Author Topic: Stuart Beam Restoration  (Read 16388 times)

Offline smfr

  • Full Member
  • ****
  • Posts: 1195
  • San Francisco Bay Area, California
Re: Stuart Beam Restoration
« Reply #30 on: July 21, 2012, 07:59:50 PM »
OK, now I know that this thing is going to run, it's time for some cosmetic cleanup!

I was very glad to get to cleaning up the bearing oil cups. It had ugly soldered-on cups, so first thing I did was to unsolder them:



Then I touched an end mill to the top of the bearing to make a nice seat for the cup, and drilled and tapped 1BA, being careful not to go through to the bore. A smaller thread would not have worked due to the existing hole.



Now to make some oil cups to fit! I started with some 3/8" brass bar, and sketched out some rough dimensions for oil cups in my notebook. First, I took about 1/2" of the bar down to 0.312", which is the largest diameter of the cup, which is the base. Then I reduced 0.2" at the end to 0.21", and threaded 1BA (fitting to the bearings as I went, since the threads were pretty short). I drilled a small hole (#58 from memory) about 1/2" in. Then I turned the rough profile of the rest of the cup, basically marking the diameter changes with a small grooving tool, and parted off.

I made an aluminum fixture with a 1BA threaded hole, and screwed the cup into it for turning and filing the other end. After some careful turning and filing, I ended up with something like this (not quite finished yet):



This was my first attempt, when I was planning to go with a hex base for tightening, but later decided that this made it look too tall, and that I could just hand-tighten. Anyway, here's my prototype cup in place:



This cup later broke because I drilled the inside too deep ;D

I roughed out 4 more cups, seen here in their respective bearings, with the prototype to the top right, and the fixture in the lower right:



A bit of filing and sanding tomorrow should leave me with 4 nice oil cups. That should add a bit of bling!

Offline smfr

  • Full Member
  • ****
  • Posts: 1195
  • San Francisco Bay Area, California
Re: Stuart Beam Restoration
« Reply #31 on: July 21, 2012, 08:00:07 PM »
Four oils cups done:



and in situ on the cleaned up bearings:



I'm really not sure how to finish the bearings. I don't like the high gloss look, so I might go at them with a green scotch pad. They're pretty dinged up and non-square, and the holes are all over the place; stuff that I can't really fix without making new ones. I just think of it as adding character to the engine :D

While fiddling with brass work I decided to fix up the cylinder drain cocks; I needed some aluminum washers of the right thickness for the cocks to tighten to the right position, so turned and drilled a piece of scrap, and parted off a few washers of different thicknesses:



I found that I could just peel off the burr left from parting and clean up the washers with a countersink.

What occupied the rest of the day was reaming the bearing blocks. It took me a while to figure out a good setup for the crankshaft bearings. I ended up with a couple of 1-2-3 blocks square to the table, with the castings clamped, and some support under the ends:



The way I got the table positioned right was to put some 7/16" bar in the mill, and approach it with the part, wiggling the carriage hand wheel and advancing the cross slide gradually until the bearings just seated on the bar:



I did this with the bearings loose on the casting, then tightened up the bolts to start off everything straight. Then I could bolt the bearing caps on, put the reamer in a collet, and ream. I kept the cross-slide in the same position (gibs tightened down) for the main bearing on the body, and the bearing on the crankshaft support, so that they match vertically.

I did the bearings on the top of the column as well, and found that one was about 10 thou shorter, so made a brass shim to go that one. The beam spindle is also a tad undersize, so I put bits of paper between the bearings for reaming with the hope that they'll be nice a snug that way.

I haven't reassembled yet, so it will be interesting to see if that affects the running. But I'm glad I got the reaming done, even if it didn't take much off!

Offline smfr

  • Full Member
  • ****
  • Posts: 1195
  • San Francisco Bay Area, California
Re: Stuart Beam Restoration
« Reply #32 on: July 21, 2012, 08:00:41 PM »
I did various bits of cleanup today. First thing was to tighten up the eccentric strap by filing down where the two parts meet. There are some odd markings on one side of the strap:



which look like filing guides, perhaps? I like them, so I'll just leave the finish as it is.

Next up, I decided to polish the external surfaces of the beam. This required taking a file to the casting, since the two sides were not very well aligned, followed by a finer file and many levels of grit.



A bit hairy, but I think I ended up with an OK profile. It took a while to polish out the tool marks on the sides, and I didn't totally remove them, but it's better.

Then it was time for the flywheel! At first I had the flywheel on a mandrel (supported by the tailstock), held only by the grub screw. That was OK for the outer rim, but when trying to clean up the sides, there was enough flex in the wheel to cause chatter, leaving some ugly marks (visible in the image below). So I moved it to the faceplate, still on a 7/16" mandrel in a collet to keep it centered.



That worked much better, and allowed me to polish the rim and one side:



before flipping it over for the other side. Shiny!

Offline NickG

  • Global Moderator
  • Full Member
  • *****
  • Posts: 1430
Re: Stuart Beam Restoration
« Reply #33 on: August 03, 2012, 07:02:45 PM »
Brilliant work Simon, I once restored a Stuart beam when I was much younger ... to nowhere near this standard but still made a healthy profit on it!  :ThumbsUp: