This can't possibly take 93 inches of laminate...

K

KYTurner

Guest
Hi,

In Lamination pro, creating a disc whose outside diameter as displayed by laminate pro is 11", I am being told that I need 93.38 inches of laminate. I admit that I am new to the program, but jeez, what's up with that dimension? The circumference of that circle is only 25 inches, so I would expect a laminate of maybe 30 inches or so. Can you explain please? File from LP save attached.
 

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mfisher

Super Moderator
Staff member
I will look into in in more detail today.
- From your post I take it you want a 11" diameter disk.
- Make sure you are reading the inches at not centimeters (cm).
- What is your first cut strip dimensions. The file when load shows 5/8"
- With your file and settings I get a 8.25" disk, needing a laminate board of 38.39" or 40.06" allowing for 20% buffer.
8 repeating units
5/8" first cut width
1613233900522.png
 
Last edited:

mfisher

Super Moderator
Staff member
The disk clipping region circular is used to change the circle size over the laminate. I reduced it down to the 8.25 to get rid of the the blank spaces.
 

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Lloyd Johnson

Administrator
Staff member
KYTurner,

That’s why you need a program like Lamination PRO. The very LAST thing you want to do is to get towards the end of this project and find that you don’t have enough to complete the design because you would have to duplicate the entire process from scratch just to get another repeating unit or two. You might be able to get away with 10% excess instead of 20% but not on your first attempt.

The big thing is that you are using just the top segments to make the design shown which means that you also get a 2nd design that will be the same size disk using the bottom segments only but it willl have a completely different design. If you use BOTH the top and bottom segments, you will need 46-1/2” of lineal laminate but the resulting design will not be acceptable to you. Fortunately, Lamination PRO shows you what all three of these options look like using the 2nd generation board you make.

The reason I am so confident of the calculations is that I have used SketchUp on many occasions to duplicate the process manually to see exactly how much lineal laminate you need to create the design. It’s a pain in the ass to do this and it takes a LOT of time, but it did make me an expert at SketchUp. If you want to reduce the amount of lineal laminate required, you can switch to the single-strip method instead of the Repeating Unit method. With the Single Strip method, you will end up with a symmetric pattern which means the bottom wedges will be the same as the top wedges and you can use half as much wood. You will only get a single disk, though, and the quality will NOT be as good as it will be if you use only the top wedges and another disk using the bottom wedges because there will always be differences when using tops and bottoms to make a single design. I speak with a whole lot of experience in this. :-<

I’ll post a SketchUp drawing that demonstrates this after power is restored to our house. It’s been out since yesterday and likely won’t be back until tomorrow and I don’t have it on my iPad.

Yes, this process requires a lot of wood. It is really worth the effort, though. Anyone that sees a 2nd generation design in a disk configuration will be amazed at your skill and will wonder how the devil you did it. I’m not sure there is any technique I’ve seen that shows skill more than multi-generation laminations. It is not overly difficult, especially when you consider that the alternative to multi-generation laminations is the ‘stacked wood’ method which takes multiple times as long and cannot give you the same quality results as this lamination method.

Lloyd
 

Lloyd Johnson

Administrator
Staff member
If you haven’t seen the PDF files at the following link, make sure you look at the one named Possibilities.pdf. It will give you a lot of ideas - especially the clock faces made from 2nd generation laminations similar to what you have designed. Remember to look for a design that makes a design you like from both the top and the bottom wedges so that you’ll get two completed clocks from one lamination project.

 

Lloyd Johnson

Administrator
Staff member
One more thing that will help you visualize the amount of lineal laminate needed is to go to your 2nd generation as shown in your first post and you’ll see that to make 8 Repeating Units takes 46” of lineal laminate. Now click on the Radial button and you’ll see that it takes two Repeating Units to make one top wedge so if you say you need 8 of these elements, it will take 16 Repeating Units to make them which means that you will need about 92” instead of 46”. But you will also get 8 wedges of the bottom wedges at the same time.
 
