5 ms·

Where can you find supplies for these kinds of projects? Each 6ft. section of rack would cost $81 plus shipping from McMaster-Carr.Never mind the other componen

by tvb12 4y ago

Where can you find supplies for these kinds of projects? Each 6ft. section of rack would cost $81 plus shipping from McMaster-Carr.Never mind the other components, that would add up quickly. I was trying to find some spur gears for a project, but wow those are expensive. I reworked it to use pulleys, but those weren't as cheap as I'd hoped, either.

itronitron 4y ago
If you're near a metal fabrication shop (stairs, metal fences, signs, etc.) then they should be able to source it for you if they don't have it in stock and also easily bend it for you. Total labor hours charged for this would likely be under four hours.
_fs 4y ago
I don't believe these kind of projects are designed to be economical :). He is building this to drive traffic to his youtube channel, which in turns, pays for the next outlandish project.
- nine_k 4y ago
  They can be made economical if you have a lot of salvaged parts for cheap / free. (As a boy, I could not have built much of the stuff I've built from 74xx ICs if I had to buy all of them new; instead, I had a bunch of PCBs from a decommissioned computer.)
  - aliqot 4y ago
    The motor for the little trolley in the video is a salvaged wiper motor.
adrianmonk 4y ago
Can't answer the supply question, but it seems to me his problem could have been solved by drilling a line of holes into the sheet metal rail. Then have a sprocket stick into those holes. It works for film in movie projectors (https://en.wikipedia.org/wiki/Film_perforations https://en.wikipedia.org/wiki/Film_perforations), so why not for a trash train? It uses fewer parts, at least. But maybe cutting a bunch of holes in already-installed rail is more work than welding rack onto it.
- joatmon-snoo 4y ago
  What you're describing is still a rack and pinion system, but likely to wear much more aggressively. I would be happy to be proven wrong, but my gut instinct is that such a system would wear out very quickly, because due to the involved forces, the sprocket teeth would wear out the holes really quickly. Film, I would assert, works because the teeth just need to align the film; force transfer just uses the filmstrip itself. Gear teeth are a reasonably complex design - settled, for the most part, I think, but still non-trivial - and do their job very well. It's a lot of "meshing together heterogeneous surfaces to maximize force transfer" problem solving.
  - adrianmonk 4y ago
    > Film, I would assert, works because the teeth just need to align the film; force transfer just uses the filmstrip itself. I'm not a projectionist or a mechanical engineer, but I reasoned the opposite way: * Film sprockets have a difficult job because the film has to be stopped and started 24 times a second[1]. It needs to be held still while light is shining through it, and then (to reduce flicker) it needs to get moved to next frame quickly. * Film seems soft and easy to damage, but somehow all that seems to work anyway. * So it's probably OK if you have a stronger material like steel and all you need to do is move at a constant speed. > Gear teeth are a reasonably complex design That's a really good point. Here's a page that covers film sprockets: https://www.sprocketschool.org/wiki/Sprockets https://www.sprocketschool.org/wiki/Sprockets And sure enough, it covers the evolution of sprocket design, saying a manufacturer "created the VKF ('very kind to film') sprocket in order to improve presentation and reduce film wear". So, although you could probably steal ideas from film, there is indeed some engineering to do. Also, the trash train designer said he wanted smooth, quiet operation. He 3D-printed the pinion gear out of plastic, which achieves that. If he'd done a sprocket and hole thing, my guess is the sprocket teeth need to be strong, so it probably has to be made out of steel. So it'd be harder to make and less quiet. I guess the main reason film does it this way is because it has to. It's flat. I still think the film-style approach is probably feasible, but now I'm convinced it has some significant drawbacks. --- [1] Apparently the sprockets that do this are called intermittent sprockets. Wikipedia has a good explanation and illustration here: https://en.wikipedia.org/wiki/Movie_projector#Film_gate_and_frame_advance https://en.wikipedia.org/wiki/Movie_projector#Film_gate_and_... Note the blue arrows showing slack between the intermittent sprockets and the other sprockets that move continuously.
imtringued 4y ago
I don't know what racks he uses but one meter of rack doesn't cost very much on Aliexpress.
- nine_k 4y ago
  Hos is the shipping?
notwokeno 4y ago
You could probably use aluminum stock from eg Lowe's as rails. I built a bunch of solar panel brackets from that last year and remember being surprised by how cheap it was. McMaster-carr is great but it's almost always crazy overpriced.
Prcmaker 4y ago
I've built scale track out of 25x6mm flat bar steel, plenty strong enough for people to ride on. I wouldn't call the time spent 'fun', but even after buying equipment you'd break even over the mcmaster track very quickly.
HeyLaughingBoy 4y ago
With mechanical stuff, if you're not being paid for it, the best approach is to design around cheap, easy to find parts. You need cheap rack? Find a way to secure bicycle chain to a flat surface and use a sprocket for the drive.
iancmceachern 4y ago
Use mcmaster to figure out what you need, and then many of these drive component type things like rack, gearboxes, bearings, etc. are made to standards. Once you know what you need, say a 50:1 nema 23 gearbox just search that on eBay or ali express. Even if there isn't a listing for exactly what you need, just message a factory/supplier thatbhas something similar posted and they can likely get it to you.
dotancohen 4y ago
McMaster-Carr is for "I need a very specific thing right now at any cost", not for projects like this. Use it as a guide to discover what is available, but only order from there if every day your project is held up is costing you real money.

by tvb12 4y ago

itronitron 4y ago

If you're near a metal fabrication shop (stairs, metal fences, signs, etc.) then they should be able to source it for you if they don't have it in stock and also easily bend it for you. Total labor hours charged for this would likely be under four hours.

