[Weldtutor]

The photo helps to explain the second part of the previous post.

Workpiece support slats are above the surface of the table sides and ends.

Side rail surface is below surface of support slats.

Loading & unloading of the table can be from either end and both sides.

[KSKID]

thanks for photo, yeah the cantilever idea would kind of be a bad idea, need to use the KISS principle on the design of my table, i tend to put too much thought into things sometimes.

[Weldtutor]

Kiss engineering is good!

I think you must be a romantic using that term to-day!

[David Bord]

Trevor, great looking project!

What would you say is the resolution of your table? When cutting a circle of of a give size, how round would it turn out? Do the start and stop points match well?

Trying to decide if gear or belt reduction will be worth the effort. I plan to make prototype suspension pieces so accuracy of around 1/16" or better would be about right.

David

[trevorhinze]

David, Thanks for the interest. I would say that the resolution of my table is easially within the 1/16th inch that you are looking for, but the accuracy of my plasma cutter itself isn't always that good. I just have a little Hypertherm350 (27amp) and I am reallly pushing it most of the time cutting stuff out of .250 inch plate. The reason that I mention this is that with anything other than a brand new tip I get a good amount of bevel, and the direction of that bevel can change from one spot on the workpiece to the next. I have not had any problems at all with start/stop points lining up, but I do always use a .25 to.50 inch tangent leadin/leadout. I can cut out an oval 2' by 3', and you can't tell by looking at the edge of the piece cutout where the cut started and stoped, so my repatibility must be pretty good, and as I have said before the resolution exceedes that of the plasma arc itself. Good luck with your table.

[Weldtutor]

use of timing belts to move my machine. They are low cost, easy to install and maintain, silent in their operation , and very sturdy.

The timing belts & pulleys appear to be close to the XL series/size.
Are they that size, or something different?

[trevorhinze]

The belts/pulleys on my X(long) axis are in fact Xl series Gates parts, the belt and pulley on the Y(short) axis are of an unknown type, I got the belt and pulley out of a large printer I tore apart a couple of years ago, they are slightly smaller than the XL parts, but they seem to work well.

[Weldtutor]

First photo shows the Z axis motor installed. (2 more motors & drives to go)

Plasma torch is located in floating mounting plate.

[trevorhinze]

Looks like you have made quite bit of progress. I will be interested to see how your floating Z axis works when you get your machine up and running. Those little rollers look familliar, are they the little ball bearing rollers that are normally used for material conveying? Seems like a good low cost solution if it works. Keep up the good work.

[Weldtutor]

Those little rollers look familliar, are they the little ball bearing rollers that are normally used for material conveying?

Yes, they are used for conveying. Most listings refer to them as transfer bearings.

Some have a stud incorporated for mounting or others like the ones I used, a flange designed for surface mounting with a fastener.

This floating Z axis design is from the Mlaws1172 plans mentioned earlier in the thread.

Bearings of this type were also used by "Accuratemike" for his CNC oxy-acetylene cutting torch. For this application the transfer bearings rode on tubing for the X & Y axis movement & is pictured elsewhere, here at CNC Zone.

[mlaws1172]

looking real good
mike

[FPV_GTp]

nice work

[Weldtutor]

Thanks for the comments guys.

Photo shows the gantry in the "parking lot."

This was accomplished by building the table top, with extended side pieces, and Z axis rails also are the longer length.

A useable work or cut area of 60" by 49" is available.

[KSKID]

weldtutor,

really like your idea of using off the shelf roller bearings for your
x,y, z axis, was wondering how well everything works with
this setup, any noticable drag?, would like your opinion on
your selection.

also, curious what do you plan on using for your X & Y Axis drive?

and for your Z-axis what kind of threaded rod/nut are you using?

thanks

[Weldtutor]

Thanks for the kind comment & your interest.

The roller (skate) bearings move very smoothly on the pipe axis rails. This was one of the pleasant rewards I experienced when the X & Y axis were first assembled. I probably rolled the gantry back & forth, by hand, for an hour or more. It seemed like it was "floating." :banana:

The Z axis has a 3/4" 6 TPI Acme threaded lead screw with a matching brass nut. This is from a satellite dish control arm as shown earlier, in post # 17 of this thread.

Currently the X & Y drives are being fabricated & assembled. These are #40 roller chains. A jack shaft will provide drive force to both sides of the X axis. More on these drives to follow, in future posts. The photo shows some of the hardware for the drives & their sub-assemblies currently completed.

[KSKID]

curious to know, what the determining factors were for you to decide on the drive system that you have selected for the X and Y axis, still trying to decide which way i should go, i like the direct drive blelt setup, less moving parts but would like to weigh all my options before deciding on one in particular.

[Weldtutor]

what the determining factors were for you to decide on the drive system for the X and Y axis,

Availability from stock, standard components, and 2 local suppliers were the main factors for me.

I also find chain & sprocket drive systems easy to work with & modify speeds.
These drives will provide the necessary power transmission & accuracy for this application.

Cable drives were first selected, but various pulley sizes, bore sizes & bearing types were difficult to source after a few initial purchases.

Ball screws & rack/pinion drives usually got responses like "we could order them for you."

Your mention of timing belts (with cog pulleys) certainly is worth consideration especially if suitable "surplus" items can be located. Again, suitable off the shelf items were not found by my searchs.

[massajamesb]

I am quite interested in this machine, but I am still unable to download the plans offered. would there be any way to get this info in my email? the reason I ask is that I am at work, and the boss doesn't like new programs being downloaded to the comp. anyway, the machine looks great, quite ingenuitive.

[Weldtutor]

Welcome to CNC Zone & thanks for your comments. :wave:

I am still unable to download the plans offered. would there be any way to get this info in my email?

The link to the plans offered, by Mlaws1172 is back in post #11.
It is not a program, but one compressed file.

You will need a CAD program that can read and print the DXF file format the plans are in. The thread with the plans makes a recommendation for a free CAD program that is available.

If you send your Email address, by PM, to the plans author you'll likely get them sent to you.
The Mlaws plans were a great help to me in planning my machine, although I did not follow them exactly.

[massajamesb]

thank you for your help, your machine looks like its coming along nicely. is there any advantage to using chain drive verses belt drive??