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The FT36D - problems with modifying


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#1 havlicek

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Posted 01 May 2017 - 06:44 AM

Mabuchi's "big guy" has the same basic issues with upgrading/modifying as their 16D and 26D motors, but some "extra" issues as well.  It has the same poor material for it's end bell, weak magnets, bad can bushing design and end bell design.  It also has the added "non-bonus" of having a weird shaft size.  The shaft is smaller than 3/32", but isn't an even metric size either.  It's difficult to find bushings to fit the shaft, even though there are still "modern" motors from Mabuchi and others that share the weird shaft size.  You can get cheap Mabuchi RS36xx motors and salvage the bushings from those, but they are tough to fit the older FT36D can without resizing them...but at least they fit the shaft properly.  The rotating "caged" bushing arrangement in the Mabuchi motors is OK when new and tight, but doesn't stay that way for long under use.  When the shaft is splined and you remove the arm without being careful, the bushing will come out with the shaft and is impossible to replace, at least in a way where it will function properly.

Then too, finding nice bearings that will fit the shaft well is all-but-impossible.  ***Even the period aftermarket bearings that were sold as being "for the FT36D can", were actually 3/32" bore...a loose/sloppy fit and made for a wobbly armature.  To make matters worse, they were flimsy, and only marginally "better" than the awful bearings Mabuchi used in their 16D and 26D motors.  With a hotter rewound arm, those bearings WILL fail, especially on a can drive motor.  I have never found a commercially-available bearing for the Mabuchi 36D shaft that fits properly AND is solid or "precision"...except for one.  Some years back, I got some Pitcan motors, or at least motors that look identical to the "Pitcan", and (of course!) took them apart, because they didn't run well, and nothing about them was particularly interesting, except for the beefy-looking bearings.  These bearings were not just solid-looking, they were really "industrial" and "precision" in every which way I could figure.  I tortured them some, heated them, spun them doing some "eyeball" checking for run-out and slop, and they seemed easily as good as any modern bearing.  Looking through my "36D" drawer, I came across what I think is my last example of these bearings, and after installing it in a can, the darned thing is still just as strong, smooth and tight as I had remembered it to be.  Here's a couple of shots of the bearing in it's new home:

IMG_2067_zpstfokbvyt.jpgIMG_2068_zpsrhbzl2nw.jpg

 

So, I guess (?) some who are into the old motors and/or curiosities, may not want to ruin an old Pitcan-type motor, but if you have one and aren't too fond of it, there is at least one thing about them worth salvaging before you toss them.  Save those bearings.  They aren't *just* really excellent quality, they may well be the ONLY good bearing that actually fits the 36D shaft well!


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#2 dc-65x

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Posted 01 May 2017 - 10:08 AM

Hi John,  :wave:

 

As you discussed, size really does matter when it comes to high speed motor shafts and bearings. The 36D shaft size is a real pain at about .0001" under .0900" in diameter. Pittman shafts run about .0920" and a "normal" 3/32 inch size would be .09375".

 

Anyhow, I don't have any Pittman 9001 ball bearings to spare.

 

I do have new packaged Pittman oilite bearings for their "open frame" style motors. The bag says "....for .092" shafts".

 

I also have new Kemtron and Simco endbells for 36D's with oilite bearings. These bearings fit the 36D shaft a bit tighter than the Pittman bearings but are still looser than I would like. A .092" Pittman shaft is a nice slip fit into these so a 36D shaft is a bit looser than I'd prefer....but still a better fit than the looser new Pittman bearing.

 

A last resort may be buy a reamer (they are out there) and modify or make your own bearings.......still not ideal compared to a "Korrectly" sized ball bearing though........ :unknw:


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#3 grooverunner

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Posted 01 May 2017 - 10:20 AM

John,

 

You have a lathe now you could do like I do and drill and ream out a 6mm  modern 16D can bushing. Like on post #24 of this topic here.

 

http://slotblog.net/...he-big-mabuchi/

 

I know it more work but if your doing a hot wind it could be your only option that's readily available part that can be modified.

 

Also I might have a fix for the weak magnet issue for hot winds, possibly to.

 

Ken


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#4 Geary Carrier

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Posted 01 May 2017 - 11:16 AM

Hi John,

 

This is the only 2.3mm ID ball bearing I've found, but is only ABEC-1, and not cheap.

 

http://www.vxb.com/2...e-p/kit9407.htm

 

 

Thanks,

g


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#5 havlicek

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Posted 01 May 2017 - 02:18 PM

Hi John,  :wave:

 

As you discussed, size really does matter when it comes to high speed motor shafts and bearings. The 36D shaft size is a real pain at about .0001" under .0900" in diameter. Pittman shafts run about .0920" and a "normal" 3/32 inch size would be .09375".

 

Anyhow, I don't have any Pittman 9001 ball bearings to spare.

 

I do have new packaged Pittman oilite bearings for their "open frame" style motors. The bag says "....for .092" shafts".

 

I also have new Kemtron and Simco endbells for 36D's with oilite bearings. These bearings fit the 36D shaft a bit tighter than the Pittman bearings but are still looser than I would like. A .092" Pittman shaft is a nice slip fit into these so a 36D shaft is a bit looser than I'd prefer....but still a better fit than the looser new Pittman bearing.

