Own triangles for seg-easy sled

[Bob Coates]

Been experimenting with Jerry Bennett s sled. Being cheap, and not sure how they would work decide to make my own wedges, first attempt was to make wedges for 12, 24, 30 and 45. It was a pain, but somewhat successful, but did not make them long enough to be really accurate. The light bulb went off and decided to make them as triangles, much more successful since the angles were twice as great with no ¼ degrees. Have made triangles for cutting segments for rings containing 15,16,20,24,30,36,40,45, and 48 pieces. Kept the wedge for 12. Shown on the sled are two.IMG_0696.JPG

[Thom Sturgill]

Equilateral or right triangles?

[Bob Coates]

The 12 was perhaps equilateral in the front picture, but all the others were right triangles as shown for the 40 segment one.

[jerry downey]

Hi Bob
I like your idea to make your own triangles.
Maybe you could tell us how you went about it?

Thanks
Jerry

[Bob Coates]

I hope this is what you are looking for. If you have anything you need clarified please let me know.


I walked before I ran. I would suggest that you try like Jerry suggests by making rings with 12 segments using a 30 60 triangle.
I attached one fence to MDF at any angle to the blade. Then attach the second fence using the 30 60 triangle. If you like what you get then make the sled with adjustable fences. Even when these are fixed you can get all his cuts using the one setting on the fence.
After happy with the fixed sled, I made the movable sled.
My first attempt at make the wedges I cut both side on an angle. For an 18 sided ring, you had to cut the angle at 10 degree on each side. etc. For the triangle I uses some old Formica covered particle board (MDF would work) and cut one side at 20 degrees. The length should be around 8 -9” Deepening on the quality of your saws miter gauge you may or may not need to adjust as explained below.
1) To check your triangle take your new 18 degree triangle, set one fence on your sled. I found that you should fix one fence and close the other to be less than the angle. Push the triangle toward the saw blade(white paper) and get it tight and then fix the other fence. Put the triangle aside to use in step 6.


2) Get some scrap wood that is rather wide 2-3.5 inches (the wider the wood, the more noticeable the error) and cut 9 segments and see if you have a good ½ circle.
3) If ½ ring is good go to step 5
If the ½ ring has segments open toward the center gently close one of the fences and cut another 9.
If the ½ ring has segments open on the outside open the fence space. This sound opposite but closing the distance at end farther from blade will make the space wider at the blade.
DON' T MOVE THE FENCE VERY MUCH AT A TIME.
4) repeat 2 until happy, then
5) Cut 18 (or another 9) segments, and make a ring. Hold up to light and to check for tightness. What you though was good in 2 you will have to readjust fence. And repeat. And repeat.... I filled a 2 gallon buck with failed wedges.
6) Once you have adjusted the fence to get tight rings you now need to adjust the triangle. Place the triangle between the two fences and draw a line to show were the hypotenuse of the triangle needs to be to match the setting of the fences. The sample shown is way over how much needs to be marked. I used a disk sander to sand to line. This may require repeat of mark and sanding. A hair slop in triangle movement is multiplied 18 times for new segments cut. This is the critical part to make sure next use will be accurate. Once you have mastered this one you only need to repeat the process for triangles for 15,16,20,24,30,36,40,45 and 48 degrees. It took almost 3 days for me to complete all.
From reading posts, it seems some turners want to set both fences at same angle and getting segments that are close to the same, I like when one is almost 90 and the other very steep. Jerry's web site show very interesting cutting when the blade is tilted, I tried it and found it too time consuming glue up the segments. I have been experimenting with mixing segment sizes in ring.IMG_0700.jpgIMG_0699.jpgIMG_0701.jpg

[jerry downey]

I hope this is what you are looking for. If you have anything you need clarified please let me know.


I walked before I ran. I would suggest that you try like Jerry suggests by making rings with 12 segments using a 30 60 triangle.
I attached one fence to MDF at any angle to the blade. Then attach the second fence using the 30 60 triangle. If you like what you get then make the sled with adjustable fences. Even when these are fixed you can get all his cuts using the one setting on the fence.
After happy with the fixed sled, I made the movable sled.
My first attempt at make the wedges I cut both side on an angle. For an 18 sided ring, you had to cut the angle at 10 degree on each side. etc. For the triangle I uses some old Formica covered particle board (MDF would work) and cut one side at 20 degrees. The length should be around 8 -9” Deepening on the quality of your saws miter gauge you may or may not need to adjust as explained below.
1) To check your triangle take your new 18 degree triangle, set one fence on your sled. I found that you should fix one fence and close the other to be less than the angle. Push the triangle toward the saw blade(white paper) and get it tight and then fix the other fence. Put the triangle aside to use in step 6.


2) Get some scrap wood that is rather wide 2-3.5 inches (the wider the wood, the more noticeable the error) and cut 9 segments and see if you have a good ½ circle.
3) If ½ ring is good go to step 5
If the ½ ring has segments open toward the center gently close one of the fences and cut another 9.
If the ½ ring has segments open on the outside open the fence space. This sound opposite but closing the distance at end farther from blade will make the space wider at the blade.
DON' T MOVE THE FENCE VERY MUCH AT A TIME.
4) repeat 2 until happy, then
5) Cut 18 (or another 9) segments, and make a ring. Hold up to light and to check for tightness. What you though was good in 2 you will have to readjust fence. And repeat. And repeat.... I filled a 2 gallon buck with failed wedges.
6) Once you have adjusted the fence to get tight rings you now need to adjust the triangle. Place the triangle between the two fences and draw a line to show were the hypotenuse of the triangle needs to be to match the setting of the fences. The sample shown is way over how much needs to be marked. I used a disk sander to sand to line. This may require repeat of mark and sanding. A hair slop in triangle movement is multiplied 18 times for new segments cut. This is the critical part to make sure next use will be accurate. Once you have mastered this one you only need to repeat the process for triangles for 15,16,20,24,30,36,40,45 and 48 degrees. It took almost 3 days for me to complete all.
From reading posts, it seems some turners want to set both fences at same angle and getting segments that are close to the same, I like when one is almost 90 and the other very steep. Jerry's web site show very interesting cutting when the blade is tilted, I tried it and found it too time consuming glue up the segments. I have been experimenting with mixing segment sizes in ring.IMG_0700.jpgIMG_0699.jpgIMG_0701.jpg

Thanks for the help
Jerry

[Roy Turbett]

There is a fairly easy way to do this using trigonometry. The key is to set your miter gauge (or table saw sled) to exactly 90 degrees. (You can check this by using the five cut method thats described in a number of youtube videos.) Put a piece of tape on your table saw that is parallel to the miter gauge and left of the blade and draw a straight line. The longer the line, the more accurate your results. Put a second piece of tape on the left side of the line exactly perpendicular to the first line. Then measure a fixed distance from right to left on the first line you drew and carefully mark the end points. Take this measurement and multiply it by the tangent of the angle you want. The tangent is a constant and can be found in trigonometry tables that are available in phamplet form or the internet. They are also stored as functions on many calculators. The resulting product is the length of the second leg of the right triangle that is opposite the angle you used. Measure and mark this distance on the second piece of tape. Use the miter gauge fence to connect the dots and you have your angle set.