Can I rip cupped board?

[Dick Holt]

I have a few cherry boards that have cupped. Worst case is about 3/16" across a 9" wide board. Can I rip this on my table saw to remove/reduce the cupping? If so, cupped side up or down? Thanks for your help.

Dick

[Peter Quinn]

I'm not advising you to do it, but I do it all the time. Its not without the risk of a kickback, so a splitter is a good idea if available. I evaluate each piece based on its cup, and most twist a bit to go along with it, but generally I like to rip cup up. Do make sure you have one jointed edge to ride the fence. If you have a BS. it is a better way to do this in most cases.

[Guy Mathews]

Have to agree. A band saw is a safer way to do this. Tablesaw will work but kickback and binding can occur. Cup up will allow the board to fall down in most cases so binding is less likely to occur but it can still occur.

[jim gossage]

I agree that bandsaw is the safest way to go. If you try the tablesaw, I would somehow attach the board (clamp or screw), cup up, to another board to carry it through the tablesaw. the carrier board would ride true against the table and the fence and minimize kickback or binding.

[glenn bradley]

Risk of kickback is too great for me. Bandsaw, jigsaw or handsaw.

[Joshua Layne]

having done this today on a couple of huge pieces of 12/4 cupped poplar and bogging the blade down multiple times and scaring the cr@p out of myself more than once, use a bandsaw. seriously.

I was a moron to do it and was lucky I wasn't hurt.

[Dino Makropoulos]

I agree that bandsaw is the safest way to go. If you try the tablesaw, I would somehow attach the board (clamp or screw), cup up, to another board to carry it through the tablesaw. the carrier board would ride true against the table and the fence and minimize kickback or binding.

good advice.:cool:

[Rick Potter]

I have done it, but I wouldn't try it without a splitter. If you don't have one rig up a quickie with a nail or something. There are a lot of sites that show how. Open part of the cup UP.

Rick Potter

[Mike Cutler]

3/16" is really not all that bad. It can be done on a TS. Cut with the cup up, and put it on a carrier board or adhere a shim piece to keep it from rolling on you.
You're going to have to joint and re-rip it anyway, so a circular saw and a straight edge, or a snapped line, could be used to do the initial cut

[Dan O'Sullivan]

having done this today on a couple of huge pieces of 12/4 cupped poplar and bogging the blade down multiple times and scaring the cr@p out of myself more than once, use a bandsaw. seriously.

I was a moron to do it and was lucky I wasn't hurt.

Joshua
That is good advise to act on. That TS will send that flying and it just isn't that much trouble to bandsaw to the line. Safety is the key.

[Richard M. Wolfe]

If you do it on the TS, rip with the cup up, as suggested. I would pull the fence away from the blade and run the board(s) across the table against the fence first without ever turning the saw on to see that they fed smoothly without any "wobble". The cup reduces contact with the table which leads to more unstable cutting.

[Frank Drew]

I agree with the majority here: Cup down rides better on the table but tends to pinch the blade as the cut completes, increasing the chance of a kickback; cup up is safer, ultimately, and it's how I always did it and never felt it too awfully risky.

If you've got a bandsaw, that's probably your best bet, and in that case I'd cut cup down, for stability.

[Todd McDonald]

having done this today on a couple of huge pieces of 12/4 cupped poplar and bogging the blade down multiple times and scaring the cr@p out of myself more than once, use a bandsaw. seriously.

I was a moron to do it and was lucky I wasn't hurt.


This is good advice. I stalled 3hp pm2000 on 12/4 cupped poplar. I crapped my pants, now I use a jigsaw.

[Glen J. Peterson]

I agree with the group. I still have all my digits but I've taken stitches from kickbacks. Use the bandsaw and save you fingers. If the cup isn't too significant, face joint the board first and that eliminates the problem related to ripping on the table saw.
Glen

[Thomas Pender]

I think the group is dead on.

I would almost never cut cupped lumber with a table saw - way too dangerous and often a hidden cuase of kickback. Another positive in ripping with a BS is that you might be able to save more of the wood once you cut it and put it back on the jointer. Another thought - depending how long you need it, there is nothing wrong with cross cutting it first. Finally, it is important to support the piece as it comes out of the BS and my wife and teenager have always been real helpful about things like that - excellent reason to have a couple of rollers. I typically use a 1/2" blade (or bigger) - 3 tpi for something like this and take it easy.

[Heath Markovetz]

Either my jigsaw is sorely lacking, or you all have the patience of a saint.

I'm pretty sure I'd not even hesitate to do that on the table saw. Maybe I'm still young and dumb.

However, if I had access to a full size bandsaw, I surely would prefer to use that tool.

[Mike Archambeau]

Perhaps you whould consider using a track saw. My Festool TS-55 has a riving knife on it. If you support the board you are cutting on a sheet of polystyrene (commonly used for insulation) it will give you the proper support, but minimize binding.

[Rich Engelhardt]

Perhaps you whould consider using a track saw. My Festool TS-55 has a riving knife on it. If you support the board you are cutting on a sheet of polystyrene (commonly used for insulation) it will give you the proper support, but minimize binding.
I cut some cupped material w/my TS55EQ about two months ago.
It was some 3/4" B/C plywood I was using for I forget what. Not that it's final use is any matter.
The plywood was 48" wide and I was using the 55" guide which was secured to the plywood using the Festool clamps.
I'd also clamped both the guide and the plywood - using the Festool clamps - to the cutting table, which lessened the amount of bow in the plywood.

Being 48" wide, the 55" guide had about 3.5" on each end of overhang.

Roughly 3 to 3.5" into the plywood - something bound and the saw came back at me.
Even though I was off to the side, the base of the saw hit me square top of the leg just below waist level.

The only thing that save me is/was the fact that the TS55EQ is a plunge saw & the blade had retracted.

The lesson learned here is if you're doing something "iffy" like ripping bowed material, allow enough overhang of the guide to use the anti kickback device in the Systainer.
or
Use the DeWalt that has the anti kickback device built in.