To torsion box or not?

Hi everybody -

I’m preparing my workspace of the x-carve to arrive in the next couple of weeks and I’m going to take some time this weekend to get started on the bench to hold it. I’ve seen lots of amazing workspaces posted here which range from simple 2x4 and MDF to incredibly flat torsion boxes, and everything in between.

I’m inclined to build the simple 2x4 and MDF solution, but I’m wondering how much I’m giving up in terms of accuracy if I do that instead of going all-in on the fancier table. How much difference will it really make?


Hey Mark,

I’ll be designing and building a torsion box for my setup. It’s one of the 100 projects funded by Inventables! I’ll post a link to the Easel file once I’m done with the design. I just need someone that already has their 1000mm x 1000mm X-Carve to tell me what the exact footprint of the machine is.

Since I obviously need the X-Carve up and running to make the torsion box, I’m going to have to mount it to something first (probably the other half of a sheet of MDF to make wasteboards). I find it a tad ironic that most things you need to make for your CNC machine require you to already have a CNC machine. Sigh…

Anyway, if you can wait a little bit, I’ll post the project and you can give it a whirl. My $0.02, and I’m happy to make change…


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Table stand is one of the most important factor for X-Carve. If it is not leveled, you will have big problems when you start carving materials. Yes several good people come up with ideas to make it looking interesting or portable even multiple use type things. I say keep it simple and as strong as posible. I wish I knew at the beginning. Straighting up and fixing it takes lot more job and money. Now my table ended up with 3/4" plywood (which worped in very short time), 3/4" MDF on top of it, still had to shave waste board to make it absolute. Just my opinion. You’re gonna make up your mind, either will have OX strong solid table or showroom looking furniture. No matter you’re doing, don’t forget to make side shelf under table for electronics. Good luck.

Hey Alan,

I learned a long time ago that if the framing isn’t right, you’re going to have problems with the drywall. This concept translates directly to the X-Carve. We’re dealing with 0.001" here, so wood warping is a huge factor. I once built a dining table with breadboard ends. During one year in Texas, the field expanded and contracted over 3/16" compared to the ends! Embarrassing…

Also keep in mind that you can have the X-Carve mill it’s own table flat. I don’t have mine yet, so I’m talking a bit out of my arse, but in previous endeavors, I’ve used the machine to determine the lowest part of the field, then subract 0.001", plug that as your Z depth, then mill the entire available field of the machine to that depth. It will make the surface flat to the spindle, regardless of how warped the board originally was, or how wonky it is to being truly level. This may be a process that has to be repeated from time to time (until you run out of wasteboard).

I think the best bet is to use a homogeneous/isotropic material like MDF, which of course has its trade-offs, like shear strength, but at least it should expand and contract symmetrically, leaving you with a somewhat flat surface regardless of environmental inputs. It is after all “waste”.


Hey Chris, I didn’t mean to offend you. I wish someone like you gave me enough warning at the beginning to have good bench. I’m talking about some people making same mistakes I did, didn’t take seriously. We were talking about this matter on anothet post, I was explaining how much level changes I have constantly and I made a joke said “I’m gonna put Granite on top of my table” everyone laugh, one of the guy said “It’s got to be matching color with my X-Carve”. And he wasn’t joking. That’s what I ment.

One needs tomake the distincion between “level” and “flat” and “twisted” or warped

The XC will operate in an off level situation just fine by I would say as much as 15-20 degrees. I may strain a bit going up hill at steeper angles but it should cut accurately.

Flat is the biggest key to consider. Mdf is porous and as such, will absorb moisture from the surrounding air via the cut edges resulting in very slight but measurable swelling along those edges diminishing as one moves toward the center. .

Manufacturing processes get it very close to truly flat, but variations exist and the environment will make it swell over time from humidity. Even if a finish is applied. Mine had a bowl type effect prior to machining it flat with a 1/2" router bit in the machine with a 1/4" collet.

