Alternative Frame: Travel Friendly Maslow Frame

I am looking to do some traveling in the near future, and would like to bring the Maslow along. In its normal state that is just too much wood and weight. My initial pencil and ruler drawing was based on using PVC and looked like this using 2 inch PVC, single Y joints, 4 way joints, 90 degree elbows, and 45 degree elbows.

frame

I figured a 2x4 bolted to the PVC to hold the work piece on the bottom. I have not figured out how the motors would attach. My current assumptions are that the frame will lean against a wall, with the option of fastening it to said wall for stability.

My main requirement would be as light as possible, and able to easily break down into a package that can be stored, also it would be nice if the materials were safe to be outside during nice weather.

I’m hoping for some ideas, PVC is not my end all material, it just seemed like a mostly sturdy material that might satisfy my requirements.

Thoughts? Ideas? Suggestions?

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I think that a downward pull on a motor would bow the topmost rail up in the center. Not sure how to address that with off-the-shelf fittings, though.
A rigid frame is important for accuracy. My experiences with PVC leave me doubtful. Perhaps some tension cables to ad rigidity? Unistrut is certainly heavier, but much more rigid. There are some aluminum extrusions that might work.

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look through the topic titled musings on frame design.

PVC is far too flexible, but you can get metal like this

https://www.industrialmetalsupply.com/Products/telescoping-tube

and have the top bar collapse down to a shorter length for transport.

With the solid top rail design, it’s the only thing that must be especially
ridgid. Everything else is just to hole the top bar in place and hole the
workpiece in place.

you will probably have a little error in the motor spacing with this type of
tube, but if you either calibrate the motor spacing each time, or hook the chain
over both motors and have them pull against each other while you tighten the
bolts, you should be able to get pretty consistant results.

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Thanks @blurfl and @dlang, rigid top rail is critical, makes sense. The topic @dlang referred was Musings on frame design.

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I really like this idea. I just like triangles…

Wouldnt it make sense to use equilateral triangles?

then you have all frame parts (beams or tubes) at the same length.
Thats more travel friendly and assembly friendly

tube s from 1 meter or 75 cm
3x1m or 4x 75cm makes a top width of 3m (if you plan to go full size)

and all joints will also be the same at a 60deg angle

this could then also make it scalable …

the trick with PVC being can you get the required angle joiners? or how to make the joiners?
that said unless you go >110mm in my experience it will be too flexible

what about a truss system (i just mentioned it in another post as well)

the truss is far too complex, replace it with simple telescoping tubes or nested angle metal

That looks like a section of antenna tower. You might be able to find some at any good sized ham radio swap, maybe a flea market, or in my collection of spare tower parts. An old TV tower could work, in rural areas digital TV has pretty much eliminated OTA TV and unused towers are rusting away unused

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I’m pretty sure it’d be easy to make a unistrut design that looks somewhere between this one and the unistrut design (essentially a copy of the wood frame) using the ‘special accessories’ available for unistrut at mcmaster.com or a similar speciality supplier, (vs. the minimal unistrut accessories available at the standard home center) and boil the whole thing down to something that’ll fit in a duffel bag or golf bag or similar conveyance (like a Drum Kit hardware bag/box or Hockey equipment bag?).

It’ll still weigh a ton (+/- 80lbs), but a frame could be made to fit in that much space, disassembled.

The truss is very ridgid and easy to take apart and transport, there are also less bulky trusses then the one in the image.

It would make a light strong top beam much lighter then metal tubes, and much shorter to pack.
Still not ideal, but it’s another option that could be explored.

It would be cool if an entire maslow could be made to fit in the trunk of an average car somehow

one crate and a bunch of short beams

Remember that almost all the force on the beam is the two motors pulling towards
each other, you have very little in the way of vertical or front/back forces on
the beam

vertical forces are supporting the weight of the beams/motors and the weight of
the sled.

front/back forces are trivial if the sprockets are near the beam, and more if
the motors are spaced out forward of the beam

Thats exactly how i came to the truss, the width and the triangles make it very rigid without a lot of weight This would make a far more rigid beam then a 2x4.

