| Gallery, Projects and General > How do I?? |
| Oval bores help |
| << < (2/3) > >> |
| Jasonb:
I can't see you distorting a tube with 8mm wall that much in a small chuck particularly if you say you are just nipping it up. There are always ways to use a thicker boring bar than will fit in your toolpost like this Jason |
| Bogstandard:
Jason, I am of the same opinion, they are fairly substantial walls to distort. Say 4mm and below, yes, but not that sort of thickness. I have never had a bored hole go oval, only tapered, and I've used boring bars made from 1/16" drills. It's got me a bit stumped. All I can think of are the final cuts are a bit heavy, normally 0.025 is about right for a fine finish, and in/out at least half a dozen times. Bogs |
| sbwhart:
ames What the material is it your turning, is it a bit of drawn tube that you are opening out. Some types if drawn tube will distort its all to do with the directionality of the grain structure as you thin the bore out it will want to move more and more. Just a thought Stew |
| lordedmond:
ALB have you tried to do a bore in a different material e.g. ali or cast iron? it may have been sold as EN1a but is it it may be GCQ ( good commercial quality ) or just junk bar end. it is just possible that it has a hard spot a 8 mm bar may deflect at the hard spot. is the bore oval or triangular ( like a three lobe cam ) they can measure like an oval its just possible that the bearings in the head stock are shot my 0.02 cent worth Stuart |
| ALB:
Jason that's one mean looking boring bar it would scare my little machine btu I know what you are getting at thanks. Bogs I will try another piece tonight and go easy on the finishing cuts. Stew it was a solid piece of EN1A 25mm in diameter it drilled ok and seemed to bore fine also nice spiral chips Stuart I have bored brass before for little stirling engine no probs and it was BS970 080A15 material I run a steel stockholding firm and I get to keep the "scrap offcuts Hmm" as for the headstock everything seems to be tight but I am not sure how to check this? Again thanks guys for your help James |
| Navigation |
| Message Index |
| Next page |
| Previous page |