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Who has 36D ball bearings?


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#1 Rotorranch

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Posted 14 April 2019 - 04:39 PM

Where are 36D ball bearings available from?

 

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#2 Bill from NH

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Posted 14 April 2019 - 05:06 PM

Jeff, check with John Havlicek. He has used them in the past, but I don't know where he sourced them.


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#3 gas

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Posted 14 April 2019 - 06:51 PM

Professor Motor has can end ball bearings.


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#4 havlicek

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Posted 15 April 2019 - 05:27 AM

In all the years I've looked, I've never found a ball bearing that actually fits the Mabuchi 36D bastard size shaft.  They are all more like 3/32" and the bore is oversized by enough to make for a sloppy fit.  I actually pressed a few 36D armatures using 3/32" drill blank axles to get past the problem, which makes boring the pinion necessary.  These sloppy bearings make for very quick bearing failure.

 

 

Professor Motor has can end ball bearings.

 

Those bearings (*even when packaged and say they're for the FT36D) are 3/32".  Professor motor also has/had FT36D can with the bearings installed, same thing, and they blow pretty quick.  Not only is the bore oversized, but they are fragile as well.  You can try using one if it's for a "shelf-queen", but for a motor that will be run hard, the best solution I've found is to use a fixed oilite by removing the caged bushing and adapting the can bearing pocket.

Even finding a properly-sized oilite is no small thing for the same reason as why the bearings don't work.  Other than turning and boring your own out of (expensive!) oilite stock, you can salvage correctly-sized oilites from the modern Mabuchi full-round "360" motors, and you can get two out of each motor.  These also have to be turned down on the O.D., but have a nice snug fit to the 36D shaft since Mabuchi has kept using that same odd-sized shaft.

There are details scattered-around in the various "Arm Winding" and "H Power" threads/forums...where exactly?  Beats me, but there's a lot of info in there!


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John Havlicek

#5 havlicek

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Posted 16 April 2019 - 06:15 AM

I should add that *I think* there was one motor, a version of the "Pit-can" that I seemed to remember had a properly-fitting and sturdy bearing for the 36D shaft size.  It's all a bit fuzzy, but even that (*from what little I remember) wasn't a straightforward solution since it had no flange.  In any case, even if that bearing was a good fit (a big "if"), those motors are pretty danged scarce.

Anyway, I'm not sure if the original poster saw this, but anyone looking-in who is also interested in bearings for the 36D shaft can double-check for other sources.  I'm pretty sure I've hit most all of them over the years, short of having 100,000 custom bearings run-off by a manufacturer.  :D


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John Havlicek

#6 Bill from NH

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Posted 16 April 2019 - 07:16 AM

I wonder what Champion used on their BB 707's? I had one in the late '60's that I put two(2) 12-hr. endurance races on in addition to 2 yrs. of weekly racing without any bearing problems. Unfortunately, I don't still have that motor, nor are the Champion people still around.


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