Just look how much width a simple truss can span without support. triangles are a magic weapon for stuff like this…

Trusses spanning large distances is finding a way to deal with bending forces.

I’m saying that the bending forces on a maslow top beam are very small, so a
truss is being optimized for forces that we don’t have to worry about.

O ok, i tought that most calibration issues where due to bending of the top beam.
And when portable then you have a top beam made of 3 or for pieces, hen you need some kind of construction that can handle these things.

What i can’t find the thread where there was talk about 30kg forces bending the top beam and causing the calibration to be off.

I’ll try to hunt it down and paste the link here once i find it.

O ok, i tought that most calibration issues where due to bending of the top beam.

I think a lot of errors of the stock maslow design are due to bending, but once
you add in any top beam, you eliminate almost all the leverage.

the stock design puts the motors out 4-6" from the arms, (attached by wood
screws) which are then attached to 4’ arms that are attached to a pice of 3/4
plywood with wood screws.

This gives the motors a LOT of leverage to bend things.

once you put in a top beam, the motors tension operates directly along the
length of the beam, but it only has 1/2" or leverage to bend the beam instead of
feet of leverage.

even a 2x4 is very stiff along it’s length (and even pretty good if the 2x4 is
warped)

And when portable then you have a top beam made of 3 or for pieces, hen you
need some kind of construction that can handle these things.

Yes, but if you use something like nested metal (either angle metal that nests
nicely or telescoping square tube) you can be stiff enough, remembering that
most of your stress is lengthwise.

What i can’t find the thread where there was talk about 30kg forces bending
the top beam and causing the calibration to be off.

It wasn’t bending a top beam frame, it was bending a stock frame design.

The stock design is very pretty, but it’s not a very stiff desing.

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i seee, Thanks a lot @dlang for being so persistent!

Now i must try to replace those thoughts and remember this … Thats the hard part

I am planning to make one with unistrut ( Home Depot has 3 sizes, depending on the needed strength, in 10ft lengths.

I am planning to get 10 of these (for the price break, and to use for other projects), but I think 3 is enough, in theory.

1-5/8 in. x 10 ft. 12-Gauge Metal Framing Channel

https://homedepot.app.link/g2WZv4K9CI

Don’t reinvent the wheel here though, if you want light and portable there are extruded aluminum “systems” that are common for trade shows (light, strong) and used in CAM systems with more traditional XYZ CNC machines. Also, supposedly you can build a system for smaller sheets, so 4ftx4ft or 2x6ft if you mostly cut signs for example.

I really am hoping someone can share how they are building legs & the 12 degree tilt with unistrut though. I would prefer to “stand on the shoulders of others!” But I will document my attempts if no one has a good design or idea to share. Also, am I over killing to use that largest unistrut?

design kits for frames

Or http://www.cnczone.com/forums/news-announcements/92565-diy-aluminum-cnc-router-frame.html

These links are Just for ideas, I am building in steel for a Rigid, slightly movable CNC setup. While I love the basic low low entry price of the Maslow, it would be amazing to see options (or a market place) for sleds, frames, etc… to avoid everyone reinventing everything.

I have already shared my SVG laser file for a sled (i have cut my test sled, but haven’t tried it) and will share my electronic case plans once I build a Case. So, things that would be nice to have from Maslow or in a Maslow market place

Maybe a full frame kit with wheels and 4x8 sheet storage
A kit with all the hardware except the unistrut (to source locally to save on shipping)

Wheel kit for moving

Electronics case(s) (although a possible design to move everything to the sled is a great goal, and makes the case and sled as a product option even better)

Sled, once a best design is sort of agreed on.

Sled

Not sure if I missed anything or if I am helping here.

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check out links to 2 unistrut frames here: UniStrut Frame designs

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