Inside diameter for pulleys

[flyguy]

I am thinking that I need to replace at least some of my pulleys. Before I pull anything off and ground my plane I need to know the stock inside diameter of the pulleys so I can shop for parts.
Any links or threads or info appreciated.

DC

[Scott]

Re: Inside diameter for pulleys

The original pulleys have only a bronze bushing running in the phenolic pulley. As far as I know you cannot buy them unless you find used. You can however buy upgrades (see below).

You will need to remove the pulley(s) in order to measure the ID to give you an OD to machine new bushings. If the ID of the pulley is not true, you'll need to clean it up first (lathe or ream) to get your dimension. All of this work will give you an adequate solution, however it is not a documented repair method if you're concerned about regulated requirements.

Alternatively you can contact the Luscombe Association dude (can't remember his name) and buy replacement PMA pulleys with sealed bearings. They're about $35 each but well worth it in my view. Search this site for pulleys and and you'll find more info and the name and number. I'll check my contacts and see if I can find it too.

[Scott]

Re: Inside diameter for pulleys

Doug
Classic Aero LLC Phone # 480 650 0883

[TimHicks]

Re: Inside diameter for pulleys

http://vb.taylorcraft.org/showthread.php?6975-An228-amp-AN229&highlight=pulley+diameter

[Robert Lees]

Re: Inside diameter for pulleys

Everyone seems to replace their pulleys with the ball-bearing ones (and nothing wrong with that), but if like mine your grooves are satisfactory, try this: I had great success re-bushing mine.

The bronze bushes ride on the bolt, not the bushes on the phenolic.

20 minutes had all the pulleys reamed out, and a further 1.5 hours saw new phosphor-bronze bushes made from bar stock (the bushes are a smidgeon wider than the pulley, so that it wears rather than the steel welded-in bracket).

10 minutes to press them all in to the reamed pulleys and all was hunky-dory. Smooth as silk and as intended, and all for a couple of hours work.

[astjp2]

Re: Inside diameter for pulleys

Once you go with ball bearings you will wonder why you didn't sooner. Some of the best money I spent on my recover. Tim

[M Towsley]

Re: Inside diameter for pulleys

I agree with Tim, above. The ball bearing pulleys are amazingly smooth. Well worth the money and not that difficult to do.

Here is a discussion on the ball bearing pulleys: http://vb.taylorcraft.org/showthread...t=classic+aero

[flyguy]

Re: Inside diameter for pulleys

Been a while, but I have done two things on the pulleys. Before committing to ball bearing pulleys I ordered new bushings. They were, of course, loose in the pulleys when I checked the match so---
I added a coat of solder to the outside of the bushings, filed off any bumps etc. for a press fit on the pulley wheels, and reinstalled the three of them on the right side elevator system.

I did this as kind of a experiment while waiting for the ball bearing pulleys, but it turned out so well that the ball-bearing pulleys (3) are now sitting on the shelf. Maybe someday.

I think I may have eliminated some drag on the elevator control system with this change, plus loosening the trim cable tension a bit more, because on the test flight I was able to do a very low speed, on the deck, stabilized pass down the runway. First time I've been able to do that with this particular 12D. Always wanted to see-saw up and down some before. I think I can pretty well eliminate the possibility that it is my flying skills getting better at this point, Chuckle.

[astjp2]

Re: Inside diameter for pulleys

Just so you know, the bushing is supposed to turn in the pulley, not on the bolt. Tim

[M Towsley]

Re: Inside diameter for pulleys

Put the ball bearing pulleys on, you will wonder why you didn't sooner.

[astjp2]

Re: Inside diameter for pulleys

Actually, I think you made your airplane unairworthy.....I meant to say that the pulley rotates on the bushing, the bolt should not wear from the bushing turning on it. Tim

[Robert Lees]

Re: Inside diameter for pulleys

Actually, I think you made your airplane unairworthy.....I meant to say that the pulley rotates on the bushing, the bolt should not wear from the bushing turning on it. Tim

How do you know that Tim? It doesn't make engineering sense to me.

Rob

[flyguy]

Re: Inside diameter for pulleys

Me either Rob. Can't figure why I would want a softer fiber material rotating on a rough cast outside diameter of a bronze bushing.

[Hank Jarrett]

Re: Inside diameter for pulleys

Yea, I'm not going to say Tim is wrong (based on how the requirements were set originally, but they made lots of materials mistakes in the old days). You normally have a bushing run on metal, not the pulley. We might need a reference on this one since on every "T" pulley I have ever seen the bushing rotated in the pulley AND the bushing rotated on the bolt.

[astjp2]

Re: Inside diameter for pulleys

All of the ones that I took off the bushing runs in the pulley, same with piper on some models. If the bushing was pressed into the fiber, they would not have just come loose. Maybe one of the other mech's on here can pipe in but I have everyone from 3 airplanes where the bushings were separate, BC12, F-19 too. Tim