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| kvom:
--- Quote ---I will only be able to make two the same, all the rest will be different. --- End quote --- That's true - different number of holes for the conn rods. And since John goaded me into action: Since my house was invaded this afternoon by 7-8 teenagers at the invitation of my daughters, I decided to hide out in the shop. It was finally time to turn the fins in the cylinders, as they had been waiting since 9/28 to be finished up. Bogstandard has a fine writeup on setting up the very thin parting tool (.025", no relief), and I followed it pretty much as written. Since the tool needed a surface grinder to create, others attempting this build might choose to use a wider, commercial tool and cut fewer fins (or no fins at all). I was able to chuck the parts in my Jacobs Rubberflex collet chuck, and the cuts were surprisingly easy. Like Bogs I had written down a list of X-Y coords for each cut, and it took only about an hour or so for all 5. Having a DRO on the lathe makes this a much easier proposition. Then I reversed them in the chuck to cut down the bottom spigot to length. One thing I did differently was using a 1/16" parting tool to turn down the three bottom fins; this avoided the thin wires that would result from using the thinner tool. My list of to-do parts is getting smaller. I still need to drill the many, many holes in the heads and make the 5 pistons, and then I can think about some assembly, a base for mounting, and some sort of air manifold. |
| bogstandard:
Nicely done Kirk. DRO's and surface grinders do make life a lot easier when doing a job like this. I do still have the extra tools I ground up for doing the finning job, so if anyone wants to build one of these engines, and doesn't think they could grind up a tool to do the job, I am sure that one could find it's way to you. Bogs |
| kvom:
I could send mine to someone on this side too. |
| kvom:
I started drilling holes in the remade heads yesterday, and "sacrificed" the first one. Once again the valve holes presented the problem. The drawings specify the depth to cut, but show a flat bottom hole. The first holes I drilled I used the points to set the depths, but doing this the valve ball sits too high for the plunger to contact. So I reset both the initial hole and counter bore to not count the point. The first hole then goes into the side mounting holes. This is probably not an issue, but it's also possible I don't need that full .4" depth anyway. A bigger problem was that the counterbore was probably a 1-2 thou. too deep and intersected the plunger hole; I think this would make the valve leak. So I now believe the solution is to use an endmill in order to achieve a flat counterbore. The plan specifies .200 counterbore. A 3/16" endmill followed by a #8 reamer should work. I'm out of town the rest of the week, so I'll try it next week. Of course, all of this is of little interest unless you're planning to build this one too. :coffee: |
| kvom:
I had a little more shop time before leaving for the long weekend, so I "caught up" on some tapping. This model needs a lot of tapped holes. Each of the 5 cylinders and their attached parts total 20 2-56 holes. Without the tapping stand I made a short while ago this would have been mission impossible. |
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