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Kevin Neelley
 
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Hi Ralph,

I use the Sorby RS2000 which is basically the same as the Stewart System. If
you are having severe vibration I would use a steady rest, even though the bowl
is only 6" deep. The steady rest might allow you to finish the bowl without
excessive vibration.

You mentioned that you have turned the bowl's lip and bottom before you have
turned the sides. Maybe, you have turned the bottom so thin that you have
weakened the structure. Personally, I turn the bowl interior to thickness,
starting at the lip, working down to the base, so the area I'm turning is always
supported by thick wood.

Maybe there is a wood defect near the bowl base that you can't easily detect.

Another thing you might try is to hollow your bowl using a 1/4" wide blade and
then switch to a teardrop blade at the final shear scaping cleanup of the bowl's
interior.

Finally, here is a remote possibility but I thought I'd throw it out because it
bit me a while ago. Make sure your chuck or faceplate is absolutely tight
against the headstock. John Jordan suggests not using a plastic washer to make
it easier to unscrew your chuck. I second that recommendation (I use Slick50
oil). Also, some poorly designed faceplates bottom on the threads rather than
against the face on the headstock, which will leave the faceplate prone to
misalignment and vibration, so you need to add a spacer washer.

I'm out of ideas but I've been there. Sometimes turnings will drive you crazy
with weird problems. All you have to do is solve them before the bowl
self-destructs.

Kevin


In article , Comcast
Newsgroups says...

I am having a bit of a problem using a boring bar system and figured someone
out there can help. I am using the new Oneway laser guided hollowing system
with the John Jordan secondary tool rest. I am also using the Stewart
system ¾" hollowing tool with the tear drop scraper blade attached to the
Oneway boring bar. I have manually rough turned the vessel to approx. ¾"
wall thickness using the John Jordan hooker type tool in the Stewart arm
brace. My problem is severe vibration when hollowing the sides with the
boring bar. I am using the same setup as described in Lyle Jamieson's
website, secondary tool rest is at lathe center height and the cutting tip
is at center line. I am able to scrape very nicely at the bottom and at the
neck but when I get to the sides it vibrates very severely. This is not a
deep bowl, approximately 6 inches deep; the wood is dry sycamore (I get the
same vibration with other woods). I have to be doing something wrong but
unfortunately I haven't figured it out. Any ideas on what I am doing wrong
will be greatly appreciated....Ralph