I have a little problem with a Weaver drive gear, and I'm hoping there is a possible solution. Turns out the drive gear appears stripped, and I have no idea if or where I can get a suitable gear to replace it. After doing all the upgrades to give this nice locomotive fan driven smoke and cruise, I'd like to get it back on the rails.
Any ideas on a replacement?
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@gunrunnerjohn posted:I have a little problem with a Weaver drive gear, and I'm hoping there is a possible solution. Turns out the drive gear appears stripped, and I have no idea if or where I can get a suitable gear to replace it. After doing all the upgrades to give this nice locomotive fan driven smoke and cruise, I'd like to get it back on the rails.
Any ideas on a replacement?
My first idea is finding another gear box from Weaver to steal the gear from. Another idea would be to contact Royz trains as he is a big brass guy. I have bought a lot of brass locomotive parts from him before. You never know what he could have. It's worth a shot. That's all I can think of. Hope you can find something that works John.
Another gearbox would be a find, but that's probably not that likely. I'll give Royz a try, can't hurt.
Bob Lavezzi bought the Weaver parts inventory when they closed. He might have what you're looking for. Contact info is in the link below.
Grj. Any possibility of removing a gear and possibly motor from a postwar or similar drive system and modifying it to fit? That kind of looks like a f3 mechanism. Just a thought.
@Bob posted:Bob Lavezzi bought the Weaver parts inventory when they closed. He might have what you're looking for. Contact info is in the link below.
I'll give him a try, thanks. 
@E-UNIT-79 posted:Grj. Any possibility of removing a gear and possibly motor from a postwar or similar drive system and modifying it to fit? That kind of looks like a f3 mechanism. Just a thought.
Well, I guess anything's possible, but the chances of a PW gear fitting on the axle and mating with the worm on the driveshaft seems like a long shot to me.
If all else fails, try Boston Gear - they may have a suitable replacement size gear in stock or be able to manufacture one.
I’ve got some gear boxes, doubt I have a direct fit Weaver, but I have some complete Samhongsa stuff, with worm wheel, we’d just need to verify gear ratio, axle OD, and LXW measurements to see if they’d fit,...when you pull it apart, we can compare notes,...clearly it’s coming apart whether you like it or not,...😉
Pat
Have you looked at replacement gears/gearbox at Northwest Short Lines (nwsl.com)? I suggest reviewing the following old catalog pages (https://cdn.shopify.com/s/file...es/Gears_1_2.pdf?263) since their newer pages are very incomplete. NWSL often has drivetrain components no one else on the planet offers.
@Richie C. posted:If all else fails, try Boston Gear - they may have a suitable replacement size gear in stock or be able to manufacture one.
Manufacturing one is likely to be the solution I suspect. Looking at the Boston Gear Website, I suspect they'd have to have exact specifications to make it happen.
@harmonyards posted:I’ve got some gear boxes, doubt I have a direct fit Weaver, but I have some complete Samhongsa stuff, with worm wheel, we’d just need to verify gear ratio, axle OD, and LXW measurements to see if they’d fit,...when you pull it apart, we can compare notes,...clearly it’s coming apart whether you like it or not,...😉
Yep, I suspect the gearbox is coming out. The gear ratio isn't critical, as long as the wheels go 'round I'll be happy. 
OK, what the LXW measurements?
@DarrellR posted:Have you looked at replacement gears/gearbox at Northwest Short Lines (nwsl.com)? I suggest reviewing the following old catalog pages (https://cdn.shopify.com/s/file...es/Gears_1_2.pdf?263) since their newer pages are very incomplete. NWSL often has drivetrain components no one else on the planet offers.
That link is bad, this is all I get.
LXW = Length and Width measurements?
John, here is a good link for NWSL.
They are under new managment and just getting back up to speed. I would suggest first emailing them and ask if they know what the correct gears are for your engine before trying to pick them out yourself.
Pete
No problem Pete, I didn't find anything searching their site that looked familiar, so I'll have to ask them!
@gunrunnerjohn posted:Manufacturing one is likely to be the solution I suspect. Looking at the Boston Gear Website, I suspect they'd have to have exact specifications to make it happen.
