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Another "Big 'Buchi" with an attitude (and a mystery solved)


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#1 havlicek

havlicek

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Posted 09 October 2016 - 11:03 AM

Recently I did up a skewed-lam FT36D and found a can in my "pile-o-stuff" with an awfully nice bearing.  All the other bearings for the FT36D's bizarre shaft size that I've seen are pretty much junk...including the "hop up stuff" sold back in the day, so I was surprised to find that one.  Well, I came across a "Pitcan" motor and surprise!...it had what looked like that same bearing.  Since the motor itself is a solid-looking-but-pitiful thing, I tossed everything except for the bearing :)  On the other one, whoever installed the bearing did it with the flange on the outside.  I think it makes more sense to have the flange on the inside, so I had at it.

I removed the rotating bushing from a pretty well beat-up K&B Royal Bobcat and opened up the brass bushing carrier until the flange of the new bearing would fit inside.  That didn't leave all that much, so after much fiddling, I soldered-in both the bushing carrier and bearing in one fell swoop (swell foop?).  This motor also had cracks on both sides of the end bell bushing, so I cut that mess out and made up a bushing strap and installed another bushing I found that fit the large shaft.  Between the can bearing and the solid end bell bushing, you wind up with a setup that is so much more solid and smooth than stock, it's like it's not even the same motor.

IMG_1752_zps5hfeoh0u.jpg

 

To pay homage to the old girl, I repainted the can K&B yellow, which every slotter from the 1960's knows is the fastest color :)

To go with all that goodness, I built and wound a new arm using the old 38/27 fave.  In the smaller .510 type arms, this wind usually comes in at a bit under .150 ohms, here it's just under .2 ohm, and that's serious biz fo sho!  The arm got a new com and was "welded", tied, epoxied and just needs to go out for balancing because this is too much arm to do a static balance...besides, after all this work, it deserves it!  

...a peek inside:
IMG_1753_zpsehynf7zz.jpg

 

Some outside glamor shots (minus the attractive model draped over the fender):
IMG_1754_zpstw7j2vcj.jpg

 

IMG_1756_zpskkmm7v09.jpg

 

IMG_1757_zpsmc7a7otv.jpg

 

I just have to jig-up the brush tubes and solder them to the hoods, and I'll post that pic later, but I learned something here.  If the two holes that attach the bushing strap to the end bell are just a little off, what's left of the end bell will either flex inward or outward to accomodate them without you even noticing so...it pays to be careful when making the strap!  This one works so well that nothing moves putting it on and taking it off...whew!

I was going to solder a short brass tube to the top of the bushing strap to allow the motor to be easily mounted by both ends in a scratchbuilt chassis (*a simple piece of piano wire bent to fit would do it), but then figured that would only get in the way of mounting the motor in other chassis.  The strap goes on and off so easily, any builder could take care of that themself!

 

-john

 


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John Havlicek




#2 havlicek

havlicek

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Posted 09 October 2016 - 04:11 PM

and...bam!
IMG_1759%20copy_zpsgu3yjymp.jpg

 

...well, almost.  I still have to cut up and fab a set of magnet shims.  Hmmm...in the spirit of the time, maybe I'll just stick some masking tape on the back of the magnets! Nah :D

 

-john


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John Havlicek





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