First time build - Steel Frame CNC Router

[Clive S]

Examorth The board that you linked is the pmdx Is an excellent BOB but for the best results it will need a motion controller like say the Ethernet smooth stepper as the PP on pc's these day are flaky to say the least. There will be more support on this forum with Mach3. Good luck with the build.

[DigiSoft]

You can check out my thread I am almost finished with my machine.
It is 90% steel

http://www.mycncuk.com/threads/5237-...LD-please-help

[examorph]

Dean - Thanks for clearing things up for me, I will be doing some aluminium work on it but was going to go down the route of using a mist rather than flood cooling, will this still be OK with the ply wood sealed base and spoil board setup? Also, probably a silly question but what are the typical depths for the ply wood base and spoil board? Just checking as I want to make sure I leave enough space bellow the spindle.

DigiSoft - Thanks for the link, I remember seeing it previously. Really nice buildd!

[JAZZCNC]

Provided you seal very well then yes with Low qty mist then yes Ply will be fine. Problem then comes from your Spoil board. Even Low volume Mist still creates mositure which gets into spoil board which isn't sealed. Often MDF is used for spoil board because it's cheap.

Really if your planning on using any wet kind lube often, even with air, then you'll want something that's resonably stable.

Depths are usually a multiple of sheet sizes so 18 or 25mm etc.

[cropwell]

I had a resin impregnated board on the floor of my trailer. It seemed indestructible. I was wondering if that would make a good base as it is waterproof.

[routercnc]

Going back to your sketch in post#19, I would extend the side pieces forward so it matches up along the whole side of the X bearing plate. You can then pickup another bolting point on the front X bearing between the 4off vertical bolts for the X bearing.

This side piece extension would be triangular in shape and fill in from the top of the gantry down to the end of the X bearing plate.

It would then (optionally) be triangular back out to the ballnut mounting point, or just go straight back.

This would provide much more support for the gantry onto the bearings for not much effort (apart from a bit more material).

[examorph]

Dean - Cheers for the advise. I swapped over the carriages for the narrower ones on the x axis and drew up the frame as per the setup you recommended using 4mm external rads on the section. Only thing I added was the box section running along the back (between the two x rail support sections) to let me mount a bearing for the belt onto (same as yours on post #7 here).

Routercnc - Thanks for the great idea, I updated the design with the following adjustments:

• Extending the plate 20mm short of the full bearing plate to keep standard sizes (200mm width x 300 height)
• Instead of being triangular back to the ball mount, I made rectangular cutouts on each side as any other way caused it to clash with the aluminium x axis ball-screw bearing supports and as a result, reduce working area.

I am going to try get access to a mill for this, but if all else fails are there any other options for cutting the steel plates?

Attachment 17424Attachment 17426Attachment 17425Attachment 17427
Gantry weight (just side plates and box section) is coming out at roughly 17.5kg @3mm wall thickness. When put together with Z axis, spindle and motors, will this handle OK with the one 3.1Nm motor on the x Axis?

Also, I checked the z extension using the 25mm tall bed/spoil board and the below image shows the spindle end going slightly into the bed at full extension. Would it be worth changing the 100 x 50 box section under the x axis rails to 120 x 50 or maybe higher?

Attachment 17428