Just a little side thought for building a layout:
When cutting out the various arcs of subroadbed for your grades or cookie cutter layout it can get a tad tiring pushing a jig saw while trying to hold a drawn line.
Plus the occasional need to change blades so the sawing effort comes from the sharp blade and not your muscle.
Something to consider, not too many folks are aware that it is very quick and easy to use a circular saw for cutting circles. It is much easier to follow the line and you can slice of a sheet of arcs in a matter of several minutes.
Couple of things to remember, use a new sharp small diameter blade, set the saw blade no deeper than the kerf between the teeth, block the sheet off the floor or table with sacrificial spacers, safety goggles and just go for it. You will be surprised how quick you can knock out a ton of subroadbed with nice consistent edges. You will need to have a firm grip and not kneel behind the saw. Always hold a circular saw to your side. Worm drive is the most stable circular saw IMO.
Depending on the grade and type of sheet goods chosen the edge finish and amount of chips flying will vary.
For perfect circles you can mount a circular saw on a trammel and simply guide it around. Inside circle edges clean up nicely with a 5" diameter 100 grit sander. The tighter the inside circle the rougher the initial finish.
I have lost my source for dished blades but I used to be able to buy dished blades for circle cutting. I am guessing too many folks simply use a conventional blade and the market was not there. With a range of ease any circular saw can be used. The easiest saw is the small DeWalt trim battery saw with 1/2" plywood. I find this to be the best application.
We did cut a very large layout with a load of 3/4" Birch using a 7 1/14" blade. Cut about six complete circles in a couple of hours.
Circular saws are not for the faint of heart.
