Stivini
12-14-2010, 08:44 PM
I am just getting into turning and my main interest is to make banjo rims. The rims are between 11" and 12" across and typically 3" high with a wall thickness of 0.5 - 0.75". Most frequently the body is 2-3 rings (12 segments) of a hardwood capped with one ring of a very dense wood. The cap is turned to a fairly sharp peak in line with the outside diameter and serves as the tone ring. I'm using cocobolo for the tone ring, but nearly any very dense wood will do. The body can be any hardwood, but those with small pores work better than large pore wood, thus cherry and maple are preferred over oak. I've successfully turned one rim so far (honey locust and cocobolo), but am having trouble with my second.
The problem child is a black locust and cocobolo rim and the trouble is tear out. I find that the cut on the part of the segment leading into the joint is fine, but the opposite face inevitably tears out. I even had a piece of the tone ring material (cocobolo) splinter off. That stopped me for the night to glue it back in! I am a novice turner, but have a good lathe (Nova, the one with the belt) and decent tools (a set of Sorby and a set of Freud chisels). I know how to keep tools sharp. I tried to feed the gouge into the work piece very slowly, but I still got the catches. I have the speed set to the second slowest speed and the blank is a little over 11" in diameter.
Do I want more speed? less? I'm using my gouges to rough out the rim, but at this rate I'll have nothing left! Would it be wise to use a rasp to knock the points off the segments, then use the gouges to finish up? Or is this wood just impossible to turn?
Thanks for your help.
The problem child is a black locust and cocobolo rim and the trouble is tear out. I find that the cut on the part of the segment leading into the joint is fine, but the opposite face inevitably tears out. I even had a piece of the tone ring material (cocobolo) splinter off. That stopped me for the night to glue it back in! I am a novice turner, but have a good lathe (Nova, the one with the belt) and decent tools (a set of Sorby and a set of Freud chisels). I know how to keep tools sharp. I tried to feed the gouge into the work piece very slowly, but I still got the catches. I have the speed set to the second slowest speed and the blank is a little over 11" in diameter.
Do I want more speed? less? I'm using my gouges to rough out the rim, but at this rate I'll have nothing left! Would it be wise to use a rasp to knock the points off the segments, then use the gouges to finish up? Or is this wood just impossible to turn?
Thanks for your help.