Wood Table/Base Design Q's

[SixOfOne]

Well once again I'm waiting on tools/parts to arrive so I started contemplating my table/base again.. My table is only going to be around 5' x 5'.
I was planning to just order the metal and weld it up but I think I can do it cheaper, quicker & square-er with wood.. I own a welder but that doesn't make me good at using it Not only that but I would have to depend on the cuts of my supplier to be correct (Already been down that road once this project).

I see a few builds on here that used LVL beams. Like this one and this one plans on it, are there any more? Zone search doesn't like "LVL" as a search term.

Anybody know what these beams cost? My local HD was less then helpful and never called me back.

Can I make my own? They look as though they are nothing more then glued up strips of plywood. How would/did you do it?

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[Devastator]

Can I make my own? They look as though they are nothing more then glued up strips of plywood. How would/did you do it?

I made the X rail supports and gantry for my Solsylva 24x48 this way. I just laminated birch plywood. Rather than go buy a ton of clamps, I vac-bagged them. I used slighty thinned Titebond 3 brushed on both sides of the bond. After they were glued together, I rounded them with a radius bit in the router and bonded and screwed on some steel angle for good measure. I had to put the radius because the inside corner of angle iron has a radius and it won't sit flat if you don't do it. I'd guess that the resulting beams have greater stiffness than extruded aluminum beams, and much better dampening.

[JerryBurks]

Not sure why you would want plywood. If the individual parts are more or less elongated beams for a triangulated space frame, the loads are predominantly in length direction. In that case you can use any regular wood profile you want (if you want to build a box with plane elements, that is a different story)

I built the cart of my CNC machine from regular 2x4 lumber (I did pick properly dried and straight pieces without knots). It does grow/shrink across the grain as any lumber but that does not change the geometry of the cart. Along the grain, the expansion with temperature and humidity is negligible, about as little as steel and less than aluminum. It is also cheap and easy to work with.

I do not have a good picture of the cart itself but below it is under the table torsion box. This is rigid enough that on an uneven floor it will rest (and wiggle) on 2 diagonal wheels only without warping the table (the finished machine is over 500 pounds). I did use Titebond and ample Spax screws.

[Devastator]

Not sure why you would want plywood.

In my case because thick laminates tend to stay straight while 2x6's warp, twist, and in some cases, split. I built my machine frame twice because of this "feature". It was straight and square when assembled, but totally twisted a week later. You should have seen the test cuts from the twisted gantry, totally horrific.

If I had to do my machine over again, I would not use any dimensional wood on it even for the stand.

I would have rather used bamboo though. I hear that works really good. My next machine will probably use bamboo or torsion box or a combination thereof with my homemade LVL stand.

They still use plywood for structural applications in aircraft, and rocket fins exceeding mach 3.

[SixOfOne]

All the dimensional lumber I have picked up at the HD is twisted before I got there, hard to find good stuff.

My setup is like the table in the first one I linked to. The table is part of the machine so flex and warpage will be bad. Once it is built and in place it will never be moved unless I do. The "Pro Desk" at the HD still hasn't got back to me and I have called them twice. I might have to call a buddy that is a contractor so I can use his account at the only lumber yard in town (they don't sell to GP, so they won't talk to me either).

At this point the price will be the deciding factor I guess. My local lumber supply consists of HD and Lowes, all the good lumber yards here died off years ago when big box's pushed them out. I would be ok with that if lowes and HD carried half the selection that my mom and pop lumber yard did 15 years ago.

I thought about using the stuff HD sells under the name "sandply" to make these LVLs, but to me its barely good enough for garage cabinets (thats what I used it for). It is flat as glass, light weight & cheap (30$ @ Sheet, I think). Extremely thin veneer on the outsides, easy to sand through by accident and tears on the table saw.

[SixOfOne]

Well just an update..

HD got back to me with some info regarding the LVL.

I can get them in 1-3/4" x 14" x 72" @ $6.33 per ft ($37.98)
They are from Bluelinx

[JerryBurks]

In my case because thick laminates tend to stay straight while 2x6's warp, twist, and in some cases, split. I built my machine frame twice because of this "feature". It was straight and square when assembled, but totally twisted a week later. You should have seen the test cuts from the twisted gantry, totally horrific. .......

