lesstoneuk
Part of the e-furniture
Retired Omnibus navigation & velocity adjustment technician
Posts: 373
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Post by lesstoneuk on Nov 13, 2020 10:50:14 GMT
In my intro I mentioned that I'm building a BR Class 76 loco. At the moment I'm doing the designing old school with pen, pencil, compass and paper. First question is I have an android tablet and a ipad 2 tablet so is there a program.... Yes I know they are apps.... For 2D CAD? . I ask because the laser cutter needs a dxf file to work with. I'm looking at a simplified bogie with a 120w brushed motor suspended on a swinging arm per axle. That'll give 480w for the loco. So second question is will that wattage be enough? The wheels will be 'Torquay Manor' tender wheels.. Right size and spokes. Third question is as there are no reciprocating forces will it be possible to use 6mm steel plate for the bogie frames and forgo axle box guides?
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uuu
Elder Statesman
your message here...
Posts: 2,808
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Post by uuu on Nov 13, 2020 11:07:03 GMT
Well, the Maxitrak class 25 loco has eight 60 watt motors, so the same power. Link to Maxitrak They claim 10 persons can be pulled up a 1 in 100 gradient. Could you add a plate at the axlebox opening to double up the thickness at that point, giving 12mm? Wilf
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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 13, 2020 11:57:25 GMT
Yes, that's not a bad idea of doubling the frame thickness locally. It'll give me a wider choice of needle roller bearings to consider. I've picked 120w as its between 100w and 150w.These motors are interchangeable. I'm looking at a 60amp speed controller. 120w motors will draw 40amps,nice safety margin I thought.
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Post by delaplume on Nov 13, 2020 12:42:30 GMT
Hello there, Ah-ha !!------- you beat me to it !! So, is this what you have in mind ?----------> -----------> You don't say what gauge it will be in---- I'm assuming 5" ???....... On BR, first generation Diesels and Electric locos had traction motors that were "Axle-hung, nose suspended" with the drive being transmitted via meshing gear wheels...........If you intend to transmit the drive direct onto the axle then don't forget to pin the wheels onto the axle... Try to keep the overall weight of the bogie to a minimum, so 3mm plate is ok and for the axlebox guides why not use some BMS angle riveted on ?? Have you given any thought to the control system to be used ?? Battery Electric models are becoming quite popular these days and there is lots of help available... Best of luck and please keep us informed...
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don9f
Statesman
Les Warnett 9F, Martin Evans “Jinty”, a part built “Austin 7” and now a part built Springbok B1.
Posts: 960
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Post by don9f on Nov 13, 2020 12:43:53 GMT
Well, the Maxitrak class 25 loco has eight 60 watt motors, so the same power. Link to Maxitrak They claim 10 persons can be pulled up a 1 in 100 gradient. Wilf Hi, I have a Class 25, rated at 480W as mentioned above and it pulls well enough with say 6 adults on our track that has a max uphill gradient of 1 in 150. However the Maxitrak gear ratio limits the speed to around 6mph and sometimes I wish it had just a bit more “oomph”, but on the whole it goes well. I imagine that if the gear ratio was lower, 480W might not be enough, but this is just my thoughts. I have two 45Ah lead acid batteries that easily last me a day, but I’ve never got round to actually measuring any volt-drop in the cabling etc. that might cause a slight reduction in power. Cheers Don
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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 13, 2020 12:53:36 GMT
Yes, that's a class 76.I intend to use a subframe with bearings on the bottom end to move about the axle. One motor will be mounted on the frame driving via toothed pulleys. The top end of the frame will have slots to allow for movement of the axle boxes. These slots will ride on a round crossbar. I've already done an excel table to work out revs/driver/driven ratios
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kipford
Statesman
Building a Don Young 5" Gauge Aspinall Class 27
Posts: 566
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Post by kipford on Nov 13, 2020 12:54:57 GMT
Quick google search shows both 2D and 3D software available for both Android and Apple including well packages like Autocad and Turbocad. I have never used any of them as I have always worked exclusively in 3D and just blow down into 2D. Good luck with your search. Dave
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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 13, 2020 12:56:41 GMT
Another question for Don, does your class 25 run on 12v or 24v?
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Post by Roger on Nov 13, 2020 13:50:54 GMT
For CAD, I'd go straight to Fusion360 which is free to hobbyists. I'd use it if I didn't already have Alibre Design with hundreds of designs in that native format. In my opinion 2D is a waste of time since it takes almost the same amount of effort to learn but is little more than an electronic version of hand drawing. Going 3D might seem like overkill, but it's honestly the way forward. 2D CAD is frankly obsolete technology. The benefits of 3D are not to be underestimated. 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.
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don9f
Statesman
Les Warnett 9F, Martin Evans “Jinty”, a part built “Austin 7” and now a part built Springbok B1.
