Replies

1. 
   EdWeber | Dec 09, 2021 05:17pm | #1

   I don't mean to sound rude but you've asked an awful lot in one post.
   There are plenty of books and articles with formulas and rations to answer your questions.
   In general, "strength" is a very subjective term, I think what you're after is stability. You basically want to keep your table from racking and don't want to use aprons if I understand correctly.
   If that the case, You're basically down to leg braces or stretchers. If you can only put stretchers on one side I would suggest top and bottom.

2. 
   jharveyb | Dec 09, 2021 07:36pm | #2

   Here is some info:
   1) For a 22"-24" long leg, the size is determined primarily by the need for enough meat where the leg is joined to whatever substructure holds the leg rigidly in place. Of course, turning it down to a 1/4" diameter dowel wouldn't work, but tapering from 1.75" down to 1.25" would be strong enough for the leg (if there is adequate size for the joinery.)
   2) The 1/75" thick top has enough strength to support itself between the legs without additional structure (aprons). A 3/4" top that big would need the vertical support of aprons.
   3) The real question is how are you going to attach and brace the legs? Assuming you are thinking of 4 individual legs rather than two slab ends, I would probably use 4" aprons mortise and tenoned into the legs, with one of them cut away with a nice curve to even as little as 3/4" width for much of the middle of one or both long sides. The remaining wood is to keep the legs located the right distance apart. To be honest, with the computer weight, I might also run stretchers the short distance between legs on each end, and one between the middle of the stretchers (H shape.) The stretchers don't have to be particularly large, just well joined to the legs and each other. I'm also thinking that at the height you plan, the table will tempt folks to sit on it, which could mean that extra bracing such as the stretchers would be helpful.
   4) The last question I would look at is just what makes sense from a design standpoint. Do skinny legs look good under a hefty slab of maple? A stretcher sized for a chair might be puny looking under a big table top. I probably wouldn't go as big as 3"x3", but legs 1.75" square would probably look appropriate. Stretchers would probably look good in the 1.25" range. Something to think and scheme about...

1. 
   andyfrog | Dec 09, 2021 07:57pm | #3

   Thanks for all this advice, I appreciate it.

3. 
   rob_ss | Dec 10, 2021 02:33am | #4

   200lbs???? Maybe in the 1970s. If your computer gear weighs much more than a tenth of that these days you're probably seriously overdoing it. It doesn't really matter as the top will likely weigh close to that too.

   Still, the best advice is to go and have a look at some tables that work for you in the shops and spot the characteristics. Generally, commercial furniture is very well designed to minimise material cost and simplify construction so it's a great starting point for something better. You almost certainly don't need anything more robust than your dining table.

   https://www.finewoodworking.com/videoworkshop/2019/07/danish-modern-desk-with-tim-rousseau is a great desk which should meet your needs. A few things help this desk to do the job - robust mortise and tenon joinery, the angle of the legs, and the lower stretcher all combine to make a desk that you know just from looking at it will be rock solid, yet is light and easy on the eye.

   As for your specific questions, that is a huge thick slab. It will need hefty legs to look right. I'd be looking at 75mm square legs. You could simply attach them to the top and if your joinery is precise it will be rock solid.
   I would:

   1. Undercut the edge to provide a less heavy edge.
   2. Round the corners.
   3. Use 75mm square legs with a taper on the inside edges.
   4. cut a 50mm square mortise inside each corner and glue the legs directly into that.

   An alternative to 4 would be to run a side apron between the 2 pairs of legs and attach the top to that. It's easier that way and may help to keep the top flat over time, though that is much better achieved with C track such as used by Cam of Blacktail Studios: https://www.youtube.com/watch?v=FqQUlLJOTMg
   Cutting the mortises exactly square requires a lot of patience and some skill. The tenons are best done using the speed tenon method on a table saw. Dominoes would be an excellent alternative if you have the device.

   Why not consider insetting a wireless phone charger while you are at it? Easy to do and fun.

   Best of luck.

1. 
   andyfrog | Dec 10, 2021 02:56am | #5

   Main desktop ~25kg
   Rendering box ~35kg
   NAS ~10kg
   Monitors ~10kg

   thanks for the suggestions