Well the new boring bar stand is just about done, which is good, because it's been holding up a couple of other projects.
Boring bar mod 2 Jun 2023 by
Terry Prendergast, on Flickr
I drilled the top for the CB750 cylinder block hold down bolts and loosely mounted the boring head, then realised that I somehow had to "clock" the boring head to the mounting block, so bought another piece of 90mm machineable round bar and first turned it to 86mm for that big hole in the table top, then bored it 33.3mm for the boring "quill", so that I could centralise it in the exact middle of that big hole.
Boring bar mod 2 Jun 2023 4 by
Terry Prendergast, on Flickr
Boring bar mod 2 Jun 2023 3 by
Terry Prendergast, on Flickr
Of course, the whole point of this was to ensure that I was gonna be able to bore CB750's (or Z1's, etc) dead centre, so I turned up another tool that was 86mm OD to fit in the big hole, 33.3mm ID to fit the quill and centralise it in the big hole, and 60.9mm on the other end, to then ensure that the quill (with cutting tip) was centralised in the CB750 cylinder when I bore it out. While I was at it, I turned the other side down to 63.75mm, as I'll "rough out" sleeves that I'll eventually bore to 65mm (836cc) to 63.75mm on my lathe, which cuts much faster than the boring bar, then just reinsert the sleeves back into the cylinder block and "finish" bore them on the boring bar.
Boring bar mod 2 Jun 2023 6 by
Terry Prendergast, on Flickr
Boring bar mod 2 Jun 2023 7 by
Terry Prendergast, on Flickr
Everything fit like a glove, I tightened down the boring head, and now I'm ready to do some boring!
Boring bar mod 2 Jun 2023 8 by
Terry Prendergast, on Flickr
I also need to bore out a cylinder block to take some 970cc sleeves shortly, so once again the new setup will work well to precision bore the alloy block for the wider sleeves, and if I need to increase the size of the sleeve holes in the top engine case, I can do that now as well.
Apart from a young d1ckhead crashing into my car @ 60 MPH on my early morning commute, I had an otherwise reasonably happy day, and picked up this ancient Aussie built battery charger from a local FB seller, as I plan to do some electrolysis rust removal in my Fireblade tank as the Evaporust didn't do much of a job and the rust has grown back. more on that later.
Boring bar mod 2 Jun 2023 2 by
Terry Prendergast, on Flickr