[Clyde]

I have just started designing my first CNC Router.

I would appreciate any critques or suggestions on the structural design in the model below.

I'm using Thomson supported rails with SPB-8-OPN and TWN-8-OPN pilowblocks/bearings.

Z axis 4" travel
Y axis 14"
X axis 30"

I'm using off the shelf aluminum (www.onlinemetals.com) channel (8"x2"x0.375"), angle (3"x3"x0.375") and plate (1/4")

The table is not yet supported in model below.

I'm hoping to route wood (hard and soft) and aluminum...

[Clyde]

hmmm, here goes again (attaching the model picture)

[vacpress]

sweet rendering- sw2004?

too dark though! please post more!

[Clyde]

I'm using Rhino3D (www.rhino3d.com) v2.0. Thinking about upgrading to 3.0 if a good CAM package is available as a plugin for a reasonable price.

I'll post more tomorrow...........maybe my monitor is set for too bright, I'll try to brighten it up.

[Clyde]

more pics.........

[Clyde]

...

[mvaughn]

looks good so far.. I'd like to see pics of a completed design including motors.

Unless the table is really meant to float.

[Clyde]

No, not meant to float......

I'm creating the model as I find parts (on ebay or whatnot).

Right now, I'm trying to find what I'll be using for leadscrews. I have one bid on ebay for the Y axis, but.....haven't won it yet. I've had trouble getting the acme rod or ballscrews for a reasonable price at the size I need. I have lot's of woodworking equipment, but no metalworking equipment for turning down the ends of acme rods for bearing mounts, etc....

I just got my used thomson rails and pillowblocks in yesterday, their in pretty good shape, the 36" rods aren't tapped for mounting to the supports (guess you have to make sure you ask every possible question before buying used equip.) even though I bought both from the same guy over the phone after doing a "Buy Now" on the 18" set for the Y axis. Now I've got to find a machine shop that can tap those case 60 rails.

more to come ............

[georgebarr]

In my opinion, the bearings and rods will allow some un-needed movement. I had this experience after using 1/2" dia. Thompson pillow block bearings on my Z axis. However, the length of the rods on my Z axis is about 27" so it might not matter for smaller machines. I am planning to buy THK bearings since I feel they do not have a lot of play or un-needed movement.

My bearings has a feature that compensates for misalignment. However, this feature allows for x,y,z axis to wiggle some instead of being sturdy.

This is just my own opinion.

Thanks,

[ger21]

George, after looking at your machine (thread here http://www.cnczone.com/forums/showth...&threadid=2865 ), I would guess your "un-needed movement" is from that big router hanging 2 ft below the gantry. You have a big lever, which doesn't take much force to twist the gantry beam.

Clyde's, on the other hand, does'nt extend beyond the y-axis shafts, so it would take much more force to get it to flex. A more compact, and sturdier design imho.

George's machine is a good example of the trade-offs involved when trying to make bigger routers.

[Clyde]

George, Thats a nice monster machine

When I first started the Y Axis/Z Axis model, I realized that I would have to give up some Z Axis travel to prevent the lever action from being too great. I still hope that a 4" travel will not be too much (may reduce to 3-1/2").

I was going to make the Z Axis 4-7/8" (8-3/8" rail minus the 3-1/2" long TWN8OPN pillowblock) But I didn't like the looks of the lever this created against the Y Axis rails. I think my intuition likes the distance between the Y axis rails to be 2 x the length of the lever created by the Z axis at it's lowest point.

[Clyde]

After looking at the view of the rendering above, I see that I can spread the Y axis rails out so that the center of the rods (ends of rods in picture) align with the ends of the Z axis rods and get more support.