[PROJECT] Bar Stock Steam Engine

[Dr Stan]

Very nice work and right along the lines I plan to do.   I've already bought & paid for a Bridgemill from Chicago Lathe to be shipped to me in the Philippines. Once I have my new shop built I'll have it shipped and also buy a 3D printer and a laser cutter/engraver. Lifting will be far less than what I use to do.

Where did you find the prints? I also plan to subscribe to Model Engineering once I've relocated.

[Cross Slide]

Stan.
I found the plans on EBay. They are very well done and fairly easy to read!
Trevor

[Cross Slide]

The next part of the Bar Stock Steam Engine is the Yoke. This is the part that will connect the rod from the Cam to the end of the Valve. I was actually surprised how easy and fast it was to machine this part due to its size. It is 1.00 x .250 x .500. I used some of the techniques I learned while machining the rails on the backside of the cylinder, which I think made it easy. 

   
   
   
   
   
   
   
   
   
   

Trevor

[Cross Slide]

More of the Yoke

   
   
   
   
   
   
   
   
   
   

Trevor

[Cross Slide]

More of the Yoke.

   
   
   
   

Trevor

[Cross Slide]

Tonight’s quick machining job on the Bar Stock Steam Engine build is the stand offs to mount the Cylinder and the Valve Body to the base. They are machined out of .250 brass round bar. I needed a set of eight .750 long and eight 1.250 long. I started off by cutting the stock on my bandsaw just a bit longer then required. I faced the first side, centre drilled, and drilled the through hole on all the pieces first. Then I faced the second side, measured length, then took them all down to finished length. 
I figured doing it this way was the closest process to a production run with the least amount of changes. I have several drill chucks for my tail stock. So I have the centre drill in one and the required drill bit in the other. Worked out pretty good. All 16 pieces done in 45 minutes total!

   
   
   
   
   
   

Trevor

[rleete]

Making identical parts is one of the biggest challenges for a hobby machinist. Congratulations on a successful job.

[Cross Slide]

The next part on the Bar Stock Steam Engine build is the Cam Bushing. This part is made out of a flute plate of brass. It has to be a nice slip fit over the cam that I made earlier. As the cam rotates with the crank this transfers motion to the valve. So it had to be a nice slip fit without excessive play.

   
   
   
   
   
   
   

Here I machined a slug that was a nice press fit with my fingers. The rod fits into the collet in my mill then into the hole in the slug. This is how I helped locate the centre of the hole with the centre of my rotary table.

   
   
   

Trevor

[Cross Slide]

More of the Cam Bushing

   
   
   

I plunge cut between the clamps leaving 0.030 extra material to remove on my finish passes.
   
   
   

Once I had all the material plunge cut between the clamps I played musical clamps. Removed one clamp at a time to remove the material that was under the clamps.
   

I then found out that my sacrificial plate under the brass should have been smaller. The amount of excess out past the part now made it impossible to get the clamp in far enough to reach the part. So I had to locate the top of my rotary table and plunge cut the sacrificial plate. I stopped .010 short and just broke the excess off by wiggling it back and forth. I was really nervous about marking my rotary table. But it worked out perfect!
   
   
   

Trevor

[Cross Slide]

More of the Cam Bushing

   
   
   
   

I used a piece of 3/4 square stock to eyeball the top of the lobe horizontal.
   
   

After it was spot drilled I used a .010 feeler gauge to find the top of the surface with the drill bit as this hole was required to be a specific depth, which was very close to the bore.
   
   
   
   

Trevor