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motor w/ generic worm

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motor w/ generic worm
Posted by gregc on Saturday, December 22, 2018 3:12 PM

how likely is it for the work gear on this ebay motor to be compatible with gears on our locos?   is there that much variation in gearing at this size?

greg - Philadelphia & Reading / Reading

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Posted by maxman on Saturday, December 22, 2018 3:22 PM

gregc
how likely is it for the work gear

Did you mean "worm"?

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Posted by gmpullman on Saturday, December 22, 2018 3:29 PM

Chances are the worm isn't going to be in the right place on the shaft, IF indeed it would be on the shaft at all. Many brass diesels and steam locos have a universal joint or sometimes a silicone tube coupling.

 PRR_N1_sam by Edmund, on Flickr

 IMG_6626_fix (2016_08_17 08_08_12 UTC) by Edmund, on Flickr

Often the flywheel is pressed onto the motor shaft and the universal socket pressed into the bore of the flywheel.

I've seen a few cases where the worm is directly on the motor shaft but usually these are on small wheel base locomotives.

What locomotive are you planning to put this motor in?

NorthWest Short Line has some good information on their site about repowering, gearing and wheel sets for equipment:

http://nebula.wsimg.com/02d6e40c2d04190212ed400d3ccb2472?AccessKeyId=08BEE66B97B387F20C0D&disposition=0&alloworigin=1

 Some worm (or spiral/helical gear) info here:

http://nebula.wsimg.com/9efc443e6b1c221c97ebd56248a29065?AccessKeyId=08BEE66B97B387F20C0D&disposition=0&alloworigin=1

 

Cheers, Ed

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Posted by gregc on Saturday, December 22, 2018 4:03 PM

gmpullman
Chances are the worm isn't going to be in the right place on the shaft, IF indeed it would be on the shaft at all.

i assume the worm(!) can be repositioned for a drive where the worm is on the shaft of the motor.   I have a Gem 2-8-0 like below

greg - Philadelphia & Reading / Reading

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Posted by Mark R. on Saturday, December 22, 2018 5:03 PM

I'd be a bit more concerned about the quality of the motor. If it's a typical 3 pole straight armature, it isn't going to run very well at all at slow speeds. At minimum, you'd want a 5 pole motor and preferrably a skewed armature for good slow speed operation.

Mark.

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Posted by rrinker on Saturday, December 22, 2018 6:30 PM

 Also, a metal worm on metal worm gear is going to be a lot noiser than the plastic worm on the metal worm gear.

 There was a really good article on chosing gearing in one of the old MRs - 50's or maybe even earlier, but I think it was 50's because plastic was an option for the gear material. Pretty much the tail end of the period when you pretty much HAD to DIY if you wanted it. Maybe it even was one of those "blue books" that was stuck in the back of the magazine. Very good read.

                                      --Randy 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by gregc on Sunday, December 23, 2018 4:38 PM

Mark R.
you'd want a 5 pole motor and preferrably a skewed armature for good slow speed operation.

'

here's a replacement motor from Bachmann which I assume meets those requirements.   

But I'm still uncertain whether the worm will mesh properly with the axle gear on a non-Bachmann loco.

 

rrinker
 Also, a metal worm on metal worm gear is going to be a lot noiser than the plastic worm on the metal worm gear.

i have a brass boxcab and 0-6-0 with vertically mounted motors with metal worm and gear.   The boxcab is quiet while the 0-6-0 growls.  Still trying to understand why.

greg - Philadelphia & Reading / Reading

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Posted by Spalato68 on Monday, December 24, 2018 11:03 AM
Dear Greg,
 
The most important factor that is crucial for (your) decision if the worm shown on your picture fits your locomotive is gear module. Module is designated as the unit representing gear tooth-sizes. If gear(s) in your locomotive do not have exactly the same module as worm on the picture, they will not mesh properly. Consequence is noise and premature wear and shortened service life of both worm and worm gear.
 
Here you can find very nice article about gear module: 
 
From my experience here in Europe, at least two modules are used in model trains I have: 0,4 and 0,5. Roco uses mostly 0,4, while e.g. Fleischmann uses 0,5. So, gears from both manufacturers are not compatible.
 
 
I do not know which module are used by Athearn, Bachmann, Broadway etc. Maybe some other modelers can help.
 
 
I am not sure I understand why you want to buy this motor, but assume you want to replace open frame motor on the picture with new motor? If that is so, then it would be nice if you can use old worm, because if it is intact, it can be used again with new motor. In lot of cases a motor replacement will give very nice running, under condition all gears are ok and exactly positioned to mesh properly.
 
