Design v1: Walled Sides - Feedback welcome (weight bearing, cross bracing, design)

Sharon – it doesn’t seem like there is much to keep that design from racking. I’d hate to see you bump into it from the side a bit too hard and send that 500# milling machine over sideways. Perhaps extending the front horizontal pieces the full width would help, but I’d still be more comfortable with the first design.

James

I think diagonal bracing can really help to prevent racking too, but I don’t have experience building suck large supports.

Does being a civil engineer licensed in 2 states qualify me? :D

Strength wise, you’re more than fine. Compressive stress from a 500 lb load on 4 4×4 legs (49 sq.in.) will only be a little more than 10 psi, which is nothing. You may want to keep the plan sized so the feet on the machine are close to directly over the legs, to keep bending stress in the top to a minimum.

Stability is the real battle, though, and JamesVavra is right: the open side is weak. The shear panels on the sides are fine (with 100% glued contact between them and the legs), though on the back, I’d be inclined to drill clear through and use bolts, with T-nuts in the legs (or better, part #90955A123 from McMaster.com). I also think you’re going to need to do this on both front and back, and just accept that you can’t have drawers.

If you have your heart set on drawers, the first design with the bed bolts will probably be OK, but I’d agree here too: widen the lower stretchers as much as possible, filling in the gap between the lower edge and the floor. You would also be wise to use a hard wood (not “hardwood”, but hard wood) because resisting racking will generate high compressive forces between the tenon shoulders along the edges of the stretchers and the legs.

-- My broker promised me he would treat my money as if it were his own. Trouble is, he did.

Thanks for the feedback, as far as compression I am pretty certain I’m over building this, and JJ you are correct, once I have the dimensions I’ll aim to have the legs as close as possible to being beneath the machine legs to avoid sagging of the top. The racking issue I was not so sure about and apparently for a reason… back to the drawing board.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

Sharon,

Use the top design but for time sake, get rid of the MT use butt joints and use large lags(bedbolts)/glue (TiteBond III) for the joinery and then of course a Torsion box for the top…..it will be a tank…..

-- //FC - Round Rock, TX - "Experience is what you get just after you need it"

With a little more thought, I would change the joinery from Butt Joints to half-laps on the strechers. Glue and Screw and you will will have a very strong frame for your top.

-- //FC - Round Rock, TX - "Experience is what you get just after you need it"

The down and dirty way is to treat the table as if it was rough framing. You can use Strong-Tie products, available at any Home depot, in conjunction with lag screws or through bolts.

You can even up grade to the black powder-coat line if you don’t want the galvanized finish.

-- criticism: the art of analyzing and evaluating the quality of an artistic work...

Thanks for the ideas. dealing with half laps and torsion boxes would be quite an ordeal – time wise. as for the half lap – it wouldn’t take me much more time to just do M&T since I’m already setting up machines for joinery which is what I’m trying to avoid.

As for the Strong-tie. this was on the design table and I was considering using these to connect 4×4 post with 2 2×4s on the corners:

I just don’t care much for the house-under-construction look that it presents so was trying to make it a bit more visually pleasing.

I am currently going to modify design #2 as posted in the original thread slightly based on a previous base that I made which was quite strong and had no tendency to rack, and will repost.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

Regarding the top: my G0619 at almost 500lb managed to flex a triple pky of 3/4” ply so much it scared me. I would laminate up a sold bench top if that is an option.

Thanks Jon, that is actually the Mill that will be mounted on the workbench. after calculating the necessary materials that I need and time estimated to build it, I decided to fork over the $150 and ordered a metal stand for it that is rated at 2200lbs.

Are you running the mill manually? or have you converted it to CNC?

-- ㊍ When in doubt - There is no doubt - Go the safer route.