Machine #2 is nearing completion

[jgro]

After about 3 months of work, my second machine is getting closer to done . A little history of what happened is in order: This spring we had rain almost every day for a month and a half. I live in a old farm house with a field stone foundation and no drain tiles. When the ground got saturated, I got water flowing through my basement, which is where my cnc machine is located. I had never bothered to seal the mdf on my machine, so it sagged all over. At first I was going to just rebuild it, but then I realized that I did not need such a big machine to do the parts that I wanted to do, so I went with a new, smaller design. I used as much as I could from my first machine.

Features:
20 x 13 x 6 cutting area
Fixed bridge - moving table design
The bridge axis and the z axis are made up of 3/4" drill rod with oilite bushings.
The moving table is made up of 1" drill rod (fully supported) with skate bearings. I used steel to make up the moving table. Hopefully there should be no flex.
1/2-10 ACME rod for the lead screws with home-made anti-backlash nuts made of Delrin
I used pull down window shades for way covers


To be done:
Limit switches and home switches
A mount for the router
A way to hold down parts. I will probably add another piece of mdf to the table surface and router slots for the aluminum track that I used on my first machine.

jgro

[The Wizard]

Hi jgro,

Nice looking machine!

I am just about ready to start building my first machine based on your great plans for your first machine (still acquiring parts). I have made some adaptations though (hope you don't mind..lol).

I shortened the base as I really didn't need that much travel plus I am really restricted for space here and the machine will have to be stored when not in use. I also noticed in one of your posts a comment about the anti-backlash nuts so I designed a set of spring loaded ones which should be easy to make on my 70's vintage Unimat lathe/mill/drill machine. I also noted your comment on gantry rigidity and will look into this once I get to that stage. I have considered an extra 'spreader' on the back of the gantry and also brackets/support blocks in the corners.

The only other change I am considering is fitting flange bearings on both ends of all the leadscrews so that the LSs are fully supported. This will require the motors to be mounted on brackets but I do not see this as a major problem.

Congratulations on the new machine and I hope you get to make chips/dust soon!

Larry

[hook'em]

jgro, nice way covers. Have probably seen it written somewhere to try that method ( those are old-style window shades, right? ), but until you actually 'see it'.... And also like the way you had the material roll over the top to allow the chips to fall off instead of get rolled up. Oh yeah, the whole thing looks great, just got excited over the covers. Kudos on a great looking piece of equipment.
Vance

[Graham S]

we call them roller blinds in the UK, scratch that we probably call them roller visualy impared these days

Great idea, well implemented A+

Cheers,

Graham

[CNCPlastic]

Of course the blinds are WHITE you racist honky pig!!!

[ljoe1969]

Will you post the plans for this machine also?

[jgro]

I really don't have any plans. I laid out a few things, but it's only about 40%-50% done. If there was a BIG demand, I could. I don't feel real comfortable posting plans that use Cranky's design for the moving table.

jgro

[ljoe1969]

I can respect that.

[jgro]

I've made some progress this past week. I added a tabletop and cut slots for the t-track, added limit/home switches to the z axis and the x axis (the one on the bridge) and made my router mount. I still need to add limit/home switches to the table. I haven't figured out how I'm going to do that one yet. Then I can reassemble the enclosure and start cutting

jgro

[mvaughn]

jgro

Can you explain the process you used to create your lead screw nuts? I'm getting close to making mine and am curious about yours, how well they work, how you made them, and anything you would change about them.

Thanks,
Mark

[jgro]

I made mine like the one shown here: how to Mount this anti-blacklash nut? the 8th post. I made my own acme tap. You can search the forums here, it's been discussed before on how to make one. The only thing that I did differently was that I chucked my piece of acme rod in my drill press and used a file to put the taper on it. It wasn't to bad, it took about an hour to do. So far the nut seems to be working fine, but I don't have much time on it yet.

jgro

[mvaughn]

Did you find that there was noticable backlash without splitting the UHMW and tensioning it?

My original plan was to just acme thread a 1/2 or 3/4 inch thick piece of UHMW. I'm trying to decide if it is necessary to make it adjustable.