How To: Sleeve Maxon motors for standard 1.5mm worm

[mmagliaro]

We discussed in another thread about sleeving up the small shafts on Faulhaber and Maxon coreless motors so that a standard model train worm with a 1.5mm bore would fit properly.  I had promised to check this out with some sleeving I found online, so here is the info.
That other thread was here:
https://www.therailwire.net/forum/index.php?topic=48274.msg640071#msg640071

THE SLEEVING:
Look on Amazon (or anywhere) for CynKen stainless capillary tube.
Among many other sizes, you will find it in:

OD 1.5mm  ID 1.0mm
OD 1.5mm  ID 0.9mm
OD 1.5mm  ID 0.8mm

Those 3 sizes will cover all your Faulhaber and Maxon motor shaft sleeving needs!   Stainless tubing is MUCH stronger than brass.
So you can press it on a short shaft with some LocTite and it should hold well and support a worm.
Cut off about 1" of the stuff with a Dremel cut-off disk, put it on the motor shaft with some Loctite.... HOLDING THE MOTOR WITH THE SHAFT POINTING DOWN SO THE LOCTITE DOESN'T FIND ITS WAY INTO THE MOTOR BEARING!!!

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I received my pieces of tubing and tested this with the 1.0mm ID tubing on a Maxon 10x17 (which has a 1.0mm shaft).  I am happy report that it works great and is easy to do.  The sleeving fits very snugly, on the motor shaft and can be pushed on by hand (but use a bit of Loctite so it won't slip).  In a typical Kato worm, it fits a little tighter, so you may not be able to press it into the worm by hand.  I pressed mine in using a jeweler's vise.  But the fit is really good.

Some photos:









When I run the motor, the worm looks great (no visible wobble).  I wish I could figure out a way to run a dial indicator against the worm to get an actual measurement of any error, but I don't see how to make that work on gear teeth.

[North Bank Road]

Thanks Max. Great tutorial!

[Jim Starbuck]

Thanks much for the tip on the tubing Max.
I received some a few days ago and used it to couple a 1mm motor shaft to a 1mm worm shaft and it worked great.
It runs true and better than other methods I’ve used.

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[mmagliaro]

Excellent, Jim!
Yes, because this is capillary tube, it is made to very exacting standards and is very strong (being made of stainless).

One other important tip, in case anybody reading this needs it, is that to actually CUT this stuff, you need to use a Dremel with a cutoff disk.  It is stainless, so a razor saw or other such thing is not going to work.  Just buzz off about 1/4" of it, then hold it (with your fingers is fine) against the Dremel disk to clean up any rough edges, or use a diamond jewelers file.   I didn't even have to clean up the interior of the tubing of any metal flash.  It pushed on to the motor shaft just beautifully as-is.  But you could use a #61 bit (for the 1.0mm ID) in a pin vise to clean out the ends of the little tube if you need to.

[u18b]

Thank you Max.

Exactly what I needed to know.

[narrowminded]

Cut off about 1" of the stuff with a Dremel cut-off disk, put it on the motor shaft with some Loctite.... HOLDING THE MOTOR WITH THE SHAFT POINTING DOWN SO THE LOCTITE DOESN'T FIND ITS WAY INTO THE MOTOR BEARING!!!

One thing I have done to apply loctite to sleeves like this is to just start the sleeve onto the shaft and then apply the loctite with a toothpick to the ID of the sleeve only.  Slide it on and let it set up.  That assures that the loctite does not get in to the bearing.  I have never had one slip at a later point using this method as it gets plenty of sleeve secured BUT, even if it did slip later you can always redo it.  Once it's in the bearing, you're done, the motor is scrap.  And it never hurts to have the sleeve facing down while the full cure occurs but the loctite will take a set very quickly, especially if you're using brass for the sleeve.

For cutting the tubing it can be handy to grip the length you're going to use in your pin vise.  They can get hot and can also disappear in your shop floor carpet.  What?! You don't have carpet on your shop floor?  I thought all modelers did.

I have used this exact method to sleeve shafts, especially when rigging parts for prototype testing.  It works well.  I have had just as much success using the brass tubing for sleeveing shafts.  The brass is usually a slip fit but a very good slip, no detectable wobble, so the shaft still runs very true.  The loctite distributing around that shaft to sleeve miniscule void tends to center the part for that small amount.  If it's a visibly sloppy fit, forget it but that's not been my experience with that method if your caliper readings suggest you've got a dimensional match.  Oh, and I've also noticed that simple blue, medium strength loctite is all that's needed.  Red might be stronger but never slipping is... never slipping, and that's all we're after. 

[mmagliaro]

Mark, I think I agree with you on all counts.  And I really like your idea of holding the piece of tubing in a pin vise while cutting so that when you cut through, your short piece is secured and doesn't go flying!

I don't think I've ever had to use red Loctite on a gear or motor shaft connection.  Blue is more than adequate.

[peteski]

Mark, I wonder where you get your brass sleeving?  The one Max recommended a while back (Albion Alloys) was too loose to work properly.  But the stainless steel capillary tubing Max found recently on Amazon, and recommended here, is perfect. It fits snugly (no wobble at all),  but yet can still be easily slipped onto the shaft.

