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N20 motors - Railway Modeller April 2018


Robin2
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I suspect these 3D printed gears might be a reaction to this.

Yes, that makes sense - I had not thought of that as I have been working with the motors without the gearbox as I don't have space for it.

 

...R

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Hi !

 

As stated above, current offerings do not meet

the need. - these are bespoke for the purpose

and affordable as a simple solution.

 

The current eBay item is  #  123215503408
(Relisted on trip with more than 10 sold !)

 

Of course these are designed for N20's with the

square brass gearboxes

The N20 are high reving and 12v geared down to 60 rpm

gives excellent torque for small OO locos.

On the 0-4-2 SDJR 25a the assembly leaves the Cab free

for detail.

 

Noel

Edited by Dazzler Fan
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Hi !

 

As stated above, current offerings do not meet

the need. - these are bespoke for the purpose

and affordable as a simple solution.

 

The current eBay item is  #  123215503408

(Relisted on trip with more than 10 sold !)

 

Of course these are designed for N20's with the

square brass gearboxes

The N20 are high reving and 12v geared down to 60 rpm

gives excellent torque for small OO locos.

On the 0-4-2 SDJR 25a the assembly leaves the Cab free

for detail.

 

Noel

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One of the variants fitted into a Hornby tender drive black 5. Yet to be tested under power as the araldite has been setting. Using bevel gears would probably have been the better option space wise as I had to do a lot of carving with a rotary burr. Won't get chance to fit pick ups until next week so will have to wait and see how it performs.

 

Wondering what gear ratio the gearbox is.   6ft drivers give about 300 revs per mile or 300 rpm at 60 mph so if that is a 300 rpm motor gearbox plus a 2:1 ratio crown wheel you are looking at 30 MPH with the motor screaming its head off.    My L&Y Pug chassis with an N20 uses Romford 60:1 gears and 14mm wheels and that seems to rev its head off but has more than enough torque to not notice whether the admittedly very light loco is running light or slipping to a stand overloaded.

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  • 1 year later...
  • RMweb Gold
On 15/07/2018 at 04:12, Dazzler Fan said:

Hi !

 

On eBay.co.uk there are Shapeways 3D HP-Nylon

bevel gears bespoke for these N20 motors sold as

2 pairs.

 

Axle Gear is a force fit on a 1/8" axle and has glue

lines; the motor gear fits the flat of the motor shaft.

 

post-12739-0-49862800-1531624302_thumb.jpg

I searched for those, but sadly they are only available in the "lower 48" in the USA. 

Anyone know of any other options?

 

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On 05/12/2019 at 14:43, Regularity said:

I searched for those, but sadly they are only available in the "lower 48" in the USA. 

Anyone know of any other options?

 

I wouldn't be buying expensive things from Shapeways when you can get them from China for pennies, as suggested by the poster above.

 

I've never used the bevel gears and prefer to use a pinion and crown wheel. By making a carrier for the crown wheel you can fix it to the axle by use of a screw, which allows the motor drive to be disengaged whilst fettling the rods etc. The pinion gears have a D-shape in them so are a simple push fit on the gearbox output - no messing about with glues.

 

 

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57 minutes ago, Ruston said:

I wouldn't be buying expensive things from Shapeways when you can get them from China for pennies, as suggested by the poster above.

 

I've never used the bevel gears and prefer to use a pinion and crown wheel. By making a carrier for the crown wheel you can fix it to the axle by use of a screw, which allows the motor drive to be disengaged whilst fettling the rods etc. The pinion gears have a D-shape in them so are a simple push fit on the gearbox output - no messing about with glues.

 

 

Ruston,

From whom do you get the crown and pinion sets?

drduncan

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7 minutes ago, drduncan said:

Ruston,

From whom do you get the crown and pinion sets?

drduncan

They aren't sets as such. They are cheap Chinese nylon gears that are on ebay, from loads of different selllers. As long as you use the same 0.5mm module gears you can pick whatever diameter and number of teeth you want to suit your requirements.

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  • 1 month later...
  • RMweb Gold

Hello Folks. As usual, I'm late to the party...

 

I have some questions about these little N20 motors. They look exquisite, and the gearbox faceplate looks as though it's capable of mounting either a Romford/Markits gear arrangement, or High Level. If that is the case, what size of  screw thread are we looking for?  M1.4, etc?   I'm currently working with a standard 12v DC arrangement. 

 

All information will of course, be gratefully received.

 

Cheers,

Ian.

 

 

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Which ones do you mean Ian ?

