Help re Gears

[John Littler 1Participant @johnlittler1]

Am building “Little Ben”, as serialised in ME some six years ago. The design does not have drive gears, just a rubber belt from the crankshaft to the hind wheel shaft. The intention is to fit gears between one hind wheel and the horn plate, using one countershaft with a compound gear between them, a bit like a Burrell. While I have sorted the DP, centre distances and the ratio, I do not know how wide the gears would have been in full size. Please can someone give me an answer on this point.

With Thanks in anticipation

[John Littler 1Participant @johnlittler1]

[mgjParticipant @mgj]

I don’t know what Little Ben is, but my Little Samson is a small type light steam tractor. In 1/4 scale the drive gears are 5/16″ and 3/8″ wide.

 

That gives a full size thickness of about 1 1/4″ & 1 1/2″. So whatever that works out in your scale, if we are talking of the same kind of machine?. 

[JasonBModerator @jasonb]

My Fowler is 1/6th scale (2″) and the gear faces in that are between 3/8 & 1/2 so full size would be 2 1/4 to 2 1/2″. Its a larger traction engine than the little samson prototype.

 

The 1″ Minnie in my avitar uses 3/16 wide gears throughout.

 

Jason

[JasonBModerator @jasonb]

Just seen it on youtube, I would not go much over 1/8″ wide, probably could not fit anything wider anyway and its not as though its going to be pulling you along

 

 

Jason

Edited By JasonB on 25/03/2010 08:45:07

[John Littler 1Participant @johnlittler1]

My thanks to JasonB & mgj. The engine on youtube, which I hadn’t seen, is not mine; if anyone is attending the “Myford” (no connection) next month, my model will be there, and running on air. The info is very helpful, thank you gentlemen. I think that “Little Ben” is probably based on a larger tractor than “Little Samson”, although not an accurate model of anything in particular, so I reckon I shall go for 1/8″ wide, which in 1:24 equates to 3″.

 

JasonB is quite correct, it will only be pulling  itself, but still needs to “look right”. I have gone for 32DP, with a ratio of 19:1. The ratio is a bit higher than the “low” gear on a Burrell mentioned by Martin Wallis in ME 27/2/2009, and is the result of the available gears in that DP, coupled with the centre distances on the model.

 

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