Twist is one that torsion box addresses really well. take an otherwise flat surface grasp the front and rear edges and turn them in opposite directions…twist. A torsion box, if constructed carefully, has internal structure that resist the forces of compression on one edge and expansion on the opposite edge, limiting or eliminating tendencies to twist. Especially if the table is semi-mobile and the floor is not perfectly flat,the tables fram is going to introduce forces to the table top that can transfer to the machine.

I would suggest getting it as flat as possible in such a way that it stays that way and machine it as @midnightmaker describes. this will also remove the factory “finish” allowing the transpiration of moisture to occur more evenly across the surface resulting in it retaining accuracy for a longer period of time.

I’m under attack of Professionals. How did you understand I’m complete nob. :blush: I’m changing all Level words with Flat. Sorry.

I’d imagine it’d cost maybe 30 or 40 bucks to get a 16" x 16" (I’m getting a 500mm XC) sheet of 1/8" thick stainless steel. I’ve been considering building my table out of 2x4 and MDF and then going out with a sheet of stainless. It’d take ten minutes to cut through holes and countersinks in the steel so flathead screws could be fun in ~30 thousandths shy of flush with the steel surface. Would this be a more economical option than building a torsion box? Actually, I’m pretty new to machining; I don’t even know what a torsion box is…

Edit: OK, pulled some Google-fu, now I see. Honestly, between not having a nail gun, the cost of the cross member wood, and the tediousness of building a torsion box, I’d lean toward the steel sheet option now. Are there any glaring issues with this I haven’t considered?

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Not a bash Alan,

Just a clarification and personal experience and 20+ years as a hobbyist woodworker.

And I am far from a “perfeshonel” I used to be a noob too. Now i am a slightly experienced noob.

I built mine with screws and glue in an afternoon…

Noob not nob… see how noob I am. Well, after 40 years of work history with mechanical devices, very complicated machines, I decided to play with woods about six months ago. Until then wood was only splint on my finger. I found myself in wonderful world of creating things instead of fixing it. I wish I start this before age 60. Now watching and following you guys is giving me the best happiness I’ve never have. Thanks.


Thanks for all the advice, everybody.

@AlanDavis, I don’t think your granite idea is crazy at all. I’ve toyed with the idea of getting a granite remnant (don’t care how it looks) and making that into the worktop since it’s flat.

I think I’m going to focus on building a solid base and start with a simple MDF top. If that turns out to be insufficiently flat, I can always replace the top surface with something that’s more truly flat without much waste.

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I like the idea of a granite top, that would be excellent but too heavy for my cart.

I built my table out of 2x4 and 3/4" MDF, with MDF and 3/4" melamine glued together for the top. With 1-1/2" of glued-up material, it seems to be extremely stable and level. I added a trim to the exposed edges of the melamine and MDF, so hopefully that will minimize seasonal moisture changes.

I wanted to do a torsion box, but decided I’d rather have the space for storage inside since I have a lot of little mods planned for the table. I’m going to have to replace my wasteboard over time as it is, so I may as well just plan on flattening it with the X-Carve every 6 months or whenever I change it out.

I made a video on how to build my table, if you’re interested.


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@MarkImbriaco - I’m sure others have had plenty of success with your originally-mentioned plan (2x4 base + MDF torsion box) but having built plenty of torsion boxes, I wanted to provide the following:

If you’re going to commingle MDF with real wood, be careful to leave some separation between the two. For instance, instead of gluing the box to the frame, cut yourself some slots in the top and use not-completely-tightened screws to affix it to the frame. Kind of opposite to how a table top is secured to the base - to give the top some room to move. In this case, you want the frame to be able to move separately from the top.

The important concept here is that wood and MDF are going to react differently to changes in humidity. If you have the top screwed down tight to the frame, that frame will torque the top when the humidity changes…not good.

My setup is a quasi-torsion box (due to airflow needs for vacuum table functionality) made from MDF on top of a metal frame. I plan to use another MDF piece for the wasteboard to start…maybe hardboard or some other alternative if I find that the humidity is affecting the MDF.

