Motor mount screws ??

I agree, HOWEVER, I would use those screws if they were cap or even phillips head. The ones I come across and have used once are slotted. mk

I dunno. I have had nothing but bad luck with philips head screws, at least the crap ones that come in ARFs. "MK"

Yep, they work great that way. Especially if you follow the instructions and use the correct drill to make the hole.

Bruce B.

gyrocptr wrote:

It seems there's a japan industrial head and a driver that fits it too. I think Bill Fulmer mentioned it. No, I've had bad luck too. If they can't put in good screws then don't put any. I usually put in 4-40 and tap the mount, when that goes bad then nuts on the bottom of the mount. mk

If you're referring to the "sheet metal" screws included with the glass-filled nylon motor mounts, I believe those screws are usually for attaching the engine to the beams of the motor mount. Once the proper size pilot holes are positioned and drilled into the mount, the sheet metal screws will "self thread" into the nylon material of the motor mount.

So why in

package?

Maybe if they would put smart wood screws in the package, they would work better.

However, they include SHEET METAL screws instead. A common wood screw has a tapered diameter shank, while a sheet metal screw has a constant diameter shank. What does this mean? A wood screw will tend to, in time, back out from vibration. A sheet metal screw will not. The material the screws are driven into is a glass-filled resin. If the proper diameter pilot hole is drilled, a sheet metal screw will not loosen.

The correct pilot hole diameters are as follows:

For a #2 screw, use a 1/16" bit. For a #4 screw, use a 3/32" bit. For a #6 screw, use a 7/64" bit.

I use a tiny dab of white lithium grease the first time I drive the screw in.

Never seen one come out, never seen one fail. Caution: If you use cheap Wal-Mart screws (not heat-treated), overtightening can actually wring the head of the screw off before the threads will strip.

Dr1Driver

Agreed. I would rather they charge an extra $.50 and put in blind nuts and socket head screws.

The problem with the screws they put in the package is that they are such soft metal and the threads are so bad that they usually snap the head off about the time you get them tight.

Yeah, I had heard of that "industrial head" screw but using a different term that I cant recall right now. Would explain why NONE of my philips screw drivers both the crappo and Craftsman tend to fit poorly and strip the sucker out JUST before its tight enough to do me any good. Socket head screws are the bomb.

Been there, done that, turned the air blue with expletive deleteds.

AKA - Cross-point, AIUI

Good point! (no pun intended) A cross-point head screw is a different animal than a Phillips head. The drivers are BARELY interchangeable, at best. Also, "Phillips" screws supplied in ARFs may not be our American standard #2, #4, etc. Phillips point. They may be some off-size metric thing. It's like the clevises supplied with a lot of "Pacific Ring" ARFs. The clevises are 2mm, not 2-56 like we're used to. 2mm is slightly smaller than 2-56, and a 2-56 clevis will strip off a 2mm rod under load.

However, the screws supplied with Dave Brown and GP engine mounts are good old American types. I've never had any problems using the slot head on these supplied screws. If you want a Phillips or socket head, GP makes the first and Dubro makes the second. In fact, GP may make both.

It`s not so much the screws as the tools used. Many "Phillips" screws included with imported stuff are not tooled "American industry standard" but "Japanese industry standard". I bought a set of JIS screwdrivers from a buddy years ago and never had a problem with a phillips head screw since. rick markel

My Model Aircraft Home Page

screws included

I believe that's what I said, "some off-size metric thing". And the post I answered referred specifically to "cross point" screws. There IS a difference in them and "Phillips head".

Dr1

Although a bit off topic, I have to comment that this seems part of a bigger problem - crappy screws. I bought some 3/8 coachbolts to fasten shelf brackets to wall studs - got them in a fair way then the heads snapped off - and I was only using a 6 inch ringy to tight em. The big problem is that i bought them from a steel supplier, not one of those bargain stores where you expect to get cheapshit stuff

David - who is wondering where all the makers of good screws have gone

Wrong again, as usual, Paul. The screws included with both GP and Dave Brown engine mounts are good quality, and are probably heat treated. I've never wrung the head off using the PROPER pilot drill and a little lubricant, as recommended in the installation instructions. Gotta read those, you know.

Many years ago, I got some (then new product) SHSM screws from Dubro. When I tried to turn them into a Dave Brown Mount, they sheared off at the head. When I sent the mount (with the screws still embedded) to Dubro and complained, they told me a batch of their screws had gotten out of the factory without being heat treated. They replaced the mount, and sent me about $50 worth of merchandise, too. Quality company there!!!

Bottom line: the included screws are good, IF you know what you're doing and follow the instructions.

Wrong again as usual?

Well, YOU knew what you were doing and sheared them off.

Try actually READING my post this time, Paul. To repeat myself: I sheared off screws that (unknown to me) had NOT been heat treated. If they had been properly finished, they would not have sheared. The ones supplied with the DB and GP mounts are properly finished and will not shear off.

Dr1