Segment angle precision

[Pete Staehling]

Okay, so I am new to segmented turning. I turned a first bowl using my Miter saw to cut segments and then made a wedgie sled and used drafting triangles on a couple subsequent bowls. I got good results with no gaps both ways. It took some fiddling with the miter saw and was pretty much trouble free with the wedgie sled and drafting triangles.

The drafting triangles will serve fine for 6, 8, and 12 segment setups. For other setups I am thinking of either using some kind of variable rig like a big protractor (or digital protractor) or making templates rather than buying the SegEasy ones. Does anyone have a feel for what the tolerance in degrees is for the wedge angles to yeild good results?

Looking at the inexpensive digital calipers the tolerances seem to run around +/- 0.2-0.3 degrees with some being worse. If that were good enough they would be super easy to use with the wedgie sled, but I suspect they may not be good enough.

I think I may be able to get almost that close with my Starrett protractor even with it's really short radius scale. I have a pdf of a really nice long scale 90 degree protractor that I can print out. With it's longer axis that I think I can get better accuracy (probably 0.1 degree).

It would be really nice if I knew what level of accuracy I needed to shoot for before I decided whether to go down one of these roads and if so which one. Anyone have a feel for what that number might be?

 

[GRJensen]

Accuracy needs to be petty much dead-on ... you don't want any gaps in your glue joints and those who try to close them up with clamps may/may not be successful. Gaps in your glue joints stick out like a sore thumb.

Do you have a disk sander? If you do, my advice would be to build yourself a sled for your sander so you can fine tune your miters. Here is a link to a Fine Woodworking article that details a sanding jig like the one I use ... https://www.finewoodworking.com/2012/07/26/sanding-jig-is-the-segmented-turners-secret-weapon

Full disclosure: I am a wedgie sled advocate. Since I started using my wedgie sled (with the wedges from Segeasy) I seldom have to use my sander to get tight, accurate miter joints.

 

[Don Bunce]

An angle block set might be of use to you.
https://littlemachineshop.com/products/product_view.php?ProductID=2553&category=

 

[Bill Raker Jr]

Okay, so I am new to segmented turning. I turned a first bowl using my Miter saw to cut segments and then made a wedgie sled and used drafting triangles on a couple subsequent bowls. I got good results with no gaps both ways. It took some fiddling with the miter saw and was pretty much trouble free with the wedgie sled and drafting triangles.

The drafting triangles will serve fine for 6, 8, and 12 segment setups. For other setups I am thinking of either using some kind of variable rig like a big protractor (or digital protractor) or making templates rather than buying the SegEasy ones. Does anyone have a feel for what the tolerance in degrees is for the wedge angles to yeild good results?

Looking at the inexpensive digital calipers the tolerances seem to run around +/- 0.2-0.3 degrees with some being worse. If that were good enough they would be super easy to use with the wedgie sled, but I suspect they may not be good enough.

I think I may be able to get almost that close with my Starrett protractor even with it's really short radius scale. I have a pdf of a really nice long scale 90 degree protractor that I can print out. With it's longer axis that I think I can get better accuracy (probably 0.1 degree).

It would be really nice if I knew what level of accuracy I needed to shoot for before I decided whether to go down one of these roads and if so which one. Anyone have a feel for what that number might be?

 

[Bill Raker Jr]

I have been gluing my rings in half's and then trimming the two half on table saw sled. No gaps in my rings.

Clamp 180 Deg half ring on table saw sled and just trim both end while the ring half is clamped. this makes rings line up perfectly with no gaps what so ever.

And I normally cut my segmented pieces on compound sliding chop saw. Have stop block for all my different angles.

 

[Timothy White]

The problem with .2 degree variance is that it is accumulative. 6 pieces +/-1.2degrees. The Seg-easy triangles are the best way to get perfect rings.

Tim
To everything turn turn turn

 

[John Torchick]

Read this with great interest. Precision on angles seems to be a key to segmenting without glue gaps. Interesting that I'm getting ready to make a jig for sharpening my skews. My son made a 30-60-90 triangle that he said might be off a couple of thousandths. Close enough for government work...and segmenting.

 

[john lucas]

I have tried all the methods and they all work once you work out the kinks. However the segeasy is the best system I've tried. I've use the sanding disc method which was the second most accurate for me. I have several miter gauges for my table saw and purchase a really good miter saw and they all work, but it's just so much easier with the segeasy. http://www.segeasy.com/

 

[Brian Horais]

I took a class from Curt Theobald once and he was all about precision. Even after using his calibrated angle gauges, he still used the 'half ring' method to take out any errors. If you're not familiar with this method, it involves using an even number of segments and not gluing each segment half together. Instead, small spacers (such as veneer strips) separate the halves while the entire ring is clamped and glued. Once the glue is set the ring clamp is removed and the spacers are removed. Each half is sanded flat on a circular sander. Even here it is difficult to get the circular sander set at exactly 90 degrees. To compensate, one half of the segment ring is flipped over and sanded flat at the edges. This completely removes any error with a resulting perfect fit and no gaps. Small errors in segment angles will add up, so precision is important. This description of the method is too brief, so take a look at good sites (such as Curt Theobald's) and you can get better explanations and YouTube videos. Enjoy the Segmenting!