Adjusting Bed, Not Motors

I’m starting to design my frame with the new shipments coming next month. I’ve heard so much about adjusting the motors in and out depending on what material you’re cutting to keep the chains parallel to the work piece. On top of that there are chain guides that some have made and also the idler sprockets that also need to adjust.

I’ve had in the back of my mind to not adjust these items above, but rather adjust the bed. I’m planning on building some z-axis adjustable wooden skids that my cutting material will rest against. They’ll be wooden so that they can act as a sacrificial piece and will be easily replaceable and cheap. The skids will then be able to adjust to the material I’m cutting in the z-axis so my top surface cutting plane always stays in the same location although the thickness of my material can vary.

I’ll model this up so I can better relay what I’m saying. If you understand my gibberish, are there any show stoppers that you can think of before I waste my time trying?

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I can’t see any show stoppers, but I just want to throw in that I never adjust my motors for the thickness of what I’m cutting and I haven’t had any issues over the normal range of thicknesses (.25in-.75in) so it might be worth making sure it’s an issue before worrying too much about.

The more I think about it this is a great solution. If you commit to say a 1in nominal thickness that leaves you with a 1/4 inch spacer for 3/4 plywood, a 1/2 inch spacer for 1/2 inch plywood, and a 3/4 spacer for 3/4 plywood, all of which would be really easy to make :+1: :+1: I like it!


That should work.

It seems like it’s more effort to move the much larger bed than the motors, but
I’m so used to thinking in terms of the ‘top beam’ design that I forget it’s not
as easy with other designs :slight_smile:

but the less you have to move, the easier I would expect it to be. So I think
you are working harder than you need to.

But I see no reason why it wouldn’t work.

I want to make my machine ith adjustable motors because I want to be able to do
things like put a 2x4 on edge and cut that.

The issue origionally came to light with people wanting to take slabs of trees
and cut into them, they commonly are 2-4" thick

I would not expect any need to adjust the motors until you get somewhere over 1"
think material.

and if you set your machine for thicker material, as you note, you can always
just add another wasteboard behind the material you are cutting to space it out.

David Lang

@bar, you would use a 3/4 spacer with 1/4 material and 1/4" spacer with 3/4"
material :slight_smile:

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I had a similar thing in mind too. You could easily stack spacers too, so you wouldn’t need as much of an assortment.

One less variable.

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:face_with_hand_over_mouth: Thanks! :grin:

So instead of the cutting material laying against an entire 4x8 board it would only rest on two, perhaps four 4’x2" board skids that would adjust. So in my mind, you’d be adjusting 4-8 bolts that would control the skid depth in relation to the “fixed” cutting plane.

Maybe it’s not worth it if you can get away with not adjusting things for materials .25-.75" thick…

Another perk was not wasting an entire sheet for a backer board but I guess you could accomplish this with spacers.

Hello all,

I too have been think about building an adjustable Bed. I would like to cut material from 1/4" to 1 1/2". In exploring this idea I have identified two issues that need to be solved. 1) the spacer and 2) the skirt.

My concept to address the spacers was to create a torsion box bed that has center channels both vertically & horizontally where spacers can be inserted.

I envision a modular skirt system that can morph to various sized work pieces. The skirt would always be at the cutting plane and spacers would only be used to lift the work pieces to cutting plane. I do not have my Maslow yet and thus have no experience. I am working on the assumption that the skirt is needed in-order to cut to the edge of the work piece.

Any feedback, advice or ideas would be greatly appreciated.


no skirt is needed at the top of the work area, as the bit goes off the top
while the centerof gravigy of the sled is well supported

a skirt is needed at the bottom of the work area to even get to the bottom as
the CG of the sled goes off the bottom well before the bit gets to the bottom of
the work area.

On the sides, if the chain is attached to the sled below the Z CG of the sled,
then you have the same problem as the bottom (as you near the edge, the sled
wants to roll over)

I think (nobody has tested), that if the chains are attached a bit above the Z
CG of the sled, that you can go all the way to the edge, and possibly a little
beyond, with no skirt and no loss of control

with the new frame design, there is a crossmember that is flush with the bottom
of the work area. If you make a L with two pieces of plywood, and cut slots in
one, you can move it in and out to match your workpiece and have it provide the
bottom skirt that you need.

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Great feedback, I had not considered the center of gravity. As much as I want to build what I think is the perfect base I think I just need to get a basic set up and start using it. Waiting gives to much time to over think.

premature optimization is the root of all evil


guilty as charged :smiley:


Waiting is not really in my nature so I have gone ahead and drawn out my concept . I am hoping that those of you with experience will be able to spot issues, flaws and offer suggestions.

This first drawing shows the frame structure.

The second drawing, frame with the bed in place with 3/4" peg holes at 4" centers.


Third Drawing, Shows raised skirt in place (darker pegs for quick placement/registration). Bed is 1 1/2" above bed and has multiples sizes which allows one to reconfigure to accommodate various sized works.


Fourth drawing, Shows lift pegs on bed. One can insert appropriate thicknesses of discs to bring work piece to shirts height.
e.g. 3/4" work pieces would require…
Lift Peg (which has 1/4" base) + 1/2" lift spacer

My last shows profiles of the Lift Pegs and a Skirt component. I envision some type of clamp incorporated into the skirt component in-order to secure the work piece. An alternative my be to simple screw the work piece down to the bed.

Let me know what you think. TIA


FYI - the 80/60 is using this technique for adjustment - just lower range of 0 - 3/4 inch by using different size waste board.

Thank you

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I love the constant flow new inspiration in the community.
Thanks for sharing! A lot to think about and to copy :wink:
I can even see it as the new calibration method as a replacement for the table cloth or wall paper.

Bee, you are absolutely right, the 80/60 design is where my thought process started. I really wanted to be able to work stock dimensional lumber (1 1/2") and did want to have to always have a bunch of misc skirt and waste boards around. I may be over thinking this, we’ll see.

Gero, I am not sure I follow you on the calibration, I am not really up to speed in that area. I will have to do some reading.