I have an OS 40 FP and the screws that hold the muffler on are getting worn because they are philips head. I went to several different stores and couldn't find a hex head type screw which I want to avoid this happening again. Does anybody know of any manufacturer that makes this screw size with a hex head? Or any suggestions for a different type screw.

I had trouble keeping the supplied nut on the muffler screw (even with blue loctite) on my OS 46FX and went to a nylon nut. Tighten once and forget it....

Hey jsf, You should be able to find something at a hardware store
ace/home depot etc. or your LHS.. If not you know you can order
from Tower or other online hobby shops..
I had the same thing on my LA 46, But I replaced with the same
screw... I just started using the right sized screwdriver and not
over tightening and gripping the head good and no problems since....

Look in Home Depot or Lowes in the "Fasteners" section. You'll find a cabinet of shallow drawers just full of differen types of nuts, bolts, washers, etc. What you are looking for is called a "Hex head Cap screw" and you should be able to find one in the right thread size and length.

Lowe's or Home Depot has them for sure, go to allen head and your troubles are over. They are 3x30mm and most hobby shops have them. Jim

3mm screws are hard to find at hardward store. the smallest I've
seen are 4mm at home depot or home base in those draws.

Hobbie shops usually have them, most .40 size engines use 3mm to attach
the muffler.
Dubro , with verious length is what my LH carries.
Don't forget to get an allen wrench, I belive they are metric also.
Use blue loctite or run a little bit richer to prevent lossing your muffler in flight.

Sometime that nut at the end of the muffler gets loose and the back end
of it gets lost.
you might also want to get some 3mm nuts to double up, so it won't get loose.

I've lost enough of them, as many other had also.
I've found many mufflers and what not at the air plane's grave yard right
beyound the flight line.lol

micro fasteners has them

When all else fails, call Micro fasteners !!! Good guy.

Last time I needed muffler screws, I found them at Tower Hobbies. Unfortunately they are going to sell you exact replacements which means you get Phillips head screws. You have to search REAL hard to find them but they are there. They qualify for discount shipping so it wont cost you an arm and a leg. If you find them with hex head then all the better.
Tom

They are not phillips head screws they are JIS (Japanese Industry standard) head screws and the angles used are close to phillips but not exact which is why they bugger up so easily. The last couple of screws I had to replace on OS engines were 3.5mm. (On some of there smaller engines OS uses 2.6mm.) So check carefully as to size. My LHS used a computer on the internet to get the size for my last screw purchase. He then turned around and picked a small package of Dubro 3.5mm off his wall display and they are socket head screws.

Why we must ask ourselves do they use screws in fractional sizes. Could it be that they are harder to find? . . .but that they can supply them?

Try JIS from Moody Tools. They have sets with #1 down through #000. #1 will work fine on most of the OS engines. Without that you'll be chasing fasteners forever.

www.rjrcooltools.com has them also.

These [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXJB22&P=Z]muffler screws [/link] should fit no problem...because the new Tower Hobbies .46 ABC engine is the OS .46 FP....when OS discontinued the OS FP, they gave the copyright/patent to Tower Hobbies who got someone to make the Tower Hobbies ABC engine...its identical to the OS 46.FP (also the .40 FP)....that is what my instructor said when I asked him about Tower Hobbies engines...I think I forgot something in the story part but the screws should fit....

I have in the past retapped them to 4x40 standard, The M3 is close but just a little smaller with a slightly finer thread, If you can get a tap cheap it will make it so much more fun finding muffler screws. Heck if you feel you want to retap I would not mind sending you a tap, I work in a machine shop and and could get one for you jsf135, Just PM me if you want one since you only in CT and I'm in MA it will get to you fast.

Dauntae

When I have trouble finding muffler screws I retap with 4x40 or the next practical size. I use RTL Fasteners allen head screws and have no problems after that. As to the long muffler screws I remove the nuts and put a good lock washer and some loctite on them. Haven't lost one yet. I also drill very small holes in the flange that attaches to the engine and wrap a wire through them and back around the cylinder. Never lost a muffler or part of one yet.