 

I use this type with a gearbox https://www.ebay.co.uk/itm/DC-12V-300RPM-Mini-Metal-Gear-Motor-Model-with-Gearwheel-N20-3mm-Shaft-Dia-UK/323966003210?epid=939823511&_trkparms=ispr%3D1&hash=item4b6de0e80a:g:tfcAAOSwThNdu8v-&enc=AQAEAAACQBPxNw%2BVj6nta7CKEs3N0qVtPmKEwMzTM3Khf816xyynwt0Puflfhp3QQnO8AiCQTh8qZV%2FsZz2u0X2mO1SszPbfWPn4ZaYeZS4zCfw4TSkY50y%2B4uGl98pC5jpO%2BY1y9SND1EBkyRWoNyGzqtuIbD2A8oZoQZcCQLnMCmh7vw0lgF%2BaRfBsSbdb1XswXswgf9WyFbY1NrO3nbFtLD%2FIsDEgqLNSWPe3IrR57MVJVQT9wETmZQhsX5Qy6tRuK0hmCL2FpdrMTXXU6sbrfP3sEm7gfyaRdT0dR1J50TbZ0uFxwKLfQZ%2Bk57llAxFEgpK9%2FJjXhEzHsOBIB4Hsj7COxCHrWPjGEqam1iiGHWun72ttJHQfODxcWuPm9aLStVc5myhIJX8mOkr1mYXyFuNlaMHjVFzY4dAdi3YwqUztbdPBmE3vxQ6lHsryqu15T9oR1bVgnhph%2BCTUjNcPpeL8%2FjXNb3BGXeOdAcbn2UMB4r%2BG9GPPbIQL0nfwjNVVW4pt9tGMWPp8KJ6hjYdM8vt6Wsnoy8cqBC1ecGQOPSPq9OFaoVgmeUZ%2Bio5zaFq9YnO1YeKADTH4Gw%2ByAtsO8XVNUB92uzRvlsshS0KPoqzvpNkXvNq1J9%2ByHc9zbK0qZfgE6GlAB6qcEZGfKNgQzhlbpnfpgqE35gg2qP6tjMb3ewlH%2FICLBwdiPK8zNcHL1FHKcOAtFUIM1AUvgOSqUShAlZmCau%2FNlGuvWILxgkXege0RnHEDWiqKjlOeRvLhf%2F5dFA%3D%3D&checksum=3239660032105197e60d9a924a95974e090e884479c0&enc=AQAEAAACQBPxNw%2BVj6nta7CKEs3N0qVtPmKEwMzTM3Khf816xyynwt0Puflfhp3QQnO8AiCQTh8qZV%2FsZz2u0X2mO1SszPbfWPn4ZaYeZS4zCfw4TSkY50y%2B4uGl98pC5jpO%2BY1y9SND1EBkyRWoNyGzqtuIbD2A8oZoQZcCQLnMCmh7vw0lgF%2BaRfBsSbdb1XswXswgf9WyFbY1NrO3nbFtLD%2FIsDEgqLNSWPe3IrR57MVJVQT9wETmZQhsX5Qy6tRuK0hmCL2FpdrMTXXU6sbrfP3sEm7gfyaRdT0dR1J50TbZ0uFxwKLfQZ%2Bk57llAxFEgpK9%2FJjXhEzHsOBIB4Hsj7COxCHrWPjGEqam1iiGHWun72ttJHQfODxcWuPm9aLStVc5myhIJX8mOkr1mYXyFuNlaMHjVFzY4dAdi3YwqUztbdPBmE3vxQ6lHsryqu15T9oR1bVgnhph%2BCTUjNcPpeL8%2FjXNb3BGXeOdAcbn2UMB4r%2BG9GPPbIQL0nfwjNVVW4pt9tGMWPp8KJ6hjYdM8vt6Wsnoy8cqBC1ecGQOPSPq9OFaoVgmeUZ%2Bio5zaFq9YnO1YeKADTH4Gw%2ByAtsO8XVNUB92uzRvlsshS0KPoqzvpNkXvNq1J9%2ByHc9zbK0qZfgE6GlAB6qcEZGfKNgQzhlbpnfpgqE35gg2qP6tjMb3ewlH%2FICLBwdiPK8zNcHL1FHKcOAtFUIM1AUvgOSqUShAlZmCau%2FNlGuvWILxgkXege0RnHEDWiqKjlOeRvLhf%2F5dFA%3D%3D&checksum=3239660032105197e60d9a924a95974e090e884479c0

 

And use these gears to transfer drive to the axle https://www.ebay.co.uk/itm/20pcs-Plastic-Bevel-Gear-Right-Angle-Drive-Plastic-Gears-16T-Hole-2mm-Toy-DIY/161667623061?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

 

I do have to ream the hole for the axle and gear shaft.

