Open Segmented Turning questions

[Hank Walczak]

I'm having trouble turning the inside of forms like this. I use a 1/2" bowl gouge and a round nose scraper. I get a lot of catches. The form is about 5" wide and about 6" tall. I am turning at 850 rpm or so. Do I need a different type of tool or is it operator error. I'm not sure I'm riding the bevel; I think I am. With all the time it takes to assemble the form, I really hate to blow these up. Any suggestions would be appreciated. Thanks.

[Dennis Daudelin]

Hello Hank,

I hope that I can help with your question on the open segments.

I can share some of my experiences with open segment turning. First, I've learned to make the segments thin, meaning not much needs to be cut off.

Then, I cut the inside as I'm building the unit, say after the first 3 or 4 rows. This way I've removed some of the "meat" at what becomes the furtherest point in the bowl from the tool rest. Now, I don't cut it to final dimension, just round it out and make the rings flow into each other.

And lastly, a bowl gouge should be fine for the cutting. If you're using a scraper, you may want to try the "newly repopular" negative rake on your grind. It might help. You may also want to try a tear drop scraper as opposed to heavy 1 inch straight scraper. The goal here is to make lots (and lots) of very fine cuts. I'm talking about sub 1/32" type cuts. No 1/16" cuts on this type of form!

Some of the segmented turners doing the larger fancy vases use the Steward System or something of this style with the tear drop scraper for getting deep into their vessels, this might work here too!

The only thing that you need after that is patience!

Dennis

[Hank Walczak]

Dennis - Thanks for the tip. I had thought of starting the interior cuts before the form was finished but didn't feel that the pieces could take the stress. I will definitely give it a try. I'll make sure the glue up has a little more set up time to be safe.

Hank

[George Troy Hurlburt]

I'm not sure but, maybe your spaces can be smaller, if so that could make the cutting a little easier. Also try turning up the speed some more on that small of form.

[Keith Burns]

Spacing looks right to me. I use a Hamlett Hollowing tool. It is a ring tool with a guard that limits the cut. I typically go down to about 3/16" to 1/4" wall. I glue up the entire piece before turning. Scrapers and gouges just don't work for me on the inside. I do use my bowl gouge on the outside without any problems.

[Keith Burns]

Thought you might like to see a photo of one I did using the tools I described.

[Dennis Daudelin]

In the middle of the night, I awoke with one more thought!

It was to consider doing the glue-up in 2 pieces; top and bottom. I often do 2 part glue-ups for my segmented pieces. And even non-segmented pieces.

I recall doing an open segment ornament (inspired by Lloyd Johnson of Woodturner Pro) in 2 pieces.

http://www.woodturnerpro.com/projects/images/christmasOrn.jpg

Doing it in 2 pieces is much easier than it sounds!!

Dennis

[Hank Walczak]

Dennis, Keith - Nice work. Dennis, I have a 24 seg. project that I was planning to do in halves. It does look like it should be easier in many ways than trying to finish that semi-enclosed form. Keith, that tool you use is a little outside of my budget for now (~$200 for the tool will have an adverse impact on my new lathe fund!). I do believe, barring trying to do some of it during assembly, that a tool similar to your Hamlett tool will most likely be the answer. Something a little more economical available? Thanks for your suggestions.

Hank