segmented turning

how do you calculate the length of a segment?? ed

I use an app for my phone called segment calculator. Gives me length and width.

I also have made up circular graph. There are rings drawn every quarter inch in diameter.Then I have divided like a pie into 8, 16, 32, and 64 pieces. I put a piece of glass over this and can draw my rings with a dry erase marker full size on the glass. Then its just a matter of measuring.

thanks john. i"ll try to make a graph. ed

Hi Ed;
Go to this address and scroll down a little to get the "Online Segment Calculator" http://woodturnersresource.com/
All you have to do is enter the measurements as requested and you get the length of segments for that ring.
Good luck
Peter F.

(Diameter * pi) / Number of segments = Length

[QUOTE=John M. Smith;2015043]I use an app for my phone called segment calculator. Gives me length and width.

John: what kind of phone do you have? I don't see an app for the iphone. Thanks

Ed, here's another site that has a lot of good info on segmented turning.......
http://www.turnedwood.com/index.shtml

Malcolm Tibbett's book "The Art of Segmented Woodturning" will give you more math than you want to know. Highly recommended if you are considering a foray into segmented turning.

+1 on Malcoms book.

thanks guys, you have been very helpful. i will try segmented work sometime this winter. ed

Check out http://www.woodturner.org/products/a...ationTable.pdf. - John

Ed, for most rings with more than 8 segments, the "diameter x pi / # of segments" works fine. But determining length is only part of the challenge; you also need to know the width, the dimension from outside to inside. That is most easily found by drawing a simple blueprint and overlaying rectangles that capture the profile.

Quote:

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Originally Posted by Bill Bulloch

(Diameter * pi) / Number of segments = Length

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That is incorrect. That formula will give you the arclength, not the segment length. The difference between the two results becomes significant for larger diameter rings. The actual formula is:

D*tan (pi/n) for radians

D*tan (180/n) for degrees

where D is the ring diameter and n is the number of segments

If you draw what you intend to make as Malcolm describes to determine the diameter of the ring and width of segment, you can use the Segment calculator on my website to calculate the segment length, calculate the length of the board needed based on cutting method and print out a cut list. You can also save your project to reuse later.
It's free, and worth every penny...
here is the link: http://marleyturned.com/Shop_Utilities.html

Larry

I will give Mr. Marleys calculator a thumbs up. I started using the woodturners resource calculator and had my difficulties with it. Mr. Marleys is dead on accurate and it will calculate ring diameters under two inch for my minatures, or my extra large turnings.