Dialing in wide panel cuts

[fastfoodkills]

Hi Folks,

I'm in the process of dialing in the final dimensions on birch plywood 3/4" panels that will be used for a shop cabinet and was wondering if there was a rule of thumb for determining the go-no-go for trimming a wide panel? For example, using a combo blade (Hitachi 40 tooth), I'd like to use the rip fence to square and trim a 38-1/2" x 28-1/2" panel down to 38x28 - figure about 1/4 inch will be removed from each side. Normally I try to avoid using the short edge against the rip fence, but this project is too big for the SMT and I don't yet have a miter slot that could be used for a nice panel sled. A buddy told me as long as the wood held against the fence is wider than the blade it's ok, but I wanted to bounce this off of the folks here. Please let me know your thoughts on this.

Best Regards,

Tom

Saugus, CA

[JR]

I don't know of any rule of thumb, but I wouldn't have a problem doing the cuts you've mentioned.

JR

edit: come to think of it I did something similar today, but more like 26" x 18". Worked like a charm.

[jackellis]

I don't know of a rule of thumb either but perhaps one way to think about this is how easily you can safely keep the narrow face against the fence. Your board would be easy to control and keep against the fence. A 38x8 panel would probably not be safe, whereas a 12x8 panel might (but then you'd be able to use the SMT in both cases anyway).

FWIW, I have a dual miter slot table that I decided not to use. If you're interested, send me a PM.

[fastfoodkills]

Gentlemen -

Thank you for your input. Jack, I'll PM you on the miter slot.

Tom

[cabinetman]

Trimming that size gives you plenty of edge against the fence. Cutting on the table saw requires concentration towards keeping the stock tightly against the fence, and NOT to watch or look at the blade. "Keeping tight" against the fence means a smooth steady pressure, but not exerted to the point that the material is hard to push. Before you make your cut, determine where your hands will be placed throughout the cut.

Looking at the blade during a cut is a distraction.
.

[Gator95]

Normally I try to avoid using the short edge against the rip fence... A buddy told me as long as the wood held against the fence is wider than the blade it's ok,

The cut you described is perfectly safe as long as you have good material support and also can control the workpiece all the way through the cut. Cabinetman is right on- you should focus on making sure the piece is tight to the fence.

The bit about the piece against the fence being wider than the blade though is bad advice. I'd never try and use the ripfence to cut a 30x10" piece. The aspect ratio is important.

Personally, for a sheet good or panel where the part I'd put against the fence is less than 20", I tend to just use a crosscut sled.

Use the blade guard and splitter!!!!

[cgallery]

Just remember you aren't going to square a panel using the fence. If the panel wasn't square to begin with, it won't be square when you cut it down to width with the fence.

To square a panel you'd need to use the SMT, or a panel sled with miter slot.

[Black wallnut]

Tom, you might also want to use both a ZCTP and a blade with a much higher tooth count to finish cut your panels. I use an 80 tooth blade myself. Cuts come out looking polished. The 40t. combo blades are useable but you may find that you get less chip out with more teeth.

[SARGE..g-47]

Agree with CB.. Gator and CG's point of you have to have square side on the side that initially rides the fence. I consider this cut to have te most potential of kick-back of any I do on a TS. In 37 years not counting pieces flying straight back which don't concern me as I don't stand in the lane... I have had 5 kick-backs and 4 have resulted from this cut.

You have to concentrate on keeping the stock flush against the fence. If you don't the friction of that much surface on the TS top will tend to twist the stock and if the stock touches those rear teeth.. it rides up the back of the blade and then no Tom Tom can determine the direction from there.

I use a spring-board (feather-board) to the left to help provide positive pressure against the fence along with strong pressure directed toward it by me. With a wider panel.. this is the only cut I am forced to stand to the right of blade which I prefer not to do. But.. after having 4 gut shots in the past.. I wear a leather apron and a coat over that briefly just in case.

If you have a BT as I once did.. you can add a feather-board to the ST by drilling a hole in the feather and runnning the miter bolt through it for this particular task.

[Tom Miller]

For panel squaring cuts in particular, the use of a riving knife/splitter makes a world of difference in the safety of this cut. (Hmmm, trying to think of a cut that doesn't benefit from a RK....)

I think some responses assume you're using a RK without stating so*, so bear that in mind.

Regards,
Tom
*except for Gator95!

[Black wallnut]

For panel squaring cuts in particular, the use of a riving knife/splitter makes a world of difference in the safety of this cut. (Hmmm, trying to think of a cut that doesn't benefit from a RK....)

I think some responses assume you're using a RK without stating so*, so bear that in mind.

Regards,
Tom
*except for Gator95!

Yeah what Tom said! When I had a kickback a few years ago a riving knife could have prevented it. A picture of the ruined panel is here.

[SARGE..g-47]

For panel squaring cuts in particular, the use of a riving knife/splitter makes a world of difference in the safety of this cut. (Hmmm, trying to think of a cut that doesn't benefit from a RK....)

I think some responses assume you're using a RK without stating so*, so bear that in mind.

Regards,
Tom
*except for Gator95!

I agree with you and Mark's confrimation.. some of us (me at least) did assume since he had a BT 3 unit.. he was using the RK.

Good call ump....

[pelligrini]

(Hmmm, trying to think of a cut that doesn't benefit from a RK....)

Not too much benefit with a dadoe stack.

[fastfoodkills]

Thanks for the info folks. Really appreciate it. Black Walnut, that's a scary looking kickback. I had this happen to me once in school about 10 yrs ago when I touched a table saw for the very first time. Instructor explained kickback, etc., but I missed a key point - never take your eyes off of the fence. It was a **** of a kickback on an old Rockwell saw. Fortunately no one was in the path of the board.

Cgallery - you raised a great point - if this panel is not square it's never going to be when I'm thought trimming it. Thanks for bringing that up. I'm going to have to rethink this entire cut before it's ruined and will seek out a finer blade, miter slot accessory and plan on building a panel sled. I've been using the saw off and on for 10 years and now the projects are getting bigger and more interesting. Guess I learn something new everyday.

Those new Festool and DeWalt track saw systems are starting to look really nice right about now. When they drop the price below a new table saw, I'll think about it.