Nuts!

[Rick RV-4]

Allright, another dumb question . . . what kind of hardware is everyone using to secure items onto the studs that are attached to the under side and back of a Lycoming engine?

More specifically, I need to know what type of nuts and washers are used to:

(1) Secure the carburetor to the bottom four studs on the bottom of the sump, and

(2) The nuts/washers used to secure the mags to the studs on the back of the accessory case.

(3) Secure the starter to the three studs on the fron bottom . . .

I believe all of these studs are 5/16"-18 (coarse thread?), but I couldn't find any nuts that match this description at the normal parts stores (Aircraft Spruce, Wicks, etc).

Losing hair by the minute . . .

[az_gila]

Lycoming calls then STD-1410 "NUT, 5/16 - 18 plain".

I think they are thicker than standard.... and are also Lycoming exhaust mounting nuts.

Aircraft Spruce hid them on this page.... $1.64 each...

http://www.aircraftspruce.com/pdf/20...l/Cat07301.pdf

The lock washers are STD-475 ... a web search of Aircraft Spruce finds them at 4 cents each...

The flat washers can be found the same way "STD-35" at an exorbitant $1.36 each...

gil in Tucson

[GAHco]

The STD 1410 is the called out item in the parts manual.

A lot of engine builders purchase the MS51967-5, I suspect for similar purposes.

http://www.gen-aircraft-hardware.com...124~124&id=126

Select the prefix ms51967
Select the suffix -5

See "Detailed Image"

This might help.

[Flying Scotsman]

Originally Posted by az_gila

Lycoming calls then STD-1410 "NUT, 5/16 - 18 plain".

I think they are thicker than standard.... and are also Lycoming exhaust mounting nuts.

Aircraft Spruce hid them on this page.... $1.64 each...

http://www.aircraftspruce.com/pdf/20...l/Cat07301.pdf

The lock washers are STD-475 ... a web search of Aircraft Spruce finds them at 4 cents each...

The flat washers can be found the same way "STD-35" at an exorbitant $1.36 each...

gil in Tucson

OK, somebody tell me...is there some magic difference between STD35 washers and regular AN washers? $1.36 each seems, um, a tad high...

Similarly for the other parts...what's special about the nuts? and the lock washers?

[Flying Scotsman]

Originally Posted by Flying Scotsman

OK, somebody tell me...is there some magic difference between STD35 washers and regular AN washers? $1.36 each seems, um, a tad high...

Similarly for the other parts...what's special about the nuts? and the lock washers?

No help?

If there's *really* a difference, I'll pony up the cash...but I'm a little loathe to pay a buck and a half for an AN960 washer, etc.

[N999BT]

The washer for the mag clamp is called out in the O-360-A parts manual as a STD-1727, Washer, Plain, 3/4" OD x 21/64 ID x 1/8 thick. It is NOT standard (except from Lycoming). You might want to call Lycon or somebody like that to order a package of nuts and washers. Compared to the price of other stuff you have to buy getting the right hardware is not that bad.

[Flying Scotsman]

Originally Posted by N999BT

The washer for the mag clamp is called out in the O-360-A parts manual as a STD-1727, Washer, Plain, 3/4" OD x 21/64 ID x 1/8 thick. It is NOT standard (except from Lycoming). You might want to call Lycon or somebody like that to order a package of nuts and washers. Compared to the price of other stuff you have to buy getting the right hardware is not that bad.

I'm not there yet, but I'll check on that one...

As far as I can tell, the nuts for the exhaust flange, for example, are simply Grade B nuts of the appropriate thread. The washers sure look like AN washers. If that is true, then they are grotesquely overpriced. I'm really not anxious to get ripped off, even for a modest amount. At a total of $3 for each nut/washer/lockwasher combination, that's $24 for the complete exhaust set, vs maybe a third of that at most.

[WenEng]

Gotta keep money in the till to pay claimswhen you sue for that defective washer.....

[osxuser]

I've seen certified lycs use all kinds of stuff. Even just off the shelf grade 5 stuff. (Grade 8 is tooooo brittle).

Use that little bit of info at your own risk. I go for the book hardware myself.