 
You can use old worm under condition that shaft diameter of old and new motor are the same. If not, and e.g. shaft of new motor is smaller, you cold maybe find a sleeve tubing to adapt new shaft to old worm. If worm is smaller, it is very difficult to widen existing bore, because it must be done so that new bore is absolutely centric.
 
 
So, this is what I would do (if I would like to replace a motor):
 
First, find out if you can pull out existing worm without damaging it. A gear puller could help here, I think NWSL has several models. Then find a motor with either the same or smaller shaft diameter. If smaller, be careful if you can find a sleeve that fits to new motor shaft, to make it the same diameter as the old one.  I assume/hope current that shaft is 2 mm in diameter. If so, it is relatively easy to find motors with same shaft diameter or smaller (1,5 mm). In case of 1,5 mm, NWSL probably can offer you a sleeve for 1,5/2 mm “upgrade”. Or you can try to buy micro tube, I bought recently brass tube from China (ebay), 1,4 mm ID, and 2,00 mm OD. It is a press fit on 1,5 mm motor shaft.
 
 
Your old motor is relatively big, meaning that it is not so difficult to find newer, smaller but much better motor. But, measure your motor to be sure new one will fit it. You can choose between coreless or iron core motors. If iron core, as others already mentioned, use only five pole motor with skewed armature.
 
 
I do not know if this seller is willing to send motor in the USA, but offers iron core Igarashi 5 pole motor that is used on many current Rivarossi locomotives for a very nice price:
 
 
I have two such motors, they run quietly. Unfortunately this motor has a very short shaft, so very probably you would have to extend it.
 
 
If you want coreless, the easiest way in USA is to buy it here:
 
 
A coreless motor with long shaft could be a good choice, like this one:
 
 
Try to negotiate a better price if you want to buy more than one piece.
 
 
In my recent post here, you can read on other “coreless” alternatives:
 
You asked in your last post why one locomotive runs smoothly, the other growls. There can be many reasons, but if both motors are the same, and equally quiet (or noisy), than maybe in loco that is noisy, gears or worm gear and worm are not positioned precisely. If one is offset just 0,1-0,2 mm from exact position, it can mean a huge difference – silent running, or a “coffee grinder”.
 
 
Btw, the task you gave yourself is not an easy one – not many modelers are able to change motors or gears, so be patient and go step by step. After a while, you will maybe have a bunch of motors, shafts, gears and tools around you – but your locomotives will start to run as silent as they never have -:)
 
Regards,
 
Hrvoje
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Posted by 7j43k on Monday, December 24, 2018 11:56 AM

Some parallel thoughts with Hrvoje:

In the US, the tooth spacing is called "pitch", as opposed to "module".  Hence there's 48 pitch and 72 pitch....

Another element is the tooth angle.  Real worm gears have teeth that are not 90 degrees to the gear face.  This angle may vary.

It really seems like a sticky tricky thing to find a worm gear that will match a worm.  Or the other direction.

 

Ed

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Posted by rrinker on Monday, December 24, 2018 12:12 PM

 At least when just randomly picking up something like that motor with the worm already attached. Companies like NWSL sell matched sets. Then you know they will mate properly.

                                  --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by Spalato68 on Monday, December 24, 2018 12:24 PM

Of course, this is a good approach because there is no doubt if gears fill fit to each other, but it can be tricky to remove gear from axle, and install new one, and quarter wheels properly.

But, if worm is still good, it seems is plastic - so it should not be so hard to remove it? If removed, just motor should be replaced. 

Hrvoje

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Posted by Spalato68 on Monday, December 24, 2018 12:25 PM

7j43k

Some parallel thoughts with Hrvoje:

In the US, the tooth spacing is called "pitch", as opposed to "module".  Hence there's 48 pitch and 72 pitch....

Another element is the tooth angle.  Real worm gears have teeth that are not 90 degrees to the gear face.  This angle may vary.

It really seems like a sticky tricky thing to find a worm gear that will match a worm.  Or the other direction.

 

Ed

 

Thanks Ed - I did not know for "pitch". I learned something newBig Smile

Hrvoje

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Posted by richg1998 on Monday, December 24, 2018 1:04 PM

I ran into a similar issue some years ago and bought the gear planning documents from NWSL when they were in Washington. Now free on the Internet.

I bought the worm and worm gears and spur gear for the drivers.

They also sell reverse worms and worm gears.

The Puller made it easier. I used a drill press to put the gears in place.

I used the intermediate gear setup like the MDC locos used so the Sagami motor and flywheel was horizontal in the loco. You can see how MDC did this at HO Seeker page. The gear planning page shows this MDC gear setup.

I also have some MDC Roundhouse locos.