 

A last resort may be buy a reamer (they are out there) and modify or make your own bearings.......still not ideal compared to a "Korrectly" sized ball bearing though........ :unknw:

 

Hi Rick  :good: 

10-4 on all.  It figures you've been down this road before (many times!).  The FT36D shaft really is an odd and irritating size ;), and for sure reaming out oilites to fit is a good option here.  I even looked at buying oilite stock a couple of months ago...and got sticker shock!  Anywho, these bearings (when you can get a hold of 'em) are surprisingly good...waaaaay better than even a correctly-sized bushing, and seem as good or better than most run-of-the-mill current bearings!

 

 

John,

 

You have a lathe now you could do like I do and drill and ream out a 6mm  modern 16D can bushing. Like on post #24 of this topic here.

 

http://slotblog.net/...he-big-mabuchi/

 

I know it more work but if your doing a hot wind it could be your only option that's readily available part that can be modified.

 

Also I might have a fix for the weak magnet issue for hot winds, possibly to.

 

Ken

 

Hi Ken.  Yep on reaming out a smaller bushing to fit  :)  Really, my post here was more about both how rare a correctly sized bearing for these is, and also how good these ones are!  ***On the weak magnet issue, other than 36D Arcos (which aren't around much at all any more) I haven't come across any good options for these motors.  All the modern Mabuchis in this general size are now full round can types, and even of those, I haven't found any with magnets strong enough to make me want to go through the torture of modifying them to fit the FT36D flat can.  Whatever other "fix" you have for the weak magnets is something I'd be interested in.  ***I did something once that was so difficult and "stoopid", it was embarrassing, even though it seemed to work!  :laugh2: 

 

 

Hi John,

 

This is the only 2.3mm ID ball bearing I've found, but is only ABEC-1, and not cheap.

 

http://www.vxb.com/2...e-p/kit9407.htm

 

 

Thanks,

g


Yeah, that's kind of a silly price for a bearing that might not even stand up to a slightly warm rewind.  Also, even though the nominal size sounds right, if it's off by even a thousandth or two either way, it would be better to just make-up a bushing!
 


John Havlicek

#6 grooverunner

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Posted 01 May 2017 - 05:17 PM

Hi John,

 

Sorry miss read you post. That's what I get for reading Slotblog on my phone :unknw:

 

As far as the magnets I came across them while looking for magnets for another project.

 

They are neodymium there the same out side radius so they fit the can, there thinner , a little longer,and a little shorter in height. Getting 100% perfect match  would great. But they looked  like they will work.

 

I'll mail you a set or two out tomorrow to try.

 

Ken

 

 

 

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#7 havlicek

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Posted 01 May 2017 - 05:24 PM

I'll give them a try Ken.  I know the real serious 36D drag guys use segmented neos for crazy-strong setups.  Too bad there isn't a "Hong Kong" updated end bell for the 36D as there is for the 16D ("160").  Then again, a drag FT36D is a pretty cool thing.


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#8 SlotStox#53

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Posted 02 May 2017 - 04:03 PM

Ooo, those neos look cool! If I remember correctly John you hollowed out oem 36D mags to fit neos in? :D

#9 havlicek

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Posted 02 May 2017 - 04:44 PM

Ooo, those neos look cool! If I remember correctly John you hollowed out oem 36D mags to fit neos in? :D

 

 

Guilty as charged your honor :D


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#10 boxerdog

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Posted 02 May 2017 - 04:45 PM

Anyone chiming in on the source for those neos?


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#11 havlicek

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Posted 02 May 2017 - 07:41 PM

Anyone chiming in on the source for those neos?

 

 

Hi Dave...here are some:

http://www.magnet4sa...-ndfeb-Magnets/

 

http://www.greatmagt...ets-c21616.html

 

http://www.magnet4le....php?cPath=1_15

 

http://www.first4mag.../neodymium-t137

 

https://www.rare-ear...com/arc-magnets


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#12 grooverunner

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Posted 02 May 2017 - 07:53 PM

Thanks John

 

I got this one....

 

Dave,

Here is the link for the ones I sent John. I had to look it up it's been a few months sense I bought them.

 

http://www.magnet4le...o7jmcjv8llp36f1

 

Ken


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#13 boxerdog

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Posted 03 May 2017 - 09:16 AM

Thanks!

 

John, as I re-read this bearing/ bushing dilemma over and over, it seems like a specially sized reamer and bushings are maybe a pretty good solution.

 

I guess the mechanics of enlarging the lams to take a real .093 shaft are problematic? That would solve the bearing/bushing issue as well as create a lot of gear options which are also an issue with the smaller shaft. Keep in mind you are talking to a guy who has never done such a thing...


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#14 havlicek

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Posted 03 May 2017 - 03:39 PM

Thanks!

 

John, as I re-read this bearing/ bushing dilemma over and over, it seems like a specially sized reamer and bushings are maybe a pretty good solution.

 

I guess the mechanics of enlarging the lams to take a real .093 shaft are problematic? That would solve the bearing/bushing issue as well as create a lot of gear options which are also an issue with the smaller shaft. Keep in mind you are talking to a guy who has never done such a thing...

 

 

Hi Dave,

 

     A long time ago, I was able to press a 36D stack onto a 3/32" drill blank by only pressing a few lams at a time.  Of course, that also mean that any com meant to fit the 36D also now had to be reamed-out.  Then too, using a 3/32" bushing in the end bell means turning one down, because the end bell pocket is so small in diameter.  No 3/32" bearing will fit the end bell either.  In the end, it turned out to be a whole lotta work for not much reward!  :D


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