siclick33

I recently bought a pair of Tamjets servo mounts and the fittings on one appears to be no 2 screws and the other is 4/40 bolts.

Has anyone used these mounts? Is one version stronger than the other?

Would you be happy to mount primary control servos to them (JR 8321s on Grumania SU27 Tailerons)?

KC36330

both my Tam A-4s used them on every flight surface, as long as you securely glue them down they work great.

Gordon Mc

My Feedback: (11)

I've used a lot of the Tamjets servo mounts.

My personal opinion is that in the mounts I had, the hole for the #2s is perhaps just a bit too big for that screw to get a really good bite. Given the manufacturing tolerances, some actually seemed OK and some just seemed to thread a little too easy for my liking. they would probably have been OK, but it just made me a tad uneasy.

Since I'm anal about that kinda stuff, I threw the #2 screws away, and used button-head 4-40 cap screws in all of them. It was a trivial change to make since the cap screws just self-thread into the plastic anyway.

Gordon

Harley Condra

My Feedback: (4)

I have been using them since they were first introduced by their designer, Rob Janiger of Sherman Oaks Ca.
He sold them under the "RJRC" brand name, but are now sold by Tam.

They are well engineered, and are a quality product.

ianober

My Feedback: (12)

Just dont epoxy them down, they WILL fail, use CA!!

KC36330

i use Hysol (which is epoxy) and it works, even tried to rip a few out one time to reuse them on something else and couldn't get them to let loose. you do need to scuff the gluing surface with some 80 grit though.....

ianober

My Feedback: (12)

I did scuff mine up and still lost a plane over it. Went through the wreckage and grabbed one of the other mounts and peeled it right back, the glue stayed on the plane, nothing on the mount. After that I haven't really used them anymore.

Harley Condra

My Feedback: (4)

If a servo mount like these comes loose in flight, it may have had a poor and improperly prepared bond.
It is difficult to bond certain dissimilar materials, so a few things should be kept in mind.

1. Choose the correct adhesive.
2. Thoroughly scuff the faying surfaces to be bonded.
3. Clean the surfaces to be bonded.
4. Avoid skin oil contamination.
5. Avoid using excessive amounts of adhesive. Excess glue is excess weight, and contributes nothing to the strength of the bond.

By drilling a pattern of #10 holes through the faying surface of the servo mount, the adhesive will flow through and act as rivets. The mount faying surface should then be scuffed with 80 grit and cleaned with alcohol or another suitable solvent prior to bonding.

Keep your fingers off the cleaned surface to avoid skin oil contamination.
Apply a film of adhesive to the faying surface of the mount, and install. Allow the adhesive to flow through the holes forming "adhesive rivets".

After the adhesive has cured, alter the "adhesive rivets" height as required to mount the servo to fit correctly.

These few steps are very simple and very easy to accomplish, and will promote an improvement in shear and peel strength of the bond.

Gordon,
Some of the mounts come with #3 screws instead of #2's. I like the the #3's myself.

check6ii

My Feedback: (12)

Ive used them on numerous planes-both turbine and props. I always prepare the bonding surfaces and wipe them with acetone. I swear by them and have never experienced any problems. If Hysol is used correctly, it wil not fail. I swear by them-

ianober

My Feedback: (12)

Mine was prepped and bonded as well, I wiped with alcohol and keyed the surface as I do with all fiberglass bonding. Could have been substandard adhesive, that's all I can figure. I have had success with them using CA, it actually melts the plastic and fuses it with the wood/plastic. But that issues coupled with the screws not fitting kind of turned me off. If the screw issue has been resolved then I might revisit them.

hooker53

My Feedback: (106)

I can get the mounts to stick, my problem is finding servo eyelets that the 4-40 screws will go through.

tamjets

My Feedback: (2)

I bought the tooling and remaining inventories way back. After that made few more commons servo mount we use in our jets.
Simple and quick way install the servos.

tamjets

My Feedback: (2)

Never had one come off and use all different way to glue it.
If you had it peel off. I better check your mechanical way of how you install your servo linkage.
Only high stress from flutter can peel it off.

Eddie P

My Feedback: (4)

Ian I still feel sick about that loss, I remember it well.

Harley, those are really good tips, thanks for listing them out like that, I'm sure it will come in handy for someone building right about now

John Redman

My Feedback: (8)

Yep, some of the best servo mounts ever. Literaly 1200 flights on my original KingKat and they never let go. Were epoxied in place with Pacer 30 minute epoxy. Still in place. Rob gave me those mounts from his first batch. These things rock!!!!!

mark handley

Hi siclick
As your in the UK check out GBR jets servo docks...they are absolutely superb and Marc is great to deal with
Regards
Mark

ianober

My Feedback: (12)

Come on now Tam. CA worked fine, will never use them with epoxy. Have you fixed the screw hole issue? I still have 3-4 of these hanging on my wall after 4 years that I wont use cause the screws dont bite.

tamjets

My Feedback: (2)

LOL....
What screw hole are you talking about.
It either 4-40 or # 2 screw.
Never had one screw come off or peel off.
CA or Epoxy was use.
Once again... only flutter stress can peel if off or rip of the skin. Which one come first it still end up with the crash.
What need to revise when is working fine from begining.

Remember how great products is....if someone don't do it right is still end up flutter and that cause the crash. Not because it peel off.

I hate to said this...
There still alot guys out there don't know how to install servo linkage for maximum mechaincal advantage to reduce slop play in the servo that can lead to flutter.

KC36330

that's been my experience with them as well, i use CA in the center to hold them down while the epoxy/hysol around the outer edges dries. can't even rip them off to reuse them later without destroying the mount.

ianober

My Feedback: (12)

Sigh

tamjets

My Feedback: (2)

I'm not kidding about linkage install.