Resawing didn't go so well

[Charles Jones]

I'm working on a frame-and-panel end for a stand-along window seat. For the panels I had some 5/4 spalted maple and I intended to resaw it to

5/8" then clean it up to 1/2" thickness. The problem is that all the boards bowed outwards very strongly after resawing; about 1/4" of bow in the middle of a 19" cut.

My "post-incident analysis" (:-) is not reaching any firm conclusions about why this happened. Does spalted wood tend towards having such strong reactionary traits? Or, could there have been too much drift compensation in my bandsaw fence that might lead to such a result?

CharlesJ

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[charlie b]

Outside dry, inside less dry. Cut in half - one face dry, one wet - resawn board cups. Let it sit for a day or two and see if it flattens out.

(this one was discussed in an earlier thread on resawing problems)

charlie b

[Charles Jones]

Yeah, I saw that one. Maybe I misread, but I was under the impression in that case that the cupping showed up a short while *after* the resawing took place. In my case the bowing took place during the cut with the inside one trying to bind against the fence.

CharlesJ

-- ======================================================================== Charles Jones | Works at HP, | email: [e-mail] Hewlett-Packard | doesn't speak | ICQ: 29610755 Loveland, Colorado | for HP | AIM: LovelandCharles USA | |Jabber: [e-mail]

[Preston Andreas]

The blade many not be tensioned enough, it may be dull, the feed may be too fast and not steady, the bandsaw may be out of tune, the angle of the stock to the blade may not be the angle at which the blade wants to cut. A lot of times it is a combination of improper tension and running the board through at the wrong angle. Mark a straight line down the top of a board. Freehand the cut, staying on the line. You will see that the stock is usually at a slight angle to the blade. Set your fence at that angle.

I also had that problem with my 14" Delta with a 6" riser. Needing to cut an arc in 11" wide piece of mesquit, I finally decided to tune up my bandsaw. It turns out the upper and lower wheels were not coplanar. That puts a kink in the blade and tends to pull the blade to one side when cutting, forming a concave cut. After I tuned it up, I put on a blade that had given me this problem ( I also thought it was dull). I managed to make the arc cut in the 11" wide stock with no problems. And the blade acted like it was sharp. The tune up took care of my problem. See the "Band Saw Handbook", by Mark Duginske for tuning up your bandsaw.

[George]

OTOH, as previously noted, the description is the classic for too wet inside. It's the reason for allowing a couple extra days between resaw and surface. I take the pieces, put the fresh surfaces outside, clamp the corners and set aside.

Spalted wood, if it is heavily spalted, has less capability, due to lignin destruction, to stress into new shapes. Turners use this to make bowls of crosscuts which would otherwise have rapidly split radially.

Now if one had a crown opposite where the other was coved, the blade problems you mentioned would come into play.

[Charles Jones]

Hmm, interesting. Either way I'm going to add the "Band Saw Handbook" to my "to get" book list and do a thorough run through of the machine.

CharlesJ

-- ======================================================================== Charles Jones | Works at HP, | email: [e-mail] Hewlett-Packard | doesn't speak | ICQ: 29610755 Loveland, Colorado | for HP | AIM: LovelandCharles USA | |Jabber: [e-mail]