Drawer box question

[RFGuy]

Dennis,

Overall impressed by all of what you shared, but I have a question. Forgive me if I misunderstand your setup apparatus. It seems to me like you are testing the worst-worst case here. I say that because aren't you applying a non-distributed load to the drawer bottom in your test apparatus? I know the scale is large, as is the piece of plywood underneath it, but it looks like you have a small block of wood to transfer the force from above to the drawer bottom under test. I am all for over-building and over-engineering things, and I don't know all of your plans for what will be stored in each drawer, but I kind of doubt you will have one large, heavy thing in the middle of each drawer. Am I wrong? I hope I am getting this wrong about your test apparatus, but I would just hate for you to over spend if it isn't necessary. I was shocked to hear you relay that even the 1/4" drawer bottom fails a 1/8" deflection test at 50 lbs, but then when I thought about your test apparatus it started to make sense. Of course, your real world drawer contents are never going to be uniformly distributed across the entire drawer bottom, but unless you have one small, heavy thing that rolls into the center I don't think you will ever see the conditions you are testing here. JMO.

P.S. Cabinet looks great as does all of your fixturing and etc. as always. I love your attention to detail and analytical mindset. Can't wait to see the finished result.

P.P.S. Also, very impressive work Chris! Thanks for sharing. Love your Festool wall as well.

[br549]

As for using 12 mm BB for the drawer frames, I’ve been wondering the same thing. After cutting the drawer bottoms from full sheets of plywood, I could still make all the frame components from the cutoffs. Does anyone know of any reason not to do so?

Beautiful drawers! In my limited experience of making drawers, I used 19 mm (nominal 3/4") 13 ply BB for the basic box, and 12 mm (nominal 1/2") 9 ply BB for bottoms and applied drawer fronts. The exposed edges of the plywood are aestically the only drawback of which I am aware to using BB in lieu of solid stock.

In my working days, we specified hardwood drawer bodies on our projects, and casework suppliers would frequently try to substitue BB, so it was common practice back then.

[dusty]

Joints to be proud of for sure!!

[BuckeyeDennis]

It seems to me like you are testing the worst-worst case here. I say that because aren't you applying a non-distributed load to the drawer bottom in your test apparatus?

Thanks RFGuy, your observation is spot-on (pardon the pun ).

I did it that way for two reasons. First, to be intentionally conservative. Second, and more importantly, because I didn't have much choice with that quick-and-easy apparatus implementation. Even with the small load pad I used, the straightedge has to be place slightly off-center on the test specimen, which means the measured deflection is a little less than the actual deflection. With some sort of large load-distributing pad, I couldn't even get close to the center. The bathroom scale blocks measurement access to the topside of the specimen (unless perhaps you could establish the compressive stiffness of the bathroom scale, and measure how far it moves), and my CNC doesn't have enough vertical range for me to elevate the specimen and measure its underside. So not wanting to spend a lot of time on this, I just followed the KISS rule.

[BuckeyeDennis]

BR549, you have erased any cosmetic reservations that I had about using BB for the drawer frames. Those drawers look fantastic, especially with the nice tight dovetails joints.