Simple way to make wedge pattern
#11
Needed to make two wedgie’s for 10 segment ring and a 9 segment ring. So I made them as shown in attached (poor) drawing. The size of AE is around 8”. DE is sized to fit between fences. Angles A and E are 90 degrees.
1 ) A miter gauge can be used to cut the trapezoid wedge. Not having a accurate way to set the miter gauge the setting was verified via Vintage Machinist Tool Combination Square Protractor Head. (at least 70 yrs old). After cutting the wedge I verified the angle by using line BD and BC. I used a dial indicator acurate to 1/100th inch to measure BC before cutting any wedges. The side BC can be found using the tangent of the angle at D. ( 40 –.839099 , 36 – .726542 from spreed sheet).
For 40 degree and BD of 8” BC is 6.71299. For 36 degree and BC is 5.81234.


The true test, cut 9 and 10 ring segments. Adjust if needed. I was lucky, both were correct on first cut.
If the ring does not close, you need to adjust the wedge

    .
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#12
You are talking above me Bob.

What is it that you really did in plain English?
It is always the right time, to do the right thing.

Hi, I'm Arlin's proud wife! His brain trma & meds-give memory probs and has pain from injuries, but all is well materially & financially.  
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#13
(10-28-2017, 08:26 PM)Arlin Eastman Wrote: You are talking above me Bob.

What is it that you really did in plain English?

I made what is in the picture, setting the miter gauge to 54 degrees, this make what in the picture and insered into the wedge sled will make 10 segment riing.
Setting the miter gauge too 50 degrees will make what is in the picture and will make 9 segment rings.  I will try and take some pictures of the pattern being made.
Jerry dosen't offer these sizes.
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#14
(10-28-2017, 08:42 PM)bob-t Wrote: I made what is in the picture, setting the miter gauge to 54 degrees, this make what in the picture and insered into the wedge sled will make 10 segment riing.
Setting the miter gauge too 50 degrees will make what is in the picture and will make 9 segment rings.  I will try and take some pictures of the pattern being made.
Jerry dosen't offer these sizes.

Arlin,
Here are some pictures
Setting the miter guage
   
Material to be cut for pattern
   
Pattern cut
   
Using the pattern in wedge sled
   
Verifying using side BC and distance at points of dial indicator  -- not the wedge that was shown in other pictures.
   
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#15
He made wedgies for 9 and 10 segment rings.
We do segmented turning, not because it is easy, but because it is hard.
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#16
So what you did is make one side 90 degrees and the other 54 or whatever you wish to make a segment?
It is always the right time, to do the right thing.

Hi, I'm Arlin's proud wife! His brain trma & meds-give memory probs and has pain from injuries, but all is well materially & financially.  
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#17
(10-29-2017, 03:08 PM)Arlin Eastman Wrote: So what you did is make one side 90 degrees and the other 54 or whatever you wish to make a segment?

Yes, I found it easier to deal with whole degrees make the pattern.  Hope is to get others doing more segmenting.
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#18
Just my opinion, most people shy away from segmenting for a few reasons. Time involved, tools needed, complicated math. There's no getting around time involved but purchased wedgies help a bit, unless you use dedicated sleds, then there is no time savings. The only tool I recommend is a wide belt sander but there's a work around for that. That leaves the math. I appreciate the work you've done and sharing it but man, it makes segmenting seem more complicated than it needs to be. The number of segments per ring dictates the angle of the cut divided by two.

360 divided by 16 =22 1/2 degrees
22 1/2 divided by 2 = 11.25 cut angle
The angle is cut on the end of each segment so 22 1/2 must be divided by 2 to determine the cut angle.

The only thing that has to happen is the cut angles MUST equal 360 degrees. If folks want an easy no fuss method and aren't opposed to fixed sleds I highly recommend a fixed frame sled miter sled. If they have to have an adjustable sled buy the wedgies.
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#19
(10-29-2017, 10:41 PM)Angus Wrote: The only tool I recommend is a wide belt sander but there's a work around for that.

To get started and see if you like segmented stuff, you don't even need that. I made a drum and a platform for my lathe to turn it into a drum sander. It works pretty well to flatten the sides of rings. Two feet of 3" PVC is a pretty cheap experiment.

All that said, I would love to have a wide belt sander.

I would post a picture but the new software and my computer are mad at each other and I can't attach pictures.
We do segmented turning, not because it is easy, but because it is hard.
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#20
That's the work around I was referring to. You can also flatten rings on the lathe with a large disc and some hot glue.
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