Replacement Belt for MTH Dispatching Board

MTH has said that the belt is not available. I tried to make one up but had no success. 

Bob, John:

I am having the same problem. Motor turns but no movement.

If you find a solution please share with the board, I will do the same.

Charlie

If you can Get the belt out. To see if it an 0 ring.  Or flat belt.

A seal and packing business can match it up. Did that with the saw mill belts. And I have extras of those..

This accessory is a disaster. I have tried to replace the belt which is made up of two parts held together by two fine fine metal pins. The pins extend above the edge of the belt and moves the man back and forth. Unfortunately, the replacement belt which I finally got from Brasseur trains in Saginaw, Mi. looked like it would work fine, but was too stiff to navigate the end spindles and would simply stop. Also, lots of sharp metal edges to cut yourself on inside this monster. I finally gave up and put it in the "maybe some day I'll try again pile." No substitute belt would work because it wouldn't move the man back and forth. The replacement belts were too stiff so don't feel bad that you couldn't get one. Notice how the accessory has disappeared from the catalogs. It's because it doesn't work for very long without aggravation.

turbgine posted:

It's because it doesn't work for very long without aggravation.

I've seen public layouts with it displayed and operating properly for well over a decade.

I think the belts die from inaction, not from use.

Looks like it's modification time. Must be a way to separate the 2.

The part is available from MTH as part number HH-5200416.  Web link is here:

https://mthtrains.com/part/hh-5200416

I have one of these which, even with the replaced belt, has been a mixed bag.  In our club another member came across one, replaced the belt, and got sketch results as well.  They have not held up to show usage.  The gear train looks solid but for some reason we have not had good luck with these.

Nick C.

It's listed, but it's not available.

Because the belt is comprised of a white nylon material and is in two halves secured together by two steel pins the point where the two halves come together have to navigate the spindles at each end results in a hangup of the belt at these spindles. So, then the motor turns but the belt fails to move. The belt need to be more supple so it can wrap around the spindles without binding. I don't know who made the original belts, but the MTH replacements were crap. They simply didn't work and they were expensive.

I talked with Mike about this at the last York show, since my belt shattered into about 6 pieces. He stated that is was not economical to make another run of belts. So for now, MTH is out as a part source. The belts die from age, whether or not the accessory is used. Just a poor part, IMHO. So I've been looking at belts used for robotic applications.There are some out there that may work, but everyone I've found requires some degree of modification to either the belt or the pulleys.  Keep looking, guys (and gals!). A solution is out there waiting to be found.

Oh, and forget about trying to find a parts diagram. The accessory was issued well before there was any thought given to exploded parts diagrams.

Chris

LVHR

Thanks for everybody that reply.  I picked this up for a couple of dollars at a local train meet.  Thought it was worth the challenge and to just take it apart.  The previous owner told me about the belt and the availability issue, but for $2, I couldn't past it up.

Couple of questions about its operation.  Does it use a momentary contact switch?  Does the man travel to the other side, turn around and pause before traveling back to his starting position?  This would explain the 2 pins on the belt.  Do you need to hold down the switch the whole time it operates, or just long enough to get the man started.

When I took it apart, a small piece of the belt was inside, about 1/2" long.  It broke apart when I touch it, but I did get some measurements off of it.  Don't know if this was stored in a warm area which could be part of the cause of the poor condition of the belt.  

I always wanted this accessory.  I'm glad I balked on getting it.  Quite a sad description of Mike Wolf's answer: "its not economical" to make replacement belts!  Geez.  How about re-releasing the dispatch board, along with an improved/durable belt, which can also replenish MTH's parts supply?

FWIW, we have been using off the shelf belts to fix these. The belt is T5 pitch, 12.5mm wide 66 0r 67 teeth. We drill a hole in one of the teeth using a micro drill bit of 0.75mm diameter, and then press in the original long pin. In addition, a collar is used on the pin to set the forward distance the belt can move towards the siding gantry. The reason is it's near impossible to get a belt with a ridge in the middle as a guide, but it's not strictly required and with some attention an off the shelf belt can be used.  While this is a 16mm wide example, at worst it hangs off the front edge of the pulleys, but may not then need the collar https://www.amazon.com/Gates-T...Length/dp/B00CJFSLMI

I was hoping I had pictures of the belt in place, but it was done at a friends house. All I could find was measuring the pitch of the original belt and then the video of it working after the replacement belt was installed.

 

Again, when I first saw one of these with the broken belt, I said one of 2 ways I know to fix this:

#1 use an off the shelf belt and modify as required to make it work- hence a T5 belt and drill the hole for the pin in a tooth- and this works amazingly well and tested on 2 units. T5-330-12 Synchro-Power Polyurethane Belt, T5 Pitch, 12mm Width, 66 Teeth, 330mm Pitch Length

or

#2 make a 3D printed belt, since TPU and other flex material are much more common.  OpenSCAD is one easy way to make the CAD design of a printable belt and even could have the ridge. I started on this, but stopped after the T5 belt worked so well and was cost and time effective. I will share the files I started when I get a chance. 

