CNC bridge mill for cutting aluminum.

[RCaffin]

With some diagonal bracing - including on the legs of the table, that should cut aluminium just fine AND steel in moderation.

Cheers
Roger

[DICKEYBIRD]

Man, I wish I had your fluency with 3D CAD Pete! I can do it but it takes me way too long. Let me guess; you use it in your day job?

I like your 1st suggestion with the plate across the front better. I have enough 3/8" flat plate to do that but planned the other method to save some of it for other projects. Someone else suggested that as the bridge gains lots of weight, it increases the chance of a tip-over at the extremes of table travel. Ouch!

I presume that your suggestion with the pucks requires the pucks to be a snug fit inside the crossbraces and needs bolts going through them into the pucks on the sides as well?

I hope I don't need to add diagonal braces to the table as well Roger. I don't want to muck up that pretty blue paint. You may well be right but my SWAG engineering says I won't have to.

[vegipete]

... the chance of a tip-over at the extremes of table travel. Ouch!

Indeed. Hopefully you can bolt it to the floor.

I presume that your suggestion with the pucks requires the pucks to be a snug fit inside the crossbraces and needs bolts going through them into the pucks on the sides as well?

No, side bolts _may_ not be necessary. It just depends on how good a fit you can get between the pucks and the cross tube inside. For extra trickiness, put a slight taper there. (Just don't distort the cross tube where the linear rail goes.) The tie rods will hold it all together.

[DICKEYBIRD]

Indeed. Hopefully you can bolt it to the floor.

It's on 5" - 900 lb capacity (each) casters right now and I pretty much have to be able to roll it around in the limited space in my shop. I may have to build in some outriggers with extending feet to stabilize it. That's a ways down the road yet. It will have medium power steppers and it'll be used for cutting 1/2" - 3/4" alum plate. It's not like I'll be slinging around an engine block with 1000w servos.

[DICKEYBIRD]

OK, Rev. 1.11. (No CAD, gotta jump up & go fix Mom's plumbing.) What say ye engineers if I face front and back of the posts at the top with 3/16" plate? I can get a great deal on 3/16" x 12" x 12" HR plate so if I do that it would be a 12" piece on the left & right sides with a 6.75" wide piece in the middle with all 6 pieces held on by lots of bolts.

Oh yeah, to deal with high CG problem, 2 adjustable "wheelie" bars will be added on the bridge side so it doesn't tip over when I'm rolling it around and a caster jams on a piece of scrap.

[RCaffin]

Wheelie bars - really not sure I would ever bother. My machine is up on a stand too, and top heavy. I don't move it much!
Maybe just sweep the floor first? (My floor is ROUGH!)

Cheers
Roger

[vegipete]

Six plates like that seems reasonable as long as you can ensure a flat even base for the linear rail to sit on. If you can roughen the mating surfaces and bond the parts together that would be even better.

[DICKEYBIRD]

OK thanks Pete. It seems like a strong, simple & inexpensive plan to me. I really appreciate any & all experienced opinions. I don't want to make a really silly design decision at this stage! I finished my po' man's mag drill so today I start drilling & tapping some holes in that beautiful top!

Roger, you may be right that I don't need the "wheelie bars." My plan is to wait until it gets the heavy stuff on top & I'll shove it around & see what it feels like. If it's top heavy & unstable, "wheelie bars" it gets. It has to be moved around quite a bit for access to the stuff stored behind it.