_fs 4y ago

I don't believe these kind of projects are designed to be economical :). He is building this to drive traffic to his youtube channel, which in turns, pays for the next outlandish project.

nine_k 4y ago
They can be made economical if you have a lot of salvaged parts for cheap / free. (As a boy, I could not have built much of the stuff I've built from 74xx ICs if I had to buy all of them new; instead, I had a bunch of PCBs from a decommissioned computer.)
- aliqot 4y ago
  The motor for the little trolley in the video is a salvaged wiper motor.

adrianmonk 4y ago

Can't answer the supply question, but it seems to me his problem could have been solved by drilling a line of holes into the sheet metal rail. Then have a sprocket stick into those holes. It works for film in movie projectors (https://en.wikipedia.org/wiki/Film_perforations https://en.wikipedia.org/wiki/Film_perforations), so why not for a trash train? It uses fewer parts, at least. But maybe cutting a bunch of holes in already-installed rail is more work than welding rack onto it.

joatmon-snoo 4y ago
What you're describing is still a rack and pinion system, but likely to wear much more aggressively. I would be happy to be proven wrong, but my gut instinct is that such a system would wear out very quickly, because due to the involved forces, the sprocket teeth would wear out the holes really quickly. Film, I would assert, works because the teeth just need to align the film; force transfer just uses the filmstrip itself. Gear teeth are a reasonably complex design - settled, for the most part, I think, but still non-trivial - and do their job very well. It's a lot of "meshing together heterogeneous surfaces to maximize force transfer" problem solving.
- adrianmonk 4y ago
  > Film, I would assert, works because the teeth just need to align the film; force transfer just uses the filmstrip itself. I'm not a projectionist or a mechanical engineer, but I reasoned the opposite way: * Film sprockets have a difficult job because the film has to be stopped and started 24 times a second[1]. It needs to be held still while light is shining through it, and then (to reduce flicker) it needs to get moved to next frame quickly. * Film seems soft and easy to damage, but somehow all that seems to work anyway. * So it's probably OK if you have a stronger material like steel and all you need to do is move at a constant speed. > Gear teeth are a reasonably complex design That's a really good point. Here's a page that covers film sprockets: https://www.sprocketschool.org/wiki/Sprockets https://www.sprocketschool.org/wiki/Sprockets And sure enough, it covers the evolution of sprocket design, saying a manufacturer "created the VKF ('very kind to film') sprocket in order to improve presentation and reduce film wear". So, although you could probably steal ideas from film, there is indeed some engineering to do. Also, the trash train designer said he wanted smooth, quiet operation. He 3D-printed the pinion gear out of plastic, which achieves that. If he'd done a sprocket and hole thing, my guess is the sprocket teeth need to be strong, so it probably has to be made out of steel. So it'd be harder to make and less quiet. I guess the main reason film does it this way is because it has to. It's flat. I still think the film-style approach is probably feasible, but now I'm convinced it has some significant drawbacks. --- [1] Apparently the sprockets that do this are called intermittent sprockets. Wikipedia has a good explanation and illustration here: https://en.wikipedia.org/wiki/Movie_projector#Film_gate_and_frame_advance https://en.wikipedia.org/wiki/Movie_projector#Film_gate_and_... Note the blue arrows showing slack between the intermittent sprockets and the other sprockets that move continuously.

imtringued 4y ago

I don't know what racks he uses but one meter of rack doesn't cost very much on Aliexpress.

nine_k 4y ago
Hos is the shipping?

notwokeno 4y ago

You could probably use aluminum stock from eg Lowe's as rails. I built a bunch of solar panel brackets from that last year and remember being surprised by how cheap it was. McMaster-carr is great but it's almost always crazy overpriced.

Prcmaker 4y ago

I've built scale track out of 25x6mm flat bar steel, plenty strong enough for people to ride on. I wouldn't call the time spent 'fun', but even after buying equipment you'd break even over the mcmaster track very quickly.

HeyLaughingBoy 4y ago

With mechanical stuff, if you're not being paid for it, the best approach is to design around cheap, easy to find parts. You need cheap rack? Find a way to secure bicycle chain to a flat surface and use a sprocket for the drive.

iancmceachern 4y ago

Use mcmaster to figure out what you need, and then many of these drive component type things like rack, gearboxes, bearings, etc. are made to standards. Once you know what you need, say a 50:1 nema 23 gearbox just search that on eBay or ali express. Even if there isn't a listing for exactly what you need, just message a factory/supplier thatbhas something similar posted and they can likely get it to you.

dotancohen 4y ago

McMaster-Carr is for "I need a very specific thing right now at any cost", not for projects like this. Use it as a guide to discover what is available, but only order from there if every day your project is held up is costing you real money.