K

KYTurner

Guest
I will look into in in more detail today.
- From your post I take it you want a 11" diameter disk.
- Make sure you are reading the inches at not centimeters (cm).
- What is your first cut strip dimensions. The file when load shows 5/8"
- With your file and settings I get a 8.25" disk, needing a laminate board of 38.39" or 40.06" allowing for 20% buffer.
8 repeating units
5/8" first cut width
View attachment 4331
You are correct. Here is another screen shot when I do the "radial cut" view. I have monkeyed around with things a bit, but the laminate needed is still way out of whack.

1613301569918.png
 
K

KYTurner

Guest
Thanks for getting back to me so quickly! I figured for a response mid week. Sorry to hear about your power - we had an ice storm and the temp has stayed low. Trees are still shedding limbs from time to time, but power has stayed on.

I have no quibble about how much laminate I have to use to accomplish a design. I have no doubt that it will be worthwhile to spend that amount of wood to achieve the outcome I desire, I am just not understanding something. Using the file I sent, if I click on Laminate, there is no measurement. When I click on Gen1, it says 16.79 inches for 8 repeating units. When I click Gen2, it jumps to 35.89 inches for 8 repeating units. After clicking Gen2, if I click Radial, it jumps to 88.79 inches. If I am doing a 10 inch disc, which includes all the width of the wood in the laminate, the circumference of the circle would be about 31.4". After accounting for kerf waste, it just seems like an awful lot of laminate.

Maybe I am overthinking things, and just have to take it on faith. I can't get into my workshop because of the chill factor now, and won't for about a week if the forecast is correct. Once I am there I will definitely experiment on some cheap wood or something to prove/disprove the length.
 

Lloyd Johnson

Administrator
Staff member
KYTurner,

You aren’t taking it on faith. You’re taking it from me and I have more experience in multi-generation laminations than, well, anyone that I know of.

I learned about MGL from reading the wonderful book from Clarence Rannefeld named Laminated Designs in Wood. Clarence was a mathematician and a good woodworker. His book has inspired many segmenters and woodturners but with the utmost respect for him, I can honestly say that nearly everything in his book was wrong. He had drawings that showed 1st, 2nd and 3rd generations of designs using 30, 45 and 60 degrees and although his designs were great, I could never duplicate one using my software until I made a coding mistake one day where I thought I was using saw kerf of 1/8” while I was actually using a saw kerf of 0” and guess what - I could then make all of his designs. The 2/3rds of his book that were designs were all impossible to make using a table saw.

He actually showed all of his formulas and his most complicated formula was the one that calculated the amount of lineal laminate needed if you input all of the data from the generations used to make the design. It was fun to try to duplicate his results using a scientific calculator but sadly, his formulas came up with results that were nowhere near what was actually needed to make the design. It was then that I decided that his very extensive formula was simply the wrong approach.

Using SketchUp to duplicate the the process of making the design using actual measurements, I found a relationship between 1st and 2nd generations, 2nd and 3rd generations, etc., and finally a radial process.

It’s trivial to start with a laminated board and use trigonmetry to determine how much lineal laminate you need, including saw kerfs, to make x number of repeating units. The only variable that changes between the generations is the angle and that, too, is trivial using trigonometry. Using the relationship between 1st and 2nd generations, you can quickly determine how many 1st generation repeating units you need to make that number of 2nd generation RUs at which time you get to use the simple formula of calculating lineal laminate required to make that many 1st generation RUs.

The same approach lets you start with 4th generation RU that needs x number of 3rd generation RUs which needs x number of 2nd generation RUs which needs x number of 1st generation RUs and finally the simple formula to calculate lineal laminate from that number of 1st generation RUs. It works every time.

The only time this will not work is if the angle you want to use is extreme such as anything more than 60 degrees. I’ve never seen anyone use more than 60 degrees for a cutting angle, though.

Lloyd
 
K

KYTurner

Guest
Thank you for your patience and explanations. I in no way meant no disrespect of your program or expertise. I have spent quite a while over the past couple days studying this, and am beginning to see the requirement for the additional length. It is still not intuitive for me to use 7 1/2 feet of laminate to wrap around a 10 or 11 inch diameter turning. I really can't wait to see it work!
 
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