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I found a lazer edge finder very useful for getting some 'sort of' ref points on the sole plate I say 'some sort' because although Stewart have revised the drawing for this part concerning the bearings the 4 studs and nuts that hold it to the boxbed would also not work.
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Next was the standard. I made a mandrill to make a press fit to the bore of the casting and drilled and tapped M6 threads in it.
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This was so that I could machine the feet of the standard 'reasonably' true to the bore.
This went all OK with a newly sharpend bit in the tool holder considering the unsupported legs of the standard and I was happy with the finish. I did however change the live centre from the one in the image to a more heavy duty one as I did not want to knock the backside out of my best one on the interrupted cuts.
Again it became apparent that the casting was slightly undersize length in order to clean the faces up. This is an important length.! I will be able to recover this though by making the cylinder bottom slightly thicker to compensate.
Small video here :- **LINK** It sounds like a steam engine already making the interrupted cuts.
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The standard was reversed and mounted onto the face plate. I was sure this setup would need beefing up for facing and boring.
Since the above image was taken I made a few tentative cuts into the bore with a 16mm solid carbide boring bar that I snaffled on ebay for a sinch. (nobody else bid.) I really am impressed with it. The bore cleaned up after 20 thou. So it seems the mandrill did its job of finding the average of the rough cast bore.
Made a few passes after the bore cleaned up and measured each of the bore ends with a telescopic gauge. To my surprise there was only 1/2 thou difference over the 2 3/4 inch length with a really nice finish. I will bore the rest out today to 1 1/8th and see if I can cock it up.
Another short video clip here :- **LINK**
When I come to make the cross head how much undersize do you think I should aim for relative to the 1 1/8th of the standards bore.?
More later I hope.
Nick