Help identifying old pinion grub screw size

[EMC]

I have some old 48p pinion gears of unknown brand that take the smallest allen wrench I own.
I measured the following with digital calipers:

0.0495" allen wrench size at the flats (1.26mm)
Grub screw diameter: 0.110" (2.8mm)
Grub screw length 3.12mm

I can't figure out what sae or metric size these are to get some replacements as these grub screws strip easily.

Any ideas? They might be old robinson racing pinions.

[RC10th]

It's a 4-40 grub screw, .050" allen.

I wouldn't think they would be too hard to find.

The DuBro wall at your LHS will likely have some.

[Lonestar]

in case you don't know where to start: 30pcs shipped for $2 or so here for the 4-40x1/8"

http://www.ebay.com/itm/2-4-6-8-UNC-GRUB-SCREWS-SOCKET-SET-SCREWS-CUP-POINT-HIGH-TENSILE-12-9-/172249487396?var=&hash=item281ade9824:m:mNVwul07tAP5FupiUTxIAfQ

[NomadRacer]

If you want to buy from a US seller on ebay, these guys are top notch. I buy a lot of hardware from them.

http://stores.ebay.com/MonsterBolts/4-40-/_i.html?_fsub=28023679018

[EMC]

Excellent, thanks guys!

[lmw94002]

Don't forget about McMaster Carr ... lol... they can get just about any screw, any size, and multiple materials...

I literally bought stainless M3 and 4-40 hardware for my RC10s and B6s... 100 pcs/box for all the the sizes... it can add up a bit, but I can do like 10+ cars of each now. I should be stocked for the next 10+ years.