Thin end on the last board!!??

[True North]

I have a timber harvester, and have been sawing cedar into 4/4.  Recently, the last board cut out of the cant has been about 1/8" or more thin on the far end. I can't figure out why. Is the blade not set correctly? I cut a cant and measured it and it was right on for both ends. It is just the last board, and it is driving me nuts! Any suggestions?

Also, if the blade is not set right, what is the best way to measure and adjust it?

[Magicman]

I'm not familiar with a Timber Harvester, but saw heads that are on rollers simply roll from end to end.  They can't get closer on one end unless the bed is higher, there is something (bark, etc) under the cant, or cutting boards which was relieving stress, caused the cant to lift up off of the bed.  You stated that the cant wasn't thinner on the far end.  If your bed was higher (out of adjustment) on the far end, the cant would have been thinner, because at that time it was a bottom board.

That simply leaves stress.  When it happens on the far end, it is kinda out of sight from the sawyer and you might not see it.  When it happens on the near end, you generally will see it.

Your 1/8th inch was divided up and was on the boards that you had previously cut.  Turning the cant over and taking boards off of each side of the cant usually will help or eliminate this problem.

Trees that have grown on hill sides, or next to open fields and have more limbs on one side will have a considerable amount of stress within the log.  They can/will give you problems.

[Tom]

A dull blade or a gummed blade can cause the blade to dive or the cant to lift  If you are cutting straight through, the last board might be being pushed down or lifted up off of the bed.

It could also be stress in the cant, but when the last board is a 4x4, it will usually lay flat.

Magicman has most of it covered.  I just started happening, I would change blades.

Look under the cant to see if it is off of the bed at the ends or in the middle.  That will show up stress.

measure the last couple of boards before you reach the last one.

[ohsoloco]

I've had this problem before.  When I experience it, it's  from the last board on the bunks lifting up on the end, usually within the last foot or two.  With my Norwood I believe it is because I have to set the clamp so close to the bottom of the board to get a 1" board that I can't clamp it very tight.  I walk along with my carriage (okay, I push it  :D ), so I can watch the board lift up as I go. 

[True North]

Thanks for the advice. I am not sure that it is due to stress in this case, because it is just the last board (even a 4/4 board cut from a 2"+ cant). I was wondering if my blade is tilted up or down (I did fine tune it with a level). It did not seem to do it with maple, but it is with cedar. Could a softer wood such as cedar cause this problem more?

[Jeff]

The Northern white cedar you saw is for the most part pretty stable. HOWEVER. Not always.    If the trees were growing on any angle, you will find stress. I've sawn some trees that grew a few years after they were wind-thrown due to an adjacent clear cut, and they were horrible to saw.  I think cedar that is grown like that is best suited to be chopped up into shingle mill bolts.

[ohsoloco]

Usually if the cant moves due to stress you end up with a board that is thick or thin on both ends.  I'd keep an eye on the end of the cant for those last couple cuts to see if you notice anything.

[Brad_S.]

Using a level to level the blade doesn't work.
You need to raise the head to about 3 inches and open the guide all the way. Use one of those metal rulers that come with a combination square that detaches from the ruler, a tape measure will not work well for this purpose. Set the front of the blade over a bed bunk and measure from the bunk to the inside of the gullet on both the left and right. If the reading is different, you are not parallel side to side. Next, push the head forward so you can do the back of the blade the same way. If the reading on the back of the blade is different than the one from the front, then your blade is not level to the bunks.
Timber Harvester made a tool for leveling a blade (I think others do as well) using roughly the same pricipals but without the need to read the fine numbers on a ruler. Try contacting Paul, Dave or Ralphat CMS (Carolina Machinery Sales), a FF sponsor listed to the left and see if they can still get you one.

[Magicman]

I cut a cant and measured it and it was right on for both ends. It is just the last board

Something is wrong here.  You stated that you could cut a cant and that it measured true on both ends.  That cant that you cut was a "last board".

You need to do some serious measuring before you start moving and adjusting.  Your blade must be parallel to the bed.  Your blade must be the same distance from each support (bunk), measured from each of them.

[Brad_S.]

