MDF vs plywood

[MilDoc]

I like the design of the power tool storage solutions in the new issue of Woodsmith, but it calls for using plywood. i have a lot of MDF (bought too much for another project) in 3/4 and 1/2 thickness. I was wondering if this would do for the cases and the dadoed shelves in their design #1, or would the MDF tend to sag on the removable shelves, or chip / crack in the dadoed case sides?

[cabinetman]

I don't get the magazine (unfortunately), but if you hold the lengths to a reasonable distance you shouldn't have a problem. An alternative would be to build the boxes as you wish and install the shelves on clips, that way if they do sag at all, just flip them over. Or, if you dadoe them in, and want more rigidity, glue a hardwood edge to the front and rear, like 1 1/2" high, and leave them short in length by the depth of the dadoes. IOW, if your dadoe is 1/4" deep, leave them 1/4" from the ends. If you use care in machining and handling you won't have chipping of the edges. I usually abrade a slight chamfer to the edges to be inserted into the dadoe so when they are inserted there is no real edge to catch or scrape on its way in.



"I'M NEVER WRONG - BUT I'M NOT ALWAYS RIGHT"

[Stormbringer]

I usually abrade a slight chamfer to the edges to be inserted into the dadoe so when they are inserted there is no real edge to catch or scrape on its way in.

That's how I do it. Big help to avoid chipping.

Greg

[MilDoc]

The plans call for slightly loose dados to make the shelves easily adjustable. But I think the idea of hardwood front & rear and chamferring the edges should work well.

Thanks again guys!

[niki]

I would go with Cabinetman advice, re-enforce the shelves with hardwood and mount them on supports so I can change the shelf location if one day I need higher space.

I think that it will be better if you make the carcass with one permanent shelf at the middle to add rigidity (depends on the length of the vertical boards).

From my experience, when you rabbet MDF, it tends to bow out (you are creating weak point and the “humidity effect” will do the rest), so strength wise, it’s better not to rabbet for shelves.

niki

[Pappy]

Since there are no long, unsupported spans in any of the projects, MDF should work finefor the shelves. The dados for shelves to slide into might be a problem. If you get them too deep, the remaining material could be too weak. I would cut them no more that 1/4", leaving 1/2" carcass material. The tolerances on the shelves are going to have to be close.

[radhak]

btw, that plan is just an abbreviated version of a very old plan from Shopnotes #9, where they have lot more detail - measurements, cutting list etc. Its also part of their give-away gift (with their SN subscription) 'The Complete Small Shop'.
With a max size of 15" x 13" for the shelves, a plain 3/4" MDF should do pretty good, without needing any edging support.

[MilDoc]

btw, that plan is just an abbreviated version of a very old plan from Shopnotes #9,

Thanks! I knew I seen a similar plan before but could not remember where.... gettin' older ... darn ...