[Hobbiest]

Just couldn't get this idea out of my head, so I had to start on it today! Should be able to finish it this weekend, and this is the first machine that I will personally fire up and run! 3/4" mdf, aluminum channel for the ways, plastic cutting board for the slides, adjustable gibs, roughly 24" by 12" by 4" of travel. The nylon isn't great as far as linear motion goes, but I am surprised at how well it does work! Gantry moves very easily, with just a pinky of pressure (very technical term there!), and if held at 45 deg angle and nudged, sends into good sliding! Will use the FET3/HT kit from stepperworld. Total cost of mechanicals estimated at $45. I won't be able to work on it again until this weekend, but hopefully I will be able to finish it then. Sorry about the poor image quality. I can't understand why it pixelated when I made it smaller!

[mikeschn]

Hey Hobbiest,

That's looking good. And at that price, the electronics cost way more than the mechanicals. And we won't even discuss software costs!

Can you give us a close up shot of the slide configuration you are using?

Mike...

[Mr.Chips]

Good start Hobbist.
Interesting use of aluminum channel, serving as rails and to stiffen the MDF. Lengthwise rigidity is the weak point of MDF.

Keep those photos coming.
Hager

[Hobbiest]

The slide design is very simple. I think that I will change the pieace of mdf that holds the upper sliders to angle aluminum, with adjustment slots, as I just don't trust the wood here. It is too thin and weak. Also have to adjust the placement of the slides to give more surface contact area.

[Hobbiest]

I also will be stiffening up the bed by adding pieces of this aluminum t-slot, with 3/8" wood strips between to make a level plane. This t-slot is pretty cool...something like $12 for 36", and it uses 1/4" bolts in the slot. Eventually I am going to try to fab UHMW slides that go inside. Might try injection molding as well, but have to get D. Gingery's book first! My main goal with this machine, is to get a good working machine together, then offer plans on it. But the machine must be able to be built from hardware store parts, and be possible to get the parts in any country, not just the U.S. and Canada.

[gbennett]

Lee Valley Tools sells a u-shaped aluminum extrusion sized to accept the 3/8" x 3/4" UHMW strips that they also sell. They also have the aluminum t-slot extrusion.

Page 133 of the catalogue

or

www.leevalley.com

[Hobbiest]

Thanks gbennett, I'll check that out!

[DJ Morrow]

Non CNC content

The reason for your pixelated pic may be one of two things:

1. JPG is a lossy format. Each time you change and save a file, you loose some detail.

2. I use MS Frontpage to do a website for my motorcycle stuff and am always reducing the size of the pic's. When it shrinks, it gets "pixelated". In Frontpage there is a feature called "resample". When the picture is reduced in screen size, it doesn't need as much information to present the picture. The resample eliminates all the unneeded data. This also significantly reduces file size thereby significantly reducing download time. When you resample the image really clears up nicely.

Probably more than you wanted to know but...

[Mr.Chips]

Hobbiest,
Is your machine built out of Partical Board or MDF?

All the MDF that I'v seen is very fine grained, and doesn't have the color variations in your frame.

Hager

[DJ Morrow]

Here's the Lee Valley page with the U-channel and UHMW

http://www.leevalley.com/hardware/pa...urrency=1&SID=

Thanks, you've given me an idea for my own work in progress machine.

[balsaman]

I noticed that too. Looks like particle board.

Eric

[Hobbiest]

They said that it is mdf, but I wouldn't put it past them to not know the difference! I agree, it does seem more like particle board, but it is plenty strong. The particular 2 by 4 sheet used for this machine has been pulling duty as a workbench top for the last couple of months. I have a workbench, but it is always covered in junk! DJ...if you use that stuff from Lee Valley, let me know what ideas you come up with, I already have a few.

[xairflyer]

I am affraid that is not mdf, like the slide idea, interesting to see how it works.

[JOE65]

Just a note.

Some time ago I tried the Lee Valley Extrusion, UHMW combo as slides for my Z axis. It didn't work for me. I was quite carefull with aliengment ect. But it ended up very "bindy" ie. it takes a huge amount of force to move it.

You can see on the UHMW where I coloured it with a felt pen in order to see where it was binding. I played for quite a while but eventually gave up and used 3/4" motor shaft with bronze bushings instead.

I'm not saying it can't be used for slides just reporting my experiences.

[Hobbiest]

So far I am confident in the design, seems like it will work well. It is after all no different than "real" machine tools, ie lathes, mills etc. How is your machine comin? Looking pretty good, from what I can see on your thread! Like I said above, one of the main goals for this, is to have available plans that can be used regardless of location. I read all your posts on RC site, and it kinda irks me that "that other guy" won't sell to anyone outside North America. I understand why, but seems to me that there is a lot of market out there. I guess thats where I come in...hehe.

