Replies

1. 
   calvin | Feb 04, 2012 05:20pm | #1

   Andrew

   I'm having a bit of a struggle understanding your attack,

   but if you use a factory edge for anything but somewhere to lay the sheet on, you might not end up with 4 sides square.

   Flipping / turning a sheet might only compound the  "slightly off" nature of sheet goods.

   The best bet would be to make a straight cut, then square off of that for the next cut.  A perfectly set sliding table on your saw will take a nice 1st and produce a perfect 2nd.

   Add to that the usual knicks and dings and maybe starting anything with a factory edge is chancy.

   Of course, you may be  applying this in a manner other than cabinet making.  Out in the field remodeling where tolerances allow, no problem. 

1. 
   andrew12 | Feb 04, 2012 05:37pm | #2

   I dont have a sliding table big enough to accomodate an 8 foot piece of plywood cut length wise. Any suggestions how to square my piece after the straight cut. 

1. 
   DanH | Feb 04, 2012 05:54pm | #3

   A good cutting guide and a sharp, true circular saw will give you a nice, straight edge.  Though for 8 feet you should somehow clamp or "buck" the guide midway to prevent flex, especially if it's a 2-piece guide (which is true of virtually all long guides).

2. 
   calvin | Feb 04, 2012 06:46pm | #4

   Well,

   The track guide system is the ticket.

   In leu of that, a shootboard.

   After your straight edge cut and then ripping on the table saw to the proper width-

   Make a shoot board that has a perpendicular rail attached that is SQUARE to it's guide.  Lay that on the ripped edge of your pc and cut it square.  The shoot board will be zero clearance, should help keep splintering to a minimum.

   If in fact I understand you.

2. 
   calvin | Feb 04, 2012 06:50pm | #5

   Andrew.

   I might have not understood.

   If all you want is two parallel edges, then yes-but I would use the rough cut (which of course will be true and clean and straight) edge run on the fence.  Now there's two pcs perfectly parallel.  Whether the ends are square to it is another story.  Remember, I mentioned hardly any plywood is perfect square-end to edge.

3. 
   DanH | Feb 04, 2012 07:30pm | #6

   How wide of pieces are you cutting?  If they're wider than will fit between fence and blade then you can't do the full job with just the TS.

1. 
   andrew12 | Feb 04, 2012 08:44pm | #7

   Thanks for your replies. I am cutting the 4x8 sheet  into two 2 x8 foot sections and then ripping them in half length wise on the table saw. 

1. 
   user-152047 | Feb 05, 2012 11:06am | #8

   Square or parallel

   You said square, that means a true 90 degree angle, if you want them parallel- same width at each end- use your straightedge to rip the sheets in half- 2x8. If you have a one piece, truly straight, straight edge then run that edge against your rip fence, to remove the factory edge. Only remove enough of the factory edge to get to unblemished ply. Then run that cut against your rip fence to get your final width. Another trick is to clamp a long straight edge to your rip fence, I use a 8 foot level, That helps to minimize any bow in the wood, also more accurate ripping. Use feather boards if you can. 8 feet is along rip unless you have infeed/outfeed tables.