My d8 14a winch cat had a small 2" round canopy. I've turned away from shoving several trees from the fear of a top crashing down 70-80' right into my lap or worse. I've removed the 2" pipe and bought a trailer of 4×4 .250" wall tube and plan on a full wrap around the tank from 1/2" plate. The canopy will bolt together for removal. Im interested in is anyone's input. #1 our late D6c canopy has 5' of operators clearance at entry-level, I was thinking about 5.5" #2 i plan on 45° about a 12" section with braces on the top rear instead of a radius bend. Same with sweeps. #3 im thinking three pillars per side on main canopy, six total. like our 17A medford canopy. Its a pretty long span. With bolt on 1.5" stretch screen on rear and sides. From you're experience, how would you build a canopy for PNW winch cat for clearing and skidding?
Look on the internet for pics. of old aftermarket ROPS on D8's. Might be cheaper to buy one. A few examples here. There has to be a lot of them out there in equipment scrap yards. Caterpillar D8 Heavy Equipment & Tractor Cabs For Sale | MyLittleSalesman.com
You materials list looks to provide plenty of strength for what you wish to do. The big problem is what are you going to attach it all to. A 14A has thin fenders and the main frame has few attachment points. Those early canopies were light for a reason.
As John C said, newer machines with certified ROPS have thicker fenders and underneath the fenders are heavy 'L' brackets that are welded to the main gearcase/framerails underneath the fenders below each rops mount to support the whole works
We were also looking at that issue with our D4D - We have a tube-lok ROPS canopy, but the anchor points for that canopy relied on the paper-thin fenders, leaving us doubting whether it would actually hold as a ROPS. If you look at a number of cats from that Era, you will see the ROPS had a sub-frame that bolted to the frame of the dozer, often on the same points a winch or ripper might bolt to. I would go to a couple of auctions and study the construction of the rops on some older dozers to get an idea of how to lay the box tubing out. If you beef up the fenders and put gussets under the canopy mounting points, it should handle a tree landing on it (how well is another question). I would also put corner gussets into the upper corners to strengthen the connection to the main pillars. Make sure your welds are perfect.
#1 - a little extra height should matter too much. #2- you probably don't even have to worry about the bend at all - a number of newer canopies just go with a 90-degree butt weld, with just a touch of overhang for a sun shade #3 - Four main pillars is all you need to provide falling object protection. The third "pillar" is typically just providing a mounting point for brush grating covering the operators station. Grating is typically a coarse mesh with 1.5-2 inch openings - think gravel screen.