Author Topic: Block port size. Bogstandardís Paddle Duck Engine  (Read 1588 times)

Offline Knock-wood

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Block port size. Bogstandardís Paddle Duck Engine
« on: November 30, 2015, 02:46:22 PM »
Iím starting my first model steam engine and have decided to use the great plans from Bogstandard. I have decided to make mine a bit bigger and have doubled the size. (20mm bore X 40mm stroke)
I see on the plans that the block port size is ō 1.6mm this would appear to be a critical size as all other dimensions are to the nearest 1/2mm.
I was wondering how this size is calculated? Is there a formula that uses boar and stroke to work this out?
Can I simply double this 1.6mm diameter for my engine? Iíve a funny feeling itís not that simple.

Offline awemawson

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Re: Block port size. Bogstandardís Paddle Duck Engine
« Reply #1 on: November 30, 2015, 03:10:46 PM »
Can't help you with the port sizing, but welcome aboard the forum
Andrew Mawson
East Sussex

Offline SwarfnStuff

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Re: Block port size. Bogstandardís Paddle Duck Engine
« Reply #2 on: December 01, 2015, 01:02:19 AM »
Hi, just did a search on "port sizing in steam engines" and ended up here.

 http://www.steamautomobile.com/ForuM/read.php?1,24667

Have a look and see if it helps or confuses. I did notice some three or four posts down someone had attached a spread sheet you may wish to check.

John B
Converting good metal into swarf sometimes ending up with something useful. ;-)