Segmented Turning / Woodworking Calculator

[Tim Boger]

I'm trying to decide on a hand held calculator specifically designed for woodworking, does anyone here have a recommendation?

There are plenty of choices out there the be sure, but I figured some folks here have already been through the trial and error process and might suggest a tool that is shop friendly and specific to our hobby.

What do you use?

Thanks ..... Tim

[David Christopher]

this is what I use

http://www.sawmillcreek.org/attachment.php?attachmentid=117712&d=1241743810

[Ryan Baker]

Why do you want to do the calculations in fraction format? Especially for segmented work, that just makes it harder, IMHO, and the fractional calculators I have seen don't have fine enough resolution for segmented work. I'd keep it in decimal. But do whatever works for you.

[Richard Madison]

Good point Ryan. Have never seen trig functions calculated in any form but decimal. And measurements with dial calipers are certainly more precise in decimal form.

[mike fuson]

I use the pocket handyman from Lowes. Used it for years. Fractions or decimals.

[Malcolm Tibbetts]

I do some pretty complex segmented work and I've never needed more than a cheap, non-scientific, $5 calculator. If I need trig functions, which is very rare, I use a computer.

[Jarrod McGehee]

David, how do you use the chart? is the measurement per amount of segmented pieces the part that is the outer diameter or ?? do you cut the angles corresponding to the amount of pieces like 60# for 6 pieces?

[Phil Labowski]

yeah. the chart helps with the length of the O.D. of the piece, but it would be nice to have a reference for the angle cuts too.
thanks
Phil

[Greg Just]

Rockler has one on sale right now for $4.99 -might work for you.

[Thom Sturgill]

Sorry if this is a bit pedantic:

The formula sum = 180(n - 2) gives the total of the included angles for a polygon of 'n' sides. 180 for a triangle, 360 for a square and so on.
So dividing that by 'n' gives the included angle for regular polygons. 180/3=60 360/4=90, etc.
Dividing by '(2 * n)' would give half the included angle (30, 45,etc) - subtract that answer from 90 to give the final answer.

Final formula of cut Angle = 90 - (180 * (n - 2))/(2 * n)

Which generates the following table:

No Sides Cut Angle
============================
4 45
6 30
8 22.5
10 18
12 15
16 11.25
20 9
24 7.5

I have used a cad program (QCAD - its free) to lay out a ring and the just used built in functions to measure the lengths. I create two concentric circles for the inside and outside diameter and then tell it to create a polygon of however many sides I need using the same center and picking a point for the center of each segment. then draw parallel lines at a given distance to create the inside polygon.

I can then tweak the results to get a piece that will contain my two circles without too much waste and yet use easy to layout measurements.



































19 9.47 20 9

[Mauricio Ulloa]

Hi,

I use two softwares: the 3D Design pro ($35) in combination with the Woodturner pro ($50). Here is the link to get them:

http://www.woodturnerpro.com/purchase.html

The width is defined by the number of segments and the OD, but the height and the length are defined by the shape of the object that you want to make. So, instead of doing all the math, I design the object that I want to make and these soft wares provide me with all the measurements of the segments. It's quite easy to learn and use.

Hope this helps a little....

[Richard Madison]

You could just divide 180 by the number of segments to get the miter angle. It isn't rocket surgery.

[Tim Boger]

I find it amazing how helpful the members of this forum can be, thanks to all that have taken the time to comment.

Tim

[Brian Novotny]

You could just divide 180 by the number of segments to get the miter angle. It isn't rocket surgery.
now, THAT was helpful

My lathe broke for good today, so before I find a new one I want to try my hands at ST. What's the best book or dvd on the subject...I know that ray allen has a watch it now video on amazon for $2..I'll watch that, but I want something that will cover most bases in one book or dvd......until I find a lathe I might as well learn how to do basic segmented work!

[Tim Boger]

now, THAT was helpful

My lathe broke for good today, so before I find a new one I want to try my hands at ST. What's the best book or dvd on the subject...I know that ray allen has a watch it now video on amazon for $2..I'll watch that, but I want something that will cover most bases in one book or dvd......until I find a lathe I might as well learn how to do basic segmented work!


Good Morning Brian,

I strongly recommend Malcolm Tibbetts book and DVDs.

Tim

[Richard Madison]

Ditto what Tim said. "The Art of Segmented Woodturning", available from Amazon or himself at tahoeturner.com. Just don't use hot glue when clamping parts of ribbon-forms together.