New skirted frame idea

Looking for a critique from experienced users before I build my first frame. I want to be able to use the full 4’x8’ cutting area, so I will build in skirting. I was thinking of a way to make the skirting adjustable to different thickness cutting materials, which has some challenges and adds to the setup time, but then I thought instead to have the skirt height fixed and adjust my cutting material to be flush with the skirt.

For my frame I plan to use plywood or MDF permanently mounted, mainly to stiffen the frame, then a spoil board over top of this, then my cutting material. For the spoil board I like the idea of XPS foam, because it’s cheap and lightweight (although messy when cut). It is also readily available in different thicknesses (I hope foam dimensions are pretty true?), so by keeping a few different foam boards on hand I can cut different thickness woods easily and always keep the wood flush to the skirt.

1/4” spoil board + 1” cutting material
1/2” spoil board + 3/4” cutting material
3/4” spoil board + 1/2” cutting material
1” spoil board + 1/4” cutting material

My only concern is the foam or cutting material being bowed and not aligning with the skirt well. But maybe the weight of the sled will help keep it flat where cutting?

Any thoughts on this project?

Take a look to this idea

I like that idea also. Will do something similar if I don’t do the fixed skirt route.

I would just make a simple 2x4 frame, add some slots, and some twist knobs so you can adjust them on the fly. Only really need the 2 sides and bottom skirting. You can print all the way to the top without tipping I think. You could even go all mcgyver and put notches in the slots for preset thicknesses of material. So it snaps into place so to speak.

Here is what I did

Here is the post where I described my build. I have more pics if anyone is interested.

Skirt is 2 thicknesses of 1/2" ply. I can choose from 1/4", 1/2" or 3/4" stock, with corresponding thickness of backer to bring stock to level of skirt.

Caveat: I have NOT run my machine yet to test how everything works out, but the machine is built to show that it can be done.

Can’t wait to hear how it runs. That is basically the same idea I had.

Any more pictures of the frame assembly? I see a lot of pocket holes there.

I need to get my garage in order, set aside some cash for material, and cut the final sled. The Raspberry Pi works with Web Control (thanks to some awesome tech support from Madgrizzle), the machine was calibrated at one time, but I played with the RPi on another project and need to get it hooked back up and going again.

I have plans to build a 12’ torsion frame top bar and a big rolling workbench with cubbies and drawers based on a Paulk workbench. I think I posted the Maslow build pics back in July, so its time for me to get off my rump and get cutting and building. Now that the 100° days are finished here in Cen TX, maybe it will be more pleasant to spend time in the garage.

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Also curious what size your made your ‘pocket’ for cutting material. I was planning to make mine slightly oversized, to accommodate MDF, which typically comes 49”x97”, but wondering if the gaps will be an issue when using 4’x8’ plywood.

Mine is just barely (1/4" +/-) over size for a sheet of ply. Probably a bit small. I suggest sizing it just oversize for a sheet of mdf, at least enough to get fingers in to pull out the sheet.

As long as the workpiece is flush with the skirt, the sled should ride over just fine without wobble. After all, the sled is huge compared with a 1" gap, so don’t be afraid to give yourself some practical wiggle room for manipulating sheet goods. Just make sure the surface of the sled against the workpiece has nicely rounded or beveled edges so it won’t catch if the skirt is slightly higher than the workpiece.

Someday I may have to rebuild my frame, I will make it bigger to accomodate mdf.

Here is a quick sketch of my frame I am planning. Any feedback would be appreciated.

The center section is a 4x8 sheet of half inch plywood, meant to be permanent. Not shown is whatever thickness spoil board I want to use. The 8" wide skirt is made of two layers of 3/4" plywood, resulting in a surface 1" above the permanent board.

The frame also gives me enough room to store extra plywood sheets.

Just looking again at your design, Jim Timple, I could probably get away with only four triangle uprights, instead of five.

The top bar is a 1.5" steel tube I ordered from MetalMaslow. Not shown are casters, and a flat plywood bottom to support the extra sheet storage.

Just for clarification on my design, I decided to show this photo. Sorry for the terrible angle. It is, after all, attached to the wall so getting the whole thing in the pic isn’t possible.

As you can see, there are no middle supports under the backer plywood. I literally attached the frame 2x4’s to the backer plywood with pocket holes. It was a bit of a PITA, but it works.

You can see the gaps on the skirt, I had Homey Depot cut 1/2" ply into 6" strips, then I cut my pieces to length. I left the gaps so that I would have a gap between stock and skirt. Skirt is glued and screwed, then screws removed to avoid potential bit mishaps. I would recommend giving yourself at least half an inch gap, maybe more, than your largest anticipated stock piece. I can’t change mine unless/until I rebuild.

The other thing I did on my design was to leave lots of room between the skirt and the top of the frame. That way, when I build a long torsion box top bar, I can play with the height of the top bar.