Very small machine screws

I found this tiny pot of machine screws in a junk shop. They are absolutely tiny but I wasn't sure what thread they are but I had an inkling they might be BA so I checked them with my BA tap and die set and they're 10BA!!!





I was looking to maybe use one to replace the screw that keeps the Bialaddin control know on the shaft but these are way too small! Nevermind, I'm sure I'll find a use for them one day!

BTW, the OD is 1.7mm!

 

They're huge @ColinG.
A recent project here used 13BA.
Drill 0.8mm then Tap M1

 

13BA! That's incredible!

 

They came from here.

BA Fasteners, Imperial Fasteners, Micro Metric Stainless, Small Screws, UNC Square Nuts, Ba Screws, Ba Bolts,

That is a switch rotor from a piece of radio test equipment. The fingers are mounted by plastic pips which go brittle and the contacts fall off and get lost.
I machined that pair of contacts and refitted them using the screws. Hope not to have to go in there again since assembling the unit is very awkward.

Sorry about off topic - but hopefully someone might find the screw link useful.

 

Believe it or not, the original BA specification goes down to 25 BA (od 0.25mm), although I don't think anyone went much below 16 BA. FYI the retaining screw in the Bialaddin knob is 6 BA- positively chunky!

 

Possibly, if you're going to fix something like a mechanical wrist watch.

 

So I am looking for a specific machine screw and it has been really hard if not impossible to find. I've been to fastenal twice (of course they ordered hex heads for me first that I had to return). I've contacted mcmaster and grainger, as well as used all the google kung foo I know how to muster. So....anyone have any recommendations for a supplier for a really hard to find machine screw???

I am looking for 6-40 flathead, torx drive machine screws (3/8"-5/8").

I would probably buy 100-500 of ea length.

 

I purchased a set of tiny screws for watch repairs from Ebay... these might work?

UK Tiny Micro Assortment Screws Eye Sun Glasses Watches Repair Tool Kit | eBay

 

Not sure what you meant by flathead. Does it mean flat countersunk type like these?:-


Torx drive.
Size: #6-40UNF x 3/8" to 5/8" length?
Do you mind hex-socket drive like those here:-
#6-40 Flat Head Socket Cap screws, Alloy Steel with Black Oxide, Fine Thread