Greg Elmassian said:
Pete, I found this a while back, perhaps some of these universals are the right size?
https://store.rc4wd.com/Punisher-Shafts_c_27.html
Greg
Thanks Greg. I stopped at a serious r/c car racing store a few weeks ago but everything was too big. Which is not to say there isn’t a smaller one!
Haven’t had time to look yet.
Pete,
Thanks for the offer and the notes on the B’mann railtruck. Your project is fascinating and well out of my skill league! A bit off topic, but I suspect a fried circuit board the boy’s railtruck and intend to open the thing up and see if I can bypass it, letting the leads go straight to the lights and motor. Different project, different thread, different time, but I wanted to acknowledge your posts.
Looking forward to your continued work!
Eric
I had a little spare time this afternoon for here’s the latest episode and pictures.
First I took the gears and drive shaft out. Here’s the crossbox with the strip of brass filed down:
THen I set out to attach the small bevel to the driveshaft using the collars. Here’s the drill to sink an 11/64 hole in the first part of the collar:
I soldered the gear to the collar with my small torch. No, there’s no flame as I posed this for the photo.
My main concern is that the gears do not seem to mesh very well. They are supposed to mesh at a 1/8th skew and I’m happy that I am close to that on both crossboxes.
Despite careful alignment and spacers, they don’t fill me with confidence that they will work in the long term. The drive is happiest one way. I have to assume they are very sensitive to the mesh angles. Anyway, I got out my 12V drill and hooked it up. (You can barely see the rollers underneath supporting the truck):
It does work. However, the collar and big bevels move a little as they aren’t tight enough, and soldering the small bevel meant they are actually very tight on the driveshaft but I still can’t stop them moving out of mesh.
Onward and Upward. Time to get a set of universals and install this thing. You may notice I moved the driveshaft a little to one side so I can reach the pivot screw of the truck when I want to install one.
The rear gear was slipping so I took the driveshaft out and soldered it on. When I put it back together I put the shaft on the other side of the axles so it won’t be so visible.
I also poked around Bachmann’s parts store and NWSL to see if I could find a universal. NWSL has them, but still isn’t reorganized to sell me one. I did find a Climax yoke for $9 which should do the job. The motor under the hood of this truck has part of a universal and in any case I will need a 2-piece drive line as it is so long.
While I am waiting for the universal (“yoke”) from Bachmann, I took down the truck and had a close look at the front drive.
Appears I have a universal and it has a square drive hole in it. I have a bunch of brass tube and square rod around, so it shouldn’t be difficult to make something fit.
Next issue is to raid my parts box for some Accucraft, USA or Bachmann track pickups. I normally run battery so they are taken off, so I should have lots of choice for this truck and the front one.
While I’m waiting for the Climax yoke, I dug out my B’mann and Accucraft coach wheel pickups. [I used batteries to light the coaches so the pickups were removed.]
The front truck is a B’mann shortie truck, which they are currently selling for $8.40 complete with wheels. I added a pair of Accu pickups bolted to the crossmember.
The bolts are now trimmed and will be painted. The wires are soldered to the pads under the front of the frame - the original used B’mann’s favorite sprung plungers, which I don’t have and don’t want.
The curly spoke wheels came from Jason at The Train Department. I think they are 7/8ths scale, but it occurred to me that I could trim the axle ends and make a cute inside frame front truck. Maybe next time. . .
Having fixed the front truck, I separated the B’mann truck half from the boxcar half and tested it with an old 12V power pack. The rear pickups came with it so it was easy to apply power there, and the motor turned nicely. No joy from the front though. I printed my wiring diagram (from the B’mann parts website) and poked around. There are supposed to be 2 yellow wires from the front truck to the PCB in the bed - mine were both in terrible condition. On the first pic you can see the corroded (!) wire on the right, out of the split insulation. [Curious - none of the other wires were bad.]
The other side had corroded deep into the underside frame:
Well, it was a pain to clean the corroded wires and solder them, but now we have continuity and the motor runs when powered from the front or the back.
The Bachmann parts turned up very quickly, and the Climax yoke looks like it will work. (This is part of the driveshaft on the Climax - one end has gears and this end does not, as only one power truck drives the shafts.) It has a square (sliding) join which my brass tube will fit, and when you take the plastic collar off and remove the piece of frame, you end up with a 4mm shat that has 2 raised parts to keep the gear turning. It was easy to drill a 5/32 collar to 11/64ths to slip over the 4mm shaft.
However, the inside of the shaft is a screw hole, so that has to be drilled out 3/32’ to slide on the truck driveshaft. Not easy to make it concentric without a proper lathe (which I don’t have,) so mine is a little eccentric. It shouldn’t matter, as the whole shaft isn’t balanced or properly engineered to be inline.
The collar has indentations cut with a dremel cutting disk, very crudely, to fit over the shaft projections and stop it spinning, and I drilled out the plastic shaft for the setscrew to go right through it and hold the whole thing on the shaft.
So far, so good. Now to cut the square tube to length, pin the thin piece to the plastic universal at the motor end the thicker one sliding over it to the truck at this end (with another square tube piece as filler.) Then connect all the wires and test.
Makin progress.
I had a couple of minutes before our guests arrived so I flipped it over and wired up the rear truck, added pins in the universals so the square tube doesn’t fall out, and reassembled it.
I then put it on some rollers and clipped wires to the front, and it worked. (I was amazed.) The driveshaft wobbles atrociously due to the out-of-round non-concentric shaft I drilled, but I left it running while I touched some paint to the tools on the roof and it seemed to settle down and start to run less rough.
If I was keeping it I would (perhaps) buy another yoke and find a way to make it centered. Maybe it’s prototypical that way? Anyway, tomorrow we do a track test on the Spa Creek & McKendree RR. . .
With a shaft that long, you may want to cobble up a center support bearing of some sort, so the driveshaft doesnt deflect too far to one side. Just a thought.
I agree, I was wondering how you could have that long of a driveshaft without it whipping around a lot. Of course a center mount on a square shaft might be tough.
Greg
David Maynard said:
With a shaft that long, you may want to cobble up a center support bearing of some sort, so the driveshaft doesnt deflect too far to one side. Just a thought.
With the eccentric universal on the back, it already deflects far too much! (But thanks for the thought.) I had wondered whether to include a center bearing, but it would have involved another universal.
Took the railtruck to the Spa Creek & McKendree RR yesterday and it ran pretty much as expected. Plenty of prototypical gear noise!
I reversed the rear truck (and the front, so the polarity stayed constant,) as it seemed noisier in the forward direction. It has a little paint on the driveshaft. It runs quite slowly, as the bevels are 3:1 ratio and the original truck is 1:1.
I also brushed some paint on the tools on the roof, as they looked odd being all the same gray!
Well done, Pete!
What happened to the one in the background, laying on it’s side?
Looks good, Pete,
Ken
That was from a raccoon that had been feeding on the radioactive daffodil bulbs…
Jerry
Well it seems it is actually a fox, motion lights came on last night, enormous fox poking around the layout, leaving occasional buildings, cars, etc on their side in it’s wake
Ah, nature
Jerry
Well it seems it is actually a fox, motion lights came on last night, enormous fox poking around the layout, leaving occasional buildings, cars, etc on their side in it’s wake
Ah, nature
Jerry
Well it seems it is actually a fox, motion lights came on last night, enormous fox poking around the layout, leaving occasional buildings, cars, etc on their side in it’s wake
Ah, nature
Jerry
Wow, a hear of three foxes!(https://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-tongue-out.gif)
