Adel Question

Mounting holes in Adels are AN3 / #10. Are there any acceptable methods when a convenient mount point or item to be mounted has larger holes (e.g. AN4 like the holes in a Red Cube, or unused bosses on a starter, or a stud on covers for an unused mag or vacuum pump)?

Make a bushing (like we do in many places on a RV), open the Adel hole to AN4, or just not use that mount point?

Correct me if I'm wrong, but I'd guess we don't want an AN3 swimming around in an AN4 sized hole.

Drill Baby, Drill...

I just clamp the Adel together with the holes aligned and drill the holes bigger. You need to clamp them securely in two places or the drill bit will grab. Using a bench vice on one corner and vice grips on the opposite corner seems to work.

The clamps that come with your engine from Lycoming have 1/4" mounting holes - so they are available.

I suspect starting here you will find what you need: http://www.aircraftspruce.com/catalog/eppages/lycomingclamps.php?clickkey=8079

Carl

Adel Question - Thank you

Thank you Carl. No clamps came with my engine. I had no idea there were Lycoming cushion clamps and that they had 1/4" mounting holes.

Looks like they will do the trick, although quite a bit more expensive then drilling out the Adels I already have.

I have drilled a few here and there with no issues. I have one of those cushion clamp install tools with the awl and modified vice grips. I modified the tool so the slot in the vice grips is now a keyhole shape to 1/4". I use the vice grips to hold the clamp closed while drilling, work great. Keeps the hole centered as well.