Posts: 960
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Post by don9f on Nov 13, 2020 16:52:31 GMT
Another question for Don, does your class 25 run on 12v or 24v? Hi, 24v from two batteries in series supplies the speed controller. This feeds each bogie in parallel, but each wheelset has two motors wired in series, which are then paralleled with the series pair on the other wheelset of that bogie. So effectively, each motor only sees a max. of 12v. Originally I had the horns working off only 12v from one battery, but now have a sound card that generates electronic horn sounds (not very well as it happens) and may go back to the original setup. Cheers Don
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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 13, 2020 20:59:03 GMT
I know I'm the equivalent to a flat earth believer but 2D I understand very well, it's what I learnt in school, had an 'o' level in.... When 'o' levels were grueling 4 hour tests. Its what I worked with for my toolmaking days. Maybe one day I'll convert but not today.
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Post by Roger on Nov 13, 2020 22:58:21 GMT
I know I'm the equivalent to a flat earth believer but 2D I understand very well, it's what I learnt in school, had an 'o' level in.... When 'o' levels were grueling 4 hour tests. Its what I worked with for my toolmaking days. Maybe one day I'll convert but not today. Fair enough, but just be aware that if you can do 2D then it's almost trivial to extrude those sketches or punch holes using sketches in a way that's already familiar. There's very little work to convert 2D thinking to 3D, and the benefits are enourmous. A circular sketch extruded just becomes a rod. A hexagon stretched becomes a bolt head. A circle cut is just a hole etc. There's nothing to it really.
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Post by andyhigham on Nov 13, 2020 23:20:41 GMT
Most of my CAD work is electrical circuit diagrams, for that 3D is as much use as a chocolate tea pot
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Post by simplyloco on Nov 13, 2020 23:38:37 GMT
I know I'm the equivalent to a flat earth believer but 2D I understand very well, it's what I learnt in school, had an 'o' level in.... When 'o' levels were grueling 4 hour tests. Its what I worked with for my toolmaking days. Maybe one day I'll convert but not today. Like you, I have 'O'Level Tech Drawing. I am a precision engineer, not a draughtsman, but it took just a couple of days on Fusion 360 to master the basics. I managed this one quite early on! saloonv3 v8 by inkaboat, on Flickr
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Post by steamer5 on Nov 14, 2020 0:07:46 GMT
Hi Les (?) On my Toby tram the frames are 3 mm with 12mm (from memory) key steel riveted on for the axel box guides.
On the CAD front I was using Draftsite, 2D, which was free, now they charge, not a lot, I have been playing in Fusion which is free, but they have just made some changes which may compromise getting dxf drawings out.....others that have the free drawing version hopefully can let us know
Cheers Kerrin
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Post by Roger on Nov 14, 2020 9:35:31 GMT
Hi Les (?) On my Toby tram the frames are 3 mm with 12mm (from memory) key steel riveted on for the axel box guides. On the CAD front I was using Draftsite, 2D, which was free, now they charge, not a lot, I have been playing in Fusion which is free, but they have just made some changes which may compromise getting dxf drawings out.....others that have the free drawing version hopefully can let us know Cheers Kerrin Hi Kerrin, I understand that following a lot of backlash they have removed some of the restrictions that were controversial.
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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 15, 2020 7:34:00 GMT
I've studied the photograph of the class 76 earlier, I'd not seen that one before. It now is clear to me that I can't ignore the fact that the axle boxes are very promenant. It looks as though I may have to delve into blackgates catalogue to find suitable horn guides and axleboxes. As these are Gresley locos, I'd start with A3 and A4 tender boxes.
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Post by delaplume on Nov 16, 2020 1:59:34 GMT
I've studied the photograph of the class 76 earlier, I'd not seen that one before. It now is clear to me that I can't ignore the fact that the axle boxes are very promenant. It looks as though I may have to delve into blackgates catalogue to find suitable horn guides and axleboxes. As these are Gresley locos, I'd start with A3 and A4 tender boxes. Why not fabricate the hornguides ??.........Angle of your choice ( steel or Bronze ), slit-saw down into the apex of the right-angle from the back.. approx 3/4 depth, introduce a piece of flat material, silver-solder and trim to suit...... Sounds like a recipe from a TV cookery show !!
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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 16, 2020 7:20:59 GMT
.... And with a flourish, sprinkle flux on from a great height a la Ainsley Harriot... lol. I'm pretty limited as to what I can do, I've only got a lathe at the mo and soldering/brazing is on the cards for next year. I've hinted at a drill press for Christmas, let's see what santa brings.
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jackrae
Elder Statesman
Posts: 1,333
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Post by jackrae on Nov 16, 2020 9:14:47 GMT
.... And with a flourish, sprinkle flux on from a great height a la Ainsley Harriot... lol. I'm pretty limited as to what I can do, I've only got a lathe at the mo and soldering/brazing is on the cards for next year. I've hinted at a drill press for Christmas, let's see what santa brings. With "only a lathe", and a bit of imagination, you can not only 'turn' but also drill and mill. All milling for my simplex were done on a super 7
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