Design for an Aluminum T-slot Bed?


(Travis Good) #1

Anyone know of a Shapeoko equivalent of this t-slot bed project?


(Dan Nelson) #2

At one point I was thinking about doing that using this extrusion:
https://us.misumi-ec.com/vona2/detail/110302261820/?Inch=0
But I never got past thinking about it. I’ve since bought individual t-slot extrusion and plan to screw it to the waste board with spaces in 2-4" spaces between filled with MDF strips.

Dan


(Rick Miller) #3

Seems like it may be easier to start with an MDF bed with just the holes to mount it to the rails. Then cut slots in the bed to accept t-slot track. You can decide what kind of spacing you need between tracks. Leave the tracks just a bit short of the length of the slots to leave room to put t-nuts in or take them out. Or, just slide 4 or 5 nuts into each track before you mount it. I could see the need to add an extra slot and track on each side and in back beyond the reach of the CNC in case you need to mount something that covers the bed. Those you may need to do off the CNC machine.

As an alternate you could just mount t-slot tracks side by side all the way across the bed. The advantage of that is that, if you happen to gouge a track, you just remove it and replace it with another.


(Reiner) #4

I am playing with the same idea as Dan. I would like to replace my MDF baseboard with Misumi HFSQN4-15250 extrusions, but have no idea yet how to fix them to the Shapeoko 3 frame… transferring the drilling pattern for the stock mounting holes to the extrusion might require a lot of milling if the holes do not line up with the slots in the extrusions exactly.


(William Adams) #5

Would a Shapeoko 2 suit? That’s where it got its start:

http://www.reddit.com/r/shapeoko/comments/2rt948/spent_the_afternoon_cutting_aluminum_on_the_s2/cnj9ia5

See https://www.shapeoko.com/wiki/index.php/Parts#Structure

I looked into this a bit. The problem is the machine is sufficiently larger that one can’t just use front–back rails, plus the lips of the rails interfere, so one has to lift them up so as to be able to load workholding bits. The extrusion also adds up quickly and becomes a budget-buster (for me at least) — basically you’d do something like to the front-back cross straps, add in some side-to-side structure, and put holes for bolts to hold it all together.

I cheaped out and just added a spoilboard and the shortest lengths of T-track I could justify (really should have made them at least a clamp’s length longer — back to front would have made using larger stock easier).


(Dan Nelson) #6

This is roughly what I plan to do with the t-track, if I ever finish my 10,000,000,000 other projects, haha!

Dan


(Phil Thien) #7

When I was studying the table issue (on my standard SO3), I had figured it would be neat to:

(1) Remove the spoil board.

(2) Repurpose the mounting holes for the spoil board to run three pieces of t-track parallel to the x-axis. Use some spacers underneath these three pieces to make sure the top of the t-track is just a smidgen (that is machine-shop lingo right there) above the front and rear plates of the Shapeoko. This will require drilling/countersinking holes in the t-track to a fair degree of accuracy. Doable, but requires some thought. Maybe I wouldn’t have to countersink, I guess it would depend on how the screws fit.

(3) Stuff each piece of t-slot track with at least a couple of nuts.

(4) Now run some additional t-track front to back of the machine (parallel to the y-axis). The bottoms of these pieces sit on the top of the t-track you ran on the x-axis. Drill each piece with three holes that correspond to the location of the X-axis t-slot pieces.

So what you would have is, t-slot that can be repositioned left to right. You just position it where you want it, then snug the screws. Then place your workpiece on top, and add some work-holding clamps.

Think of it as t-track tic-tac-toe, with three horizontal pieces instead of two., and the vertical pieces can slide and lock anywhere along the horizontal pieces.

The only thing that prevented me from doing this at the time was: (1) Didn’t have any t-track available. (2) Concern over flatness and deflection. I have found my MDF spoil board to be flat to within +/- a few thousandths, I think I can adjust the t-slot even better. And I think for my smaller unit, I can provide some additional stiffness under the x-axis t-track if needed very easily.

Edit to add: (1) Now that I looked at my SO3 again, I remembered the tops of the lower (x) t-tracks would not be able to be flush with the SO3 front/rear. So I’d have to add washers between the x and y-axis tracks, which is how I planned on shipping things “just right.” (2) On my SO3, the middle x cross-member could support two runs of track, and that is likely what I’d do for additional flexibility.