TR2/3/3A TR3 throttle linkage bell crank.

[mctriumph]

Thin wall bushing are called "empty cartridges " Find the caliber you need, and a gun range.
A 12mm shaft magically becomes 1/2 inch when a 45 caliber casing is pressed on to it.
Mad dog

 

[DavidApp]

What caliber for a 1/4" shaft?
Not sure how good the cartridge case would be as a bearing.

When I worked in the UK we would use DU bushes which are a thin steel shell lined with Teflon. Made great bearings.

 

[mctriumph]

25 caliber is a rare cartridge but not that hard to find. Casings are commonly .011 or .012
added to a shaft increases are .022 or .024 total.
Mad dog

 

[Frank Canale]

I had put this project off till I got an old Atlas lathe from the shop I worked in during high school. Yes some 40 years later I had the lathe that I had played with many years ago. The lathe has had many years of abuse but I felt it would suit my needs. I decided after some precise measurements it would be better to machine a new pin to match the original after I removed it. Heating the joint to melt the silver solder and a gentle twist the pin was out and could be reproduced, yes on my old lathe. The new pin was silver soldered back in the mounting plate including a detail that would only matter to me. The cotter pin hole is orientated the same as the original. I doubt any two were ever done the same but a fun detail to take note of. Now the pin is back to original size, the next task is to put a bronze bushing in the bell crank. I located a 5/16 OD 1/4 ID bushing at a local industrial supply store. The original pin size measured above the cotter pin where there is no wear was a few thousands under 1/4. Knowing this I could know how much to machine the bell crank undersize so when I pressed the bushing in it would shrink the ID so I was able to achieve an exact .001 clearance Pin to bushing and now have a buttery smooth bell crank. I added shim washers above and below so there is minor room for the bell crank to move up and down on the shaft. This was a fun project to test the old lathe out. I know this is way over kill but it keeps me interested in my project as I still have a long way to go. Frank

 

[DavidApp]

Nice repair. I punched out some brass washers to take up any slack and give a good wear surface for the bell crank.
I had considered a bronze bush and may do that in the next batch I make. Did you use Bronze or Oilite?

David

 

[Frank Canale]

Hi David,Your new bell cranks look great. I actually used an oilite bushing. I don’t believe there will be enough heat in the bell crank to hurt the oilite bushing. One thing I will start looking for is replacement pins that the linkage snap over. Mine have wear spots in them and need replacing. Frank

 

[CJD]

It's sooo nice having a lathe, isn't it?!

 

[Frank Canale]

Once you have one, all the things you need to fix have a new path to completion. Some times you get to make an excuse to use the lathe, it does make some things a lot easier to do. Frank

 

[karls59tr]

Hi David,Your new bell cranks look great. I actually used an oilite bushing. I don’t believe there will be enough heat in the bell crank to hurt the oilite bushing. One thing I will start looking for is replacement pins that the linkage snap over. Mine have wear spots in them and need replacing. Frank

What size was that oilite bushing?

 

[Frank Canale]

I have to apologize about some details that I am mistaken about. I went off my memory rather than look back at my notes. I used a 5/16" x 1/2" x 5/8" bronze bushing. The plastic bag that the bushing came in list it as
Bronze bushing "FEB" SS-10-16-10. This is a SAE 841 sintered bronze oil impregnated bushing. I used a 3/8" 4 flute end mill to bore the bell crank, this makes for a very round hole for the bushing. I turned a mandrel to hold the bushing so I could turn the OD of the bushing. The pin that the bushing rotates on has a diameter of .310" , same as the original. The ID of the bushing is roughly .003" to large so I turned the OD of the bushing to .377" so it has a .002" press fit and shrinks the ID of the bushing to leave .001" clearance.The height is roughly 9/16 and this was accomplished by filing the bushing after it was pressed in. I will be truthful that I did not get this fit on the first try. It took 2 tries because I then knew how the bushing would shrink. Sorry to bore you with the math to get the fit I was looking for. I did this exercise just to see if the old lathe could still hold tight tolerances. It can but it is slow, no digital readouts mostly you have to sneak up on the measurement you are shooting for. Frank

 

[Joel M]

I recently refurbished my original bell crank with a quick and cheap repair. Most of the wear was in the bell crank itself so I just drilled the hole to 3/8" and pressed in a 1/4" x 3/8" oil impregnated bronze bearing purchased from Lowe's for $4. They didn't have a 5/16" x 3/8" so I had to drill the bearing to 5/16" after install. I'm not sure if the drilling operation will affect the lubricating properties of the bearing, but hopefully the repair will last long-term. There is almost no slop in the assembly now and it took less than an hour.

 

[Frank Canale]

This is why I shrank the bushing to keep from having to do any sizing to the ID of the bushing. In this case it won't make any difference as the bell crank only moves a small amount. The drilling, machining on a lathe, reaming of the bushing ID will most of the time smear bronze over the lubrication pores and limit the lubrication process. I tend to way overthink the repairs, improvements to my parts as the repairs are so much better than original and will outlast me if I ever get my car finished. Frank