Source of Maxon/Faulhaber 4:1 Gearheads

[narrowminded]

I managed to get 4 gearheads cut down today. My Sherline definitely has too much run out for those tiny drills. I need to remedy that. Lots of good tips here.

On this one, if the tailstock is off center there will be an adjustment for center and with a dead center and indicator you should be able to dial it in.  Side to side is adjustment, and if vertical is actually bad it would require shimming on most typical tailstocks.   And once the tailstock is true you're part way there.
If you're making a new sleeve just start with an oversize material and turn to diameter then drill, all in the same setup.  That will inherently run very true as the machine center that it all originated from never changed. 

It's picking up center on existing parts that the chuck runout becomes an issue.  And on that one, if I understand the Sherline chuck mounting correctly, it's threaded with a tapered hub to center it, not unlike what I think is the planetary scheme on these motors.  That might be proprietary to Sherline and even if not, it's very limiting on available spindle attached devices like chucks and collet holders as it's not very common (translating to expensive). 

If chuck runout is really bad you could try to fix it by machine grinding individual jaw grip faces based on your indicator readings.  But that's also not a "fix all" because three jaw self centering chucks tend to vary a bit (a few thousandths?) at different diameters because of variations in the scroll that closes them as well as wear and the scroll's assembly tolerances.  If you chose to do that you should pick the material size that you're most likely to want to grip with great accuracy.  The accuracy at the other sizes will be what it is, probably pretty good but not guaranteed.  These are the things that make really precision tools so expensive, making all of those variables with tight enough tolerances so that stack up is still miniscule.  And for the rest of us poor folks we use workarounds.

What I would consider if I was up against this issue with that machine would be to get a proper sized piece(s) of hex brass that I could make sleeves from as described above.  Make sure you log the face of the hex and jaw number that coincides with that face and hopefully you could remove it and reinsert it later holding an acceptable runout tolerance.  Still indicate the bore every time you go to use it just to be sure.  A few sizes will probably be all you need as there tends to be some common worm sizes in the industry. 

Another thought, you might remove and advance the jaws one groove at a time and see if one position is better than another.  You still install them in the proper sequence, just advanced one groove.  I wouldn't be surprised to see minor changes and if so, log the best positioning for future reference.  And if you're lucky...

 

[mmagliaro]

With all this talk of run-out, I put one of the gearheads in my lowly 3-jaw chuck and checked with a dial indicator on the gearhead case.  Wow.... The run-out is *under*.001".  The dial is graduated in .001" marks, but  I'd say the run-out is around .0007"  - it's more than 1/2 a mark, but less than a whole mark for sure.  So yeah.  I'm lucky to have gotten a factory 3-jaw chuck that good.
(What narrowminded said about 3-jaw chucks varying in their run-out depending on how big a thing you put in them because of
the scroll is very true... so maybe 10mm is near this chuck's "sweet spot")

Someday, I'll drop a grand for a natty precision Bison chuck or similar, but until then...

[mmagliaro]

I did another one.  This time, I tried balling up a pea sized wad of masking tape and stuffing it into the gearhead before doing any cutting, hoping that it would block most of the metal dust.  Well, it did.  But it didn't stop all of it, and getting the wad of tape out afterward was a pain.  So not a strategy I'll use again.  I just use a small brush and acetone, and just keep washing and wiping it out, wiping the brush on a paper towel after every swipe.  It takes about 15 minutes before I'm really sure it's clean.
 
I upped the RPMs to 1500 when boring out the teeth to make room to put the threaded insert back in.  Didn't really help on the destruction of the edges of the teeth.  I still had to go around the inside with a #11 Xacto blade and scrape each tooth valley to remove the metal "flash".  Again, only took about 15 minutes, and it's not too hard, but just another task I was hoping to get rid of.  I'm using a pretty low-cost boring bit I got off of "Bang Good" or one of those import cheap tooling places.  It makes a beautiful finish on the inside of the can, and it is carbide, but it's probably just not sharp enough to cut out those teeth without leaving bent over edges.  Fortunately, the planetary gears never run on the extreme end of those teeth where the damage is.

