Hi PD's....but  ........ I think the batteries are FLAT in your abacus   

0.1227" x 25.4 = 3.11 mm pitch
3.11 x 48 scale  = approx 150 mm pitch [149.599 actual]
149.599 divide by 25.4 = 5.8896" pitch

Now speaking as an ex - Renold Australia Power Transmission Engineers [trainee engineer].....low speed 'crank link' chain was manufactured in 6" pitch but this was for LOW speed earth moving type appliances or ball mills etc...... not for 25 to 100 RPM applications

Conventional roller chain as developed by the French Mr Renold was limited  to 4" pitch or shall we say 100 mm

So I see the use of this 0.1227" pitch chain is about 47% over scale size....fine to use but just need to understand the actuals........Derek

Greetings,

I don't know if you have found your chain yet but here is a site that I get a lot of chain drive parts from. I have used the plastic chain on several O scale (1/48th) logging locomotives and it looked great and operated well. I have also used it to drive the throttle of several live steam locomotives.  You can get sprockets in all kind of sizes.

http://www.servocity.com/html/gears___sprockets.html

I hope this helps,
Andre

Some may think I"m nitpicking here but the drive chain will be exposed for inspection. If it is to large it will look out of scale. I know the proposed smallest chain is 98 links per foot. I'll draw a mock of the chain in auto cad and determine if it looks out of scale. Thanks for the mathematics lesson Derek!

Quote from: Philip on December 25, 2009, 05:29:01 PM
Derek,

this is just a nonfunctioning wood and plastic model.

Thanks Andre. I'll most likely use that chain.

I also have a question about hull design. Is the hull suppose to be tapered at the stern on the bottom of the vessel to aid in water flow to the paddle. The boat pictured seems to be square just before the paddle. I presume its tapered below water level. Is that squared end the rudder? Is the rudder suppose to lead the or trail the paddle?

Thanks again for all the comments.

If it is to be a static model and not operational, you might be able to find something in cosmetic jewelery.
Regards,
Gerald.

Hi Phillip

Before you get to wrapped up in whether the chain is EXACTLY to scale consider this; If you construct a model to EXACT scale it will look somehow 'wrong'. A good example is model cars - you know the sort of Burano quality diecast things. If you measure for instance the size of a door piller it will be about twice the thickness it should be. This is not because of manufacturing limitations, it is because if the pillers were the 'right' size our brains simply will not accept that they are capable of holding up the roof of the car - this is known as 'scale effect'.

As Derek rightly says the chain I've suggested is slightly overscale - but it may very well look right on the model.

Anyway here's a picture of some components laid out on a centimetre grid to give you an idea,

All the best

Stuart

Hi Stuart,

Your chain and sprocket picture are worth a thousand words. I'm not looking for an exact replica. My cad drawing was 16' breadth and my model is 17' 1/4". Slightly larger, but I can live with it.

I'll be placing an order Monday morning.

thanks,
Philip