Trim screws.

[Ragwing nut]

There is a hole in the barrel to light oil during inspections.

[PA1195]

Hi Tim I'm aware of sintered bushings being pre-lubed with oil, but for this application would it benefit by having the threads coated with some lasting lube or anti-seize compound? Oil isn't forever and the assembly isn't sealed...the oil hole and end trim pulley are open to ingress. I can see adding an O-ring to the pulley-shaft area to close that gap.

Motorcycles have gone to anti-seize lube in some applications versus oil or plain lithium grease subject to frequent movement. It lasts longer under the motion which that trim tab is likely exposed to in flight. Just a thought and question.

Gary

[astjp2]

Gary, I use texas 880 or Mobil 28 grease, but if it gets dirty it becomes lapping compound and erodes the threads faster, the heavy oil should be sufficient for 10-20 years on a brass/steel connection that is not directly exposed to the environments.

Mike, I only have seen the hole in the stab tube that the screw rides in, never one in the barrel for lube. Do you have a pic or drawing of one you can send me that has this? I have 4 barrels that are worn out and none have a lube hole. Tim

[PA1195]

I ripped off some pics of the trim assembly from CF-CLR that shows the build.

[Robert Lees]

Trim screws came in, these are a package deal, barrel and screw for 175 + shipping. This is an owner produced part, so no paperwork but i can provide the material spec if someone absolutely needs it. PM me your address and I will ship them out USPS priority mail. As an owner produced part, you as the owner/operator will need to do a dimension check with your mechanic to install. Tim

That sounds a good deal. When I had a small batch (3) made here in the UK in 2012, they cost me $250 for the barrel and screw. I did have the barrels made of stainless, for corrosion protection. I'm sure Hank will throw his arms up in despair!

The bronze is a sensible option rather than brass...it limits galling (as previously mentioned), is stronger. I had my screws made of phosphor-bronze, which has an element of self-lubrication.

Tim, if you end up with a spare set, I'll take them off your hands for my stock, but let those more in need take first dibs.

Rob

[astjp2]

That sounds a good deal. When I had a small batch (3) made here in the UK in 2012, they cost me $250 for the barrel and screw. I did have the barrels made of stainless, for corrosion protection. I'm sure Hank will throw his arms up in despair!

The bronze is a sensible option rather than brass...it limits galling (as previously mentioned), is stronger. I had my screws made of phosphor-bronze, which has an element of self-lubrication.

Tim, if you end up with a spare set, I'll take them off your hands for my stock, but let those more in need take first dibs.

Rob

Rob, do you want to stop by and pick one up? Or is it going in the mail?

[Robert Lees]

Rob, do you want to stop by and pick one up? Or is it going in the mail?

Probably mail, Tim. My beloved 5011M is still up the Kyber without a pass, due to two cracked cylinders. I hope they get fixed by the 24th of this month...I have another trip planned! But not your way this time more south-east USA. I'd like to come your way later in the year.

So for the timebeing, see how your sales go, I don't need a set, but willing to pay you for one if you end up with a spare after everyone else.

Rob

[Hank Jarrett]

Rob,
No arms up in despair here. Stainless may gall but as long as the ones in service have lasted I think they were pretty well over designed. In the US the only problem I would see is that the FAA wouldn't accept a material substitution without paperwork that weighs more than the plane. Not sure they would have a way to find out. I am REALLY interested in the Permatex Copper Anti-Seize. The lubrication folks have learned a WHOLE LOT since the 1940s! I need to get some of that stuff to play with. The standard lube for the trim system was probably AeroShell Fluid 3 (a general purpose mineral lubricating oil) but the trim screw isn't even listed on the lube chart I have.
Looks like the Permitex is available on Amazon at https://www.amazon.com/dp/B000HBM8HU. Under $14 for a can that would probably do every newly exposed trim screw for the next 5 years.

Hank

[M Towsley]

Regarding lube, all I know is whomever used whatever lubricant in mine causes it to be very difficult to turn in cold weather. Be aware of that.

[Hank Jarrett]

I want to get some of the Permatex Copper Anti-Seize Lubricant ( https://www.permatex.com/products/lu...ize-lubricant/ ) and see how it works with the 485 Naval Brass. It is supposed to be designed specifically for use with copper alloys and is a much more modern lube than the general purpose oil called out for most of the Taylorcraft running parts. A LOT has changed in the lubrication world since our planes were built!

Hank

[Ragwing nut]

Gary, I use texas 880 or Mobil 28 grease, but if it gets dirty it becomes lapping compound and erodes the threads faster, the heavy oil should be sufficient for 10-20 years on a brass/steel connection that is not directly exposed to the environments.

Mike, I only have seen the hole in the stab tube that the screw rides in, never one in the barrel for lube. Do you have a pic or drawing of one you can send me that has this? I have 4 barrels that are worn out and none have a lube hole. Tim

I will have to look and see if I can find one.

EDIT: I found the print for the screw. I have not found the print for the barrel yet

[Hank Jarrett]

As far as i have found there ARE no drawings of the barrel out there. I am hoping a drawing can be done from the machining of the latest replacement trim system parts. One thing we have seen is there looks like there have been several sets of replacement trim screw sets made in the past. The one from my plane is NOT the same as many others. If you plan to replace your trim parts replace the barrel and the screw! The threads may not match if you don't. The thread shape on one of mine is different from what most guys have. It is a squared off free running thread. It works fine but I doubt it would thread together with my other planes parts. My square profile thread one does have a lube hole in the barrel as I remember, but it was only for putting a drop of light oil in on annual. Haven't been able to check teh other barrel. I doubt the hole would work for the Permatex lube.

[PA1195]

My intent in asking about trim screw lube was not to drift from Tim's availability and sale of parts. I hope it's still the main topic.

But wear happens and unless the parts are accessible for inspection it may be years between recover before they are serviced. In addition to normal use of the trim some minor wear can occur every time the elevator is moved up or down. The rear trim pulley and cable remain stationary while the screw turns slightly inside the deflected elevator. Have a look sometime with the metal covers removed. Mine are lexan so I can observe at will.

The point above about concerns in cold weather and increased resistance to trim is valid. We deal with it daily in Alaska. It can be due to material interference from shrinkage (parts get tighter), or if lube is involved from increased viscosity and resistance to turning. One other issue friends have with large trim tabs and perhaps a worn rear trim pulley V-groove or lube on the trim cable and pulley is slippage of the cable. Once it slips resetting of the trim reference is required.

I think a very thin coating of proper lube like anti-seize or grease with imbedded anti-friction agents should delay wear on the threads and reduce turning friction. As far as the shaft and oil hole any anti-friction lube can be thinned with solvent and applied. The solvent will evaporate leaving the base product.

Gary

[Hank Jarrett]

Great points Gary. I hope to talk to the engineering guys at Permatex next week (if I can get through to them. Sometimes it is hard to get past the sales and marketing guys). If the Permetex product looks good they should be able to tell us which solvent would be best. Might even be able to tell us how much to thin it and how large a hole is needed to insure good distribution. I have a feeling the lube hole IS NOT original and most of our trim systems lasted half a century with just a splash of lube. I think we can do better on the next half century. The only impact to Tim' parts "might" be to add a lube hole, but I wouldn't grab the drill just yet.
Hank

[astjp2]

The gentleman who built the parts gave me a drawing, I am posting it in the tech references section.