That is something I didn't see coming! And no real reason why it shouldn't work a reasonably long time, especially if a couple of the washers are reasonably slippery like nylon. Pity the self-lubricating ones I know of (e.g. acetal/Delrin) are too brittle for this method... does anyone have recommendations for this?
Thanks everyone for the info! I have been able to place 3 non-conductive washers in front of the rear flywheel totaling .045" and .015" behind the front flywheel by splitting washers and putting them over the shaft! It seem to work for now but if it looses a washer or wears one out I will then try the flywheel removal process... and I will have to be prepared to replace the motor should something go wrong during the flywheel removal!
SeeYou190i prefer a fine threaded c-clamp.
In fact I've taken to using modified adjustable bar clamps to reduce the amount of 'turning' involved with very long fine-thread clamp screws. I note that some of these clamps are made with a hex that will fit a nutdriver to semi-automate some of that... if you stay out of the way of the whipping handle!
Overmod.The one advantage of using a vise is that you don't have to hold the clamp
Put the clamp in the vice.
Vices usually have coarse acme threads, and i prefer a fine threaded c-clamp. You can get much more control.
-Kevin
Living the dream.
SeeYou190I would love to see how you are installing flywheels where this becomes a concern.
Balancing them after installation is not that much of a job, either, although you have to jig the motor a bit carefully to figure out the points to reduce. Checking them for static balance before installation is imho trivial; enough so that I don't ASSume the things are perfectly concentric or balanced as provided.
Certainly using C clamps (with a ball pivot on the screw jaw) would get the job done nicely, although if it had an Acme or equivalent screw I'd want to grease it.The one advantage of using a vise is that you don't have to hold the clamp, the flywheel, perhaps the mandrels, and the motor in careful alignment while turning the screw in.
I do have concerns that some modelers might use the considerable force or ignore something wrong when doing this sort of operation -- NWSL would not put all those caveats in its instructions for no tangible reason. This in particular when removing flywheels that are particularly recalcitrant for some reason, or if a replacement motor has a slightly different shaft diameter that goes unrecognized. I was trained not to leave a drilled hole unreamed if it were to be given an interference shaft fit, but that appears to be precisely what NWSL recommends if the fit appears 'too tight' when engaged. In this context that is probably dixie quality for dime problem again.
OvermodMany easy ways to install them unbalanced, and bend shafts, too.
I would love to see how you are installing flywheels where this becomes a concern.
The flywheel (if you have a good one) is balanced from the factory. I know they do not use a dynamic balancer when they are manufactured, but the shaft hole is centered and the machining is symetrical, so they can be assumed as balanced.
There will be a slight press fit to get it onto the motor output shaft.
The only way to get it out of balance would be to either displace metal on the inside diameter of the flywheel or bend the motor shaft. Both of these would require considerable force and a willingness to ignore when something is obviously wrong and just force it through.
I have always used a nomal C-Clamp with homemade mandrels to install flywheels onto motors. No heat, no forcing, and no fuss.
Never a problem.
I guess I could get out the good old 4 ton porta-power if I had a problem, but that would just cause more problems.
SeeYou190Everything you posted sounds like a $10.00 solution to a dime problem.
There are many easy ways to install flywheels.
Removing them is the fiddly bit.
Heat is still a bad idea, no matter how complicated it is.
I wonder if any use of anaerobic material or other adhesive on loose-fitting flywheels has been tried. If it has, then heat might be a more sensible 'assist' in removal. That strikes me as being firmly in the zebra category, though.
OvermodGentle heat for installing flywheels may make sense
Everything you posted sounds like a $10.00 solution to a dime problem.
There are many easy ways to install flywheels. Removing them is the fiddly bit.
Gentle heat for installing flywheels may make sense ... e.g. putting them in a plastic bag in hot water. Use an IR spot thermometer to ensure you don't get them hot enough to damage plastic motor parts via conduction -- there is a large thermal mass in the flywheel, and only a small one in the shaft. Conversely you might chill down the motor-and-shaft assembly, which is the 'other half' of what's normally done when making critical interference fits IRL equipment.
You could heat them with hot air, but it's the temperature in the bore that is most significant, and I suspect keeping the heating properly 'even' until the flywheel has reached an equilibrium temperature might be tedious and long for the 'benefit' gained -- you want good heat transfer from a controlled-heat source, which to me means liquid at a temperature low enough not to induce burns...
