"Install rubber grommets onto servo"?

With each servo you should have a small plastic bag with additional servo wheels, 4 servo wood screws, brass eyelets, and the rubber grommets (they're the small black rubber things). They go on the 4 corners of the servo (along with the brass eyelets) to provide a small amount of vibration dampening for the servo.

What your grommets look like exactly varies as the manufacturers change them over time. In this picture you'll see 3 examples of what your grommets might look like.

To add a bit, the brass eyelet should be installed with the flanged end down.

Since the grommet bears directly on the wooden servo rail, the flange is not needed on the bottom. Install the brass eyelet with the flange up, to provide a hard bearing surface for the servo screw. This will keep the servo screw from digging into the grommet. Do not fully compress the grommet when tightening the screw, or you will have very little vibration isolation for your servo.

Welcome to R/C. Feel free to ask questions, and keep us posted.

Dr.1 Driver "There's a Hun in the sun!"

screw from digging into the grommet. Do not fully compress the grommet when

I have to disagree here. If the flange is installed up then that allows the servo screw to compress the grommet to much, because of the nonexistence of a surface "area" of that side of the eyelet it just digs right into the wood. The flange at the bottom allows the screw to be tightened "just right" for all intents and purposes. I know what your saying DR1 however you and I both know to many newbies overtighten their servo screws and loose most or all of the vibration protection the grommets provide. rick markel

My Model Aircraft Home Page

Wrong answer, DR. The brass eyelets go in from the bottom, with the flanges down.

CR

Dr1Driver wrote:

On 4/24/2004 2:10 AM Ted shuffled out of his cave and grunted these great (and sometimes not so great) words of knowledge:

As you have seen, you will receive a lot of very good information here. You will also see SOME conflicts and differences of opinion. For the most part, I would say that 95%++ of the information is good. After awhile you will also be able to figure out who is providing the best knowledge/expertise and in which area or areas.

Welcome to the hobby.

Take offs are optional. Landings are mandatory.

Eyelet actually goes in from the bottom. At least that is what all the instruction books that came with my radio gear advise. Gord Schindler MAAC6694

Each S3004 servo should have two holes in each mounting tab, four in all. The grommets (little black rubber donut shaped things) go in there to absorb vibration. The brass eyelet goes in the grommet flange down to keep the screw from squishing the grommet too much.

Welcome to the hobby, and remember, when in doubt, ask!

Morris

Agree

Sorry Dr1-man, but you got it bass-ackwards. Flange on the brass bushing goes DOWN against the SOFT wood servo rail.

I think you're out voted on this one.

Not.

The flange is there to prevent the eyelet digging into the servo mount (usually wood), effectively shortening the eyelet and allowing the screw to over-compress the grommet.

Since manufacturer-supplied servo mount screws have a wide head (integral 'washer', as it were), that is sufficient for the straight (upper end) of the eyelet to seat against, the screw cannot shove the flanged end of the eyelet into the wood and it cannot over-compress the grommet.

The screws should be run in until the screw head bottoms out on the un-flanged end of the eyelet - the length of the eyelet sets the amount of compression for the grommet.

Cheers, Fred McClellan The House Of Balsa Dust home.mindspring.com/~the-plumber AMA L180201 IMAA LM 090 NASA 6512 LHA 2 WB 233

Think about it, Morris. The grommet bears its full surface area against the wooden servo rail. It won't squish too much on that side. The screw, however, is only a small circle of steel against the much larger rectangular grommet. With the eyelet in flange-up, there is a larger bearing area for the screw to seat against, and less squishing will occur. I've tried it both ways, and will always install my eyelets in flange up. Dr.1 Driver "There's a Hun in the sun!"

Not on my servos. If you use the proper eyelets that go with the grommets (there ARE differences from manufacturer to manfacturer), then it will be slightly shorter than the grommet is thick, allowing proper grommet compression before the eyelet seats against the wood. Dr.1 Driver "There's a Hun in the sun!"

No voting required. I do it my way, you do it yours. The newbiew will do it his way. He may decide one way of another is best for him. Dr.1 Driver "There's a Hun in the sun!"

Well....if you read the instructions with the radio it will tell you flange down!! Look at the pic for crying out loud. I vote with the majority on this one. I always put mine in flange down. That way I can tighten the screw until it gets snug without pinching the grommet to much. Hey I need all the help I can get. Eddie Fulmer

On Sat, 24 Apr 2004, Dr1Driver wrote

I think you are wrong DR1 but respect your view to do it your way. The intention is that the bush fits from the bottom so that when you tighten the screw until the screw flange meets the unflanged end of the bush, the correct compression is applied to the grommet to give the dampening that the manufacturer has determined is appropriate. With the bush flange against the bearer it is not practical to over tighten. If fitting the bush from the top, over tightening of the screw will push the plain end of the bush into the bearer and over compress the grommet.

Sideways?

When you have nothing else to do, you might try installing an eyelet your way, without the servo or grommet. See what happens to the eyelet.

If you're drilling the pilot holes with the correct bit (# 56 for standard #2 servo mount screws) I think you'll find that you can run the screw in to your heart's content, merrily shoving the sharp end of the eyelet into the wood.

Try it the right way 'round and you will most likely strip the screw head slots.

Only one of the two orientations can be correct, and the guys who make servos say your way is wrong. It doesn't really matter if you've had no failures, but it's the same thing as installing flat washers wrong way down.

You might also consider the servo mounting screws from Micro Fasteners. Hex drive, not Phillips.