Confused

[Daniel Shuflin]

I need help with this summary chart. I am assuming that width is the width of the board I am using. If I bought a board 1/2" by 3" I would need to rip it to 2.18". Is this correct.
What does the length stand for?
S.E.L. Stands for segment length. This is the length of the top of the trapezoid. Which is the distance between the saw blade and the fence. Is this correct?
The base of the bowl is a solid disk that is a 1/2" thick round blank that is 2.4" in diameter. Is this correct?
The Outer diameter and Inner diameter are the diameters of the ring after it is glued. Is this correct?
Last, why is Inner Diameter of Ring 2 a -0.4"?
Hope I made myself clear.
Dan

 

[mfisher]

Daniel
Hopefully you have watched the segeasy videos as suggested in another thread. If you have not yet, take the time to watch Lloyd's videos on Segment Pro. They will answer a bunch of your questions.
- The Width column gives you the width the board needs to be cut for each ring to have enough material for the wall thickness based on the profile you are building to. So You are correct.
- I tend to make things simpler for myself because I do not mind removing wood on the lathe. For example from your cut list I would rip a board 2.25 inches for rows 2, and 3.
- Take a look at the function in SP Summary window of "Optimize Board Width"
- Length is the minimum board length you need to cut the number of segments (12) for that ring.
- For SEL refer to the other thread you had in the non segment turning forum. Also watch the segeasy vids for sel measurement and cutting.
- Yes , you have the base correct 2.4" solid, 1/2thick.
- If the segments are cut properly to the SEL from the proper board width , yes the OD is the diameter of the ring you are making.
- to answer your question regarding ring 2 we would need to look at your project file. You would need to attach the *.json file to a post.

In SP. at the top there is a SHARE button click on it.
you will get a drop down menu of Help, Export, Import.
Select Export.
You will get a dialog box telling you the name of the json file and where it is stored.
It should be in a folder of Documents/My Segment Pro.
Attach it and let us take a look at what you are working on.

 

[Ken Sherwin]

"S.E.L. Stands for segment length. This is the length of the top of the trapezoid. Which is the distance between the saw blade and the fence. Is this correct? "

I believe you will find that the SEL is the length of the outside or long side of your segment. The distance between the length stop(installed for repeatability of the segments) and the saw blade is shorter than the SEL because the long edge of the segment is at an angle to the blade. It is actually off by the cosine of the angle between the stick or fence and the blade. For example, if I cut a 12-segment ring, the angle between the stick and the blade is close to 15 degrees and the cosine(15 deg) is .966. I will set my stop at .966 * SEL, cut a segment, and measure the resulting segment to protect a sudden flash of stupidity like forgetting to properly zero the scale on the saw.

Since I put the cutting chart into Excel to make sorting lines and editing out unneeded columns easy, multiplying SEL by the cosine of whatever angle I'm using trivial.

"Last, why is Inner Diameter of Ring 2 a -0.4"? "

On the Negative ID, I get this when the OD I entered is less than the board thickness required for the wall thickness I entered. In your case, I see the board width is 2.18" so 2 of them butted together will total 4.36" yet the OD is only 4" To achieve the 4" OD, the ID ends up being -0.36", rounded to -0.4" when turning the ID out to round.

Did this help or did I confuse things more?

 

[mfisher]

"S.E.L. Stands for segment length. This is the length of the top of the trapezoid. Which is the distance between the saw blade and the fence. Is this correct? "

I believe you will find that the SEL is the length of the outside or long side of your segment. The distance between the length stop(installed for repeatability of the segments) and the saw blade is shorter than the SEL because the long edge of the segment is at an angle to the blade. It is actually off by the cosine of the angle between the stick or fence and the blade. For example, if I cut a 12-segment ring, the angle between the stick and the blade is close to 15 degrees and the cosine(15 deg) is .966. I will set my stop at .966 * SEL, cut a segment, and measure the resulting segment to protect a sudden flash of stupidity like forgetting to properly zero the scale on the saw.

I generally use a caliper to mark the SEL on to a thin strip board. I place the marked board on the cutting sled and move the sled up so the strip is touching the blade at the mark. I then run the stop up to the end of my strip. I then cut a segment and measure. If needed I make the micro adjustments the fence and cut another segment. Then recheck the SEL.

The Woodclub I use is still shut down because of CV19. So I can't get in and take photos of my set up. The important thing is the measurement from the blade to the stop has to be measured along the miter angle Not 90 degrees to the stop.