Yep, I suspect the gearbox is coming out. The gear ratio isn't critical, as long as the wheels go 'round I'll be happy.
That link is bad, this is all I get.
Length and width, ...this way we can see what can fit in your hole,..that and measure your axle, should be the same, but one never knows till the caliper says so,...😉....if you don’t have any luck with the other’s recommendations, let me know and we’ll figure out something,....
Pat
I may have a line on a solution, we'll see. I talked to Bob at All About Trains and he may have the wheelset with the gear, that would be a simple bolt-on solution, and put a big smile on my face. Of course, he might not, I'm going to send the wheelset down to him to see if he can match it.
I can understand your being excited if they DO have an exact match, but for the long term I'd be concerned that I would be looking at the same problem again at some point in the not-distant-enough future. Can anything be done to prevent the gear from wearing so badly?
Dale
Nothing that I know of short of making sure it's well lubed and not putting too much of a load on it. Part of the problem was a rod was apparently hitting one of the rod bolts and I guess that big 'ol Pittman just wanted to go.
We'll see if I can even get a match.
@gunrunnerjohn posted:Nothing that I know of short of making sure it's well lubed and not putting too much of a load on it. Part of the problem was a rod was apparently hitting one of the rod bolts and I guess that big 'ol Pittman just wanted to go.
We'll see if I can even get a match.
About the only thing you can do is double check the back lash if you get lucky and get a direct replacement part......if the back lash is a little sloppy, ie; a lot of lost motion before engaging, you can use a jewelers file to sneak up on bringing the gearbox closer to the worm wheel, only downside to that, you have to make trapping shims to put on the base pan to tighten up the now bigger gap,....kinda sucks, but doable,...
Pat
Sounds like it might be over my pay grade. 
Well, the news got a little worse. Once I got the gearbox out and could see the worm itself, it's all chewed up as well. So, not only do I need the wheelset with the gear, I need the worm as well. The whole gearbox is trashed. So now I'm looking for two pieces...
That's a Weaver? I've never seen a belt drive Weaver steam engine.
@Bob posted:That's a Weaver? I've never seen a belt drive Weaver steam engine.
You have now!
@gunrunnerjohn posted:Well, the news got a little worse. Once I got the gearbox out and could see the worm itself, it's all chewed up as well. So, not only do I need the wheelset with the gear, I need the worm as well. The whole gearbox is trashed. So now I'm looking for two pieces...
Have you had any luck with any of the other’s suggestions contacting the folks that have OE Weaver parts?....or is the jury still out?
Pat
The Jury is still out, I'm going to send it down to Bob at All About Trains, he has tons of Weaver parts. Maybe he has the whole gearbox, wouldn't that be swell!
I was surprised to see the actual worm all worn to a nub, they usually wear out the bronze gear.
@gunrunnerjohn posted:The Jury is still out, I'm going to send it down to Bob at All About Trains, he has tons of Weaver parts. Maybe he has the whole gearbox, wouldn't that be swell!
I was surprised to see the actual worm all worn to a nub, they usually wear out the bronze gear.
Yep,..usually the bronze or brass worm wheel is the sacrificial lamb,....if you can’t get any Weaver genuine parts, that looks mighty similar to 3rd Rail’s drive system, as I’m sure you’re aware,....if no joy with the Weaver vendors, try Scott and see if he has a gearbox with a shaft that long, or longer, and trim back to your length,....if Scott has a worm wheel and gear box arrangement, seems the only crucial measurements you’d need are axle OD, and worm shaft height,.....but most of the 3rd rail steamers I’ve seen apart look awfully similar to the pile of poop you have sitting there now,......more than one way to skin a cat,....😁😁😁.......
Pat
How did the worm get chewed up? Those are usually steel and *shouldn't* get chewed up by a bronze worm wheel.
@harmonyards posted:Yep,..usually the bronze or brass worm wheel is the sacrificial lamb,....if you can’t get any Weaver genuine parts, that looks mighty similar to 3rd Rail’s drive system, as I’m sure you’re aware,....if no joy with the Weaver vendors, try Scott and see if he has a gearbox with a shaft that long, or longer, and trim back to your length,....if Scott has a worm wheel and gear box arrangement, seems the only crucial measurements you’d need are axle OD, and worm shaft height,.....but most of the 3rd rail steamers I’ve seen apart look awfully similar to the pile of poop you have sitting there now,......more than one way to skin a cat,....😁😁😁.......
