Lycoming mounting ear nuts

I've misplaced the nuts for my 540 mounting ears, so I guess I'm buying new. They are called out in the IPC as STD-596, and Lycoming is quite proud of them . Cheapest I see is $3.64 online (Spruce wants $4.75), and I need 16 of them (double nutted.)

Can I substitute AN316 3/8-24 for this? Is there anything special about the Lycoming variety? I mean, if one was going to pay $4.00/nut, why not make it count? http://smithprecisionproducts.com/products/titanium-jam-nut-38-24


Thanks.

I "think" your grade 5 AN should be just fine, but you really want to "know".

I think I would be sure by getting several grade 8 bolts from the store, a $4 nut, the AN nuts, and some grade 5 hardware nuts. Oil them all, use a hard, flat washer and torque them to failure for comparison. I believe you will find the AN is just as good as the Lyc nut. But that is me, and I really want to know, with data.

Or just call Barrett for their professional recommendation, or order from them.

I did call Barrett on your suggestion. They said they use AN315-6.

Good to hear - Can't go wrong w/BPE.

Locking means?

AN 316 is thin "shear" nut, not appropriate for this tension application.

I assume titanium is not appropriate.

My real question... what is the locking means?... I would have thought castle nuts.

johnbright said:

AN 316 is thin "shear" nut, not appropriate for this tension application.

I assume titanium is not appropriate.

My real question... what is the locking means?... I would have thought castle nuts.

Click to expand...

My mistake, it's 315 not 316. My reply above referenced the correct AN nut.

Locking means is internal tooth lock washer and torque.