Shadow Build

[ATinkerer]

Your precision and attention to detail is a good example for us all.
Appreciate your efforts to post the details of your work.

Gordon

[John H]

Thanks Gordon. Just as I suspected, the last cut with the boring bar showed the hard spot being .001" high. Only way to proceed is to ID grind the bore to the finish of 1.1185. The first few cuts caused the stone to chatter but as it got closeer to a perfect circle it settled down.

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For the two final passes I changed the speed to 17000 rpm and finished it off exactly to size.
Nice when things go per plan.

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[ATinkerer]

John:

Nice looking finish from what I can see of the bore.

When I think things are going according to plan, I usually find out I didn't understand the situation correctly.

Gordon

[John H]

I always get nervous when it comes down to half thou measurements. For some strange reason the last cut wants to take a big bite. The main shaft pressed in perfect. Next step is boring the crank pin hole to size. This is where things went badly with the other crank. So a lot of extra time was spent checking and double checking alignment before starting the boring.
Here I'm going for a finish bore of 1.057 which will give me a .006 interference fit. One down, one to go.
Love my coffee mug.

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[Lotus54]

Thanks for the excellent updates. I always like seeing how you do those operations.
I really like my mug with grandkids on it too.

[John H]

Time to press the big pin in the flywheel. I've been coping with this problem on the press for years. The end of the ram is, well, rounded such that it's near impossible to get perfect alignment when trying to line up a pin perpendicular to the bore. So today will be taking it all down and machining the end true to the ram. Not sure what the thread profile is on the end but it's not standard and it took a 4' bar and all the umph I could muster to get it apart. There was no way I was going to get this screwed together again with such threads so ran the threads for the cap on the lathe just enough to find the error in the 12p thread. After an hour of chasing and dressing the cap goes in perfect. Now back together.

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[John H]

The press worked perfect. I should have trued the ram a long time ago. The 1/4" tungsten rod makes aligning the flywheels much easier. The side clearance for the rods is .016" which is about right. The runout from one main shaft to the other is .004 so the lead hammer and the Madrona stump will be put to work to get the runout within a half thou.

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[ATinkerer]

Good photos of precision work.
Wonderful that it continues to progress well.

Gordon

[John H]

The tedious part now is to zero the runout. With the truing stand and the indicator now it's just a matter of using the the lead hammer in the right place or in this case, spread the flywheels a bit.

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When everything is true then the crank pin nuts are tightened to a number close to 250 ft pounds. Yes, that's a 3' long cheater pipe on the socket.

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[ATinkerer]

I'm surprised you don't have a 1 inch drive torque wrench.

Gordon