Boring bar setup and use

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

Try this. Sharpen your scraper again. Turn the scraper blade down to the left until it starts to cut. Expose less of the blade to the wood. Your toolrest should be close, but not so close that the blade will hit when you back out. You should be close to the project so that your arms and body will help reduce vibration. The project should be stairstepped so that more wood is into the bottom. In other words reduce as you go down. Use a gauge so that you know where you are at. Others my have more input, this is all the suggestions, I have at the moment. GT

hint (for next bowl) - hollow it out in 1/2 inch lengths, leaving at least

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You say you're using the teardrop scraper. If you're using the large radius portion at right angle to the side, you may have too much cutter surface attacking the side. Turn the cutter to expose a smaller surface to the cut, and use a very LIGHT cut. See if that helps.

Ken Moon Webberville, TX.

Thanks to all who answered. Ken, the reason I am using the boring bar is because I want to get real thin walls for piercing. I do not intend to use it except for that purpose. My hollowing technique with the Stewart type system is more than adequate but I don't trust myself for real thin walls (1/8" to 1/16"). I wanted to answer Ken's post which others may have had the same question. I will continue to read the posts and reply again later. Thanks......Ralph

You may half to rethink to whole thing here Ken. Turn wet using gouges like Binh Poah does. Finish the product all in one session. He uses mostly maple for his projects. GT

you are doing it wrong if you want thing walls on bowls. Try it this way:

1start with a nice piece of freshly cut ash. (I choose this wood for a good reason, keep reading) 2 turn your bowl, leaving walls about 1/2 to 3/4 inch thick - get the outer wall to the final shape.

1. put a bright light behind the ash
2. turn from the top edge towards the bottom - go about 1 inch max - turn it thinner and thnner until you see the light
3. stop and see how thick it is - start up again and turn thinner, keeping uniform light - stop and measure occasionally
4. when it's the thickness you want, memorize how the light looks, and proceed to turn down the next segment (1 inch max) to match the luminance. blend so you don't see the line (by luminance)
5. proceed this way to the bottom (which you should leave a little thicker)
6. sand lightly and spray with laquer

9 pierce away

after you do this, you will

1. understand why I specified fresh ash
2. realize that the wood is fully dry and finished in one session
3. realize that it's easy to turn paper thin
4. realise that you can make somethign "too thin", and it doesn't feel right
5. not bother with hollowing tools and lasers for bowls bill

Thanks Bill I appreciate your input.....Ralph

Hi Bill

I would say that covers it real well !!

Have fun and take care Leo Van Der Loo

william_b_noble wrote:

Hi Bill,

Good description of a good technique. Thanks.

Turn to Safety, Arch Fortiter

GT wrote quote:

"You may half to rethink to whole thing here Ken. Turn wet using gouges

like Binh Poah does. Finish the product all in one session. He uses mostly maple for his projects. GT"

If you look at any of the Binh Pho videos or DVDs you will see him using at least three different types of boring bars whilst turning his thin walled vessels. He explain how to use them and the advantages he gets from them.

Regards....Mike