Joe...howz about putting a larger copy of that photo on, I would like to see the disign closer. Is the center panel wood? 600 pxels works for me on here, can prolly go up to 800 or so.

[mikeschn]

That's quite a lofty goal you have there, a machine that can be built, "and run" anywhere. It's do-able of course... so keep up the good work.

When you say "the other guy", do you mean Cranky? Why won't he sell out of the country?

And yes, it looks like particle board to me too!

Mike...

[ballendo]

Hello,

Couple thoughtson this thread so far...

It's definitely NOT MDF. If I were you, I'd stop now, get some real MDF. and work back to this point. Because PB is inferior to MDF in nearly EVERY way. surface smoothness, ability to hold fasteners, stiffness, etc... (FWIW, MDF will have a much more uniform color, which will be darker; and it will be heavier--noticeably!)

Next, the comments about the UHMW slide system shown are not a surprise. Because UHMW "moves" a LOT with variations in temp and humidity... The way to have success with UHMW is to use THIN pieces as "wear strips" on some underying structure...

Actually this is true for most plastics, which is why when you look at the "engineered" plastic bearings (IGUS, RULON, Simplicity, etc.) they are nearly always relatively thin.

Hope this helps,

Ballendo

P.S. I know you don't want to "start over", but I'm more than a bit sure that once you see and use REAL mdf, you'll be glad you did.
Saying this PB version is only a "test" won't work either, because PB will move MUCH more with humidity and temp changes than MDF. In your design, you're dpending on the width of the table to remain constant. MDF will improve your odds considerably.

[balsaman]

If you going to make plans, you need to consider the fact that not everyone will be as careful at building the thing as you are. Adjustibility will need to be designed in. What if the guy doesn't cut the table evenly? The gantry will be loose on one side and tight on the other.

BTW, Cranky is very good at making plans almost anyone can build. He takes a lot of time considering what I have mentioned above.

Eric

[arvidb]

Also, if you are going to sell plans outside the US, you will probably have to think about having a metric set of plans. Of course, we (who use the metric system) can recalculate all measurements to mm (for use with metric rulers, etc), but some imperial components (UNC threaded rod, MDF 1" thick, etc) may be quite difficult to get.

Arvid

[Hobbiest]

Very good point arvid! I'll have to find out the measurements standardly available in metric system. Cranky won't sell his plans outside North America because the window channell used in his plans is not available in all places...among other reasons. I didn't want to call him by name out of respect, and not wanting to downplay his plans, because his designs are very nice. He however, has been very rude to me on several occasions, as well as other people I have spoken with, and so I don't care for him too much personally! He also seems to think that all of his ideas are his own "inventions", which is definately an idealistic way of looking at things. Nothing that I have seen of his is anything that hasn't been done before. He is very good at working outside the box, which is a thing that most people who build things don't do. It is a lot easier to work some overtime and buy a part, than it is to make it! anyway, enough about Cranky John!
The particle board is something that I just happened to have laying around the garage, and so I thought I would figure out the disign elements with it. Once I have everything the size that I want it, it'll only take a couple of hours to transfer the measurements and make it out of mdf. This will give me a chance to get all of the pattern measurements down too, and use CAD to figure out the best nesting pattern, for the least waste. This design is adjustable, in that it uses adjustable gibs on all of the sliding components.
Ballendo...UHMW most definately is not dimensionally stable. I have a 2" by 3" by 4' piece in the garage, that is constantly changing! This should be a design that anyone can build, as the only cuts that need to be great, are the parralell edges for the ways. But as even Cranky says, sometimes you have to cut outside the lines, and then sand perfect! Any of this stuff can be done with basic skills, and heavy DESIRE! I taught myself how to build cars, because it was something that I really wanted to do. When you don't have the proper tools, you figure it out with what you've got. That is where I come in. I have built two cars, using hand tools, a hand grinder, die grinder, hack saw, mig welder, hand drill, and a lot of perseverence! I don't have a table saw, miter saw, mill, or lathe. All of my stuff is built in my garage, by me, using a jigsaw, hand drill, skillsaw, sanding block, hand files, etc. Anyway, you get the picture (I get very long winded sometimes...pant...pant).
When the designs are all fleshed out, I will put it to the test by having my wife build one! She isn't clueless when it comes to tools, but she does have basic mechanical skills and knowledge.
Thank you all for your input, I by no means take any of it as a knock...even if you told me I'm stupid! I just don't care about what other people think about me! You guys are all great, and everything that you say here can only improve the finished product!
Cheers!