cutting panel angle

Message

yahtzee · #1 Post by **yahtzee** » Thu Nov 08, 2007 9:34 am

getting ready to start a pair of T48's seeing one of the panel angles is 56 degrees, what is the best way to get this angle cut

loaferz · #2 Post by **loaferz** » Thu Nov 08, 2007 9:46 am

I think in the plans, Bill says that you can fill any imperfections with PL. Just cut the wood to fit, maybe get the angle as close as u can, sand it a bit, and fill the rest with PL.

Mark Coward · #3 Post by **Mark Coward** » Thu Nov 08, 2007 10:08 am

loaferz wrote:I think in the plans, Bill says that you can fill any imperfections with PL. Just cut the wood to fit, maybe get the angle as close as u can, sand it a bit, and fill the rest with PL.

That angle is in the front, if you don't get it close it is a lot of sanding and difficult to get it even. It makes more sense to cut both of the joining panels 17º adjusting their lengths as necessary. Not only is the 56º angle difficult to cut, no matter how close you get it there will be sanding and filling to blend in the angled ply edge with the smooth outer ply of the horn mouth. Two 17º angles results in a butted joint, much less work to get a smooth finish. Definitely what I will do from now on, having done it the other way.

(I amended my post based on Dave's convincing math for 17º, the principle is the same - cut two smaller angles instead of one big one)

DAVID_L_PERRY · #4 Post by **DAVID_L_PERRY** » Thu Nov 08, 2007 10:15 am

If you have a table saw you can lift the panel up on some packers to gain a little bit more than the 45deg that the blade gives you, but it wont give much. I got it as close as I could and allowed the PL to work...

the other option is to split the difference between the two panels (5&6) so each panel is then cut with an angle of 17deg angle (90-56 = 34/2 = 17)

I didn't do this as I wanted panel 5 to extend straight to allow a recess for my transit cover:-

So I had to go with the 56deg angel - or as close as I could get...

Dave

yahtzee · #5 Post by **yahtzee** » Thu Nov 08, 2007 10:25 am

seems like there are a few different ideas on angles....maybe trying a few different things on scrap first....thanx for the quick responses

brodave2 · #6 Post by **brodave2** » Sat Nov 10, 2007 9:38 am

when I was building my omnitops I used a piece of straight scrap, about 3/4" thick by 2" wide. I used a couple of drywall screws to attach it to the edge of the piece that needed the steep angle, the strip wider than the panel to be cut. I stood the panel up with the scrap against the rip fence, and away I went. Last few steep angles I've done on my titans, I just stood the panel up and held it against the rip fence. You really don't need the angle though, the PL will fill the void between the 45 degree angle and what it should be, you'll have less than an eighth of an inch gap on the wide side. When you sand it down it will look like just another layer of the plywood. I use a 4 1/2" right angle black and decker grinder I got from walmart with a rubber backing pad and heavy resin backed sanding discs to do my sanding. You have to be careful when the discs are new, they'll cut the panel. You can take 1/8" off 1/2" plywood in one swipe if you're not careful. After you hit a couple of drywall screws with the disc, they settle down a little. The same disc will level any drywall screws going through like they were butter. The grinder sells for about $50, and it's worth twice that.