New Trim Pulley

[Mark Julicher]

I finally made a new Trim Crank Pulley and have attempted to upload photos of the process here.

[Mark Julicher]

Re: New Trim Pulley

More trim pulley thumbnails

[mhorowit]

Re: New Trim Pulley

You got the groove by chucking the material in a lathe and locating a bit with the correct angle? - Mike

[mulwyk]

Re: New Trim Pulley

My, my...ain't she a purdy little pulley!

Well done, Mark!

Why not run off a couple dozen of those little beauties? I'm sure there's plenty of folks here that would be happy to send some cash your way in exchange for a new trim pulley!

Bob Gustafson

[Mark Julicher]

Re: New Trim Pulley

Mike, I got the groove by having my son chuck it in his lathe and putting a cutting tool on it. This one was his first try. It is a little thicker than OEM, but that means I wont get the edge chipping as easily as before.

Bob, I've sort of thought about the idea of making some blanks with just the pulley groove and a small center hole just like you see in my photos. That way it is more of an owner produced part. The rest of the work is easy and does not need any special tools. I could probably do a set of 1 front and 1 rear pulley and sell as a set for about $25 depending on how much interest there is. Besides, my son is looking for an excuse to put CNC gear on his home machine shop tools.

[M Towsley]

Re: New Trim Pulley

Mark,

Though I am not ready to address the pulleys just yet, I would purchase a set. Nice job!

[mulwyk]

Re: New Trim Pulley

Mark:
Yes, count me in too. When you're ready maybe you could post here with final price and contact information. Thank you, Mark!

Bob Gustafson

[Doc]

Re: New Trim Pulley

Mark: Thanks for dropping by the Bulverde, TX hangar this weekend to tell me about the pulley - your pictures look great. Just a note to the membership that I have an OEM replacement pulley on the shelf from the Brownsville factory - Contact is Will Fierro at 800-217-1399. He is very easy to work with. Doc

[jdoran]

Re: New Trim Pulley

Mark,

I tried a standard pulley myself once, but it wouldn't grip the cable right. I came to the conclusion that the real pulley has a sharp v-groove that wedges the cable in the bottom of the groove to prevent slippage.

Ami I right, and how did you deal with that on your pulley??

John

[Mark Julicher]

Re: New Trim Pulley

John,
Your conclusions are mostly correct.
An OEM trim pulley gets very narrow but slightly rounded at the bottom of the groove. I had a chance to looks at Doc's new OEM pulley and see that. The pulley I made is a sharp V botom which works well, but is not the same as the OEM shape. BTW, I don't claim to be the originator of any of this good info. This forum has had many a discussion about trim pulleys and I can't tell you how invaluable the tribal knowledge found here has been in keeping my plane going.
When my #1 son bought some machine tools I asked him to try turning some phenolic block and that led to the pulley as a test project. My only concern was how to get the shaft splines to bite into the phenolic without destroying the pulley. As it turns out, the splines are small enough that they go into the shaft with gentle persuasion and still grip very well. Once again I find the genious of the Taylorcraft is the simple but effective approach to its design.

[jdoran]

Re: New Trim Pulley

Your discussion about the pulley reminded me of a tip I discovered.

If your trim adjust screw ever gets frozen, remove pulley to expose the threaded shaft with the dowel pin.

Take an old aircraft spark plug and cut a slot at the top (where the plug wire attaches) big enough for the dowel pin to fit in. I used a pneumatic cut off tool for making this slot. Simply slide the spark plug body (hollow part) over the frozen shaft, line up the dowel pin into the slot you cut, and put a wrench on the 7/8" hex at the base of the plug to turn the shaft to break it loose. This trick will remove the temptation of trying channellocks or something on the pulley itself. I kept the old spark plug for future use, but I found a generous portion of 90w oil on the screw keeps it freed up for a long time.

John