EMT is very good in tension, moderately good in compression (if you can prevent
it from flexing) and poor in flexing. If you have the appropriate bracing
between the tubes it could be good. We’d need to see more about what you are
proposing.
David Lang
Thank you. I just got back from hardware store. I purchased 19 tunes 25 1/4"x 6" bolts ans some new drill bits. Oh also 16 ga galvanized steel to use for gussets. I plan on starting with mini sized frame with ability to expand if needed. But I live in mobile home park and do not believe I really need full size. But like knowing it can be expanded if needed. I have time. Expecting delivery in January. As I just recently joined the project.
More thinking on what you said. I was thinking of aircraft cable x’d between sections but new thoughts might be better. 4" pvc drain pipe syrounded by the emt conduit in box shape. Using pvc pipe to cut dow any rotation possible.
Think i will design this with 8’ top and bottom that can be extended 2 additional feet for full size. 8 feet easier to fit in my shed.
Martha
Thinking more on what i want for my frame and thought of a sub topic.i have read of others complaining that maslow was difficult to use on small items. My thought are just to use so.e styrofoam. Route out area small piece needs.and then just place small piece into the foam to hold in place it still has flT surfaces for maslow to use.
the maslow 4 will be easier to use on small stuff as it adapts to any size
‘frame’
but yes, you will want a skirt around the workpiece to give the sled something
to ride on while cutting the small workpiece.
you can do things like your foam idea, but for many projects you have scrap
material the same thickness that you can use, and you only need a few inches on
every side.
David Lang
My first Maslow frame was the ‘regular Maslow frame’ - However, the timber noticeably twisted over time, and I ended up replacing it with a torsion box made from Aluminium box sections (cheapest and easiest option for me here)
Can you share with us a picture of your aluminum torsion box frame?
Any thoughts on making a square out of welded angle iron for the 4?
Could weld a 4x8 with arms off the corners for the anchors and drop a waste board in the frame.
Any thoughts on if it would hold up to the pressure?
as always, the devil is in the details 
with large enough angle iron, it would easily stand up, but there is angle iron
that is light enough that it would have no chance.
you want to be able to pull with ~50 pounds of force and not be able to measure
deflection.
David Lang
I have actually done exactly as you have stated to cut some smaller projects, and it worked like a champ!
These were about 6" tall & 3"wide (give or take), cut on 2 boards about 7" x 15" x 1/4"-3/8" (I think I got 4 out of each). At the time all I had was the Maslow so had to figure out how to support the sled. I was given the wood by the client, so I did not have extra scraps to use to support it. I had 1" thick foam board from Lowes (The green stuff used for insulation). Created a pocket, press fit the boards into it, and used some counter sunk screws on the corners to ensure it didn’t move, and voila!!
Thank you. Looks really good to me.
That is what i am aiming for. But trying to be able to store in my shed. I live in a mobile home community. I just saw a frame that someone made of wood that had smaller main frame but had arms up and out at about 45 deg for attachment instead of the big beam across top and bottom.i am thinking of galvauzed steel built like a micro crane with triangular construction. Wondering about being able to make arm supports to be able to rotate for storage. Maybe about 3 ft arms constructed like micro size crane might work. All 4 arms anle to swing. Thinking also if wheels to roll around are ok or not. Trying to think things out. Have 4 months or so before i expect maslow 4 to arrive.
Another thought i just had. Maybe u channel the ones about 1.5 inch back to back welded with steel welded ends to reduce any flex for the arms?
Or maybe i should be thinking a different way. I have about a 10’ x 10’ deck as part of my wheelchair ramp. Maybe horizonal would be better but deck is ot completely flat. 2 x 6 some have warped a little. But maybe using foam on deck and routing foam to hold board would work.
Or would some kind of torson box to place on deck be better? Live neae Seattle Wa so we do get rain
The original Maslow frame design was arms out from the top corners, that was
changed to the solid beam because the arms were flexing so much under the load
that it significantly affected the accuracy.
what control do you have of your driveway? can you sink anchors into the
driveway and run it that way?
David Lang
yep, if you have a good deck, add anchors in that.
completely flat is not as critical as you think, since the sled rides on the
workpiece, independent of the surface under it (if your workpiece is flexible
enough, that could be an issue, but it may be a lot flatter than your deck)
David Lang
try just anchors in the deck and foam under the workpiece as a wasteboard. If
that doesn’t work well enough for you, go to a torson box
what’s accurate enough for you may be different than what’s accurate enough for
me.
David Lang
No real control. Park keeps control of that space. But I do have wheel chair ramp that is 15" above ground. I.e. half way up then almost 10’ square deck with a corner chopped of due to road clearance setback. But plenty large enough to lie 4x8 sheet on and use maslow4. Post for rails can be used for mounting belts. Maybe place say 1" styrofoam down and place board to be routed on that. Or is small pieces into that. Park really is very short on parking.
I have tremors in arms and legs. It is almost impossibe to use power tools safely anymore. But thinking if I can figure out 3d cad that making things that I want to make may be possible again. One thing is certain. Just about any cnc is going to be able to produce better than I can on my own. Could possibly make a board with embedded nuts to clamp board down like a torsion box. But would need th maslow to make the box as I cannot control hand tools well enough.
remarkably little workholding is needed when you are working on full sheets.
They are teavy enough to not move much.
If you can drove screws, you can hold it down in any case (brass screws when
possible so that WHEN you make a CAD error and cut across them, it’s no big
deal)
sounds like your deck is a good place to try. If nothing else, you can use the
maslow to make a better frame with clap holes (or dogholes, a standard of ussing
20mm holes on 96mm centers in a grid, then you can use stuff like sections of
3/4" PVC as stops to run the workpiece against)
David Lang