The press/vise approach is a good one, although I think I'd recommend that you have parallel (or articulated) jaws wide enough to keep from off-center pressure. I would be tempted to use washers of appropriate thickness (file slightly if desired and check square) if the shaft is to protrude through the end of the flywheel.
For a number of reasons I think brass instead of a steel drift would be a bad idea. Although I sympathize in principle with the idea of using a material that won't 'scratch' the flywheel bore. I'd be tempted to consider using an undersize drift given a coat of good tough paint on its OD...
- -Even modest heat can assist any interference fit in dissimilar materials. This is a very common methodology. There are no drawbacks if competently done.
Sure, we did it a lot in industrial environments. If you want to install a ring gear onto a diesel engine's flywheel, sure heat is the correct way to do it.
On a model motor it is simply not a good idea and presents extra risks. It is irresponsible to suggest this as a good method.
It is obvious this is just theorizing and not based on actual experience.
There are too many small parts in a model motor that could be damaged by heat.
Be careful with your motors, take chances elsewhere.
I found NWSL instructions related to flywheel install:
I followed it each time and result was always satisfactory.
Hrvoje
Spalato68Yes, a flywheel could be much easily removed if heat is applied. But heat source must be very precise, to avoid damage of plastic motor parts.
I see no way the benefits of heat, which would be minimal, would ever overcome the unnecessary risk that would be added.
No heat! That is a bad idea.
Here is a picture of the other side of a flywheel (from Athearn Genesis locomotive):
To install it back, I use a big vise and press gradually, but release after each small press and rotate a flywheel a bit, and repeat this procedure until finished.
Yes, a flywheel could be much easily removed if heat is applied. But heat source must be very precise, to avoid damage of plastic motor parts. I found very interesting discussion on German forum, you can read it here, use Google translator for english version. I do not have a torch, and frankly, I would hesitate to use this method for mentioned reason. But if I had a torch, I could try with one motor, I have them a lot, so destroying one is not an issue. So I would know, if this method would work without motor destruction.
But at least for install it back on the motor shaft, a "heat" method can be used. Then an ordinary oven can be used, if someone does not have a small torch at hand. Care is then required only not to burn your fingers
I concur with using Hrvoje's method, using the correct diameter drift punch (like a nailset but with precise flat end and cylindrically-ground diameter) and either a small brass hammer or the deadblow type lastspikemike mentioned. But be sure you have careful padding everywhere below the area of work -- two things will happen when the shaft comes out of the flywheel bore: the motor will drop suddenly and the flywheel will try to pull the drift sideways and roll with the rods off the vise. Trying to grab for one will accelerate the other... have soft padding all the way down, and predict strange ricochets...
I recommend that you measure the space from the flywheel face to the end of the shaft on each end -- a plunge gage as previously described in the tapping thread would be just the tool for this, as (likely) would the drift you used for removal. You can lightly mark the shaft if you like.
As a suggestion for REinstallation, a subject not broached so far: I do not know if the flywheels are chamfered either side of the bore. You'll want to use the same care reinstalling the flywheels straight on the shaft as you do taking them off, especially if you have to reinstall delicate parts of the motor before you seat the flywheels down all the way.
I'm tempted to have you clean up the very ends of the shaft so there are no burrs or mushrooming, and then ensure an entry chamfer on both flywheel bores. Gently "press-fit" the flywheels onto the shaft ends as far as you can go with hand pressure, then rest the 'bottom' flywheel on something like a leather pad on nearly-closed vise jaws (or the two rods), with a similar pad on top and a hex socket of nearly the OD of the flywheel. Tap on top of the socket with the brass/deadblow hammer until the flywheels are nearly to depth. Work very gently and very slowly, using an elastic 'strike' but little swinging force, just what's necessary to get the flywheel to move. You may need to make a shim of slightly less than 2mm diameter to hold the first flywheel in position while setting the second, or if the shaft is longer, turn the assembly over so the first flywheel that reaches 'depth' is down, with shims of the right shaft offset in place of the rods and the end of the shaft bottomed square against a hard surface like closed vise jaws.
There is a simpler way to do it, although it may seem a bit brutal J. On following pictures a principle is shown. I have done it this way with many Roco motors, and did not damage any motor yet. For these pictures I used two motors, one without flywheels, and the other with flywheels.
