Elmers VR75 build log

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spuddevans:
After a bit of thinking I came up with a plan of action.

I started by gripping the cylinder in the mill-vice, and using my edge-finder I centred and zeroed the DRO's on the exact centre of the bore. I checked 3 times to make sure I was bang on centre ("We don't work to the thousandth of an inch, we work until it's dead on!")

Then using a wiggler with a pointed end I found the centres of all the offset flange holes.

And duly noted all the DRO readings on the whiteboard for both ends of the cylinder. Then I was able to work out exactly what the offset for each end was, and my guesstimate had been right, about 0.3mm out.

Armed with this vital information I then proceeded to make the cylinder top cap.

I chucked a bit of Brass into the lathe and faced it and also took a cleaning cut off the side, only a skim as it is a 22.5mm bar and I want 22mm.

Then, throwing all caution out the window I went with my gut and transferred over to the mill to drill the offset holes. Unfortunately my gut forgot to tell me to take any pics of the drilling, but I'm sure you all can imagine what it looked like.

Then with abandon I decided to keep it in the mill reasoning that I have it centred and the DRO's zeroed on centre, so why not mill the little register that goes into the bore of the cylinder. With some thought I realised that I could use my boring bar with the tool turned the other way and the mill reversed. And you know what, it worked fine.

Perhaps a little slower than doing it on the lathe, but setting it up in the 4jaw would have cancelled any time saving.

Then it was merely a case of returning to the lathe, roughly centering it and then parting it off.

And with a couple of M2 socket cap screws (I didn't have any short enough for the 2 blind holes, but will shorten some later on) holding it to the cylinder.

Next up will be the slightly more complicated "inboard cap" with it's packing gland.

Thanks for looking,

Tim

Stilldrillin:
I like what you did with the boring bar, Tim! :bow:

That's thinking outside the box........ :clap: :clap:

David D

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