Weird problem with panels

[Mike Schueler]

I haven't had much shop time in the past few months, but recently I've been trying to build a pine toy box for my little guy.

I've built the panels for the front, back and sides and flattened them with a hand plane then sanding. Then I measured the diagonals: not square.

I did what everyone would do in a similar situation: cut more off!

The short version is I can't seem to get the panels squared up. Right now, they are about 25 inches by 35 inches (front and back panels). The diagonals are about 1/2 inch off. However, when I measure the length it's essentially the same all the way down -- 35 inches. The I measure the width, and it's all about the same as near as I can tell with tape measure.

I think what I am doing wrong is using the fence for both length and width cuts, but I don't have a cross cut sled. But anyway, if length and width all are the same, and the sides look parallel, wassup? How can I fix this without a cross cut sled?

THanks.

[Joe Scharle]

Well, you're right about the fence. It will accurately cut square trapezoids as well as square rectangles.
I would lay down lines on the panels with a framing square to get a picture of what I am looking at and go from there.

[David DeCristoforo]

Your panels are "parallelograms". They measure the same top and bottom and the two sides are the same length but they are "racked" out of square which is why the diagonals do not measure the same. You don't mention, however, how you are trimming the panels. If you are using a table saw with a miter gauge and your panels are out by a half an inch, something is seriously out of whack. But even with everything adjusted properly, accurately crosscutting a 25" wide panel with a miter gauge is going to be "iffy". You state that you don't have a crosscut sled and the question begs to be asked... Why not? It is very easy to make one. Needless to say, you would also want to determine that the miter gauge slot is parallel to the saw blade.

[Paul Ryan]

Mike,

David is right, if you are trying to cross cut a 25" panel with a miter gauge "good luck". My suggestion use a nice big framing square and figure out what corners are not square. If you dont have a cross cut sled build one before you go any farther, you will thank yourself. Other wise if you really want to get the toy box done before you take on something else. If you have a circular saw clamp a guide edge down and cross cut your panels that way. The panels will have a much better chance of comming out square with that method than using a miter gauge to cut that large of a panel. I cross cut large panels with a circular saw, 40t freud blade, and and guide for a long time before I bought a table saw worthy of a cross cut sled.

[Mike Schueler]

OK, it's the replies I was afraid of...

Anyway, using a square pretty much all the corners are off.

I guess I haven't built a sled yet because I hardly have time to build fun stuff, but I have the plans for the "ultimate" one in Fine Woodworking, so I guess I'll be ordering some stuff for it.

BTW I hate my circular saw and use it only when necessary.

[Rick Hubbard]

How can I fix this without a cross cut sled?

THanks.

Hi Mike-

Here is one possible solution (that I have used myself on more than one occasion).

Using a large T-Square (one like used for drywall would be fine) scribe a line across the panel at each of the long edges. Next clamp a piece of stock (with a known straight edge) right on each of the lines. Then flip the panel over and take a router with a flush trim bit and let the guide bearing run along the board/plywood you clamped on each end of the panel. The end result will be a square panel, but it will be slightly reduced in length.

One more thing- be sure to clamp a block against the outfeed edge of the panel to avoid tear-out.



If you don’t have a relatively robust router or if you have a less than razor sharp bit, it might be a good idea to trim some of the material from the panel with a hand saw so that the flush trim bit doesn’t need to take a very big bite.

Rick

[Paul Ryan]

I guess I haven't built a sled yet because I hardly have time to build fun stuff, but I have the plans for the "ultimate" one in Fine Woodworking, so I guess I'll be ordering some stuff for it.

Mike,

You don't have to build a fancy cross cut sled, just about anything will work. Check out Norms panel cutter, that is basically all you need. It would only take you about an hour if you have the materials on hand. I didn't go that all out on my cross cut sled. It is basically a piece of plywood on 2 hardwood runners with a rear and front fence. It can cut upto 25" panels. Anything larger I still use my circular saw. The hardest part is cutting the hardwood runners that slide in the miter slots to the perfect fit. Norms plan is super simple and you could always build something more advanced at a later date. But I have a feeling once you build norms design you will use that for years and years.

[Cary Falk]

I never had much luck dialing in a sled. I have the incra sled now and I can fine tune it with the mitergage. In the past I he squared up panels by the router/ flush cut method and the circular saw/ straight edge method. I have also used a jointer. If you set the infeed table depth at the amount that it is out of square on the fat edge, you can lower the thin edge onto the edge of the outfeed table just past the cutterand proceed as normal. I wouldn't do any more than about a 1/16 at a time.
You have to do a normal pass to clean up the ripple you have on the leading edge.

[Darrell Bottoms]

Mike,

You don't have to build a fancy cross cut sled, just about anything will work. Check out Norms panel cutter, that is basically all you need. It would only take you about an hour if you have the materials on hand. I didn't go that all out on my cross cut sled. It is basically a piece of plywood on 2 hardwood runners with a rear and front fence. It can cut upto 25" panels. Anything larger I still use my circular saw. The hardest part is cutting the hardwood runners that slide in the miter slots to the perfect fit. Norms plan is super simple and you could always build something more advanced at a later date. But I have a feeling once you build norms design you will use that for years and years.


Happen to have a link to Norm's sled plan?

[Paul Ryan]

I am sorry I don't have a link to his sled plan. When I wrote that I was worried that someone would ask. It is a super simple design with 1 miter gauge slot runner, a piect of plywood and a small rear fence. It was from the episode Jigs #0101.

[harry strasil]

Just take a piece of plywood big enough to lay your panel on and using your router, cut a 3/4 groove a half inch or so farther from one edge than the distance from the edge of your miter slot to the saw blade. Cut a 3/4 hardwood strip about 6 inches longer than your sled slot and glue and screw it in place. make sure it slides in the slot with the saw blade retracted, then raise the blade and make a cut along the edge. Now using your framing square, making sure it is square to start with and with the tongue on the edge you cut, clamp it to the sled and glue a piece of 3/4 on edge for a stop to hold the panel against. You now have a crosscut sled in about a half hour.

[Vince Shriver]

Quick and dirty fix: take a piece of pre-cut sheet goods (ie 24" x 48" ply or mdf) from the BORG and tape it to the panel (use the good double sided carpet tape). Have the new piece flush with one edge, making sure it does not hang over the adjacent edge at any point. Using the new piece as a guide, route the edge that isn't flush. You now have two adjacent edges square, so do the same thing with the two remaining edges, aligning the piece with one of "squared" edges. Pre cut sheet goods are usually square, but it good to check before you use it as a template.

[Paul Atkins]

I have squared up stuff like that with the jointer. If the ends are parallel. mark the sides where you want the line to be and creep up on it like you would if you were making a taper. Another way is to shim the corner on the sled so the piece is square with the blade and cut it.