I tend to overbuild. So doing what Tibbits and other have done I just use (diameter * 3.1416)/number of segments = SEL.
this is close enough. While it would be more accurate if tangent calculation were used. If I want a 6 inch dia ring I will build a 6 1/8 or 6 1/4 ring and turn it down to 6 inches.

 

[Daniel Shuflin]

Daniel
Hopefully you have watched the segeasy videos as suggested in another thread. If you have not yet, take the time to watch Lloyd's videos on Segment Pro. They will answer a bunch of your questions.
- The Width column gives you the width the board needs to be cut for each ring to have enough material for the wall thickness based on the profile you are building to. So You are correct.
- I tend to make things simpler for myself because I do not mind removing wood on the lathe. For example from your cut list I would rip a board 2.25 inches for rows 2, and 3.
- Take a look at the function in SP Summary window of "Optimize Board Width"
- Length is the minimum board length you need to cut the number of segments (12) for that ring.
- For SEL refer to the other thread you had in the non segment turning forum. Also watch the segeasy vids for sel measurement and cutting.
- Yes , you have the base correct 2.4" solid, 1/2thick.
- If the segments are cut properly to the SEL from the proper board width , yes the OD is the diameter of the ring you are making.
- to answer your question regarding ring 2 we would need to look at your project file. You would need to attach the *.json file to a post.

In SP. at the top there is a SHARE button click on it.
you will get a drop down menu of Help, Export, Import.
Select Export.
You will get a dialog box telling you the name of the json file and where it is stored.
It should be in a folder of Documents/My Segment Pro.
Attach it and let us take a look at what you are working on.

Thank you sir. This helps quite a bit. I have watched a few of the videos but I will go back and watch them all before proceeding.

 

[Daniel Shuflin]

I generally use a caliper to mark the SEL on to a thin strip board. I place the marked board on the cutting sled and move the sled up so the strip is touching the blade at the mark. I then run the stop up to the end of my strip. I then cut a segment and measure. If needed I make the micro adjustments the fence and cut another segment. Then recheck the SEL.

The Woodclub I use is still shut down because of CV19. So I can't get in and take photos of my set up. The important thing is the measurement from the blade to the stop has to be measured along the miter angle Not 90 degrees to the stop.

I tend to overbuild. So doing what Tibbits and other have done I just use (diameter * 3.1416)/number of segments = SEL.
this is close enough. While it would be more accurate if tangent calculation were used. If I want a 6 inch dia ring I will build a 6 1/8 or 6 1/4 ring and turn it down to 6 inches.



View attachment 4130 View attachment 4131

You said: The important thing is the measurement from the blade to the stop has to be measured along the miter angle Not 90 degrees to the stop.
I have been measuring at 90 degrees.

 

[Ken Sherwin]

mfisher's way is simpler and easier to understand than mine. I was a machinist and engineer for 48 years and am accustomed to using the digital readouts on mills and lathes. (Yes I put a DRO on my antique Craftsman table saw I inherited from my dad.)

 

[mfisher]

mfisher's way is simpler and easier to understand than mine. I was a machinist and engineer for 48 years and am accustomed to using the digital readouts on mills and lathes. (Yes I put a DRO on my antique Craftsman table saw I inherited from my dad.)

Thanks Ken.
As you know so many things can get off when building a segmented vessel from the ring not being perfectly round, not being perfectly centered, etc.
Main reason I over build. That way I really don't need to fret over the SEL needing to be dead on down to the thousands.

Totally understand your wanting to have perfection as a machinist.

 

[mfisher]

View attachment 4128


Dan

Dan,
I would suspect that you moved one of the node points for ring 2 in the profile view to the far left or off grid to the left.
When I did playing with a profile I came up with a minus number for ring 2 by doing that.

 

[Lloyd Johnson]

Daniel,

Mike and Ken have provided great answers and I thank them for this.

To add a little more to this conversation, the outside diameter is calculated based on the number of segments and the Segment Edge Length (S.E.L.). The inside diameter is a result of using a board of the specified board width. In my opinion, the formula that has always been used to calculate the board width is a little generous. I suspect this has been done to always give you a little more wood for turning away than is absolutely necessary and I'm going to continue using the formula as it is for that reason. So while both the SEL and board width calculations are correct based on the formulas, the inside diameter looks goofy because you are creating a ring that is 4" in outside diameter but using boards that are 2.18" which obviously means that anything over 2" is unnecessary. When I get the chance, I'll probably force the board length to be no more than 50% of the outside diameter to remove the goofy factor. I think this is a safer thing to do than arbitrarily reduce the board width by making it more conservative.

