Tim Brennan said:
Thanks guys.
Yes I was more concerned by my ability to follow a pencil line. I have a dts 400 too which may come in handy.
I'll try clamping a piece of wood
Tim,
Clamping a guide board to sheet goods or whatever is a time-honored method for making a straight cut. It can produce acceptable results IF the material to be cut is smooth and flat, and IF the guide board is straight and smooth, and IF you can successfully hold the saw flush against the guide board for the entire length of the cut. That's a lot of "ifs".
Before I started using Festool saws and guide rails, I tried that method. Unsuccessfully. Perhaps you can do it, but I found that the cut line wandered as I started stretching out for parts of the cut.
One of the keys to Festool saws is the guide rail. With the guide rail, a large number of variables are removed. The cut line is dependent on where you place the guide rail.
For square cuts, I use a Woodpeckers 12" Woodpeckers Carpenter Square. (The 12" Precision Woodworking Square will work fine too.) One side is placed on the edge of the material and the other side is against the guide rail. There are other, faster methods for repeated cuts, but this method has served me will for several years.
You may want to consider buying a Festool guide rail and the Carvex Guide Rail Base:
http://festoolusa.com/power-tool-accessories/jigsaws/carvex-bases-and-inserts/guide-rail-base-for-carvex-jigsaw-497303 . I have a Festool Trion jig saw with the guide rail adapter. I've used it several times to make rail straight (pardon the pun) cuts.
Good luck with your project.
Regards,
Dan.
p.s. I've been thinking about a Carvex, but my PS300 (D handle) Trion still works very well. If I ever buy the Carvex, I'd probably get the accessory kit too. At $200 it's pricey, but all the accessories are in one place and always available.