Just got the install pictures from my friend. The collar is just used on the pin to prevent the belt from sliding forward off the pulleys. Crude but effective instead of a rib inside the belt.

Great idea to use an off--the-shelf belt, I'm going to keep this in mind.

I am curious as to how this whole thing works? What does the pin do?

Big Jim posted:

I am curious as to how this whole thing works? What does the pin do?

The belt simply rotates a complete loop. If you watch the pin from the side, it moves in one direction, stops horizontal motion at the pulley, then turns and moves the other direction creating the back and forth motion of the figure. The pin simply is the method the belt transfers the motion to the slotted moving gantry with the figure. Think like a crankshaft that converts rotary motion to linear reciprocating motion, but the belt is an oblong crankshaft, and the resulting motion is extra long linear motion. The pin is literally the pin of the crankshaft. Go back and look at the pictures I posted earlier. The pin is just stuck into the side of the belt. The belt then is stretched over the 2 pulleys. The motor only turns the belt one direction however, in doing so, the pin actually moves back and forth when looked at from the front. That pin pushes the little rolling carriage on the metal rail via a slot, which is what allows it to make the full 360 loop rather than having to reverse the motor. The limit switch is there to park the belt and thus figure at the one end. You press the button, the motor turns the belt, the figure moves down the track to the end, then pauses for a second as the pin now slides down in the slot following the pulley turn, then pulls the carriage back until it hits the limit switch and stops, thus externally the little man parks at one end, then then commanded to "change the board" moves down until the end- then due to the slot has a minor pause, then moves back to the starting point and stops. The little carriage has a rack and pinion shaft such that the brass rack rod hitting the endstops at either end of the travel turns the little man on the shaft to face or walk in the direction of travel. The motor turns the belt, the belt pin drives the moving carriage, the moving carriage carries the little man.

https://www.youtube.com/watch?v=lZODzdY3HR0

Just replace the gear with a belt making an oblong horizontal path, and the blue moving carriage with the slot is the same but moves a much longer path horizontally.

I like my postwar one.  Works like a charm.   

Vinny26 posted:

I like my postwar one.  Works like a charm.   

Nothing wrong with a postwar one, but the difference is, the MTH one is much quieter (DC can motor) and has a much more impressive rotating board update than any Lionel version. Yes there are going to be 2 camps- old classic - and claim reliability and originality, and then there is the new modern wiz bang- and yes- the entire point of this topic is the belt can and does fail, and was a weak point in the design as manufactured by MTH- however, bonus factor- the DIY crowd can buy up these broken cast away "inferior" units for a fraction of the price, fix them for maybe even under $10 with an off the shelf belt, and perform better than new and last just as long if not longer than any film belt in an original one. This was never meant to be a debate of old vs new, just how to fix the new ones, but if you want to go there........

Sorry for the rant. My point was, I'm sitting here watching a topic of frustration for a lot of folks who bought these, had them break, then could not buy new belts and likely, that's because the spare belts on the shelf self destructed. So MTH said we aren't going down that road again, and people are left flapping in the wind. How many users have these broken sitting on a shelf? How many are beyond frustrated and came here for help? I come along, I measure the pitch and other belt details, having been in the 3D printing hobby that uses these light timing belts, I attempt to share knowledge of a cheap and reliable and now tested and proven solution. That solution should be widely available worldwide since we know the technical specifications and these belts are quite common given the 3D printer and CNC movement over the last 10 years, with massive production and low cost of these belts. The belt I linked from Amazon was just over $2 shipped to your door. I've seen the price range on these, but they can be had for some where between $15 clear down to an insane $2. Heck, the OEM belt from MTH was more than that shipped. Again, I'm just a bit frustrated and actually trying to help folks who may have given up hope, might have been quite upset, sitting there with a broken unit and no parts from MTH, and give them an option. Comments on a Lionel one- in this topic??? Who does that help?

 

Jetguy posted:

The point of this topic is the belt can and does fail, and was a weak point in the design as manufactured by MTH- however, bonus factor- the DIY crowd can buy up these broken cast away "inferior" units for a fraction of the price, fix them for maybe even under $10 with an off the shelf belt, and perform better than new and last just as long if not longer than any film belt in an original one.

I'm sitting here watching a topic of frustration for a lot of folks who bought these, had them break, then could not buy new belts because the spare belts on the shelf self destructed.   I'm frustrated trying to help folks who may have given up hope, might have been quite upset, sitting there with a broken unit and no parts from MTH, and give them an option.  Comments on a Lionel one- in this topic??? Who does that help?

