I've just started making a Sugden Special. The first task to make the crankcase casting look something like a crankcase. The first problem!! This stuff machines like toughed steel!! The only way I was able to get an acceptable finish while facing the back of the casting was to use a Sumitomo cutter, when I came to drilling and boring, my selection of (newish and all sharp, Suttons) drills didn't/couldn't make the full depth, and the hole looks like it had been chewed out by a termite. So I tried boring the hole.....HA, it just laughed at me. The little barsteward.
Looking at the faced off surface, the only acceptable bit of machining so far, its covered in tiny marks, porosity of some kind I suppose.
I no longer have the material spec, but from memory its a common UK high strength casting alloy.
I've looked at a Sumitomo boring tool, apart from the cost, the minimum bore is bigger than the crankshaft bush, so that's out. Glanze have some really small boring bars..... are they any good. Should I bite the bullet and get a solid carbide boring bar??
Currently I'm even thinking about machining a crankcase from solid 6061 T6, which I have and it machines beautifully, but obviously that's a fairly major decision as it involves a huge amount of work.
Anyone have any ideas??
cheers
Bill Pudney