My next machine

[chuckknigh]

Well, after learning the limitations of a homebuilt gantry machine, I'm going to embark on another homebuilt design. This time I'm going to let myself be inspired by Mr. Kleinbauer...but with a few upgrades of my own.

I'd like to know your opinions...and any suggestions for improvement.

Here's his design, the 7th Sojourn. I've heard good things about it, and it seems well designed, so it's a good starting point for my project.


My intention is to build a moving table machine, as a learning experience. I intend to do something similar to his 7th Sojourn, but intend use window frame extrusions for all the linear ways, including the two on the bottom, in place of his pipe and rollerblade bearings.

I've found a local source for this extrusion, and it's nice, rigid, and fairly precise. It's a good choice for rails, because it's very consistent, and quite strong. It'll provide me with "fully supported" ways...a good starting point for a design.

For my slides, I could either use cutting board plastic (nylon?) or vinyl slabs I got from Home Depot, with a structural carriage made, probably, from MDF.

I might make a few other modifications, as the design evolves...that's why I'm asking for input.

So, what do you think of the basic idea? Suggestions? Improvements? Balsaman, this will be similar to your original machine, but made with cheaper components.

-- Chuck Knight

[ynneb]

Hey chuck why dont you request for this thread to be moved to the log section. This way you can build upon it. You have made a good introduction to it already.

[chuckknigh]

Well, I thought I might pin down the "final" design before posting in the construction-log section. I know a few people on here have built Kleinbauer's machines, and more than a few people here have been "inspired" by him. I'm hoping I can learn from their experiences, and come up with a better overall machine.

One major weakness in my original gantry design was the fact that the rails would sag under the weight of the gantry. I ended up supporting them, but they'd still shift a little bit, since it was a gerry-rigged solution. The other primary problem was the "play" in the gantry...since the rails would move, even slightly, it allowed it to get out of square, and even bind under certain conditions.

Neither problem was particularly bad, or even insurmountable...but like I said in another thread, it needs to be rebuilt anyway, so why not start with a blank sheet of paper, and some experience from the previous machine?

With this new design, I hope to correct those problems, and improve on its performance. I learned quite a bit from building prototype A.01 and the bug fix, A.02. I liked the space efficiency of the gantry design, but I think the moving table design will have other advantages, including stability of the bridge, which the moving gantry did not have.

I wonder if turning it on its edge, and making it into a "mini panel saw" would have any advantages? It'd end up being a benchtop sized machine, that way...I'd have to counterweight the Y axis somehow...but a counterweight can be as simple as a torsion spring, or even a brick on a rope running behind the machine.

I wonder if there'd be any other tradeoffs to an upturned machine? I'd use the same clamping system I did on my first machine, so workpiece movement would not be an issue.

-- Chuck Knight

[chuckknigh]

This is the "panel saw" type of arrangement mentioned above. I think with a fixed bridge design, but just turned on edge, it may be an improvement for my workshop. It would take up a large amount of bench space, but it'd still be just "benchtop" sized.

Regardless, I think that if I could figure out how to negate the weight of the Y axis, it'd be a trivial matter to build something like this, using a fixed bridge design. Even something like a brick could serve as the counterweight...and yes, I'm being completely serious.



-- Chuck Knight

[jstuedle]

Another advantage to your "panel router" design would be chip clearance. All scrap would fall away from the cutter.

[ger21]

Originally posted by jstuedle
Another advantage to your "panel router" design would be chip clearance. All scrap would fall away from the cutter.

Actually, if you're making deep cuts in plywood and MDF, I'm pretty sure the chips and dust will stay in the cut, as they tend to get packed in pretty good.

[chuckknigh]

Plus, the machine I showed uses vacuum clamping, which holds not only the sheet, but the individual parts as they're cut. Of course, this is not insurmountable, either...just takes a little planning.

As for the dust, I think I'd have to have a good vacuum fitting and brush on the head, but that's just common sense.

OK...now design and engineering suggestions. That's what I'm looking for... Anyone?

-- Chuck Knight

[xlr]

If you haven't already, You should buy the plans from John. They are well done and it will save you a lot of fustration later on.

Robert

[Randall]

Yes I highly recomend his plans. they are cheap, they will save you time, and its the right thing to do.
Randy

[chuckknigh]

But I don't want a 7th Sojourn. It's a good source for inspiration, though...I want something which was derived from its basic form.

Gotta' admit, though, that his plans do seem like a reasonable bargain, if they're even remotely complete. And, in total fairness, the idea to use the window frame channel can be attributed directly to him.

Thanks, John...

-- Chuck Knight

[Randall]

The plans are great,Your mods may pose some problems.
My feeling is this he provides nice entry level machines which are very accurate and he charges very little and offers fantastic support. Plus if we dont support him he goes out of work and we lose a valuable designer and teacher. If you buy those plans you wont be sorry and if you dont like the plans Ill buy them off you.

Randy

[xlr]

Randy I agree.
The plans are very reasonable and im my case was an investment . Sure you can muddle through and perhps build a machine by looking at some pic on the net but why not build a machine with a proven track record. Even if you don't build it exactly, the plans will certainly give a builder insight as to why something was done a certain way.

The plans are cheap. What is your time worth muddling around trying to figure out what to do next?
I built John's Brute and am very satisfied with the plans and the results.
The other great thing about John's plans is the support you get from him and others in the group making it the best bargain in CNC.

Robert