IMO, the fact that the cant is good but the last board is thin just confirms what others have postulated: the cant is being lifted off the bed during the last couple of cuts. For some reason, upward pressure is being put on the cant as it is cut. If the clamp motor is worn, it may not be exerting the pressure needed to hold the cant in place. However, I would exhaust potential blade issues before tearing into the clamps. Checking how parallel the blade is to the bed would seem to be in order. Does it do this consistently with all your blades or just some? I'm wondering if the blade is set more on the top side than the bottom and causing a pressure differential?

[Larry]

I've been sawing cedar too...except mind is a most pretty pink color.   I am faced with the same problem of thin ends...sometimes...and caused by tension.

Most of my logs are small so I take 3 slab cuts and on the fourth roll, cut straight to the bed with the exception of the last board...cause I know it won't be my target thickness.  On the last board I just flip it and take the waste off the new top side.

Today I was sawing 1 - 1/16" thick.  By design the last board on the deck is around 1 - 5/8" thick.  After flipping I sawed to my target 1 - 1/16"

I read the post at lunch and hoped for a real bad boy to take pictures of...not to be.  In the second and third picture the waste strip measured 1/4" at the ends and a little over 3/8" in the middle.  Hope ya get the idea.










Other ways to deal with the problem...I could have flipped the cant about half way down and saved a saw line.  Some folks will leave the dog board extra fat and let the end user worry about it...works ok until somebody calls you a thick and thin sawmill.  My way is positive...every board ends up the exact same thickness.

[backwoods sawyer]

I had my mill set along side of a manual mill to help him get caught up on a back log of logs, and what he would do with the last cut was to walk on the board to hold downward pressure on it being careful to only step directly above a bed rail and as close behind the saw as he could.
He later shut off his mill, came and pulled the wood off my mill.

[True North]

Got it cutting good now!!! 8) 8) 8)

Thanks for all of the great advice. I don't know what I would do without it.

Finally made a sale of 1000 feet of cedar 4/4!!  That will come in handy for Christmas. How far do you guys go to deliver lumber? We went 300 miles to deliver this. It seemed like a lot, but felt better when we had cash in hand.

Thanks again, and have a great Thanksgiving

[Tom]

What did you find?

[paul case]

whats the cedar worth a bd.ft? ive got some pretty nice er cedar that someone traded for sawin some and i would like to saw n sell but i dont even know what is a fair price.  pc

[Magicman]

Got it cutting good now!!! 8) 8) 8)  Thanks again, and have a great Thanksgiving

What did you find?

I hope that he didn't ride off on his Thanksgiving Turkey without telling us what he did/found ???

[ohsoloco]

Yeah, what's the scoop True North  ???

[True North]

Sorry guys,

I have been really busy and not able to sit down a write until now. The bunks were fine, so I took the advice on how to properly level the blade. It needed to be tweeked a little. Then, I clamped on a 1 1/2" board and looked under it to see if it was sitting flat. Sure enough, the far end was up off of the bunk. I gave it a karate chop, and it popped down in place and it cut fine. So, I am not sure why the far end is lifting when I clamp it now or how to fix it. Again, sorry about the late update, and thanks a million for the advice.

To answer Paul's question, I sold this stuff for $0.90 per board foot delivered. If anyone has any input on whether or not that is ok, let me know.

Have a good Thanksgiving!

[Tom]

If you came out ahead, then its OK.  :D :D

[Magicman]

Thanks, TN.  A final chapter helps the next guy (and us) who has the same problem...... 8)

[paul case]

was that $.90 for green or dry?  just wonderin  pc

[Brad_S.]

TN,
I don't know if this applies to you or not but I'll throw it out there.
The part of the clamp that actually contacts the cant/board on a TH can get bent up or down and deformed, especially if you have been wrestling large logs. When your clamp tip is bent, it may exert pressure in the wrong plane and raise or tilt the cant. If your clamps are bent, pound them back to straight with a heavy hammer. Same with the tabs on the edge of the bunk that hold the cant when you are not using the posts. If those are bent, straighten them and weld them back to the bunk.

[True North]

That was $0.90 green.

Thanks, Brad. You called it!! One of them is bent. We will have to see if I can fix it without screwing it up more!!

Happy Thanksgiving