Actually, never mind about your brass tubing - this stainless stuff works the nuts, and it is much stiffer than brass. I'm all set!  Thanks again Max!!

[narrowminded]

Mark, I wonder where you get your brass sleeving?  The one Max recommended a while back (Albion Alloys) was too loose to work properly.  But the stainless steel capillary tubing Max found recently on Amazon, and recommended here, is perfect. It fits snugly (no wobble at all),  but yet can still be easily slipped onto the shaft.

Actually, never mind about your brass tubing - this stainless stuff works the nuts, and it is much stiffer than brass. I'm all set!  Thanks again Max!!

Yes Pete, it's the Albion tubing variety pack.  One comes in even numbered steps and one comes in odd numbered steps, in .1 mm increments with a .1mm wall.  Example: .3mm ID x .5mm OD or .6mm ID x .8mm OD.   Measuring the ID with pin gauges I have seen as little as one half thousandths to a high of one and one half thousandths oversize in that tubing.  Both of those will be adequately centered, if not perfectly centered, by the surface tension of the Loctite evenly distributed in the bore.  It's a natural characteristic of the material, much like oil does in a close fitting bearing.  Clean the burrs from the cut end so they aren't mechanically holding the sleeve offset and go for it.   Absent the proper drill size to clean out the cut end of the bore, rubbing the sleeve up and down the closest fitting steel wire you've got and then, still on the wire, spinning the sleeve between your fingers, holding it at an angle to the wire so it rubs the sharp cut edge in the ID, will probably accomplish this adequately.

This was a suggestion for those who might already have the brass tubing sizes in their toolbox.  With Loctite in the bore the runout will be almost guaranteed to be be no worse than one half thousandth of an inch, more than adequate for this purpose.  That is on the assumption that you're sleeving real numbers, not taking a stab at it as I noted in the reply above.  And if you're working with motor shafts, Maxon but almost any manufacturer, it's reasonable to assume that the shaft dimensions are quite good.   It's offered as a legitimate alternative to folks who may have the brass handy but not the SS tube. 

For what it's worth, I have most often sleeved with the brass tubing because I had it, in just about every size made, and never had a brass sleeve job not accomplish the need perfectly, including when I have double sleeved a shaft where a bigger step was required.  It's an option and if the result isn't perfect due to errant dimensions it can be redone when you get the proper size, SS or otherwise.  This is only intended to add helpful information, not to be argumentative.

[tehachapifan]

So, a hacksaw won't cut through this stuff but a Dremel wheel will? Which wheel (it's been forever since I purchased one of those)? Does this tubing wreck the cutting wheel in short order?

[peteski]

Yes Pete, it's the Albion tubing variety pack.
. . .
For what it's worth, I have most often sleeved with the brass tubing because I had it, in just about every size made, and never had a brass sleeve job not accomplish the need perfectly, including when I have double sleeved a shaft where a bigger step was required.  It's an option and if the result isn't perfect due to errant dimensions it can be redone when you get the proper size, SS or otherwise.  This is only intended to add helpful information, not to be argumentative.

Max started this thread specifically about the SS capillary tubing, and I simply agreed that it to me also seem to be the best choice for motor shaft sleeves. 

I didn't think you were being argumentative Mark.  Yes, both are valid options.  Maybe my reply seemed argumentative?  I hope not.

But after actually trying both, I find the SS capillary tubing far easier to deal with than the Albion Alloys brass tubing.  And I believe it is cheaper too.

[mmagliaro]

You can cut through stainless tubing with any standard Dremel cut-off disk.  It does not ruin the disk.  If you are cutting on stainless or tungsten for a few minutes, then yes, the disks do actually wear down and they get smaller and smaller in diameter as you go.  But to buzz off a little piece of tubing... no problem.

[peteski]

You can cut through stainless tubing with any standard Dremel cut-off disk.  It does not ruin the disk.  If you are cutting on stainless or tungsten for a few minutes, then yes, the disks do actually wear down and they get smaller and smaller in diameter as you go.  But to buzz off a little piece of tubing... no problem.

Besides, abrasive cutoff wheels are designed to be wear item.  They wear down, and not just on hard metals.  That is why they are sold in multi-packs. 
I actually save the smaller worn-down wheels for some special jobs where smaller wheel is actually advantageous.

[narrowminded]

So, a hacksaw won't cut through this stuff but a Dremel wheel will? Which wheel (it's been forever since I purchased one of those)? Does this tubing wreck the cutting wheel in short order?

A typical abrasive cutoff wheel is all you need and no, it won't hurt the wheel.  As thin wall as that tubing is you could probably get hundreds of cuts from one.

[nickelplate759]

Besides, abrasive cutoff wheels are designed to be wear item.  They wear down, and not just on hard metals.  That is why they are sold in multi-packs. 
I actually save the smaller worn-down wheels for some special jobs where smaller wheel is actually advantageous.

I never have smaller worn-down wheels. I always break them first