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With the math done and verified, time to start on the eccentrics. The basic engine plan calls for the single eccentric or the slip eccentric collar be fixed to the crankshaft with a grub screw. Makes for an easy adjustment. The 5a Stevenson plan calls for the eccentric to be keyed to the crank...

Let me know if you can't find your drawings. I'll share mine. Bob S

Hi packrat, here we go!! Today is the start of the Stevenson reverse for the Stuart 5a engine. The basic 5a engine plan includes two types of valve mechanisms. One is a single fixed eccentric, and the other is a slip eccentric. The plan for the Stevenson is sold separately. Stuart sells a...

The valve chest, valve and valve spindle are next. I did not take a whole lot of pictures on this because it is all straightforward machine work. Nothing remarkable. The packing gland for the valve spindle is the same general design as the cylinder lower cover. It involves a ½” British Standard...

Back on the cylinder with some work on the portface. Use parallels to set the portface horizontal to the mill table as closely as possible. Mill the portface clean and tap the bolt pattern for the valve chest. And then there was trouble. There is a difference between 1.250 and...

Starting on the cylinder today. The Stuart 5a cylinder casting is wonderful. It is spot on in dimensions and is wonderful to machine. The steam ports and exhaust are right on dimension and very sharp. The cores are clean and uniform all the way thru. No work at all was needed on any of that. The...

Today are the top and bottom cylinder covers. These are a fairly straight forward turning process. The covers are cast iron, with no cast bosses to help in the turning process. However, there is enough material to grip during the machine steps. As with all the other castings, they are way over...

Next for the piston rod is get it between centers with the dividing head to shape the crosshead portion. Mill the crosshead to the final width on both sides. All of the nice-looking cast features on the crosshead are gone. Start profiling those shapes back in. Work the lower end and side...

The piston rod and crosshead are one single casting. As with many of the castings, this one is way oversized. The casting has a very nice profile, but it will all go away during machining. I’m not sure what Stuart uses for the connecting rod and the piston rod castings. It turns like some kind...

Today is a short update to finish the connecting rod. Round over the end of the con rod on the rotary table. Center the rotary table directly under the mill spindle. Clamp down a slab of aluminum and drill for a 3/8” pin. Secure the connecting rod on the pin and round over the end. The rotary...

Fellow steamers: Greatly appreciate the discussion about “horsepower”. All good questions and points. Chapter 19 of “Model Stationary and Marine Steam Engines” by K.N. Harris talks about testing engines and shows some dynamometer apparatuses. The Greenly dyno is very interesting. The 5a is...

These are LED strip lights they put in. 4 foot long, like fluorescent fixtures. Very bright. I use a cell phone camera and get dark areas and shadows too. Found that zooming in close and standing farther away cuts that down.

I wasn't sure how those reverse spotface cutters attached to the shaft. Now that I know, it would easier to make. Today is the big end brass, the bearing portion of the connecting rod. The 5a kit comes with castings for the big end brass. As with the main bearing castings, I’m not going to...

Thanks. These Stuart kits are great to work. A small erratum to the last post. The photo “Standard 11” shows drilling the top of the standard flange for the bottom cover and cylinder. Drill these holes to exactly 3/16” for now, as opposed to the 13/64” shown on the plans. The reason will...

I flipped a lot of mental nickels on doing the standard. Thought of doing it on the mill, setting up on the lather cross slide. Also thought of mounting the casting on a squared-up plate and use the plate as a "tumble jig" on the mill. Then I remembered Andrew Smith's book on making the #10V...

Thanks packrat, this build is going well. Time to get started on the engine standard. The rough casting is absolutely fabulous. It machines very well and has a smooth nice finish. It is very symmetrical all around which makes setup easy. A couple of small holes here and there, nothing to...

Ok, understand. I'll ty that next time. However, using my mentor's press was a good reason to go over for a visit.😁

I turned the flywheel for this engine a few years ago. Then we moved, so the shop got packed up. Unfortunately, there are no pictures of the flywheel setup and rough turning. The process involved clamping the casting to the face plate with packing under the spokes to make some standoff. The...

Picking back up on the counterweights today and finishing up the crankshaft. CA glue holds the counterweights to a flat faced jig for turning round. CA glue is strong but is vulnerable to heat. So, use a piece of ¼” steel plate to provide some pressure to the set up. The Stuart drawings don’t...

Hi Jojo, I agree, silver soldering the crank is the way to go. Thanks. The Stuart 5a kit includes cast iron castings for the counterbalance weights. There is a small nub cast into the inner part of the rim. It’s visible in the photo. I am not sure what that nub is for. It is not shown on the...