 

So far I've only used them in small locomotives and railcars which aren't expected to do a lot of work.

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Hello Dave, you are right on the target. Nice one. 

 

I also bought 2 of these little motors. From what I can see, there are 2 small, tapped holes, above & below the 'D' output shaft. To my feeble mind, the gearbox faceplate is just right to accept a fold-up gearbox. In that way, I can use the normal Romford reduction set. I'd envisage something in the range of 30-40:1 ratio.  The tapped hole had me worried. Not having a tap to the correct size would mean a 'bodge'. Bodges are ok, but I'm concerned about messing up a gearbox with such a small motor.

 

The worm will need to be bored out to accept the 3mm output shaft, but I'll do this on a lathe. 

 

Cheers,

Ian.

 

 

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I've been experimenting with the n20 motor/gearbox in bigger and bigger locos. First was a 7mm Ruston 48DS, more than adequate in this tiny loco and well out of sight in the engine casing. Latest is a 7mm Hunslet 05, weighted up to 450g at the moment it can still spin the wheels quite easily. Both these are used at 1:1 from the attached gearbox, the Hunslet has the turned back configuration - this would be narrow enough to fit between the frames of an O gauge loco with a 1:1 spur gear drive. However the Hunslet frames are narrower than normal and this wasn't possible so it has a 1:1 chain drive instead.

Next build may well have one of these fitted where the gearbox of the full size loco is, driving on the jackshaft axle. The power of these tiny motors is incredible, power consumption is small and they don't seem to get hot.

More recently I acquired some n30 motors, these are longer but they bolt directly on to a High Level gearbox. I had one total failure but at 99p that's not too serious.

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4 minutes ago, Michael Edge said:

I should add that putting a worm drive on the end of this superb little spur gearbox negates the whole point of using it - it works well because it doesn't have an inefficient worm drive.

 

Thanks Michael. I haven't gone down the route of bevel gears, I'm wondering how you'd mount the motor. I can certainly see some applications, however.

 

Cheers,

Ian.

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There is also this thread 

I am currently in the process of developing an RC project using an N20 motor but I'm still faffing about with it. The N20 motors with the integral gearbox could be useful  and you can select the voltage/output RPM to suit. They come in different drive shaft sizes but 3mm seems to be the most common, probably because this is the size used on RC cars. Also this mounting block is I think of value too as are bevel gears like this.

 

You can cut off the lugs on the mounting blocks and glue them inside the frames as an alternative to the traditional worm and worm wheel gearbox.

 

There's lots to choose from.

 

Cheers

 

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Quick question (and probably a very silly one) but when using the bevel gears with this set up, I assume you put one on the motor drive axle shaft and the same size bevel gear on the wheel axle. As there is no grub screw, do you just superglue it to the axle?

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1 hour ago, ianLMS said:

Quick question (and probably a very silly one) but when using the bevel gears with this set up, I assume you put one on the motor drive axle shaft and the same size bevel gear on the wheel axle. As there is no grub screw, do you just superglue it to the axle?

I use 5 minute epoxy or Loctite 601. If gluing, apply the glue to the bore of the gear - NOT the shaft - that way you'll avoid getting glue in the gearbox.

Michael E is absolutely right about the benefit of not using worms. They're only something like 25% efficient if you're lucky, whereas a bevel gear approaches 90%.

I've been using some extremely small motors with planetary gearboxes, and they also prove immensely powerful, relatively. A motor 6 x 8 x 16 handling a white metal loco quite happily.....

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1 hour ago, Giles said:

 

Michael E is absolutely right about the benefit of not using worms. They're only something like 25% efficient if you're lucky, whereas a bevel gear approaches 90%.

 

 

Poor old worm gears getting maligned as usual ;)

 

When comparing gear-train efficiencies we need to compare apples with apples. There's not a lot of difference between a 40:1 worm set and a 40:1 train of spur gears. The total gear ratio has a major impact on the friction.

 

Some people say you can't back-drive a worm which is simply not true. I have an ancient Tri-ang DMU which has the original two-start brass worms driving replacement nylon worm-gear axles (can't remember who sold them now) and it's quite easy to back drive the motor. The main reason is because the gear ratio is quite small. It might only be about 10:1 but I'd have to count the teeth to find out.

 

Conversely if you make a 50:1 reduction from a train of spur gears it will resist back-driving because of the amount friction that a 50:1 ratio produces.

 

 

 

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