What size and thread are the head screws for an O.S..35-S? There is apparently at least two generations or versions of the .35-S. I believe the one in question here would be the last version before the FP series. The originals are phillips head and I'm trying to find socket head replacements for a couple engines.

 Thanks!

Hi Wayne,

Just an FYI:  Dick Byron sells sets of head and back plate socket head screws to use in the OS .35S  Very reasonable price!  I have used several of those sets, w/ no problems.

Bill

We buy from Micro Fasteners in NJ, the M3 X .6 x 12mm socket heads.  These seem to fit MOST of the 35-S engines. They started carrying this odd
size a year or so ago.  Just need to cut down the length for the rear cover screws, as only the 12 mm size is available. Good people to deal with!

 Bill,

 I'm not having luck anywhere else so I think I'm going to get some of these from Micro Fasteners. I found a thread gauge and these are indeed 3x .6mm thread. Apparently .6mm thread is an oddball size. These original head screws are 10mm long. Do you happen to know if the 12mm will have to be shortened so they won't bottom out before the head gets tight?

 Thanks,

 Wayne

Not sure where I found this but I saved it and ran across it a few days ago. I think it belongs in this thread.

M2.5 x 0.45 and M2.6 x 0.45 Pet-111, 10FSR, 10-25FP
M2.6 x 0.45 Max-10, 15, 20, 25
M2.8 x 0.6 (specially made for OS) Max-1, 11, 111-15, Max-19
M3.0 x 0.5 all SHCS in 3mm sizes
M3.0 x 0.6 Max-S30, S35. Max-H 29, 35, 40
M3.5 x 0.6 Max-H 60, 60-61 FSR
1/8"x40 Max-1, 11, 111-29, 35. 50, 58

 Hi Bill,

 I just recieved some of the alloy 3x.6x12mm allen screws from Micro Fasteners. They fit perfectly, but they do bottom out. So, like you said, they will have to be shortened just a bit.

 Thanks!