Frame design options

I’m about ready to order my wood and start building but I did have a few questions on your folding design.

Where do the motors mount on the top beam? At both ends as far as possible?

The 66" 2x4s that make up the frames height, would I be able to cut down to about 60"? If so, I would have a place to store the maslow in my garage.

Where do the motors mount on the top beam? At both ends as far as possible?


The 66" 2x4s that make up the frames height, would I be able to cut down to
about 60"? If so, I would have a place to store the maslow in my garage.

I started off with the ‘that looks about right’ criteria, but the more I dig
into the option of shortening these, the more it looks like this is really the
correct height.

you want the motors to be ~18" above the top of the work area (you may be able
to cheat this down to ~12", but that will mean the motors are really working
hard to move the sled to the top center), and you need ~9in below the edge of
the bottom beam to give the sled room to move down far enough for the bit to cut
to the bottom of the work area.

so 5" for wheels [1], 1.5" bottom 2x4, 3.5" for the 2x4 that supports the
workpiece = 10", just about the minimum for the lower spacing.

you then have 48" for the workpiece and 18" to the top of the top beam, for a
total height of 76" (plus a couple inches for the motor, so call it 6’6" total)

out of this 76" you have -5" for the wheels, -1.5" *3 for the bottom 2x4, top
2x4, and main beam = 76 -6 - 4.5=65.5" for the vertical supports.

so you could cut the 66" verticals down by ~1.5" but anything more than that and
you are going to run into problems, either at the bottom of the work area, or
the top.

you could tweak the sled a bit to give you an extra inch or two of space at the
bottom, and you can probably get away with cheating a little at the top. So if
you have space for one with 60" verticals, but not 66" verticals, build what you
have space for. Just be aware that you may run into grief at the top center, or
with the sled hitting the ground at the bottom, depending on how you tweak

[1] note, taller wheels work well, and if you use taller wheels, keep the
distance between the top of the bottom workpiece support to the ground the same,
and move it down on the wood and shorten the vertical pieces.

David Lang


Also remember, you can tilt this third option to roll it into a space, then stand it up. Really, I don’t know of any 5’ high garages…

Well, I built one with Unistrut and have it running now.

Made a couple of mistakes, but being able to reconfigure things easily was nice.

Biggest opps was it was too tall to go out the garage door when I wanted to get it out of the way… wound up shortening by about 6" and using those pieces as offset adjustments for the top bar… I left them “long” so that I could play with that position, although so far it’s been fine where I eyeballed it.





The castor mounts tend to flex a bit… I worked on that some today and they seem better, but may still have to revisit that. Doesn’t matter for machine use, but moving it around my “shop” it matters.

The back triangle is large enough to slide sheet goods in and store them. I’m going to put a strip of unistrut or a 2x4 across the bottom to keep the legs from trying to “fold” toward the center when I’m wrestling plywood.


Cool build! I’m glad to see a unistrut design. I’ve been thinking that would work great and I’m glad to see that it does

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Ditto @bar’s comments. I’ve got a frame that is mostly wood with a couple of 10’ Unistrut crossbars which will support the motors and eventually a panel saw option. It’s really great to see someone build the major frame components from Unistrut as well.

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You guys with the idea of the panel saw are what mostly led me down this path… I wanted the stiffness, and have a rough design in my head to add a “panel saw attachment” the way I laid it out. That will come later.

But it certainly seems stiff enough, no issues there.

Why not use a circular saw on a sled? Make it so the saw can be turned 90° and lift it off the table manually when needed.

Speed is the main reason for me… Maslow isn’t a speed demon at moving that sled :slight_smile:

But it is an interesting idea. Might get real interesting if the blade hung up though.

After the kinematics and sled are sorted out I hope that full bit depth cuts will be close, plus it might make sense to start looking at larger chain sprockets for higher speeds. Although it’s hard to beat the cut speed of a 15A (7.5 for you 220v guys) circular saw that you’re pushing through a panel. A long time ago I saw DIY plans for one using EMT with cut up nylon tubing over U bolts. A2Equipment, another good choice, has shut down, alas.

We might find out how strong the chains are really, and how far that saw would fly. Safety chains and stand out of range?

Probably not a bad idea (standing out of range)…

To tell (another) one on myself, my first real cut on the Maslow, with a new, slightly unfamiliar router, I apparently managed to not get the bit tight. Of course I’m standing close and watching what’s happening when all of a sudden the cutting sounds weird. I can see the bit coming out of the router. Trying to get everything stopped at once made me again think an e-stop will be a future addition :slight_smile:

It stayed “contained” under the router, thankfully, but I could see that going flying at speed.

Been there, although it pushed back up into the router. Then there was the day it decided that the Z was at 35 inches, drilled a hole into the frame, and wanted to keep going - fortunately it didn’t strip the Z button. Make it easy to tell where it thinks the center is…

@Bar, have you considered adding Z axis limits within the range of the router’s travel? Maybe, say, +1 to -1 inches (or +25/-25mm) or something else that makes sense? Do the X and Y even have limits?

The parts for my little control box have arrived, latching power switch (advertised, interestingly, as an eStop) for the mains AC, a 22nn AC voltmeter (no reason, just looks cool), red 12V 22mm LED (have a box of them), might use it to say there’s 12V but the eStop is hit, and a mushroom eStop to cut the 12V DC since Bar says that’ll stop the motors but not cause a loss of position. It takes a while for the 12V from the supply to drop so just cutting the AC isn’t good enough.

If/when the spindle SSR firmware command gets implemented I don’t know if losing 12V will also cut off the signal to the SSR. If not I’ll probably need to add a relay or two to cut that power

I hadn’t thought about adding limits of the movements, but I can see how that would be valuable. The trick is that the z-axis would have to know where it started from in absolute coordinates (which is achievable, but not done right now)

Knowing absolute start is required and a difficult one to solve from another application of a similar problem I’ve been involved in (we wound up using a hard limit switch), but if we could put in (configurable??? :-)) limits that we want to maintain (±1" or whatever) then we would at least sometimes limit the damage.

adding support for limit switches would be good, and hooking limit switches up
to keep the router from moving far enough to damage the drive would avoid a lot
of problems.

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with the stock design, the sled rotates as it moves around the work area, so you
can’t use a saw on it.

With the new sled types, you may be able to do that, but it will depends on the
weight distribution of the sled as to how well it works.

Yeah, I’m more inclined to just build a “panel saw” attachment for my frame (which was my original plan).

Early on I did correspond with @bar on the old forums about adding some “quick cut” options in Ground Control - a “straight down cut” or a “straight line cut” that you could just drop in place and say “go” - i.e. a poor man’s panel saw (or just a convenience feature to keep from having to go to another program, lay out a single line, generate g-code, etc.) just to get a single, simple cut.

I’m sure we’ll get there - the device is young :slight_smile:

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there are the buttons to move the sled around, you should be able to use those.

Round about how much did that unistrut run?

I think I dropped about $90 on strut, then bolts, nuts, fittings, etc. - probably $150 when I was done. Not the cheapest, but like I said, I have plans for expanding into a panel saw use… and it’s definitely stiff enough I think (I used the full height for the top beam/motor mount, and the 1/2 height stuff for the rest. The piece of plywood is bolted to it and structural for the legs. I then use a sacrificial piece over the top of that, although you wouldn’t have to I guess (just have to replace the ply occasionally).

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