Lots of tension in my mahogany!

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Blog entry by CharlieK posted 03-22-2017 10:13 PM 2097 reads 0 times favorited 14 comments Add to Favorites Watch

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Recently I was ripping a piece of mahogany on my table saw and there was so much tension in the board that I couldn’t complete the cut. In fact, it was binding so tightly on the blade that I had to work to get the board off of the saw.

I haven’t experienced this kind of wood tension very often. What is your favorite way to deal with this kind of problem?


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14 comments so far

View johnstoneb's profile (online now)


2910 posts in 2166 days

#1 posted 03-22-2017 10:24 PM

drive a screwdriver in the kerf to widen it.

-- Bruce, Boise, ID

View Grumpymike's profile


2238 posts in 2308 days

#2 posted 03-23-2017 12:31 AM

I have some small wedges in my apron pocket just for that scenario. Watch the outfeed end and if the kerf starts to close up insert a wedge or two.

-- Grumpy old guy, and lookin' good Doin' it. ... Surprise Az.

View Mikesawdust's profile


325 posts in 3032 days

#3 posted 03-23-2017 08:44 AM

wedges definitely, I work with a lot of rough air dried lumber and have had it stop the blade. Of course once it’s cut it is going to need flattening again. I would let it sit for a day after flattening it to see if its settled or needs another flattening.

-- You never cut a piece to short, you are just prepping that piece for a future project

View ScottM's profile


639 posts in 2140 days

#4 posted 03-23-2017 11:49 AM

My question in return would be, what do you do with the wood after you manage to get it off the blade? In other words, is wood with that much tension good for anything?

View Bobsboxes's profile


1367 posts in 2657 days

#5 posted 03-23-2017 01:49 PM

I also drive a wedge or screwdriver in the saw kerf. I had a hundred feet of 4/4 hickory and it was loaded with tension. As I cut it, it would blow apart or pinch in. I reaiiy had to use it for some window trim, to far to go get more, so I ripped all the boards, let it sit for a couple of days, and them trimmed everything up. Installed it and it still looks good today.

-- Bob in Montana. Kindness is the Language the blind can see and deaf can hear. - Mark Twain

View CharlieK's profile


555 posts in 3786 days

#6 posted 03-23-2017 03:22 PM

You guys are great! I will definitely try using wedges sometime. That said, I think a bandsaw is probably a safer solution.

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View CharlieK's profile


555 posts in 3786 days

#7 posted 03-23-2017 03:26 PM

My question in return would be, what do you do with the wood after you manage to get it off the blade? In other words, is wood with that much tension good for anything?

- ScottM

Good question!! Ideally, I would scrap it, but sometimes you have to play the cards you are dealt. In this case I have a 17bf piece of mahogany and I just can’t bear to toss it out.

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View Rich's profile (online now)


2796 posts in 583 days

#8 posted 03-23-2017 04:15 PM

My experience has been that the pieces are bowed after the cut. If they are wide enough, I can generally get a straight edge on them, and they hold their shape pretty well. Narrower cut-offs aren’t salvageable.

-- No matter how much you push the envelope, it'll still be stationery.

View JimYoung's profile


281 posts in 1580 days

#9 posted 03-23-2017 04:41 PM

I have a Microjig splitter on my zero clearance insert. It has a secondary splitter that fits loosely in the insert and will actually be pulled out by the wood if it starts to close in from wood tension and hold the kerf open. It is a nice automatic feature and doesn’t require stopping or starting the cut. I don’t work for Microjig, I just like this product.

I have worked a little with Mahogany and have experienced similar internal tension when cutting and milling it. I’ve searched out and asked questions on this topic, and basically you need to expect this and deal with when milling this type of wood. I was resawing 4/4 to 1/2” and was able to alternate bowing boards in the glue up and weighed it down for a few days and it stayed flat.

-- -Jim, "Society is well governed when its people obey the magistrates, and the magistrates obey the law." -- Solon

View EarlS's profile


1027 posts in 2341 days

#10 posted 03-23-2017 05:39 PM

I also have the microjig splitter and it works great to keep the board from pinching the blade.

-- Earl "I'm a pessamist - generally that increases the chance that things will turn out better than expected"

View pintodeluxe's profile


5653 posts in 2806 days

#11 posted 03-23-2017 05:53 PM

If I encounter wood with tension, I rip it oversize. Then joint it again, before ripping to final width.
A little paste wax on the riving knife helps.

Also, make sure the core of the lumber has an appropriate moisture content. If it’s not kiln dried, that can magnify the problem.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View Patternguy's profile


53 posts in 685 days

#12 posted 03-24-2017 02:08 AM

We used 20,000 board feet a year in a shop I once worked in and every so often you would get a board like that.
It would be thrown to the side of the rack until a suitable application was found for it.
Fortunately, we were able to just get another off the lumber rack.

We used to joke that the elephants probably pi#%ed on that tree.

View Mainiac Matt 's profile

Mainiac Matt

8028 posts in 2322 days

#13 posted 03-24-2017 05:49 PM

I wonder if it’s reaction wood.

If so, I will keep moving for some time.

-- It’s the knowledge in your head, skill in your hands and motivation to create in you heart that makes you a woodworker. - Mainiac Matt

View PaGeorge's profile


21 posts in 430 days

#14 posted 03-27-2017 03:22 AM

As a kid wood wedges were something everyone had when ripping,,sort of,in a way a fundamental part of using a table saw..I still use them to this day.

-- PaGeorge

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