"Henge", 3 Axis Cnc, Fixed Gantry, Moving Table

[Greeny]

A half way to Robin's suggestion to reduce the overhang would be to place the Z screw outside the blocks so the risers (in red on "A") can be removed.

This would reduce the overhang by 30mm, but widen the Y plate by 75mm to accommodate the screw. Although some weight could be saved by having a cut out as in drawing C1
However the risers also serve to stiffen both Y & Z plates, so i'm not sure.

I would be interested to know anyones thoughts on this (or any other part)

Cheers

Note: The orange X & Y plates are 10mm steel guage plate it would be easy to up them to 12 if i removed the risers, only adding 4mm to overhang
Drawing B & C are the same just different angles.

[Greeny]

Sinking the rail blocks into the plates i think i could reduce overhang by about 16mm (8mm + 8mm)

I don't think i can reduce it further as the rails are fixed to the 2 outside orange plates and move with respect to the center plate.
If i sank the blocks any deeper the rails would interfere with the centre orange plate.
They move over the whole length of the centre plate so, if i went any deeper, i would have to put a groove in the whole length of centre plate weakening it.

Basically i'm saying the orange plates must be at least a rail height apart, so i could only sink them about 8mm each.
Or have i misunderstood?

Cheers

[Robin Hewitt]

If you can't do it, you can't do it. Picture shows it is possible. The white arrow points to a 1mm clearance between the X axis linear rail in purple and the 8mm linear Z axis shaft in yellow

[Greeny]

Thanks Robin,
However, am i right in thinking that's only possible when using unsupported round rails on z?

I think I'm probably interpreting your drawing wrong, as there's a lot of stuff there and I'm not sure how it all fits together in 3d, do you have a side on view?

Cheers

[Robin Hewitt]

What you could do is slip pairs of linear blocks on to two pairs of linear rails, lay two rails on top of 2 rails at right angles then slide the blocks around a bit and see where the metal of the Y and Z slides can fit in around it.

Does that make sense?

[Greeny]

ok, will give it a go, thanks.

[Greeny]

Aha!
I think i see now. Playing with two pairs of rails it took about 60 secs.
I will take some photos & do a couple of drawings later this evening. (i'm supposed to be working now... shhh)
Cheers