Yep, that will be my next stop if I can't get the Weaver parts. However, that's going to be a lot more work, I'd love to find the drop-in replacement.
@Lou1985 posted:How did the worm get chewed up? Those are usually steel and *shouldn't* get chewed up by a bronze worm wheel.
That's the mystery. I was a bit surprised to see it all worn down in the middle, first time I've seen one of those go like that. I've replaced lots of bronze gears and the worm looked unfazed.
There are worms that are double-enveloping (smaller diameter in the middle) that have more contact with the worm gear. Most likely not a Weaver design but you never know. Google it for a picture.
Maybe stock drive products out of New York would have something that would work
John , are the gearbox axle bearings a snug fit in the gearbox case ? I have some Williams , Weaver, Samhongsa boxes where those bearings were loose when the bottom cap was snugged down as tight as it can go. I had to make some brass shims to lock those bearings in place to stop them from turning in the case. The lash was far too great before I installed the shims. They pushed it all together snug and the lash now seems proper. You might look out for that when putting it all back together. Assuming your new gears don't come with a new case. Even with a new case I'd still want to make sure those bearings were held properly in place and not spinning in the side of the case. A little judicious use of loctite might provide a bit of insurance. j
I'll be taking care when reassembling, right now the object of the exercise is to find the correct parts to put it together.
@romiller49 posted:There are worms that are double-enveloping (smaller diameter in the middle) that have more contact with the worm gear. Most likely not a Weaver design but you never know. Google it for a picture.
I don't think this is the case looking at the gear.
Have you tried NorthWest Short Line for the gears? Not certain they've got something. But, probably worth a shot.
Also, try Des Plaines Hobbies in Illinois. They have a lot of O scale parts and such.
Fred
John is following the prudent path of trying to find Weaver parts to replace these. The problem I see with replacement gears is having to maintain the shaft centers, drive and axle shafts. If this was not a belt drive but a direct drive motor to driveshaft a replacement gearbox could simply be tilted to match the motor angle.
Using a new gearbox with different shaft centers in belt drive engine would require a new belt. A whole new problem.
Pete
@Fred Brenek posted:Have you tried NorthWest Short Line for the gears? Not certain they've got something. But, probably worth a shot.
Also, try Des Plaines Hobbies in Illinois. They have a lot of O scale parts and such.
Fred
NWSL said they have nothing that would work.
@Norton posted:Using a new gearbox with different shaft centers in belt drive engine would require a new belt. A whole new problem.
Yep, obviously the Weaver parts would be the best way to go, so that's where I am right now.
Wow, I’m usually an optimist but after seeing the photos I’d say without original replacement parts this engine is a shelf queen. Having gears made would probably cost more than the engine is worth. Let’s hope you can find them.
Yep, it doesn't look good. 
bob2 on the 2-rail forum seems to know a lot about older brass. I seem to remember him scratching some stuff, too. Maybe try reaching out to him?
Fred
Good plan, I think I can use all the help I can get!
John, hope you have made some headway in your search for direct replacement parts. However if you have not I think you can get what you need from Boston Gear or KHK-USA, others. Many years ago I sent stripped gears worm and wheel to Boston and they sent me back exactly what I needed. If you contact them they may be able to do the same for you. What is the number of teeth on the worm wheel ? You can rest assured these are not custom cut gears they are stock items Most of the gears in Samhongsa boxes were .5 modulus which is the metric term for Diametrical Pitch. Say that worm wheel was 16 tooth at .5 modulus. The diameter of the worm determines the skew angle on the wheel's teeth. This alone gives the gear houses all they need to know. Trying to count the teeth in your photo best I can tell is about 16. That is part of the problem a small diameter does not load as many teeth so each carries a larger load. I would be tempted to replace the bronze worm wheel with steel and use delrin for the worm and treat it as a sacrificial part since it is easier to replace. Attached are a couple of documents from gear suppliers that you may find helpful. j
https://www.bostongear.com/-/m...info-spur-gears.ashx
KHK has a similar document to Boston Gear but more metric in their terminology.
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