So I built this folding workbench a while back and the extra working space has been so good. I can pack it away by my sheet-good storage to get another car in the garage workshop, and I can haul it down into my basement whenever I need to do some room-temp work over the winter.
(pardon the dust...)
Problem is, over time it has developed quite a bit of racking motion. I thought about it some, and I think it's because the wood has shrunk since I bought it. Particularly the cross-member I pointed out with the arrow above. This allows the legs to splay out further than 90-degrees, and the stretcher on the bottom was originally sized for less motion than that. Plus, when it racks, it seems to be putting a lot of torque on the cross-member just above the one with the arrow, and the only thing preventing it is a couple screws into the end grain on that board. So... not a great design. I see this design everywhere on pinterest, youtube, etc. I'd love to know how others are faring. But for me, I need to address it.
I put the lower leg cross members on the inside of the legs - this made the stretcher shorter. But it also prevents me from installing anything underneath, like an angled cross-brace.
So I cut the cross braces out and screwed on some new ones to the outer side of the legs. This had a minor issue, it blocked my nice handles on the aprons, so I cut them a little short and angled them to retain portability.
Now I need to make the folding angled braces. I want to put them on the inside of these new cross braces and mount to the underside of the top sheet of plywood. Kind of like this:
Does anybody know if there are any geometry restraints to keep in mind when designing a folding cross brace? Like does the hinge need to be exactly in the middle of the brace, or do I have some leeway? Considering the amount of force that's possible to go through these pieces, I want to make them out of hardwood, and I'd rather not waste a bunch trying to figure this out.
I'll be getting back in the shop in the next few days or so to start trying stuff, but any thoughts are welcome!
Only thing I can think of re. the brace hinge is that it needs to fold flush, which usually means that it needs to be sliding or pivot such that the hinge center of rotation is close to the legs pivot axis. Could you hinge the braces to the lower leg crosspiece and have the other end register in a pocket or pin to a bracket on the underside of the top?
Yep that was essentially my idea here. The more I think of it the more my brain hurts though, so I'll probably just end up trying a few things to see what works.
Spent a little time thinking this through last night. I'm just going to put a bracket/bearing piece on the leg cross member, and another on the underside of the table top, and have a cross brace split in the middle with another hinge.
I'm going to leave one side of the angled member about 6" long so I can pin it through the other side to lock it straight.
Not you. I copied and pasted from my Google photos page and apparently they didn't get uploaded to Craftisian, rather linked from Google, and Google didn't like all the traffic. Guess I gotta stop being so famous 😉