Having said that, as a practice, I always export the Summary to Excel and the first two columns I delete are the outer and inner diameters along with other columns that don't need to be shown. They aren't necessary because if you cut the SEL and Board Width correctly, the outside and inside diameters take care of themselves. This lets me greatly increase the size of the font so that I can print the summary on a single sheet of paper, post it on my bulletin board and see it from across the room. The only columns I keep are the Row *, Board Width, Length, and SEL. I also leave the individual segment count for different species if I'm making a painted segment bowl.

Before I print it, though, I look for Board Widths that are similar and when I find several, I change all of those board widths to the widest one shown. This lets me cut boards much more quickly because there are fewer board widths required. This does, of course, make a few rings with a slightly smaller inside diameter but turning away wood from the interior of a board is done in seconds which is a great time saver over cutting more boards at different widths. I always try to get the number of board widths down to around four, if possible.

In Excel, you can change the font to a large font and then give instructions for the report to be printed on no more than one landscape page. I give an example of doing this in the first tutorial on this 5-part tutorial:

Beginner's Project - Open Segment Christmas Ornament

I've done a poor job at providing content for the segmenter that is just getting started with open segment turnings. So with Christmas fast approaching, I thought this would be a good time to correct that with a project that is seasonally appropriate. I've made a five-part tutorial that shows...

woodturnerpro.com

Lloyd

View attachment 4128

I need help with this summary chart. I am assuming that width is the width of the board I am using. If I bought a board 1/2" by 3" I would need to rip it to 2.18". Is this correct.
What does the length stand for?
S.E.L. Stands for segment length. This is the length of the top of the trapezoid. Which is the distance between the saw blade and the fence. Is this correct?
The base of the bowl is a solid disk that is a 1/2" thick round blank that is 2.4" in diameter. Is this correct?
The Outer diameter and Inner diameter are the diameters of the ring after it is glued. Is this correct?
Last, why is Inner Diameter of Ring 2 a -0.4"?
Hope I made myself clear.
Dan

 

[MichaelB]

I am wondering why the S.E.L. when multiply by the number of segments doesn't equal the length in the species section. As in the attachment line 4 shows the S.E.L. to be 3.2 but the 10 segments shows 26.7. What am I missing?

 

[mfisher]

I am wondering why the S.E.L. when multiply by the number of segments doesn't equal the length in the species section. As in the attachment line 4 shows the S.E.L. to be 3.2 but the 10 segments shows 26.7. What am I missing?

I hope I can help you out to understand the number in the summary sheet.

Length (column C) : Is the total board length you need to make the 11.9" ring with a little fudge factor for safety when cutting.
For row 4 it is 32.1 inches for cutting 12 segments from the board

When you have multiple species SP calculates for each species with a fudge factor.
Looking at the Species section to get the 10 maple segments for row 4 you would need a board 26.7"
You would need a board of a minimum of 5.2" for the 2 Padau segments.

When adding the Board length in the species section it will not add up to the lenghth in column C. The reason is the added length for safety.

 

[Lloyd Johnson]

I am wondering why the S.E.L. when multiply by the number of segments doesn't equal the length in the species section. As in the attachment line 4 shows the S.E.L. to be 3.2 but the 10 segments shows 26.7. What am I missing?

Michael,

Yours is the number one question I am asked when contacted directly for support. The answer is that you are using the Economy mode of cutting segments.

When you cut a board into segments, you flip the board edge after each cut or if you’re using a wedgie sled, you switch from one fence to the other fence that is angled in the opposite direction. With either method, if you put those segments back into the position from which they were cut, you will see that with a 12 segment ring there are 6 long SELs and 6 short SELs on each long edge of the board.

The simplified calculation for the Economy board length for 12 segments is:
(6 * SEL) + (6 * shortSEL) + (11 * (angledkerf))
As Mike has said, you need to add your own allowance for clamping and safety.

Woodturner PRO also calculates the length of board you need if you wish to use the Grain Match mode. This is what you use if you want all of the
long SELs to be on the same side of the board. With this method, you would cut the board into 12 strips at 15 degrees at a length of the long SEL. You would then take each of those strips, and change the miter angle so that you can make the other 15 degree angle. This wastes a lot of wood and takes a lot of time.
The simplified calculation for the Grain Match length for 12 segments is:
(12 * SEL) + (11 * (angledkerf))

I use the grain match mode if I have a piece of maple that has a long band of pencil spalt on one side of a board. The grain match mode lets me wrap that spalt line around the bowl.

Lloyd

 

[MichaelB]

Thank You for your response.