To remove flywheels, I used a vise, two steel rods, a pin of slightly smaller diameter than motor shaft (shaft is 2 mm) and a hammer. Two steel rods should be tied together on both sides in some way. A bigger vise should be used than as shown on picture:
CPbuff they look like they may unscrew but before I put the pliers to work I want to make sure!
They do not unscrew. They are press fit onto the motor shaft.
I have a small bearing splitter and a modified C-clamp I use to remove them, but I am sure there are simpler ways to do it.
If they are moving back and forth that much, then the motor was perhaps built missing a thrust washer or two. Can't add those without removing the flywheels, and if removing the flywheels will damage the motor - well, replacement is likely the only course of action.
One way to get press fit anything off is to heat it. If you don't care about the motor but want to reuse the flywheels, a regular propane plumber's torch will work, otherwise you need something smaller. And of course the universal couplings in the end are plastic and unless you can pull those out first, they will melt.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Mel,
BB motors are different from Roco motors used in Athearn Genesis locomotives, they are pressfit, but very tightly, metal on metal. It is very hard to remove them. It can be done, but not by twisting them. At least that is my experience.
And yes, one of soultions is to replace the motor, as you explained.
I don’t have any newer Athearn locomotives than the BB series and it is very easy to use a Mabuchi motor as a replacement.The Athearn motor (bottom↑) has a 3.2mm shaft and the Mabuchi (and most can motors) have a 2mm shaft.To me the Athearn motors are worthless so I just twist the flywheels off the shaft and replace them on the Mabuchi FK-280SA 14200 motor.
https://www.ebay.com/itm/MABUCHI-FK-280SA-14200-DC-6V-12V-12300RPM-High-Speed-Dual-Shaft-Tiny-Mini-Motor-/113844887737
The flywheel fits a 3.2mm motor shaft and needs an adapter to mate the 2mm Mabuchi motor shaft. Evergreen #224 ⅛” OD tubing fits perfect in the flywheel and the ID fits the 2mm Mabuchi shaft perfect.I’ve done this conversion to 8 Athearn diesels and everyone worked out perfect.I haven't dinged any motor by twisting off the flywheels. When the first flywheel comes off I grab the shaft with vicegrip pliers and remove the second flywheel. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
CPBuff,
Do not try to remove flywheels by twisting them in any way. There is a very good chance that doing that you will completely destroy the motor. If your locomotive has motor used by Athearn for years, than this motor is made by Roco. With this motor, commutator (I do not know if you know which part is that – see one picture here, it is part A) is sitting very tight on motor shaft, as flywheels also, but iron core of motor rotor is not so tight on motor shaft.
So, if you try in any way to twist the flywheels (especially by holding motor rotor with one hand), you will rotate also the collector, but not the iron core - all wires coming from rotor to collector will break, and motor is practically destroyed. I have done this with one of my motors, but damage was not important because I anyway replaced all Roco motors with coreless motors in my Roco locomotives.
If motor is under warranty, then return the whole locomotive for repair/replacement, because as Mel wrote, this is too much play of motor rotor. If not, then try to find someone more skilled, because first flywheels must be removed, and then motor completely dismantled and appropriate thrust washers (e.g. NWSL) installed – and that is not an easy task.
If the motor shaft moves back and fourth more than 1/64” the motor is bad. Is it under warranty? Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
No, the worms on top of the truck are solid both front and back! As speed ramps up the complete flywheels, shaft and armature move foward ... The worm gears and driveshafts stay in place, hence my temp fix of stuffing cotton at the end of the driveshaft on inside of the flywheel end ,where the driveshaft enters the flywheel.
Where is it moving, is it pushing the whole drive shaft including the worm on top of the truck? It's fairly common to install thrust washers on either side of the worm in each truck tower to keep the loco from bucking on grades.
So if I can't get the flywheels off without a puller, what can I do to shim or put washers (plastic ot non conductive) on the main shaft to keep the motor from moving forward as it gains speed. The motor has about a 1/4" of free play and when the speed ramps up the complete shaft , flywheels and armature move forward, which in turn make a heck of a noise, if I hold the flywheels back its quiet... I current just stuffed a little cotton from a Qtip in the front flywheel to make the front driveshaft push the shaft toward the back. (just a temp fix).
With older BB Athearn's, I could hold a flywheel in each hand, and twist and turn until it gave up.
Better to invest in a puller.
Mike.
My You Tube
They are press fit.
How does one remove the flywheels off the motor of the athearn AC4400AC , (the big gold things?) , they look like they may unscrew but before I put the pliers to work I want to make sure!