[narrowminded]

I did another one.  This time, I tried balling up a pea sized wad of masking tape and stuffing it into the gearhead before doing any cutting, hoping that it would block most of the metal dust.  Well, it did.  But it didn't stop all of it, and getting the wad of tape out afterward was a pain.  So not a strategy I'll use again.  I just use a small brush and acetone, and just keep washing and wiping it out, wiping the brush on a paper towel after every swipe.  It takes about 15 minutes before I'm really sure it's clean.
 
I upped the RPMs to 1500 when boring out the teeth to make room to put the threaded insert back in.  Didn't really help on the destruction of the edges of the teeth.  I still had to go around the inside with a #11 Xacto blade and scrape each tooth valley to remove the metal "flash".  Again, only took about 15 minutes, and it's not too hard, but just another task I was hoping to get rid of.  I'm using a pretty low-cost boring bit I got off of "Bang Good" or one of those import cheap tooling places.  It makes a beautiful finish on the inside of the can, and it is carbide, but it's probably just not sharp enough to cut out those teeth without leaving bent over edges.  Fortunately, the planetary gears never run on the extreme end of those teeth where the damage is.

Are you able to tell what material the teeth are made of?  Is it the same as the case or an insert?  If they are SS it will be gummy cutting and prone to that action.  Super sharp edge can help but that might be just part of the deal.  And if it is SS it will be a bear to deburr as well. 

[peteski]

I did another one.  This time, I tried balling up a pea sized wad of masking tape and stuffing it into the gearhead before doing any cutting, hoping that it would block most of the metal dust.  Well, it did.  But it didn't stop all of it, and getting the wad of tape out afterward was a pain.  So not a strategy I'll use again.  I just use a small brush and acetone, and just keep washing and wiping it out, wiping the brush on a paper towel after every swipe.  It takes about 15 minutes before I'm really sure it's clean.
 

I would highly recommend Parafilm "M" laboratory film to stuff it inside the gearhead.  It is a paraffin-based film with no adhesive.  I use it for lots of applications.  Decades ago some modeler started using it for masking midel automobile kit bodies for painting and wrote an article about it in one of the modeling magazines.  Even Testors sold the stuff as a hobby product for a while (ad very inflated prices). I bought a box of it from a lab supply house - it will last me for life.

I would take a piece, stretch it to make it thinner and more pliable, then loosely roll it up and stuff it in the gearhead.  Then you can use a toothpick or tweezers to pack it in tight.  When done, you can easily remove it with a pair of tweezers. It will make your life much easier.

As for cleaning, nothing beats an ultrasonic cleaner with Naphta as the cleaning fluid. It will vibrate all the shavings out, and dissolve the lubricant.  Once cleaned, let it sit to dry out, or use compressed air to blow it dry. Of course then you will have to re-lube it before reassembly.

[mmagliaro]

Are you able to tell what material the teeth are made of?  Is it the same as the case or an insert?  If they are SS it will be gummy cutting and prone to that action.  Super sharp edge can help but that might be just part of the deal.  And if it is SS it will be a bear to deburr as well.

I don't know for sure, but I really doubt the teeth are stainless.  They just cut too easily, and I can scrape the flash off the edges too easily with an Xacto blade.  A file can pretty easily cut them also, as I've experimented with these in the past.  The pinion and planetaries themselves are stainless.  I know this because even with a Dremel and a cut-off wheel, you really have to work on those buggers even to grind them, let alone cut through them.
Crazy thought, but I wonder if they are aluminum?  Aluminum can cut with this "buttery" soft problem.
Maybe 1500 just ain't fast enough.  2000 is the limit on my spindle, but I don't think an extra 500 rpm is going to matter that much.

[narrowminded]

Crazy thought, but I wonder if they are aluminum?  Aluminum can cut with this "buttery" soft problem.
Maybe 1500 just ain't fast enough.  2000 is the limit on my spindle, but I don't think an extra 500 rpm is going to matter that much.

Aluminum on steel would be a decent choice of materials and would lend itself to broaching or in a turned piece, rotary broaching which would be an excellent choice with a piece already in a lathe.  That's if they are machined.  They might also be die cast and could even be a zinc/ aluminum.  Those would all have the potential to leave chip as described.  I'll see one soon enough now, I guess.

