Master Conrod for the Five Cylinder Rotary

master conrod on 5-cyl rotary

The master conrod for the five cylinder rotary worried me since the beginning of this project because there is so much involved in machining it.

master conrod on 5-cyl rotary

Machinging the small end of the master conrod with it held on the rotary table.

The Unimat 3 as a milling machine is just perfect for this type of work as it is very delicate and easy to set up.

There are some points to learn with regards to using rotary tables. Having not had any formal machine training I have done lots of this by trial and error and collecting the information on the rotary table page.

master conrod on 5-cyl rotary

The slot in the big end of the master conrod is for the slave conrods.

The rotary table is now in the vertical position.

The difficulty here was clamping the conrod tight enough with the bolt through the centre so that it did not rotate of it′s own accord.

master conrod on 5-cyl rotary

Master Conrod for the five cylinder rotary connected to the piston using a 2mm drill. I think I will make the gudgeon pins from mild steel or even brass.

This is really zoomed in and you can see the marks, there are a few hours of fettling required to get the conrod looking perfect.

The distance between the big end bearing and the gidgeon pin is 24mm.

The engine on it′s stand with the pistons and master conrod lying underneath.

The overall engine is approximately 85mm in diameter (just under 3.5 inches in old money).

Some more work is required with the master conrod to get the bearings in and final fetling.

5-cyl rotary

..and now a short video showing the initial trial runs, it’s times like these that this hobby is just so exciting:

About Nigel 241 Articles
Have been making models since I was around 7 years old and using a lathe from the age of 11, a self taught engineer with a passion for making model engines.

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