About a week ago I got an email from a Guy I have made engines for in the past asking if I would be interested in helping him out with a flywheel.

He is part way through the build but the flywheel casting has several problems, where have I heard that before? Firstly it is cast from aluminium rather than iron. The two halves are misaligned by 3mm. Both the rim and the spokes are excessively heavy when compared to photos of the original, this may be to compensate for the use of aluminium. The flywheel has a large balance weight but this is supplied as a separate casting to be screwed on not an integral part of the casting requiring drilling through the face of the rim to fix it.

Being the chap that I am my reply was I should be able to help, let me have more details. Over a few evenings a new flywheel was developed based on some images he sent me and about 20 screen shots that I senyt back until a design that was acceptable was arrived at. Still slightly wide at teh rim but as the scale goes down you need a bit more mass at the rim but not as thick as the original drawings.

A slice of 190dia cast iron bar was ordered from M0-machine along with some other materials that I wanted and today I made a start roughing it out. I had ordered a 25mm long piece but it was closer to 29mm so a fair bit of searf to get it down to 23mm overall thickness then 18mm at the rim. Two 6mm holes were counterbored from both sides so I could screw it into some previously tapped holes in my faceplate.

I took a light skim off the first side then with that against the faceplate took some heavier cuts to start bringing the thickness down. 300rpm, 1.25mm depth of cut with a CCGT060202 “spare corner”

Not too bad a roughing cut