Torsion box for a moble table saw base?

[Nathan Dekens]

Well im still rolling around ideas in my head of how to setup my 2-car garage so that I can use it as a shop then put everything away when the car needs to be parked. An idea that I have is to take my Granite top ridgid saw and put it on a 8ft long by 3 to 4 ft wide moble base with a router table and fold up out feed table. I came across the torsion box design when I had seen the recent thread on the ultimate work station. Now my question is would a 8ft x 4ft torsion box made from plywood skins and an MDF core be able to handle the weight of the granite saw (500lbs) and the additional 100-200 lbs of router table and out feed tables im going to throw at it? This thing is probably going to be close to 1000lbs when its finished.

[Tracy Hall]

Well im still rolling around ideas in my head of how to setup my 2-car garage so that I can use it as a shop then put everything away when the car needs to be parked. An idea that I have is to take my Granite top ridgid saw and put it on a 8ft long by 3 to 4 ft wide moble base with a router table and fold up out feed table. I came across the torsion box design when I had seen the recent thread on the ultimate work station. Now my question is would a 8ft x 4ft torsion box made from plywood skins and an MDF core be able to handle the weight of the granite saw (500lbs) and the additional 100-200 lbs of router table and out feed tables im going to throw at it? This thing is probably going to be close to 1000lbs when its finished.

Hi Nathan,

I hope it helps, but I am building the same project at home right now for my R4511 saw. It's only 6 1/2 feet long instead of the 8 feet you are building, but the torsion box only deflects down about 1/16 of an inch when my dad and I stand on it (about 425 pounds). Here is what I drew up in SketchUp. I used 1/2 mdf for the bottom and inside of the torsion box and 1 1/8 sub-floor plywood for the top skin. I also designed the torsion box to accommodate room for 2 more casters in the middle if sagging is a problem.

Tracy

[Nathan Dekens]

Wow! pretty awsome! Would love to see pics when your done with the project and hear about what you would change and/or keep the same. How thick did you make the webbing in the box?

[Tracy Hall]

Wow! pretty awsome! Would love to see pics when your done with the project and hear about what you would change and/or keep the same. How thick did you make the webbing in the box?

The webbing is 3" with the 1/2" bottom face for a total of 3.5". That way I could face the MDF portion with some 1x4 poplar. But I changed my mind and used plywood instead. I don't remember exactly where I got the size, but it may have either been from a video of David Marks or Mark Spagnolo (woodwhisperer dot com) on building Torsion boxes.

I'm lucky if I get 30 minutes a night to work on it, so pictures might take a looong time :D. I'm still in the process of cutting down the bolts for the casters (got them too long quite awhile ago) so they don't hit the casters when they rotate.

One change I would make right now is to put the top on the mdf sooner than I did. I left it sitting in the garage too long and it warped at bit. I thought no big deal, because the bottom of the torsion box would straighten it out. Wrong :( (naive thinking?) The subfloor actually warped the torsion box a little bit. Good thing I put it on with bend up. Currently the base is about 1/8" higher in the middle than the ends. I'm hoping that all of the weight of the saw and the boxes will flatten it out a little bit.

Tracy

[Lee Bidwell]

Tracy,

Cool concept. It looks like you are removing the saw cabinet from the factory legs. Are you still using the OEM dust ramp, or did you do something different? I'm interest to know how the saw cabinet is supported.

thanks,

Lee

[Tracy Hall]

Tracy,

Cool concept. It looks like you are removing the saw cabinet from the factory legs. Are you still using the OEM dust ramp, or did you do something different? I'm interest to know how the saw cabinet is supported.

thanks,

Lee

Hi Lee,

I decided to build a ramp instead of using the OEM ramp for two reasons. 1) so I can build and move the saw once instead twice (once to remove the ramp for measurement, second to move the saw to the new location), and 2) so I can enlarge the 4" hole in the back to a rectangle that has the same area as a 6" diameter pipe in case I decide to upgrade my dust collection later. The attached picture is my current idea (side removed). The ramp is removable (from the front) so I can bolt the saw to the box (I hope). Still haven't decided if I'm going to seal the edges of the ramp with silicone. The dust box is only 6" high so as to make the table saw about 36" off the floor.

The saw will be supported by 3/4 plywood on top of 3 vertical plywood sides, left side, right side, and back. If it's a problem I can always add another board in the front near the front of the ramp.

I'm also having a problem with the left front corner caster that came with the saw. Whenever I try to move the saw, it doesn't lift that corner. I have to lift the front corner while trying to move the saw. Not fun.

Tracy

[Lee Bidwell]

Thanks Tracy. That should work nicely, and I think it's a good idea to plan for a 6" dust port. Keep us posted with your progress.

Lee

[Josiah Bartlett]

As far as strength goes, the taller you make the torsion box the stronger it is, with the same material for the top, bottom, and webs.

[Ben Hatcher]

My tablesaw with router wing is in a torstion box. My webs are 3" if I recall and the skins are 3/4 osb. I cut holes in the bottom skin large enough for my casters to be mounted inside the box. I screwed them into the bottom side of the upper skin. This way, when I roll it around, the low sides push cords, hoses, etc. out of the way of the wheels. I mounted two toggle clamps to the front of the box that do a fine job of keeping it where I want it.

[Erik Christensen]

My table saw base torsion box is 3/4" MDF top/bottom with 1/2" ply webbing - overkill I know but I wanted it to be RIGID. I recessed the casters so as to not raise the table height too high. Saw is mobile but really needs 2 people to maneuver around. With saw plus extension table & cabinet full of stuff it must weigh 1,500#+ and base has no noticeable deflection (when it rolls over a dip in the concrete floor the caster lifts vs base flexing).

[Nathan Dekens]

Cool rig, by chance do you remember the dimensions of your webbing? 5" square?


My table saw base torsion box is 3/4" MDF top/bottom with 1/2" ply webbing - overkill I know but I wanted it to be RIGID. I recessed the casters so as to not raise the table height too high. Saw is mobile but really needs 2 people to maneuver around. With saw plus extension table & cabinet full of stuff it must weigh 1,500#+ and base has no noticeable deflection (when it rolls over a dip in the concrete floor the caster lifts vs base flexing).

[Erik Christensen]

Nathan - spacing was not even due to some of the odd shapes driven by the saw footprint & casters but max was 6"