Worm driving a worm gear on an intermediate shaft. A spur gear next to it it drives the spur gear on the driver. I also had a Quartering tool.

Two locos. 45 to 1 and 72 to 1. Motors mounted in bath caulk. Very quiet.

 

I would recommend looking closely at the NWSL page for gears and motors, couplings.

 

Rich

 

N

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Posted by gregc on Monday, December 24, 2018 6:17 PM

richg1998
I would recommend looking closely at the NWSL page for gears and motors, couplings.

i have.

the older Pittman motor shaft diameter appears larger than most newer motors.  So either sims or replace the worm and gear.

richg1998
Motors mounted in bath caulk. Very quiet.

so is noise due to metal worm on metal gear or isolating the motor from the frame?

greg - Philadelphia & Reading / Reading

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Posted by 7j43k on Monday, December 24, 2018 6:26 PM

NWSL sells adapter sleeves for shafts.

 

Ed

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Posted by gregc on Monday, December 24, 2018 6:36 PM

yes, not sims, adapter sleeves

greg - Philadelphia & Reading / Reading

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Posted by richg1998 on Friday, December 28, 2018 6:30 PM

Yes, adapter sleeves called bushings, shaft adapter, reducer. Download the gear planning documents and read carefully. I have used them many years ago. I also mounted motors in bath caulk like I said before and carfully adjusted for minimum gear lash and left it alone for twenty four hours. Not tight, just the required space according to NWSL. Metal worm to plastic worm gear.

Nothing touching the motor after the shell was in place.

NWSL had evrything I needed. A cheap dial caliper did evrything. No guessing.

Rich

N

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Posted by gregc on Tuesday, January 01, 2019 5:05 AM

are adapter sleeves for gears or worms?

greg - Philadelphia & Reading / Reading

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Posted by 7j43k on Tuesday, January 01, 2019 10:54 AM

gregc

are adapter sleeves for gears or worms?

 

 

Yes.

They're for fitting things with bigger holes onto smaller shafts.

I've use them once.  Because of the very slight slop in fit, they can't run dead-concentric.  For each use, then, it's a matter of judgement.  Is it concentric ENOUGH to work.  Usually, you have no choice.

For my use, I was fitting a universal joint onto a motor shaft, so running a bit eccentric was no problem at all.

 

Ed

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Posted by gregc on Tuesday, January 01, 2019 11:03 AM

not asking about diameter, asking about length, the length of a hole and presumably the sleeves in a worm vs a gear

I was able make some sleeves with layers of aluminum and paper that make a tight enough fit.

greg - Philadelphia & Reading / Reading

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Posted by 7j43k on Tuesday, January 01, 2019 11:38 AM

I believe NWSL reveals the lengths in their catalog, along with diameters, material and prices.

If you need a shorter, you can shorten the sleeve.  If longer, use two or more.

 

If layers of aluminum and paper work for you, sounds great.  Cheaper, and you don't have to wait for delivery.

 

Ed

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Posted by Spalato68 on Tuesday, January 01, 2019 1:53 PM

Or maybe in Home Depot a brass tube can be found, like I found one where I live (in a store similar to Home Depot in USA): 1,4 mm ID, 2,0 mm OD. When pressed on 1,5 mm motor shaft, you get nice tight, absolutely centric fit. And all that for 1,1 USD for a tube 1 meter long. 

Pressing such tube can be a problem if motor shaft is short, and you want to make it longer - brass could bent. But, if price is like above, it is worth to try. 

Hrvoje

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Posted by gregc on Tuesday, January 01, 2019 1:56 PM

richg1998
I also mounted motors in bath caulk like I said before and carfully adjusted for minimum gear lash

i wondering about using something maleable to mount the motor.   It seems to me that gear lash is likely to be larger than desired by just glueing a motor in place unless the glue/caulk shrinks.

if the gear were tight, the glue could flex and maintain a tight fit.   Not sure how to accomplish this.   maybe a rubber band around the worm

i tried adjusting a motor (not planning on replacing).  When overtight, the motor stalled.   couldn't find the sweet spot, hence wondering if somethign sprung would be good

greg - Philadelphia & Reading / Reading

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Posted by rrinker on Tuesday, January 01, 2019 2:04 PM

 For a vertical mounted motor like that, if replacing the motor with a can motor, I'd think some sort of brass strap would be the way to mount it. L shaped bracket, which bolts to the loco chassis, and then a tradle of some sort glued or screwed to the motor and attached to the bracket, either soldered or screwed to it. a slight oblong hole in the base of the L would allow it to shift for gear lash adjustment, but the natural amount of play in a clearance hole may very well be enough of an adjustment.

                                    --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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