Simple (?) question about LP

Discussion in 'Lamination PRO Support Forum' started by cnsranch, Aug 31, 2017.

  1. cnsranch

    cnsranch Jerry Prinds

    Glue ups done - ready to cut out the center strip - here's my question...
    Cutting instructions are changing when I zoom in and out. Board width is approx. 4.5x...when I zoom in, inst. change - width from 4.59 to 4.5, then 4.56, 4.56, 4.54, 4.55, 4.53, 4.54, 4.56, 4.53, etc.

    Is that intentional to accomodate for my actual board width? I'm confused.
  2. mfisher

    mfisher Super Moderator Staff Member

    I set up a simple 3 board lamination. 2 inch , 1/2 inch, 2 inch. Gen 1 angle set at 30degrees
    At the laminate setting when zooming in it stays at 4.5 inches for board width.

    I restarted LP, set up the board again 2, 2.5, 2, 30 degrees
    laminate was 4.5 inches for board width.
    clicking direct to Gen 1 without zooming in , 5.49" (13.95 cm)
    zoom in 1 click. 5.48 (13.91cm)
    zoom in second click 5.49 (13.95)

    Only thing I can think of is a number rounding thing. Lloyd would be the person to get a more detailed answer from.

    What version of LP are you running. I am running 3.2.018
    Malcolm Douglas likes this.
  3. cnsranch

    cnsranch Jerry Prinds

    Running the same version......
    My southwest design is set up as follows:
    First and third boards - 15/16"
    Second board - 3/8"
    First cut width - 1 3/8"
    45 degree cutting detail
    Strip width - 1.88"
    Center strip - .250"
    Export range - 1.10"
    Repeating unit - 2.75"

    I can zoom all the way in and get a width of board of 3.17"
    I can zoom all the way out and get a board width of 4.59"
    Actual board width is 4.55"
  4. Lloyd Johnson

    Lloyd Johnson Administrator Staff Member

    With the multiple generations, cutting angles, saw blade thicknesses, etc., there isn't a way that I have found to calculate the exact board width. So instead, I use the image on the screen with a zoom factor to come up with an estimate. As long as you have a reasonable zoom factor, the result is a rounding error. If you zoom in to an extremely high zoom factor, the estimate is no longer valid.

    My only option is to remove the capability of zooming to extremes or to remove the data altogether and removing the center is up to the user and I don't see much of a need to do either of these things.

    Just use a reasonable zoom method and the calculations should be a rounding error off and certainly not enough to make a discernible difference in the finalized design. Every time I make a generation board, I compare the width of my board to the calculation and it has been nearly correct. When it isn't exactly correct, the reason is my cutting and assembly, not that the calculation was wrong.
  5. cnsranch

    cnsranch Jerry Prinds

    Thanks for the response, Lloyd - makes sense.
    Good to know.....I suddenly had a board width that was way off and couldn't figure out what I did wrong. I found that I could use the zoom to get the estimate almost perfect to my actual width.
  6. Lloyd Johnson

    Lloyd Johnson Administrator Staff Member

    I didn't think about that but it a great idea. Seldom can I follow cutting instructions and get perfect results. By changing the zoom, I'm likely to find a zoom that will match my actual results.

    However, it is also simple to simply take your actual board width, subtract the desired center strip width and divide by two. That is the distance the saw blade should be from the fence and it works every time.
    mfisher likes this.
  7. James Allison

    James Allison PRO Member

    lamination Pro allows optional settings for the saw kerf 1/8" and 3/32". My Thin blade produces a kerf of 0.1".
    Do I need to change anything in LP to account for this in calculating the block lengths or the board lengths?
  8. Bob Beaupre

    Bob Beaupre Administrator Staff Member

    James 3/32" = .09375", I would go with that
  9. Lloyd Johnson

    Lloyd Johnson Administrator Staff Member

    I didn't see much of a need to support more than just the two settings as anything else fits within a rounding error and the change in the design is not discernible. As Bob said, 3/32 can be assumed to be .1" and as you build your pattern, this difference will be the least of your concerns.
  10. James Allison

    James Allison PRO Member

    Makes sense. I have built a practice board with the 1/8" setting and it looked good thru Gen 2. Gen 3 I had trouble cutting them to the same size. I wasn't sure whether I should cut the blocks to the LP block size or to work out the center of the pattern and cut to that. I ended up doing the best to find the center but you can see the differences I ended up with in the photo. Sizes ranged from 2-3/8 to 2-3/4 wingtip.

    Attached Files:

  11. Lloyd Johnson

    Lloyd Johnson Administrator Staff Member


    I'd say that looks a lot like my first attempt and frankly, you've done a great job getting it this good with your first try. You will quickly learn how to improve your cutting accuracy and on your next attempt, it will be far better.

    I have on my to-do list a follow-along project that will be specifically for showing different methods I've come up with to create multi-generation designs with good accuracy. I don't have all the answers, but I have made all of the mistakes and have learned from them.

    Bill Renfro likes this.
  12. James Allison

    James Allison PRO Member

    Thanks for your kind words and encouragement.
    One other Question re: Repeating Unit, Is that the size after the cut or is it the c-c distance on the board?
  13. James Allison

    James Allison PRO Member

    Sorry, that is confusing after I reread it. Basically, does the repeating unit include the kerf?
  14. Lloyd Johnson

    Lloyd Johnson Administrator Staff Member

    A strip is something that results after you cut it from a board. If that strip is 1" wide and you glue two of them together to make a chevron (a repeating unit), the width of that repeating unit is 2". Saw kerfs were necessary to make the strips but they are not part of any final design.

    Lamination JPRO shows you where saw kerfs are to be made but the designs shown on the generation boards always have the kerfs removed and all calculations are shown after the kerfs have been removed. A repeating unit of 2" means that if you cut using the instructions shown, the resulting design will be exactly 2" after you make it.

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