Hey @AlanDavis, zero offense taken or meant. Just sharing my philosophy on building a proper foundation.

You guys bring up some excellent points:

  1. If you’re going with a vacuum table, then a torsion box design makes things a bit more complicated. I imagine that large diameter holes cut out of every cross brace to allow for air flow would facilitate that. It would also have the additional benefit of making it lighter with little loss of strength. The cross braces in my design will all be of plywood to optimize strength in all directions.

  2. One of the techniques I am planning on messing with is cutting dovetail joints. One of every two mating pieces will need to be machined with the board being clamped in a vertical position. I’m imagining a 12" x 1" slot in my wasteboard and some custom clamps in order to facilitate the process.

  3. With regards to the torsion box taking up a bunch of space - The height of the torsion box slats doesn’t have to be that high to provide rigidity. I haven’t cut out any prototype slats yet, but even if the torsion box is 3" high, compare that the the thickness of a two pieces of 3/4" plywood and a 3/4" piece of MDF. You’re now at 2-1/4", so not that far off. Also the additional weight might of all those plies might be a factor when designing the cart if your X-Carve is mobile.

Don’t shoot, I surrender.
I had no intention against what you do. I just try to tell him was “first think you must understand that, you need work bench which doesn’t warp or changes the shape”. You took it very seriously and made me look art attacker. I’m not. Matter affect this is not my occupation. I Manage 4 States and highly educated 58 Engineers. I start creating some goodies in my Basement for hobby to relax and slow my damn brain down a little. But I can see that good woodworkers are a little too sensitive and I have to choose my words more careful. Okay, you are good, what ever you did was outstanding, I wish I know as much as you know. I wish you’re close by to me, than I can buy you a lunch as forgiveness. Cheers.

So, can you tell me what is the main purpose to build Mobile station for X-Carve. Space saving, or storing when you’re not using ETC.

Yes, I think space saving and protecting the machine is the primary goal here. The X-Carve takes up a considerable amount of space, depending on which rail kit you choose, especially if you only use it part time in the shop. Even if you primarily use your X-Carve for projects, you’re still probably going to doing a lot of cutting of wasteboards and work pieces with your table saw. A lot of folks try to leverage that space in very interesting ways.

One guy ingeniously built his X-Carve into his table saw outfeed table to double his usage. Outfeed tables are extremely helpful with just regular table saw projects are a standard part of most semi-serious woodworking shops. He pops the top off his table saw outfeed table and raises his machine up out of the inside! He’s brilliantly using a drill to power a chain drive, I was thinking about attempting this with gears cut out with the new Easel gear generator.

Check out the video here…

Now that I think about it, if your X-Carve table isn’t doing double-duty, since most of our shops are cramped for space, then it’s nice to be able to wheel the machine out of the way when you’re working on other projects. Since the X-Carve is somewhat autonomous once you send the Easel file, you could theoretically move the laptop and X-Carve cart out of the way and work on other projects in the shop while it’s cutting…


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Exactly Chris, I put Table Saw, Router table, sanding station in same bench for that reason. But X-Carve bench taking most of the space I could use in my Half basement, (Other Half belongs to my Wife like every other assets in my home).
That’s clever idea. I’m actually following you from beginning. Good job man. Hope to see more.

Alan, you buy me lunch and I’ll buy you a few beers (and one for me too!)

If you were in mechanical engineering you got me by a long shot. I am a self described wood butcher and know just enough to e dangerous.
That’s why I heat the shop with a wood stove, to hide the evidence! :blush:

As for being mobile I have my XC in a corner and if i need to get to the far rear corner, all I need to do is pull it out for acess. It also works for the workpieces that exceed the cutting area as i can extend them out the front and back and use the “tile” function in vcarve pro.

@joec makes a valid point hat i had no considered about different materials and differing rates of movement. unfortunatly for me I am already glued and screwed down top and bottom.
Time will tell if I am hosed too. maybe my diagonals will help…