Mashima motor - beginner's question

[gordon s]

I'm part way through building a Comet B1 chassis and have put together the motor and gearbox. The Mashima motor came with two small screws, but this means mounting the motor horizontally. Any problem in doing this? All the Mashima's I have seen have been set vertically, but the screws supplied are too large to fit the vertical holes. The vertical holes are also on a different pitch so opening up the smaller holes in the motor mount doesn't help. I've tried that already....

 

[buffalo]

No problem at all, so long as you can get the body on. I've always thought it a bit strange that 12mm and above Mashimas come with two different sized holes. Some gearboxes have holes for both types, some motors come with larger screws, others with smaller screws and, just now and then, you get two of each size. All very mysterious.

 

Nick

[Tim V]

Go with it, at least you can get to both screws, if it was mounted vertically, you wouldn't be able to reach the lower screw. This way you can remove the motor for free running tests.

[gordon s]

Thanks guys, I felt it was a bit of a daft question, but didn't want to go any further and then have to take it all apart again. It just fits into the Bachmann B1 body even with a flywheel fitted.

[Kenton]

No problem at all, so long as you can get the body on.

 

... and get it on without fouling those terminals.

 

The advantage of a vertical mount is that one terminal is down (between the frames) and one up in the boiler, or somewhere there is usually space. This way around it may present a problem and there may not be enough side play to stick electrical tape on

 

....other than that it should make no difference

[hollywoodfoundry]

No problem at all, so long as you can get the body on. I've always thought it a bit strange that 12mm and above Mashimas come with two different sized holes. Some gearboxes have holes for both types, some motors come with larger screws, others with smaller screws and, just now and then, you get two of each size. All very mysterious.

 

Nick

 

The motors as supplied by Mashima do not have any screws with them, they are added by the motor supplier, so you get whatever the supplier thinks is required. However in this case, it seems that Comet have decided you should use the 2mm threaded holes and mount the motor sideways. In looking at the design of the gearbox, the smaller 1.4mm threaded holes would be too close in with that gearbox etch design.

 

As has been said, it makes no difference to the operation of the motor, only clearances inside the body.

[gordon s]

In all fairness to Comet, the smaller holes are there and on the correct pitch, but I was unable to use them as there were only two motor screws supplied. Opening up the smaller holes would mean they would have to be slotted outwards to accommodate the larger screws. It would probably have been OK and could possibly provide some vertical adjustment on the motor to aid gear alignment, but my fear was that it could move over time and ultimately reduce or increase the worm/gear wheel interface.

 

As it stands there is room in the Bachmann body to take the sidemount motor and flywheel. I've also used the Comet extender to reduce the ratio further to 50:1 and was pleased to see the B1 body will still allow the motor gearbox to fit with a mil or two to spare.

[RedgateModels]

As has been said, it is an advantage if you can fit the motor in with the flats top and bottom, as it's way easier getting the motor off the gearbox if you need to

 

 

From memory, when I ordered the mash for the 2-8-2 Geoff asked which screws I wanted, I may be dreaming though .......

[artisan100]

By default we supply the larger screws with the 16xx series motors, but we can supply the smaller ones if required. Indeed we show the motor mounted in either orientation on our scale size printout of motors and gearboxes. When designing the GB5 we wanted it to be able to cope with as many motors as we thought might be in common use, so it has 8.0, 8.5 (for the Mashima MHK10xx series) and 10.0mm dimples/holes.

Always happy to answer a query, whether by phone, email, pm, or open forum.

 

Geoff

Comet Models

 

P.S. It's looking good already, Gordon. Very neat piece of soldering on that crosspiece to stop the motor diving down between the frames under load. Keep going and you'll do fine.

[gordon s]

Thanks Geoff. I really must compliment you on the kit. It's going together really well although I've just started on putting the cylinders together and already I can see the valve gear on the horizon, so I'm bracing myself. As I said on ER's, my biggest failing is reading instructions and manuals as after five minutes of flicking between text and sketches, I find myself wandering off piste and starting lots of small assemblies. Inevitably I usually find that I should have done a) before B) and end up having to rework the offending piece.

 

By the way, the additional bearing you can see on the centre shaft of the gearbox, is a minor repair I had to do after getting carried away with a broach and leaving the centre shaft too sloppy. I soldered a couple of 12BA washers on the outside and then opened them up, only this time checking more often. I'm going to attach a second bracket under the motor and then use some BluTack or an elastic band to fix the motor. The bracket is just a scrap piece from the etch sheet.

 

I am very pleased with it so far, but that's testament to the ease of assembly and precision of your kit more than the skill needed to put it together...