Resawing Logs have tough spot to cut thru - Why?

[Jesse Tutterrow]

I have been using my bandsaw (Grizzly 17" 2HP, timberwolf 1203AS 1/2" blade) to rip some walnut logs, less than 12" diameter, into spindle blanks. In the middle third of some rip cuts I will hit a "tough" spot where it is almost impossible to push the log any further. When I can get it to move forward after about a 1/2" the cut will go back to normal cutting. This does not always happen, even in the same log. I have inspected the "tough" area and have not found any indication of nails, rocks or any foreign object. What would cause this?

 

[Richard Coers]

My guess is that you are feeding too fast and the gullets of the teeth are full. What is your tooth count? I buy 1" blades with what they call a 3/4 pitch. That's 1 tooth every 3/4". If you are using something like 3 teeth per inch, that is too many teeth for cutting 12" of wet wood.

 

[Roger Chandler]

The ability of a band blade to clear the kerf is especially important on green wood. As Richard mentions above, too fast a feed rate will not allow that to happen as it should.

Another thing....my experience with Timberwolf blades is they are not well suited for green wood. They do okay for resawing boards, but green wood is another animal. My preference is to get a blade made for green wood.......I cut lots of it on my two bandsaws. My go to blade is the Woodturners Blade from Highland Woodworking........the reasons are that they are thicker, at .032 than standard blades which are .025, and the teeth set is wider on them by design, which makes them clear the kerf better.

I have a couple of 1.25" wide blades for my Jet 18" bandsaw, but find the 3/8" wide 3 tpi Woodturners Blades from Highland actually do a much better job on cutting out bowl blanks from logs than the wider, less teeth 1.25" blades. Cutting boards from logs might be a different thing, and I have used those wider blades for milling my own rough lumber from logs over the years.

 

[Jesse Tutterrow]

My guess is that you are feeding too fast and the gullets of the teeth are full.

That sounds reasonable, but why only for some cuts of the same thickness and only for about 1/2 inch in the middle of the log? Would not the gullets fill with sawdust earlier? How does the problem solve itself in about a 1/2 inch? The speed that I push the wood through the saw remains constant except for when it becomes almost impossible to push. Should not the gullets empty of sawdust as they pas through the bandsaw?

I am not trying to be augmentative just trying to understand.

Here are the Blade Specs:

Timber Wolf® 1/2" x 3AS

Blade Designation: Roughing or Milling Green Wood/Logs

Width: 1/2"
TPI (Tooth Per Inch): 3
Blade Thickness: .032
Kerf: .056
Tooth Hook Angle: 6.5°
Tooth Set Pattern: AS (alternate set)
Radius of Cut: 2 1/2”

Thickness of Work Material to be cut
Kiln Dry Wood: Hardwood 3" - 12" Softwood 3" - 12”
Green Wood: Hardwood 3" - 12" Softwood 3" - 12”

 

[Tom McClellan]

One not always obvious thing to check is making sure nothing from the log is snagging on the guides, lip of the table, fence or the lip around a blade insert. If it happens at the same physical location every time on this log, maybe it is because that distance corresponds to where some other part of the log is catching something.

 

[Richard Coers]

Another consideration is the blade temperature. I've had a blade basically fuse wet sawdust to the steel. Same on bandsaw tires and bearings. If the blade is warm and the dust really sticks to it, it's going to take a bit for the gullets to clear. On a bandsaw mill you add a trickle of water to lube the blade. When cutting pine you add pine-sol to the lube tank, or even a bit of diesel fuel. With 3 tpi, you will have to really slow down the feed when ripping 12" thickness. One indicator of proper feed speed is sawdust left in the kerf. If you have sawdust left on the cut surface of the wood, the gullets are full and there is no room to pull all the dust through. If the wood in the cut is clean, the gullets had room to pull it all the way through.

 

[Jason Van Duyn]

Not sure if this is the case for you but your halfway through the cut sounds like the internal stresses of the wood are releasing and causing the kerf to close up. Just a thought, thick wood moving out of square and true is pretty common from what I have notice. Otherwise I would say that it might be the wood itself. Occasionally I come across some walnut that has sections in it that are very hard, kinda uncanny. It hasn't happened too much but there has been some walnut that I wouldn't turn because it was so difficult to work.

JVD
www.vanduynwoodwork.com

 

[Curt Fuller]

You haven't mentioned if you're using a fence. When I use a fence to rip logs I've found that the blade will bind if the fence and the cut aren't pretty close to perfectly parallel. Bandsaws are notorious for wandering so I usually chalk or draw a line to follow instead of using a fence.

 

[robo hippy]

First question I would ask is do you have a 'flat' on the log section? If you don't have a dead flat surface, or very close, it is easy for the log to rock a bit and that will make the blade bind. This can be an up/down or side to side rocking. The best blades I have found are the Lennox Diemaster bimetal blades. The teeth are M42 HSS, and cut longer and straighter than any other blades out there. On another note, walnut, for reasons unknown to me, tends to dull every thing more quickly than any other wood I have worked with. Like Curtis said, I prefer to use a like to cut to rather than a fence...

robo hippy

 

[Zach LaPerriere]

As Jason says, a likely case is that internal stresses are causing the blade to bind. Does the saw slow down at all? Perhaps the bind releases after the troublesome spot...

You might try a blade lubricant, or borrow some Pam from the kitchen.

Contrary to Roger's experience, I've found the Timberwolf blades to be excellent for ripping green/wet wood. I like the 3/8" blades. 1/2" would have 25% more blade, though I doubt that makes a huge difference.

Finally: it could just be that your blade is getting dull and that trouble spot would benefit from a new blade. I for one have waited too long to change blades and a tough pieces of wood suddenly wakes me up to that fact.

 

[Bill Boehme]

If you are shoving the wood to get the saw to cut that is just backwards from what you should be doing. As mentioned previously, you might be loading up the gullets and then the blade will stop cutting. It will get hot and then bind. If the cut is bowed that is a sign of forcing the cut. The blade might be dull or numerous other issues. Check the guides to make sure that they are set correctly. I agree with Zach that the Timberwolf blades work just fine for me.

 

[Jason Van Duyn]

I also use timerwolf blades, wet and dry and I have no complaints. My experience with other blades is limited so there might be better stuff out there. I will say though, at least on the blades I use, is that they dull out faster than they feel to the touch. I also agree with Robo hippy's comments in that if the wood is not flat there will almost always be binding of the blade due to the wood rocking. It doesn't take much for the wood to not have a sufficient flat. So its probably a combination of factors. Cutting wood for myself I do understand how its easy not to have a joiner large enough to flatten misshapen wood. Even the slightest bump from what appears to be a really good chainsaw cut is enough to make things difficult. How thick of a cut are you making? The thicker the cut the more likely it is the blade will bind?

JVD
www.vanduynwoodwork.com

 

[Don Wattenhofer]

What you really need for cutting half logs for turning blanks is a band saw mill. The blade is 1 1/4" wide with less than 2 teeth to the inch and the lube system is built in. The blade will wonder up or down when it becomes dull due to dirt in the bark or iron buried in the wood. I just recently cut a red oak crotch where the hardest part was blocking it up enough to cut thru the center of the the 3 piths.