Spring, Sprang, Sprung ... Maple bowing... help

[earl wojciechowski]

I am ripping some maple and running into a problem. Not sure why it is happening and what to do.

Bought some 4/4 6" width maple, 9' long. Jointed one edge and face. Then ran through a planer until 3/4" thick. I have a nice straight edge to start with.

I am ripping the wood to a width of 1.25 inches wide. Flat, straight edge against the tablesaw fence. About 1/2 to 3/4 of the way through the rip, the cut piece starts to bow. I end up with a bow of 3/8 to 1/2" over the 8' length. Also, the piece being cut from is also now bowed. This has happened on two different pieces of maple. The bow is on the 3/4" edge, not the face (not cupping).

Any suggestions or thoughts greatly appreciated.

Earl Wojo

[Jeff Duncan]

That's pretty typical with maple....when you cut it your releasing internal stresses in the wood. Only way to get straight stock is to joint 1 edge, rip oversize, re-joint, re-rip and cross your fingers

good luck,
JeffD

[Peter Quinn]

Any suggestions? Rip to rough width first, leave 1/2" extra for jointing. NEVER flatten, straighten, and plane to final thickness before ripping into strips. This will almost never work with any species. You have disturbed the balance, the woods equilibrium is merely relative to its present dimension. Alter that dimension considerably and it will adjust itself. No coming back from that. Oh, and maple is so unstable I have actually seen it do a back flip on the bench while I was stopping to eat lunch. At least it felt that way.

Maple: Strong? Yes. Wear resistant? Yes. Heavy? Yes. Handsome? yes. Stable? Not so much.

[Mel Fulks]

Yep .As they said in days of old..... Right On!

[Richard Coers]

Could also be a kiln drying error. Too quick through the kiln, or lack of conditioning can create internal stresses.

[Mel Fulks]

I will not say that there is no such thing as improperly dried lumber ,but I will say wood movement is normal and moulders are fine for some things ;but when wood has to be straight there is no substitute for a skilled workman looking at what the wood is doing and making decisions to control it. The specific case cited is consistent with maple and working with rough sawn pieces as individual pieces is the only good way to straighten them. I have seen shop owners rely on s4s machines to make door parts and such and it does not work. Platinum is expensive because it ain't like wood.

[Rick Fisher]

I live on an Island and as such, we battle humidity here .. If I bring hardwood, ( especially maple ) .. home from the store and cut it .. it usually goes like a banana ..

I buy the wood, store it in the shop for a week .. let it " climatize " .. And its usually always stable.

I can buy a board, rip it and watch it twist. Take the same boards, stack them for a week, then rip the same pieces and they are 90% better.

[Bill White]

Yep! Tension wood, moisture, blah, blah.
I have had this happen with walnut that was cut 40 yrs. ago.
Bill

[J.R. Rutter]

I have seen shop owners rely on s4s machines to make door parts and such and it does not work.

It works fine if you approach it as a skilled worker would: rip oversize, crosscut where needed, choose which face to run down and which edge to run against the fence. It just isn't practical to process a couple of hundred board feet per day any other way.

Agree that just shoving long strips through will just give you slightly smaller strips with the same shape!

[Mel Fulks]

If it works for you that's good. For those who have asked for technique suggestions using jointer and planer I doubt they would see improvement with moulders .A large job of exterior shutters we did varied in length from 8 ft to 3ft they were made of Hon. Mahogany.The boss ran the parts himself through the moulder.He then declared 18 percent of them to bowed or crooked to use. Since more of the long ones were rejected than short ones his actual material loss was about 45 percent. I remember when no one could have done something like that without being fired.As to what can be done in a day, cell phones and radios have slowed things quite a bit. Toy slow feed machines are a factor too.My "don't work " statement was too sweeping....but I did say "I told you so " on that shutter job pretty accurately .

[J.R. Rutter]

Yeah, it is hard to finesse an 8 footer on the moulder!

[jim gossage]

We've all been there. I think what you're talking about is crook, not bow. Crook is along the edge, bow along the length of the face, and cup across the width of the face. Acclimating the wood and picking very straight grained wood can help to minimize this. If a perfectly straight piece is mission critical, the joint-rip wide-joint-rip method should work. Often, however, the crooked piece can usually be straightened out w careful clamping and gluing, esp if it is narrow.