New take on the 80/60 frame... 3 sheets of plywood + 1 sheet of MDF

I have been planning my first Maslow build and thus reviewing many of the plans here in the forums for the frame. My plans have been to build a Maslow with a cutting area of 5’ X 8’ so I can fit a full sheet of standard 4’ X 8’ plywood or a 5’ X 5’ sheet of baltic birch. The frame will be made from 3/4" plywood ribs built into little torsion boxes for rigidity. The 12’ main top beam is made out of glued up CDX plywood to make a poor mans LVL for dimensions of 3"X6"X144".

The spoil board will be 1/2" MDF with a 96mm grid of 20mm holes so I can use the same bench dogs from my PaulK Workbench. This will enable me to position a board anywhere using a couple of dogs underneath the material and then two side friction clamps on the sides.

I have a couple of questions, how high do I need to make the top beam above the cutting area to be able to cut these two sizes of sheets (4X8 & 5X5)? Right now it is about 18" above the top of the cutting area, but that seems like I might need to go higher to ensure the sled can get to the top middle.

I welcome any feedback and tips on what might not work.

Here is an image of the sketchup rendering and one image of the sheets that I will cut for the frame pieces.

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Another question I had was how to determine the best chain length for this? Is measuring in SketchUp a good estimator for the longest length (farside lower corner from each motor mount?)

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That should be about the right measurement. I would leave yourself another foot or so to stay on the sprocket and in the tension mechanism

the spreadsheet lets you experiment with different dimensions and see the effect

you want to minimize the max tension (top center) and maximize the min tension
(bottom corners)

as far as chain length goes, simple trig gets you the diagonal length, and
then you need an extra 6-12 inches to wrap around and allow for the tensioning

once you get to a 12’ top beam, the distance from motor to motor (plus 6" or so)
is longer than what you need for the diagonal to the workpiece opposite corner.

a stock maslow gives you 11’ of chain, if you go to a 12’ top beam, give
yourself 13’ and you are good. This will easily cover cutting a 5x5’ workpiece
as well as a 4x8’ workpiece, but depending on how high above the workpiece you
go, you could possibly need a few more inches to the far corner of the 4x8’ when
you give yourself enough height above teh 5x5’

David Lang

Thanks David, that is really helpful. Do you have a sense of how far up and out the motors should be from the cutting surface with a beam that long?