 

You offer a GREAT and much appreciated suggestion/s!   

Just to make clear.  I have the MTH besides the postwar one.  The MTH one is dead.  Belt broke

Looking for suggestions on how to fixture the belt and drill a straight hole into the side of the belt without breaking out.  The size drill will be either  .75mm or 1/32" diameter hole in the belt.  It is such a small hole and the side of the belt is not very thick.  How deep should I go? I'm thinking 3/8"deep in a 1/2" wide belt.  

I thank all of you for your help.

Jetguy posted:

FWIW, we have been using off the shelf belts to fix these. The belt is T5 pitch, 12.5mm wide 66 0r 67 teeth. We drill a hole in one of the teeth using a micro drill bit of 0.75mm diameter, and then press in the original long pin. In addition, a collar is used on the pin to set the forward distance the belt can move towards the siding gantry. The reason is it's near impossible to get a belt with a ridge in the middle as a guide, but it's not strictly required and with some attention an off the shelf belt can be used.  While this is a 16mm wide example, at worst it hangs off the front edge of the pulleys, but may not then need the collar https://www.amazon.com/Gates-T...Length/dp/B00CJFSLMI

I was hoping I had pictures of the belt in place, but it was done at a friends house. All I could find was measuring the pitch of the original belt and then the video of it working after the replacement belt was installed.

 

@Vernon Barry someone had a good question regarding how to drill straight into the belt without having the bit break out.

 

Also, the belt you suggested is apparently special order from Gates, although there are other similar belts available on eBay

I think this is a club board.

Mth why a belt like this?.  I'll give a point. For using the top and bottom for back and forth

But. . this should of been done with a long worm. And the gear attached to the trolley. 

Switch at each end.

An acme thread and nut could be used too. 

2 bearings at end to support rod. Simple... And this would of been a lot less to make.

And would last for a long time. 

That might be my fix. 

I guess. Even using a long bolt and nut would work too. 

But you would need to add a gear. A worm you can use that with a motor with a gear on end  To turn it. Less work..

Ok, I bit the bullet and bought an off the shelf belt. I managed to drill enough of a hole that I can get the pin in place. More on that in a separate post later. 

My question has to do with the wiring. I managed to break off one of the wires that goes to the stud panel. The outside has 3 posts: the top 2 are for the switch, and the side 2 are for power. But on the backside, there are 4 wires. 2 are black. One goes to a disc capacitor and then ties to the frame. To which stud does the other end go?

Thanks in advance for your help!

Chris

LVHR

This subject seems to need a boost. Both black wires go together on the bottom post. I had two to repair so I got extra belts in case I screwed up attaching pin. Also the shipping would have more than doubled price of belts. Anyway I did not screw up any so I have extra flexible belts with out pin holes. Reading all of the above problems and solutions I did not see any one else complain about the other manufacturing problems. On one the motor had to be raised to keep the gears from disengaging. Both of them had the sticky oil problem that happen with the oil used in both Lionel and MTH after 20 years. Some one mentioned the belt slipping from the MTH replacement. On both the belt tensioner was locked in place by not training the assemblers and poor engineered tensioner. Over all accessory is built well and others parts are over built.

To everyone who contributed a suggestion or idea,THANK YOU!!!!  My MTH Dispatching Board is now repaired and operational!

LK: Thanks for telling me where the broken wire went. Your belt tensioner comment is spot on as well. Poorly designed, and poorly assembled. It took a bit to get mine free. It is better than it was, but that is not saying much. I did not disassemble the motor and gearbox. It was running slowly when I first tried it, but gradually freed itself and was running fairly well when I stopped for the night. Is Red-n-Tacky  a suitable grease for these plastic gears?

Jetguy: The belt wants to wander off the idler roller, but cannot, because it is wider than the original belt, and there is not enough space for it to clear the roller. And I do have a spacer on the pin to the trolley to help keep the belt in place. What we need is a replacement roller design. I have an idea which should work, have no access to a 3D printer. If anyone has access to one and is willing to help us out, please contact me via email. 

BTW, drilling the hole for the pin is a pain in the tush. I ruined the first hole as the rubber just did not stay put while I tried to drill it. I finally hit upon the idea of clamping it securely in a vise with flat metal jaws. This kept the rubber from wiggling. But I still could not drill a straight hole. The bit traveled out near the middle of the tooth. So I reversed the belt in the vise, and drilled from the other side: Same result. At this point I took an Exacto knife and cleared out the rubber in the middle. This left me with 2 rubber posts with holes. I put the pin in, and it stayed. Not a perfect solution, but it works, at least for now. I'm not worried about a damaged tooth or 2 weakening the belt. I found out mine has steel belting inside the rubber.

Chris

LVHR