Tom,
With all of the joints in my table glued and with biscuits in each joint it is a very solid frame. I don't know what the plywood will do for you, except to add weight. Exact dimensions of the table aren't important either. Mine is about 30 X 70", mostly because I wanted it smaller than a 4 X 8 sheet. Bigger also adds weight, which I don't want or need. Adding a plywood surface doesn't buy you much and adds weight to the table, so I left it off. The 2 X 4 leg support pieces at each end of the table are spaced close enough together to support the circular saw between cuts, if the pieces of sheet stock being cut aren't large enough to hold the saw. The photos are actually of my first cutting table, made many years ago and the whole frame was made from 2 X 4 stock. A few years ago I decided that it was becoming too heavy for me, so I replaced the outer frame with 1 X 4 boards, keeping the 2 X 4 cross pieces from the original table. This removed about 15 lbs of table weight and made it much easier for this 76 yr old man to carry around.
When making each cut, I usually position the sheet so the cut will be roughly down or across the center of the table. This is to keep both pieces of the sheet stock from falling as the cut is completed. Gravity holds the sheet stock in place, and I clamp my straight edges to the sheet stock rather than to the table.
If I'm using the table along with my miter saw, I have a piece of plywood large enough to hold the miter saw (about 16 X 30" that I place on the center 2 X 4 of the table with the ling edge of it on the 1 X 4 at the working side of the table. I drive two screws through this piece of plywood into the 2 X 4 center piece of the table, and then place the miter saw on this piece of plywood. Long pieces of trim or stock yet to be cut are frequently placed on the table behind the miter saw until I'm ready to cut them.
There are two small pieces of 1/2" Baltic Birch ply attached to one side of my table (you can see them in the first 2 photos). These are each attached with one screw off center, so the piece can be rotated to extend about 2" above the table surface, or rotated 180 deg to be completely below the table surface. When I want to place a sheet of material on the table, I turn these tabs so they extend above the table surface and then tip the table over on it's side with these tabs down against the ground. I then place the sheet stock on edge against the table with the bottom edge of it sitting on these tabs. I then reach down and grab both the table and the bottom edge of the sheet stock and lift the table into it's upright position with the sheet stock lying flat on the table top. I then rotate these tabs so they no longer extend above the table and re-position the sheet stock so the first cut will run roughly down or across the center of the table.
I then measure for the cut and attach my straight edge, set my circular saw to cut about 1/4" deeper than the sheet stock is thick, and then make the cut. I don't use foam on the table top and just cut into the top surface of the table. Adding foam makes the sheet stock slide around too easily. If I ever make so many cuts into the top surface of my table for it to become weakened or just too ugly, I'll just make a new frame and move the Banquet table legs to it. I once used foam as a backer and cut my sheet stock on the floor, but my age and my knee replacements have all but eliminated my ability to work at floor level now.
If the sheet cut is made roughly down the center of the table, neither the piece nor the off-cut will fall at the end of the cut. I can then remove the undamaged off cut (because it didn't fall or break off) and re-position the remaining piece to center the next cut on the table, re-position the straight edge clamp and make the next cut.
In the third photo you can see my 108" straight edge clamp and the HDPE block attached to my circular saw that guides the saw along the straight edge. I have since made a HDPE guide that slides on top of the straight edge and the shoe of my circular saw is attached to it, positioned much like a track saw. This saw also has a piece of Lexan attached to the bottom of it with a clearance slot for the blade guard that also has a narrow slot for where the teeth of the saw blade rise up out of the stock being cut. This provides a "zero clearance" function that nearly eliminates edge chipping of the cut. I don't have a sacrificial strip along my straight edge clamp to reduce chipping, but this piece of Lexan performs the same function.
I much prefer my cutting table over saw horses for most uses and have almost eliminated
my desire to use saw horses completely, but I still use saw horses occasionally if I want to set up a temporary work table, or support a scaffold. For about every other application where I once used saw horses, I now prefer to use my cutting table.
For moving sheet stock I recently made a wheeled carrier out of some 3/4" cabinet birch
ply and a pair of large diameter wheels re-purposed from an old high wheel lawn mower I actually made two of these. The first had smaller lawn mower wheels and no handle holes for pickin it up easily. This was my second build and I much prefer it. The dimensions of it aren't very important either, but I used a scrap of 3/8 ply as well as a piece of 3/4 ply to widen the slot between the two sides and make it easier to use with any common thickness of sheet stock. Even the 1" Baltic Birch will fit in it.
In use, I usually place it roughly centered under the sheet stock, but it can also be placed under one end while you lift and carry the other end. With the blunt pointed ends of the center plywood spacer in it, you can just drop the sheet into the carrierb and it will right itself without the need to even touch it. The larger diameter wheels roll over my door threshold and rough lawn much better than the smaller wheels of the first carrier that I built too. I used the stub axles from the lawn mower too and just drilled holes in the flat steel plate that's welded to the axle to mount it to the carrier with a couple of long screws.
I also purchased a "Gorilla Gripper" to help me carry sheet stock, but found that it didn't do too well for 5' X 5' Baltic Birch ply mostly because I'm not tall enough at 5' 8". so I bought one of these.
https://smile.amazon.com/Stanley-93...527869653&sr=8-1&keywords=stanley+panel+carry Since it attaches to the bottom edge of the sheet, rather than the top like the Gorilla Gripper, I prefer it for carrying Baltic Birsh sheet stock. It works pretty well for 4 X 8' sheets too, and is much more reasonably priced than the Gorilla Gripper.
That's my driveway in the last picture, not the street. My driveway circles my house. My shop is to the right of the photo and my house to the left.
Charley