Pt? If you mean pressure treated, I dont think so. Hell, they could be made of foam, wouldnt surprise me!
I have a cheapo menards compound miter saw, my Dad's got a table saw.
Ya pressure treated, we aways just say pt, lol! Just as another FYI the Lowes kobalt 12” chop saw is only $250 and is a great saw for the money, we bought 2 about 5 years ago at $299 and we left in the box, and the other gets tons of use and has been really durable, we have had several dewalts an this has been a good unit!
The easy way to make the tapered part is to make a bunch of oversized square blanks, like if you wanted the taper to be 4’ tall and be 12” at the base and 6” at the top, make 4’ by 13” blanks, they need to be consistent, you can always make them bigger and run both sides through the table saw several times to get it parallel, and make sure all them are the same by the end, i also like to make a couple spares in case I make a mistake! Lol
Now the jig...I use a peace of plywood, it needs to be larger than the finish base size, so something 18” by 5’ is nice. I like to set the saw at 46° to have a little more back cut and let the outside of the miter be tight, now run the 18” peace through the saw only cutting the minimum off, now you have your cutting edge of the blade referenced, next you need to mark the taper you want on one of the blanks once you have that marked, line up that line to the cut line you made on your 18” sled, temporarily clamp it in place, then screw a 1x4 4’ long to the opposite side to keep it from moving and one on the push side of the sled, I usually put a screw top on bottom of the blank to hold it down, or you can make other ways to hold it down, have done it several ways, but am trying to keep it simple, lol, and you will cover up the the screws with trim anyway.
Now you can run all of you blanks through. Now you need to reset your jig or make a new on if you desire, now you take the first peace that you had you lay out lines on an do the opposite, if you are a little scared to commit, you can always mark a parallel line on your taper and like you jig up to that, then check the results, if you happy but it’s too big simply narrow the fence and keep making passes until you get the width your looking for...run the rest of the blanks, now you have tapered and mitered blanks, I prime and painted them including the edges, it makes things last longer, once dry I assemble them in half’s, makes a jig to help that as well, a peace of plywood with 2 boards screwed at the angle, this allows you apply glue are adhesive caulk to the seam and use finish nails to hold it together,then you can take assemble the two half’s around the post. You need and inner frame to secure to, but that’s pretty simple
