 3/8.

If it's 40TPI it's probably a 1/8 inch BSW thread, but they seem impossible to find, so just use a 5-40 UNC thread. Identical major and minor diameter, identical pitch, it's just the profile of the pitch is slightly different.

5-40 UNC x 3/8 inch Slotted Countersunk Screws (ANSI B18.6.3) - A2 Stainless Steel: Accu.co.uk: Precision Screws - https://www.accu.co.uk/en/countersunk-flat-head-screws/35074-SFK-5-40-3-8-A2

 

[Andy78]

Leesparkykent has it cock on. The yoke fixing screws are standard 3.5mm but the faceplate screws are always 3mm.

 

[rsgaz]

Leesparkykent has it cock on

but they're imperial

I thought we were talking really OLD, old stuff.

 

[Andy78]

I thought we were talking really OLD, old stuff.

I think it will be 3mm, I have never known MK grid of any age to use anything else. The OP quoted an imperial size of 1/8" which is 3.1mm. I'm guessing they will be 3mm.

I have only ever seen imperial grid plate screws (not MK) being much larger, like 4BA CSK.

 

[Kitchen10]

Thanks for all the replies. I've looked at the website Leesparkykent suggested, but they want £4.19 postage for three screws! I emailed them but they won't reduce the postage.

Does anybody have some lying around?

Here's the screw in question, on top of the bank of switches:

Thanks,
Henry