dscott
Elder Statesman
Posts: 2,438
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Post by dscott on Nov 18, 2020 2:00:31 GMT
All the wheels are coned to 2 degrees and the weight which is considerable seems to slam the wheels down into any hollow sections. It came off twice. The first being my fault for putting the coupling hook into the wrong hole. So when putting more power it slewed over. The second was some pointwork that had rusted up over the lockdown. I cleaned it out more and splashed even more oil over it. We spent 3 hours working to clear weeds and free ALL THE POINTS before our first run of the summer. Poor thing looked like a TRAINCRASH.
David and Lily.
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lesstoneuk
Part of the e-furniture
Retired Omnibus navigation & velocity adjustment technician
Posts: 373
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Post by lesstoneuk on Nov 18, 2020 2:18:34 GMT
It may look like a train crash but it certainly grows on you.
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Post by David on Nov 18, 2020 10:31:48 GMT
Not only do you get your dxf output, but you get 2D drawings of your 3D model with zero effort, and a permanent precise archive of what you've created. Once you've mastered it, you'll never go back because everything else seems like hard work. I mostly agree with the recommendation, with some caveats: 1. Autodesk are tightening the screws on the hobbyist version of F360. I'm guessing more and more functionality will be disabled as people find ways around the things they're taking away. F360 is scriptable, meaning someone who knows it well enough can sometimes work around their hobbling, so Autodesk might keep taking away more things in response making it less usable for us freeloaders. You can't believe anything they say - "full functionality will always be free for the hobbyist!" - that was either naive or a known lie when it was said. They must have known plenty of commercial shops would use the hobbyist version, or hobbyists would fudge the $1000/year income limit. 2. You don't get 2D drawing with zero effort. I've never got a good drawing out of it, and I haven't read a good word about F360's drawing feature. And they're hobbling it on the hobbyist version starting last October, see point 1. 3. I'm not sure how good the DXF output is. You'd think it would be amazing given it's Autodesk's own format, but I've had some iffy output. I'd open it in a 2D CAD package and check it over before I sent it to a laser or water jet cutter. Their 2D sketch drawing function is really good though, and generally easier to use than a 2D CAD program modelled on AutoCAD as most seem to be. I'm just not convinced the conversion to DXF is all it could be. F360 has what I assume to be a good 3D modeller, and I'm sure people who know it can make the CAM sing, but it has a lot of rough edges too. There's all sorts of places in the UI and other things where they're bungled it. The location of the custom thread definition files changes with every update for example and it's buried in a deep, difficult to find and remember location. There's a lot of terrible programming and UX design in F360. If all that sounds like sour grapes, it is! But you can't expect a company to let people use something for free that other people pay $1000s/year for, it just doesn't make sense. I agree with the general recommendation to go to 3D CAD. The trick is finding one that is affordable. I think Model Engineer magazine had a deal with Alibre for Atom which I'd have been interested in if it had CAM enabled. That's not a problem for someone without a CNC machine.
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dscott
Elder Statesman
Posts: 2,438
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Post by dscott on Nov 19, 2020 0:06:41 GMT
We then got lots of teasing from other Club members as there was no alternative picture of Lily on page 3.
We are a FAMILY Club as well.
David. and Lily thought it was very funny.
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lesstoneuk
Part of the e-furniture
Retired Omnibus navigation & velocity adjustment technician
Posts: 373
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Post by lesstoneuk on Nov 23, 2020 8:26:16 GMT
Taking on board all of your most welcome advice, I've now opted to a) go 24 volts b) upped the motor amperage to 150 Watts a piece giving a new total of 600 Watts. Now I'd prefer belt drive, it's quieter and just as forgiving as chain. Any comments there would be appreciated.
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jackrae
Elder Statesman
Posts: 1,333
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Post by jackrae on Nov 23, 2020 12:10:59 GMT
If using belt drives it's essential that you maximise the number of teeth in contact on the smaller drive to prevent tooth jumping. This tends to preclude large reduction ratios (>2:1) unless you use an idler 'wheel' to ensure sufficient wrap around the smaller (drive) pulley. As per chain installation practices, position the idler wheel on the non-loaded belt run. And keep belts tight and correctly aligned! Once the belt shows any tendency to jump teeth it's scrap.
But why not chain drives. They don't make much noise in comparison to the noise of flanged wheels running on the track; they are less liable to 'jump' teeth, they require less tension to keep them running, they are more tolerant to mis-alignments and they tolerate large reduction ratios with minimal teeth in contact with the chain.
I'd suggest you avoid the temptation to use a 'simple' gear-to-gear transmission where a pinion on the motor shaft mates with a larger gearwheel on the back of the running wheel. Too noisy and subject to wear.
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lesstoneuk
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Retired Omnibus navigation & velocity adjustment technician
Posts: 373
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Post by lesstoneuk on Nov 23, 2020 14:22:04 GMT
I definitely don't want an all gear drive. I was edging towards a belt drive having worked out an active excel sheet to use driver and driven toothed wheels, motor rated rpm and loco driving wheel diameter to give me the maximum theoretic mph. I also bought early on three EIM magazines that detailed building a 5" gauge battery electric. The author used an idler to increase the active teeth and keep the belt tension up.
