Stuart Double 10

[rickhann]

I am seeking advise from previous builders of the Stuart Double 10 on how to fit the middle crankshaft bearing. The drawings are unclear and the directions in the plans are directed toward machining the crankshaft bearings for the 10V or 10H. No problem fitting the end bearings, but the center section requires a split bearing. Obviously when you split the center bearing the center of the bearing is changed in relation to the center of the end bearings. Do I compensate by the difference when machining of the casting, do I make up the difference in the bearing itself. My concern is getting good seating for the bottom 1/2 of the center bearing as it is free to move. I have a few thoughts, but would like to hear from someone who has built this engine. Rick, Cape Cod, MA, USA

[Roger]

It would help somewhat if you posted the drawings. Text descriptions are not very easy to grasp. You don't have to have built one of these to be able to comment on how to go about making something. It's all Engineering, you just have to see what needs to be made.

[jasonb]

I would mill away the bottom half of the supplied extruded bearing material and soft solder on a piece of brass or bronze then shape the outside so it once again resembles the extrusion. You can then machine this along with the other bearings before melting the two halves apart to give your split bearing.

If you don't think you can shape the external curve then the ctr bearing can be made square and fitted into a milled pocket with square corners rather than the "U" shape needed for the extrusion.

The other option is to make a round split bearing and have a separate top plate to retain it. The 3/32" hole shown on the drawing is to take a pin to stop the bearing rotating.

[uuu]

Are the bearings a bit like this:



So you can thread slide the ends onto the crankshaft, but not the middle one.

In which case Jason's suggestion sounds like the right idea.

Wilf

[jasonb]

Drawing for all you Loco boys who don't know your stationary engines

[keith1500]

I am not bad with either imperial or metric but 1 and 21/64th centres ! That’s a fraction under 11/32 and its where a glance at the Zeus tables comes in handy to see where it is.

Interesting bearing arrangement. Hopefully more photos to follow....?

[Gary L]

Apr 6, 2020 18:25:40 GMT uuu said:

Are the bearings a bit like this:



So you can thread slide the ends onto the crankshaft, but not the middle one.

In which case Jason's suggestion sounds like the right idea.

Wilf

I was very young when I built my Double-10, and I distinctly remember just splitting the centre bearing with a fine saw, and filing out the centre housing with a round file to a snug fit. There is a gap between the two parts of the bearing, but the protruding grub screw holds the lower part of the bearing in place longitudinally and radially, and the snug fit stops it rattling.

I would do it much better nowadays of course, but crude though it is, that's how I interpreted the drawing back then and it does actually work!

Gary

[rickhann]

imgur.com/0dMUkvX

Thanks for the suggestions. I am doing pretty much what jasonb described. I milled the bearing extrusion sockets with a ball mill so that they were all in a line. I bored and fitted the two end bearings to the base. No problem. To construct the center bearing, I silver soldered a piece of brass to the base of the center bearing. I then used a slitting saw to create the two halves and soft soldered them together. Then I bored the center bearing to correct diameter, Slid a rod through the three bearings and milled the center bearing profile to match the two end bearings. When installed, the lower half of the center bearing is several thou higher the the bottom of the socket. I intend to use a bit of JB Weld to fill the gap so that the lower half of the center bearing will fit the socket tightly. I am pretty sure it will work. I have not completed it yet, but have tested the fit. The crank is a bit tight, but better than loose. After installation I intend to lap the bearings in with Timesaver lapping compound. I am trying to attach some photos. Hope the links come through.

[rickhann]

imgur.com/gZjeSof

One more photo. I have not mastered the technique for posting multiple photos

[Jim]

Hi Rick,  in imgur if you go to the 'V' symbol at the top RHS of the photo in you Imgur album and 'click' it, a drop down menu appears. Click 'Copy' on the

BBCode (forums) then in your post where you want your picture to appear  press Command + V and the Imgur link to your photo that you copied will appear.

To check all is ok with your picture click BBcode at the bottom of the Post and your message will show along withe the photo you want to share. Click 'Preview' and you will be back to your post as it will finally appear on the forum.

I hope this helps

Jim