Gears, Where To Buy

If it is driven by a worn, it is a worm wheel.  

It's a worm and a worm gear.  Brass is one of the worst materials for worm gears.  A steel worm meshing with a bronze, Delrin, phenolic, etc. worm gear is way better.  Brass will not last.

I'm not familiar with your model (I'm just a 2R guy) but I deal in gears and re=powering on a nearly daily basis.  Because I know absolutely nothing about your model I can't offer specific replacement parts.  Maybe others, more knowledgeable on your model can offer direct replacements.

If not North West Short Line (NWSL) might be able to assist.

Good luck,

Jay Criswell

Stock Drive Products, SDP/SI might be worth a look...

https://shop.sdp-si.com/catalog/?cid=p270

Steve "Papa" Eastman posted:

Need a little help. I'd like to replace the axle gear on a CMC loco. Being as it is run off a work gear, the teeth are at a slight angle. What type would it be called. Any suggestions for a place to buy one. I'd actually to prefer a brass equivalent. With quite a few CMC/CMT in my stable I'd like to have a few extra.

thanks

Steve

 Steve,

First thing you need to do is to identify what the gear is.

Two basic types - English and Metric (surprise). The English gears go by pitch, and that is a ratio of teeth to the diameter at which it meshes with the worm. (Typical are 48 pitch, 32, 24 (which is pretty heavy duty, but I like it).

The metric ones go by 'Module' size and is a ratio of teeth to diameter (typically called 0.5 Mod, 0.6 mod, 1 mod, etc).

So if you can take the OD and count the teeth, (and try to measure the inside diameter between the teeth), you can get an idea of what the gear is.

The other important factor is the angle of the teeth. For an English gear set, you check to see how many of the grooves on the worm (not this one) pass per revolution of the motor. For single threaded worms, it's usually a 14.5 degree angle , for double threaded (you get two threads of movement per revolution, it's 20 degrees.

For this vintage, I would suspect it's English, and single thread for a steam engine (smaller wheels may require a double threaded worm). Also probably a 32 or 48 pitch based on what I see in the photo. Measurement will bear that out.

NWSL is primarily selling metric gears, so unless you change out both, they may not be much help. But their gears are really good. If you want to get really fancy (and I may do that with the std gauge K4), they sell a 0.6 Mod gearbox and offer in 3/16" axle bore as well as metric sizes. Has ball bearings in it and will last your lifetime and probably the next owner as well. They run $48 or so. You would have to modify the motor mount and add a coupling but will never have to worry about gear mesh again. Look at page 4-13

Northwest Short Lines site.

Can you tell I've been looking for gears myself? My favorites are the Boston sets with steel worm and bronze worm wheel. 32 or 24 pitch.

I'm picking up a Gold Standard GG1 at York (like the one Kirk had at Pittsburgh). Also got a couple of extra motors that have the 24 pitch worm installed at spares (which will go into another loco! I don't think these will ever fail, they are 1/35 HP and about 4 inches in diameter).

Any chance you are going to York, Steve?

Jim Waterman

Just curious: Does CMC not supply parts for their motors? Forgive my ignorance!

Tinplate Art posted:

Just curious: Does CMC not supply parts for their motors? Forgive my ignorance!

CMC is long gone. 

Steve

10-4, and THANKS for that info!  

Steve, try McMaster-Carr, for anything like that.  Fantastic site for all kinds of parts like that. Www.mcmaster.com

Steve,

Here's what my machinist buddy and I used on my CMC Camelback below:

Axle gear - SDP/SI Stock Drive part no. A 1M 6-Y32030 - Nylon

Worm Gear - WM Berg part no. W32S-3D - Stainless

I looked both up this morning and they are still available.

We originally had a stainless precision axle gear but the lateral play in the divers - almost like a real locomotive - would make the gears grind awful when it went around curves, so we went with nylon, a little less precision and more quiet. We drilled through the drive axle and pinned the gear with a tiny spring pin as seen. This setup has worked well and reliable. It did require some minor machining to get everything to fit. If another vintage CMC engine ever found its way into my collection, I'd do the same setup.

I spoke to Rob briefly at York 10/17 on how we did it. The pressed fiber gear was a real design flaw on these otherwise really nice looking pieces. I know he's mentioned the CMC locomotive tooling was gone, and the drive lines were unreliable. I hope they can get things together to make new.

Contact me offline with any further questions

CJ Meyers posted:

Steve,

Here's what my machinist buddy and I used on my CMC Camelback below:

Axle gear - SDP/SI Stock Drive part no. A 1M 6-Y32030 - Nylon

Worm Gear - WM Berg part no. W32S-3D - Stainless

I looked both up this morning and they are still available.

 

Your "axle gear" (actually the worm gear) is acetal (generic Delrin) which is a good thing. Nylon is a poor material for gears and should be avoided.

I got my Niagara Delrin replacement gears from Stock Drive Parts. 

Follow Jim Waterman's advice. There is a lot to learn before selecting gears.

Pete

It sounds like having machinist skills and knowledge of metals and polymers is almost necessary for these repairs and/or modifications! Definitely out of my league! Best of luck!

So that worm wheel is a 32 pitch, 30 tooth gear.  20 degree pressure angle (which means worm moves two teeth per motor revolution. Guessing your engine can really scream.

Curious as to what you paid for the SPS and Wm Berg parts (and where you got them). Good stuff, not cheap.

Jim

Hey Steve. Did you ever obtain new gears for your engine?  My engine has a tooth cracked on the axle gear. It still works but I suppose it is just a matter of time before failure.