[peteski]

Aluminum on steel would be a decent choice of materials and would lend itself to broaching or in a turned piece, rotary broaching which would be an excellent choice with a piece already in a lathe.  That's if they are machined.  They might also be die cast and could even be a zinc/ aluminum.  Those would all have the potential to leave chip as described.  I'll see one soon enough now, I guess.

The gearhead I have seems to be some sort of soft stainless steel alloy (if there is such a thing).  It is slightly ferromagnetic (when I test it with one of those strong rare-earth magnets).

[metalworkertom]

Aluminum on steel would be a decent choice of materials and would lend itself to broaching or in a turned piece, rotary broaching which would be an excellent choice with a piece already in a lathe.  That's if they are machined.  They might also be die cast and could even be a zinc/ aluminum.  Those would all have the potential to leave chip as described.  I'll see one soon enough now, I guess.

It's magnetic for sure. I had a ragged cut that seperated some teeth. Broke a couple off and definitely sticks. The case and teeth are definitely seperate parts not sure if photo will show it .

[narrowminded]

Well, I've oiled up the tape measure, sharpened the hatchet, and dusted off the ball peens.  All I need now is some of those gear thingies.

[narrowminded]

@metalworkertom sent six gear sets and one motor that arrived today.  I'm in the middle of another project right now but will get started on the puller design and will get some cutting as soon as I can.  I think I've got the general plan for the puller and it will not use a collet, I don't think. 

[mmagliaro]

Guys, I thank you for suggesting pulling the insert out instead of machining it off as I have been doing.
It turns out, we're really over-thinking this. 
I can get one of these out in 60 seconds!  I do have an M5.5x0.5 tap, so I ground the tapered part off so I could essentially use it as a "pull bolt", and then...

The following pics tell the story.   No special tools. 

[SkipGear]

I have a new one I'm playing with. 8mm plastic "ring" gear housing but metal sun and planets on the final. 4:1 reduction on the final and much easier to cut down. Now I just need a way to mount it to the motor. Was thinking of sleeving this and an 8mm motor together, some of the Faulhaber's are done that way. 10mm 16:1 and 8mm 4:1 gearboxes shown with the giant dime for size comparison.

[narrowminded]

Guys, I thank you for suggesting pulling the insert out instead of machining it off as I have been doing.
It turns out, we're really over-thinking this. 
I can get one of these out in 60 seconds!  I do have an M5.5x0.5 tap, so I ground the tapered part off so I could essentially use it as a "pull bolt", and then...

The following pics tell the story.   No special tools. 

Now that I've got one to look at I see the thread is more substantial than I thought based on memory of a picture I saw some time ago.  I also thought that the end cap was shouldered at full diameter of the case so there was nothing to push against.  That was why I was thinking about a collet to grip the body.  As it is, I will go ahead and make a puller that pulls straight out with a collar that presses against the shell.  Is there reason to press out the opposite end?  I assume it assembles in a bore similar if not identical to the motor end. 

And what about salvaging the parts to make a second one?  Especially the gear case couldn't be readily duplicated but would there be sufficient length left to get another useable part?

[mmagliaro]

Now that I've got one to look at I see the thread is more substantial than I thought based on memory of a picture I saw some time ago.  I also thought that the end cap was shouldered at full diameter of the case so there was nothing to push against.  That was why I was thinking about a collet to grip the body.  As it is, I will go ahead and make a puller that pulls straight out with a collar that presses against the shell.  Is there reason to press out the opposite end?  I assume it assembles in a bore similar if not identical to the motor end. 

And what about salvaging the parts to make a second one?  Especially the gear case couldn't be readily duplicated but would there be sufficient length left to get another useable part?

On the 8mm, the threaded insert IS shouldered to the full diameter of the case and sticks out the back, unlike the 10mm and larger.  I don't think there is any salvaging to be done.  The ring of metal that one removes from a 16:1 gearhead is not nearly large enough to be made into another gearhead.  I think on a 64:1 or larger, it's possible, but not on the 16.