Engines > Restoration of Model Engines

Stuart Beam Restoration

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smfr:
[Copied from *cough* another site. Apologies if you've seen this before.]

Hi folks

I've been working on restoring a Stuart Beam, and thought that I should put up some photos. I bought this engine along with a 501 boiler on eBay in 2010, before I even had a lathe, and fixing it up was a good excuse to get one ;D

The engine had its share of problems, a really ugly paint job, and some odd modifications. It had obviously seen quite a bit of use, with some notable wear on the conrod big end, a fairly loud knocking when running, and a lot of looseness in the parallel linkage.

My goal is to get it back to a nice quality, smooth-running engine. This is my first real steam project with the lathe.

Here's the engine in its original state:

Stuart Beam by smfr123, on Flickr

smfr:
Some more pre-restoration pics:

No fish-bellying on the linkage:


The previous owner loved brass! So much so that they put thin brass strips over the entablature arms:


They did something awful to the steam chest: drilled a hole in the side for the displacement lubricator, which forced them to set the valve mechanism at a weird angle:


Oil cups soldered onto the main bearings:


Another bit of brass covering the flywheel, and aluminum disc press-fitted onto the pulley:

smfr:
Step 1: paint stripping.

I don't have any pics of the stripping process. Basically I smeared the painted parts in Citristrip http://www.citristrip.com/, put them in a ziplock bag overnight, then cleaned everything off the next day.

After stripping, I put it back together. Looks better already!



Only then did I noticed how loose it was, so it got pushed to the back of the workbench, pending lathe availability.

smfr:
Steps 2-N

Lots of work represented in this picture:



I decided to machine new parts for the parallel linkage, since the existing ones were rather sloppy, and not very pretty.

There are eight parallel links, machined from CRS bar. I first drilled and reamed the holes, then turned between centers, using the crosslide to get the fish belly taper. Then the ends were rounded off using a rounding fixture. They still need final filing and trimming to thickness, and I think I'll remake a couple of them; you can see a few boo-boos if you look carefully.

On the right are the various linkage spindles, make from 3/16 drill rod, and the linkage spacers. In the lower right is the new crankpin. This needs a slot cut in the head to allow it to be tightened up.

On the left is the original connecting rod, but I added bronze bushings to both ends to tighten things up. The hole in the big end was actually oval from wear. I've also made bushings for the beam, but have not yet drilled and reamed out the holes in the beam to fit them yet in the photo.

smfr:
Now for some work on the column. I noticed that the arms weren't parallel with the base, so had to correct that in two ways. First, I enlarged the bolt holes in the bottom of the column to allow for some adjustment. Second, I re-machined the top of the column. I also skimmed the top and bottom of the column between centers (via the original punch marks!) to correct the fact that it was too tall.

Here I'm tidying up the base of the column (it wasn't machined square by the original builder).



Now it's time to clean up where the arms attach. Note the 1-2-3 block used as an angle plate.



This leaves the arms about 10 thou closer together than they should be, but I can take that up in the linkage spacers.

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