The 1/8" hole was then drilled.
I paused for quite a while thinking how the 1/16" hole should be done. According to the plan, it should be 1/8" away from the center of the disc. I thought of re-chucking the job in a 4 jaw and offset it like the way shown by some folks on YouTube. But I don't have an idea how to offset it by the required 1/8" from center. Since I've the mill squared up, I thought using one of the horizontal axes to do the offset. First, I've to find the center of the job.
This was what I did
The 1/8" hole that was drilled was aligned with the MT1 center. Once the center was established, I moved the x axis by 3.175mm and drill the 1/16" hole. This is the smallest hole I ever drilled since I started this hobby. I was afraid to break the tiny HSS drill but the operation went without a glitch.
The stock in the chuck was transferred back to the lathe to be parted off.
But... the 1/16" hole wasn't deep enough to break through the bottom...
The challenging part was to mount the stock back to the 3 jaw to face the other side till the 1/16" hole show up. This took me quite a while till I decided to hold a engineering square to the face with the motor turning at slow speed. After a few attempts, I managed to get the part turning without visible wobbling.
Facing was done carefully as I only have a little stock sticking out of the chuck.
I stopped with the hole showed up.
Test fit was done with the supplied pin & shaft.
The fit of both are rather tight. I'll still use a drop of Loctite to avoid the parts falling apart.
I reported in my previous post on the flywheel that it's 1/8" hole was a sliding fit to the crank shaft. When I tried inserting the shaft to the flywheel, I couldn't get the shaft into the hole. The part must be warm enough the last session to allow the shaft to just slide in. I think I'll heat up the flywheel when inserting the shaft during assembly.
The completed disc with pin & shaft viewed from another angle.
That's all for today. I'll be making the piston in my next instalment before starting on the rest on the mill.
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