Sure I can see that happening. Building a machine frame or gantry from such studs will lead to trouble. I was only talking about the cart structure. What I meant is if you build a proper space frame with diagonal bracing it can be made dimensionally very stable. I did not buy the wood at HD but at a lumber yard with well sorted quality.

[SixOfOne]

I think "table/base" wasn't the best choice of wording, frame would have been better. For a table top machine I agree this would be overkill.. Like in your machine Jerry the frame is (I'm guessing) a torsion box of bamboo. How is it attached to the rolling 2"x4" table?

My garage floor looks like it was poured on a Friday at 4:45pm. So rolling it around is out of the question for me (not only b/c of the re-leveling but I might get stuck in a gully never to be seen again, lol). The guy that poured my slab screwed the pooch so bad. In order for me to fix it I flooded the house with a fire truck, then let the water dry a little. Got a can of spray paint, marked the puddles, then waited again and repeated with another color. It looked like a topo map of the grand canyon. In the end I re-flooded the whole 1st floor with cement to level it out but never did the garage.

Here is a quick sketch I did to calc how many I need..



Stolen idea from bobmagnuson, if ya see this Bob, thanks

[Devastator]

Here is a quick sketch I did to calc how many I need..



Stolen idea from bobmagnuson, if ya see this Bob, thanks

Man, that is nice. Getting ideas for my next machine. I like how he incorporated the ribs in the sidewalls. So how much do you figure it will cost you to build your base? Looks strong enough to pour self leveling concrete on.

[SixOfOne]

With 11 LVLs the "beef" of the table could be built, so $430-ish. Then hardware, skinning, bondo, primer & paint idk.. It would have to be skinned to add even more strength to the frame and doll it up a bit.

As soon as I have all the other parts for the machine built (or at least mocked up) I will know my final size for the frame. I haven't priced steel for a frame but by the looks of things wood will be cheaper.

[Devastator]

That's not too bad for price. I have a 48"X48" machine in the planning stage. I'll be watching your build.

[vtx1029]

I was going to build a LVL base but ended up going with 8020 because I found a place that sells used extrusion. You can check out my former plans http://www.cnczone.com/forums/open_s...3-crp_4x4.html

[SixOfOne]

Well yesterday I through together a drawing in sketch-up of a steel frame.
3" x 3" w-1/4" for the angle
2" x 2" w-3/16" for the bed and lower shelf
3" x 3" w-3/16" for everything else


Today I got a quote from my metal supply and it was only $400 for all the above (I was shocked).

I am thinking about getting a quote for it all in 1/4" wall.. I got the quote for 3/16" because I thought it would be the cheapest but still useable.

Do any of you think 1/4" wall is necessary?

[CarveOne]

I would recommend making the bed from 3" x 3" also. The lower shelf can stay as it is. It will need some corner bracing, two at each corner, either diagonal tubes or steel plate triangles. At least under the top corners. They may not be needed at the lower shelf.

[Devastator]

I liked the wood base better, only because I can't weld for crap. I found that the more steel I added to my machine the better it worked, but I'm not sure it is that critical for the base as long as it stays straight. I do know that wood has better dampening but if I was a good welder, I would use steel too.

Sorry I can't lend any experience to the wall thickness question.

[TurnTex]

I just bought the LVLs for my CRP4848 build today. I bought 1 3/4" x 14" x 16' LVLs from a local lumber yard for $121 each. I just finished jointing planing them to make them smooth and straight and then ripped them to 7" wide. My top frame will be double up 7" wide with single "joists" every 12" o.co.. My legs will be 3 pieces glued together to make a 5x5. I used to be a custom home builder and know the strength of LVLs and 7" wide would be plenty strong enough but I wanted to double them up for weight and mass. I will then have a bottom shelf for storage and will wrap the entire thing in plywood to provide rack resistance. I plan to put some doors in the side for storage and possibly my computer with a fan. I am also going to put in some drawers for tooling storage.

Just came in from the shop to eat dinner and am about to go back out and start putting it together!

[Devastator]

Just came in from the shop to eat dinner and am about to go back out and start putting it together!

Do you have a build thread? I'd like to see your work.

[TurnTex]

Do you have a build thread? I'd like to see your work.

I was not going to do one but have had a couple of folks asking so I started on here: http://www.cnczone.com/forums/cnc_ro...ral_texas.html

It will probably not be as detailed as many since I am the type that likes to jump in and get things done. Doubt I will remember to stop and take pics!