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Mcewan Pratt 10 hp


 

well....... here he is again the confused American
Ive opened my KB McEwan Pratt Baguley 10 hp and find myself stymied again
Do I build it compensated or not?........having looked around NGonline etc. I've not been able to find a build
thread....so any advise from the group would be appreciated as I struggle along?
thanks as always?
Joe Gilmartin


 

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Mark Clark reported his experiences in Narrow Lines 185 (7mm NGA magazine) titles “Baguley Pratt 10HP 0-4-0PM”.? If you are a member then just search the archive with “Pratt” and it will come up.

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He wasn’t very impressed with the motor/gearbox arrangement and ended up doing what I think I will do.? That is using the first bit of the gearbox giving a ratio of 54:1 and mounting the motor vertically to the front of the body.

?

I think the editor gave KB Scale the opportunity to comment but they declined. ?The editor and Trade Liaison Officer said they would be interested to hear of other people’s experiences in building the model but I can’t remember anyone writing in. ?

?

Good luck, Robin

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From: [email protected] [mailto:[email protected]] On Behalf Of jogil476 via groups.io
Sent: 19 July 2023 21:05
To: [email protected]
Subject: [o14] Mcewan Pratt 10 hp

?

well....... here he is again the confused American
Ive opened my KB McEwan Pratt Baguley 10 hp and find myself stymied again
Do I build it compensated or not?........having looked around NGonline etc. I've not been able to find a build
thread....so any advise from the group would be appreciated as I struggle along?
thanks as always?
Joe Gilmartin


 

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I should have added that (now I have re-read the article in NL 185 that Mark struggled with the compensation as the compensated wheels gave too much movement between the fixed front wheels and the fixed rear jackshaft drive.? He said if he built another he would make it fixed.

?

Cheers, Robin (now I remember why mine is still in the box!)


Do I build it compensated or not?........having looked around NGonline etc. I've not been able to find a build
thread....so any advise from the group would be appreciated as I struggle along?


 

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On Jul 20, 2023, at 09:13, Robin Edwards <robinglos@...> wrote:

?

I should have added that (now I have re-read the article in NL 185 that Mark struggled with the compensation as the compensated wheels gave too much movement between the fixed front wheels and the fixed rear jackshaft drive.? He said if he built another he would make it fixed.

?

Cheers, Robin (now I remember why mine is still in the box!)


Sounds like Mark Clarke’s experience of this kit is similar to other people’s experiences of building a Mark Clarke kit….

Andrew


 

Very short wheelbase 4-wheeled locos don’t need compensation provided that they have been assembled correctly as the tolerances between the axles and the bearings provide just enough flexibility to do the job - unless the track is really awful.

In this case, with a jackshaft axle to be driven as well compensation is actually undesirable.

There isn’t a huge amount of information out there on the prototype loco (not helped by the fact that were a number of variations even within the small class), and the one survivor has been so heavily rebuilt that it isn’t much help either.

When I first got the KBscale kit, I set about bringing all the information I could find together in the hope of producing as near accurate a model as possible. I had got a long way down this path and had produced a good detailed drawing when I lost it all to a hard-disc crash (on a MacBook too), I gave up after that! (Although I still have the kit.)

The etchings are for the most part excellent but there are other issues which won’t be easy to overcome. On my kit, the wheel tyres and wheel centres were rather less than an interference fit, for example, and securely fixing the very nice sandbox castings to the running plate could be an interesting exercise too. On the prototype there were some “interesting” angle fabrications behind the sandboxes which are difficult to see in the few surviving photographs but would be very visible on a model - and they aren’t included in the kit.

Finally the controls in the open cab (so also very visible) were far more complex than the kit provides for and most surviving photos (and the drawing in an early REVIEW) proved to be misleading. I eventually tracked down a photo of one in a scrapyard pile which showed the controls - it was in a long past copy of the NGRS “The Narrow Gauge”.

David Woodcock
Champlon, Belgique


 

It is a shame that David lost his information but it reminded me that I had seen some images on the NGRM Forum of the blueprints. Like most drawings of this nature, they take a bit of time to interpret to work out where the designer thought that things like to controls should be positioned. Quite often what was built differed from the original design but these images may help with the approximate placement of controls.

Cheers, Robin

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of David Woodcock via groups.io
Sent: 20 July 2023 22:22
To: [email protected]
Subject: Re: [o14] Mcewan Pratt 10 hp

Very short wheelbase 4-wheeled locos don’t need compensation provided that they have been assembled correctly as the tolerances between the axles and the bearings provide just enough flexibility to do the job - unless the track is really awful.

In this case, with a jackshaft axle to be driven as well compensation is actually undesirable.

There isn’t a huge amount of information out there on the prototype loco (not helped by the fact that were a number of variations even within the small class), and the one survivor has been so heavily rebuilt that it isn’t much help either.

When I first got the KBscale kit, I set about bringing all the information I could find together in the hope of producing as near accurate a model as possible. I had got a long way down this path and had produced a good detailed drawing when I lost it all to a hard-disc crash (on a MacBook too), I gave up after that! (Although I still have the kit.)

The etchings are for the most part excellent but there are other issues which won’t be easy to overcome. On my kit, the wheel tyres and wheel centres were rather less than an interference fit, for example, and securely fixing the very nice sandbox castings to the running plate could be an interesting exercise too. On the prototype there were some “interesting” angle fabrications behind the sandboxes which are difficult to see in the few surviving photographs but would be very visible on a model - and they aren’t included in the kit.

Finally the controls in the open cab (so also very visible) were far more complex than the kit provides for and most surviving photos (and the drawing in an early REVIEW) proved to be misleading. I eventually tracked down a photo of one in a scrapyard pile which showed the controls - it was in a long past copy of the NGRS “The Narrow Gauge”.

David Woodcock
Champlon, Belgique


 

Well ….
Thank all of you for the information and though it advice
l have the Review article and have now printed out the NL article?
I have built the frame(uncompensated) and have niw boxed it back up whilst I consider my options?
(maybe have Mark C build a drive for it)
and go back to trying to source O14/1:43.5 parts over here?
joe