Years ago I made a Stuart 7A with a double eccentric. I kept on breaking cast iron double eccentrics so I used a short length of bright mild steel bar. One good double eccentric.

I did not use a jig, just a four jaw chuck with a lot of measuring and checking. I think I had a chucking stub on either side of the double eccentric.

Have fun!

JA

Richard

If you have access to it Andrew Smith in his description of building the Stuart "Cygnet" (5A ) details a method of machining of the double one piece eccentric in the Apr '82 issue of Engineering in Miniature, page 377-378. I've sent you a PM.

John

Edited By John Purdy on 07/04/2023 17:56:31

If they are split eccentrics, they do not need to be pinned together, and the angles can be set individually after they have been fitted to the shaft.

Hi Richard B,

I rebuilt my double ten for a steam launch a few years back and made separate eccentrics for each end with small grub screws to lock accessed through the eccentric strap for setting. I made them from free cutting mild steel and off set them in a simple fixture held on the face plate to ensure accuracy of throw one to another and squareness to bore. The setting proved simple and easy to do on final set up.

I described this here on the build log on Model engine Maker forum at the time – you may find it useful.

Best – Tug

PS Though I haven't described it I have used the same method to make the eccentrics on the 'Marine Condensing Engine' thread described elsewhere on here to equal success.

Edited By Ramon Wilson on 08/04/2023 10:34:49