Skate-o-rail (patent!)

[budP]

la_coterie
Nice design, would you post the patent number for the bearing?
budP

[Kipper]

pmsl...I'll wager the makers of this design may object. Jet Rail.....Pat Pending was the nutty Professor in Whacky Races...Wasn't he?

[M1K3]

I hope the setup works as good as it looks. Im using the setup in my new design..

[vojnik]

Originally Posted by M1K3 I hope the setup works as good as it looks. Im using the setup in my new design..

Hello
If the cnc is made of wood you will have big problems with banking/deformation of the gantry from side to side. You should make the gantry support much higher and even better if you put a support at the bottom of the gantry.

In an aluminium cnc you will have same problem but it´s much smaller.

[M1K3]

Hey thanks for the input! The machine will be made of steel and will have a bottom support as you have drawn. My last cnc I built was wood and suffered terribly from the problem you speak of. Im trying to lighten up the machine significantly as Im not sure how much weight the skate-o-rail setup or the 1" bars will handle..

[vojnik]

You can make the gantry support higher and have the same weight if you put some holes in it. Just an idea.

If you want to calculate the deformation in the middle of the bars you can use these formules.

deformation in your unit = (F*L^3) / (48 * E * I)

E(steel) = 210000 N/mm^2 or 135483600 N/in^2

I(solid bar) = (pi*D^4) / 64

I(pipe) = pi*(D^4-d^4) / 64 D=outer diameter, d= inner diameter

If L = 30", D = 1", F= 100N about 10 kilos or 22 lbs

I = pi*1^4 / 64 = pi/64
deformation(in) = (100*30^3) / (48* 135483600 * (pi/64)) = 0.00846" or 0.21 mm