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stevep
Elder Statesman
Posts: 1,070
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Post by stevep on Nov 23, 2020 15:21:01 GMT
I know Jackrae advised against using a gear-to-gear transmission, but this is what is fitted to my 08 shunter (based on Charlatan). It has a steel pinion, engaging with a tufnol gear wheel fixed to the back of the wheels. It is not at all noisy, and there have been lots of Charlatans made. I haven't hear of them failing.
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Post by delaplume on Nov 23, 2020 17:09:42 GMT
Hello all, Just a couple more to add to the mix}------ 1) Quill shaft, as per full size locos ---------- en.wikipedia.org/wiki/Quill_drive -------- 2) Variomatic Vee-Belt as per Raleigh Wisp / Mobylette mopeds...
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Post by andyhigham on Nov 23, 2020 17:34:54 GMT
The big disadvantage of both chain and gears is the grease picks up dust and grinds it into the gears/sprockets, especially on ground level. Toothed belts are pretty resilient I have a 30mm wide one on my 90BHP race bike, it has lasted 2 seasons of winding on 10K RPM and dumping the clutch and hundreds of full throttle clutchless gear changes. Another option would be a "poly V" belt
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jackrae
Elder Statesman
Posts: 1,333
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Post by jackrae on Nov 23, 2020 18:55:57 GMT
Don't get me wrong. I'm an advocate of toothed belts. As a young engineer I first used them in a trawler's hydraulic power drive system way back in 1970 (to the shock horror of the local boat engineers) Correctly designed, sized and installed they are the "bees and knees"
Non-toothed drives, ie neither chains or toothed belts, all rely on friction to effect power transfer; friction equates to heat and wasted energy, something an electric loco needs to avoid.
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lesstoneuk
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Retired Omnibus navigation & velocity adjustment technician
Posts: 373
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Post by lesstoneuk on Nov 23, 2020 18:56:36 GMT
I'm old enough to remember the Kawasaki gpz305. Everything was eithe chain drive or there were a few shaft drives. At the time we were sceptical as to whether it was a viable kwacker but look now, even harley-davidsons use belts now.
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Post by coniston on Nov 23, 2020 23:26:51 GMT
I'm old enough to remember the Kawasaki gpz305. Everything was eithe chain drive or there were a few shaft drives. At the time we were sceptical as to whether it was a viable kwacker but look now, even harley-davidsons use belts now. I had one of those as well. not a bad commuter bike but the ZZR600 that followed was somewhat more capable. Chris D PS, I'd go for tooth belt - quieter, very wide range available and low profile so less space required. Add a back idler to gain wrap if required but I'm sure you can find info on the web about design for the power required (not much really 150W)
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lesstoneuk
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Retired Omnibus navigation & velocity adjustment technician
Posts: 373
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Post by lesstoneuk on Nov 24, 2020 5:02:03 GMT
I'm old enough to remember the Kawasaki gpz305. Everything was eithe chain drive or there were a few shaft drives. At the time we were sceptical as to whether it was a viable kwacker but look now, even harley-davidsons use belts now. I had one of those as well. not a bad commuter bike but the ZZR600 that followed was somewhat more capable. Chris D PS, I'd go for tooth belt - quieter, very wide range available and low profile so less space required. Add a back idler to gain wrap if required but I'm sure you can find info on the web about design for the power required (not much really 150W) One question that I find difficult to find an answer to is.... How do you measure toothed belts? I realise that now I have asked it there will now be thousands of sites appearing on Google. Sods law
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jackrae
Elder Statesman
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Post by jackrae on Nov 24, 2020 8:34:13 GMT
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lesstoneuk
Part of the e-furniture
Retired Omnibus navigation & velocity adjustment technician
Posts: 373
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Post by lesstoneuk on Nov 24, 2020 8:49:37 GMT
You're an absolute gentleman, exactly what I needed. Thanks
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Post by andyhigham on Nov 24, 2020 9:03:30 GMT
HTD belts are the best They will be designated along the lines HTD LLL-PM-W LLL=Length P=Pitch M=Metric W=Width
All in mm
Tension is correct when you can twist the belt 45deg between thumb and finger in the middle of longest run
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Post by andyhigham on Nov 24, 2020 9:10:39 GMT
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jackrae
Elder Statesman
Posts: 1,333
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Post by jackrae on Nov 24, 2020 9:43:13 GMT
HTD belts are the best They will be designated along the lines HTD LLL-PM-W LLL=Length P=Pitch M=Metric W=Width All in mm Tension is correct when you can twist the belt 45deg between thumb and finger in the middle of longest run If the centre to centre distance is short the 45degree rule does not apply
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dscott
Elder Statesman
Posts: 2,438
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Post by dscott on Nov 25, 2020 2:32:14 GMT
I get all my stuff from Bearing Boys and they have been superb. As seen ti the Photos of The Beast. After your first order they send you a 10% off the next order which is tempting. They also do many other types of bearings including the CNC stuff. Just call and have a chat.
David and Lily.
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