Okay turners I need your help!
I’ve made about a half a dozen segmented bowls all about 12-14″ across and 5 inches deep. They’ve all been salad bowl style. I made two smaller ones, but I like the bigger ones better.
Anyhow, in all of my bowls thus far I have stuck to simple segmented design, that is, all octogonal rings offset between layers. The simplest of segmented bowls, in my opinion. For each ring I just cut eight identical pieces at 22.5 degree angles and clamp them all togethor with a ring clamps ganged togethor.
When I’m done turning and even after sanding more than what I think I should have to I seem to always have tearout between the end grain to end grain pieces on the same layer. I’ve tried gluing the endgrain joints and not gluing the end grain joints without any luck.
Does anyone have any suggestions for me to try? I can post pictures if my explainations are unclear.
Thanks,
Adam
Replies
segmented bowls have that problem, as explained to me, the fibres are not supported past the glue line so they will naturally tear off. same thing happens with solid wood, you get some tear out on the end grain. chipping will also happen with segments because the wood is not supported by adjacent fibres. a sharp tool may help. Also i use 12 segments which means more work up front but there is still some broken bits.
Are you assembling the stack so that when you cut the endgrain you are cutting "downhill?"
I'm not quite sure I know what you mean by that.
I've attached some pictures of the most recent bowl. You can see the problem in both pictures.
Thanks,
Adam
First, always glue the joints. You don't want the piece flying apart on the lathe.
As you turn the inside, the gouge starts cutting each segment at its centre. As you proceed, each cut starts closer to the leading edge of the segment and ends closer to the trailing edge. All the tearout in your photos is at the trailing edge, where you'd expect. Sharp tools and a light touch will help. When you get close to final thickness, stop and sharpen the gouge again.
Examine the segments carefully when you first cut them. Some chipping on the outside corners is OK because those get turned away first, but any chipping on the inside corners is a reject. Examine the assemblies as you glue them up. Any joint that looks bad at this stage will only look worse later.
HTH
Graeme
It would be helpful if you could post a drawing of what the actual segments are shaped like and the direction of rotation as you cut.
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