Im building a Sig Kougar w/.46 TT. The kit include nylon/glass engine mounts. Can you tap nylon/glass mounts? They instruct to tap mounts but aluminum in pics.
Thanks

Absolutely. Use the same techniques for the glass/nylon mounts as you would aluminum. Actually, I like them better. Has a self-locking characteristic.

I drill and tap them always, never have had a problem,.........Paul

Me too. I like them better than aluminum.

Is it necessary to tap the mounts if you drill a hole that makes it a tight fit for the bolt, and you use lock nuts and washers?

I've done it both ways, and have put lock nuts on the tapped one for good measure. Never had had a problem.

If you do tap the mounts, leave the bottom 1-2 mm untapped, force the screw to tap out the mount. Kinda acts like a lock nut.

BTW-I learned that little trick here on rcu...

Just like Wildnloose said. Works great.

Clair

I mark the spot for the hole with the great planes center finder, put them on my drill press (after 25 years of drilling crooked holes by hand) and drill for the correct tap size. After I tap the hole I use over legnth bolts with locknuts.

I have never had one come loose.

I also use a cutting lubricant (tap oil) for a cleaner cut, plus it eliminates teh chance of breaking a tap off .

I have always preferred bolts and lock nuts, but recently had to tap a mount because the bottom could not be reached to add nuts.

Now, I've done this before, numerous times, and never had a problem. But this time after one flight, I started my engine for a second flight and saw a washer under the head of a mounting bolt "rattling".

I grabbed my hex wrench only to find the threads stripped. I checked and found another one of the holes with stripped threads.

I'm not sure if the mount's material was defective or what, but I'd never had one strip out before, let alone two. (I pulled the mount and set blind nuts into the bottom of the new one. )
Dennis-

Hey Guys,
Appreciate all the input. Big Help! This is one great site!