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| Parting off and general HSS tool sharpness |
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| Ross:
Hello everyone. I did a bit of turning on the lathe today just to test the various tools etc.. I centre drilled and drilled a hole (all technical stuff) :thumbup: And I turned part of the rod down to 10mm diameter. The standard cutting tool I used cut through the aluminium like butter as it should! I put a little groove in the rod too, but the real trouble came to when I wanted to part off the piece I'd just done. The metal wasn't having any of it and the tool was just making nasty marks and squeeking. Before. I snapped or broke something I gave up as parting off was like cutting through butter at college. I'm not convinced that my parting off tool is sharp, I can run my finger all over it and it just doesn't feel sharp hence the nice marks it has left in my masterpiece! What's the best technique to sharpen these tools if any? And some pictures to show: |
| -steves-:
Hi ya Ross This is where you could do with the little diamond covered wheel that David (Stilldrillin) showed you, as the tools you have there (same as my first ones) as as blunt as anything :( I would suggest sharpening them as a first point of call and then see how it goes from there. Does it do the same on brass? After sharpening if its still no better, then check the rigidity (however its spelt?) of the tool, tool post, top slide, cross slide etc. Parting off on small machines takes a bit of a knack and a lot of setting up, sharp tools etc. I will freely admit, I put a small groove in now and then turn to the hacksaw to finish the cut, particularly on steel, though brass below half inch diameter isn't an issue. I am sure the more experienced will give you better pointers :) Best of luck P.S. I don't think that is HSS in the picture..... I find that a sharp HSS tool will cut very well, but do go blunt quite quickly, again, particularly on steel. A really sharp tool is a god send :thumbup: |
| DMIOM:
hi Ross - it might also be worth checking that the tool height was correct (p.s. belated welcome to the mad mob!) Dave |
| picclock:
Hi Ross If that's aluminium then it should be very easy. First check that the tool height is correct by trapping a thin piece of metal (razor blade or similar ?) between the tip of the tool and the work. If the height is correct the thin piece will be exactly vertical. Sharpen the end of the parting tool with a stone or grinding wheel to give it a good edge. Fit the tool so that the overhang from the toolpost is just over the work radius size. Ensure that the tool is at right angles to the ways. Lock the carriage to the bed and ensure that the gibs are tight. Using a slow speed, say 150 rpm, feed the tool into the work. If the tool chatters it may be that the gibs on the compound slide are not tight or that the rigidity of the toolholder is poor. If the cut looks like its going to be OK douse the work with wd40 or paraffin and slowly advance the tool until done. Most parting problems come down to rigidity of the setup and the correct tool height. I found that parting was much improved by removing the compound and replacing it with a steel block. Also I replaced the headstock bearings with taper roller ones which gave an improvement. Good Luck Best Regards picclock |
| Bernd:
I'll add my 2 cents worth here. First that looks more like a carbide grooving tool than a cutoff tool, and as mentioned else were it isn't sharp. I would try a HSS cutoff tool if you have a small bench lathe such as a 9 X 20 or smaller. It's not rigid enough to cut with a carbide tool. Bernd |
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