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Segment measurement table

I

Ira

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Sep 5, 2004
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Location
New Boston, NH
I am about to attempt my first segmented project and was reading the article about segmented bowl construction in the latest issue of American Woodturner. It is actually the second of a three part article on segmented turning and this part mentions a table that can be downloaded from the AAW website that lists segment dimensions, edge lengths etc. but I am unable to find it. I am at some point going to purchase one of the software products mentioned but for now I am doing all of the math on paper and calculator. I would just like to have something to check my math against. Thanks for the help!

Ira
 
The math is easy with a pocket calculator.
The diamater of the ring you want - time 3.1416 gives you the
distance around the outside of the circle - divide that number by
the number of segments (4 6 8 12 ) and you have the length of each segment.
:cool2:
JRJ
 
Ira---

I found the following book in my public library:

"Segmented Turning, a Complete Guide", Ron Hampton, 2003, Guild of Master Craftsman Publications Ltd, ISBN 1-86108-337-8.

In the back of the book, it has a complete table of miter angles and segment lengths/widths.

As for the math, it's rather simple, and if you have a programmable calculator you can very easily set up a simple program to calculate miter angles, stock width, and segment length for you---even for compound mitered segments.

Good luck, and hope it helps,

Henry C. Gernhardt, III
 
JRJ said:
The math is easy with a pocket calculator.
The diamater of the ring you want - time 3.1416 gives you the
distance around the outside of the circle - divide that number by
the number of segments (4 6 8 12 ) and you have the length of each segment.
:cool2:
JRJ
Click to expand...

What you get from the above is something that is actually just a bit larger then what you intended, which isn't a bad thing, since you can turn it down to the right diameter.
But do not use this method for the inside diameter, as it will be a bit larger, and you can't turn that down to the right diameter. 😱

It all has to do with cords and the basic geometery we all took years ago. This method takes the partial circumference and it makes the the cord length (ie the straight line that connects two end of a arc). Which works for outside diameter, but not for inside. Since the arc distance is slightly longer then the cord distance.
 
Hi Ira,

There are probably 5 or 6 different commercial programs available to help you with the math. Some of them are very simple, some a little more involved. If you have Microsoft Excel, I have a spreadsheet I used for sometime to help me automate some of the math before I purchased the programs. I would be glad to share it with you to use until you've had a chance to determine if you like segmented turning, and to research the commercial programs. It's fairly simple, and with a little explanation as to what goes where, it may be of some help. Also, there is a very simple program written by Tony Leonard I found on another forum's files section. It was available for download, so I presume it may have been freeware. Let me check into that, and if it is free, I'll be happy to send it on. Have fun with the segmented.

Bob Way
 
Last edited:
Bob, I would also be interested in the Excel, writing a spread-sheet to do this is on my "round to it" list.

... and any Freeware software is at least worth checking

TTFN
Ralph
 
"But do not use this method for the inside diameter, as it will be a bit larger, and you can't turn that down to the right diameter"

I'm new at this, but don't you turn both inside and out??

Joe

BTW, how do you do that fanct quote thing?
 
blackhorse said:
"But do not use this method for the inside diameter, as it will be a bit larger, and you can't turn that down to the right diameter"

I'm new at this, but don't you turn both inside and out??
Click to expand...

That's what I thought at first, then actually did some figureing and it came out a bit larger

BTW, how do you do that fanct quote thing?
Click to expand...

The quote button in the lower right hand corner of each post
 
blackhorse said:
"But do not use this method for the inside diameter, as it will be a bit larger, and you can't turn that down to the right diameter"

I'm new at this, but don't you turn both inside and out??

Joe
Click to expand...
It is like cutting a board too short -- no matter how many times that you re-cut it, it will still be too short. Likewise, if the inside diameter starts off too large, no matter how much you turn the inside, you can only make it larger, not smaller.

Bill
 
Last edited:
There is a program called woodturnerpro that will help you design and layout your segmented turnings, giving you exact dimensions, thickness, angles, and lengths. It a free trial for 30 days and well worth the $30 to license it.
 
Ira said:
I am about to attempt my first segmented project and was reading the article about segmented bowl construction in the latest issue of American Woodturner. It is actually the second of a three part article on segmented turning and this part mentions a table that can be downloaded from the AAW website that lists segment dimensions, edge lengths etc. but I am unable to find it. I am at some point going to purchase one of the software products mentioned but for now I am doing all of the math on paper and calculator. I would just like to have something to check my math against. Thanks for the help!

Ira
Click to expand...

Hi Everyoned,
Thank you all for the input. I have the math down, I'm using the tangent formula offered in the article I mentioned and I am just looking for the table mentioned in the article. The article states the table is downloadable from the AAW web-site and contains segment measurements for rings from 1 to 20 inches and for vessels with 6 to 24 sides. I have looked everywhere on the site but have been unable to find it. I would like to have it at this point simply to check my math.

Thanks again!
 
Brian Hahn said:
Go to the American Woodturner page here .

Near the bottom of that page are links to four PDF files on an introductory segmented turning project:

Quick Start Segmenting Project
Cutting Summary
Quick Start Drawing
Tablesaw Segment Cutting Sled Plans
Click to expand...

Hi Brian,
That table is for a specific project. The table I am looking for has meaurements for rings between 1 and 20 inches in diameter and for projects with 6 to 24 sides. The article states it is downloadable from the AAW web-site but I cannot find it.

Thanks
Ira
 
n7bsn said:
What you get from the above is something that is actually just a bit larger then what you intended, which isn't a bad thing, since you can turn it down to the right diameter.
But do not use this method for the inside diameter, as it will be a bit larger, and you can't turn that down to the right diameter. 😱

It all has to do with cords and the basic geometery we all took years ago. This method takes the partial circumference and it makes the the cord length (ie the straight line that connects two end of a arc). Which works for outside diameter, but not for inside. Since the arc distance is slightly longer then the cord distance.
Click to expand...

I'm sorry that you didn't understand that the purpose of making it just a little larger so you could turn it down to the desired size. I always make my ring just oversize so they can be turned down.
 
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