Huge problem with new Laguna resaw king band saw blade

[Aaron Wingert]

I cut a lot of flitches from small logs as well as do a fair amount of cutting smaller turning blanks from longer/larger boards. After going through countless Timberwolf 3tpi blades (mostly 3/4") I finally upgraded to a carbide tipped Laguna Resaw King band saw blade. $149 plus shipping.

Last night I mounted it in my 14" Powermatic saw, got it tuned up, tensioned and running slick and smooth. I jointed a smooth face on a small 8" diameter log, and with the smooth face on the table I went to resaw the log in half. 10 seconds after starting the cut BOOM! Huge violent catch, like nothing I've ever experienced. I stopped the saw and looked everything over and couldn't find anything out of place with the saw or the log (not pinching, etc.). So I grabbed a 4" board of mahogany and cut a perfect 1/16" veneer off the face of it. Next I grabbed a 4" board of cocobolo and attempted to do the same thing. BOOM. Another huge catch. Tried it again and got it on video doing it a 2nd time.

Guys I'm stumped. The roller guides are set just behind the teeth. I don't see any irregular teeth. Not touting myself as an expert by any means, but I have set up many dozens of blades on bandsaws and have not experienced anything like this before.

Here's the video of the catch on the cocobolo. Turn your sound up. I normally run a table insert but removed it for the purposes of trying to get this figured out.
https://www.youtube.com/watch?v=B56Esf8sMk8

I'd appreciate any help any of you can offer! Barring any revelations, I'll be on the phone with Laguna on Monday.

[Aaron Wingert]

354284Here's a view of the guides and blade

[Aaron Wingert]

354285Here's how it did in mahogany. Nice!
354286

[Andrew Hughes]

Put your throat plate back in or make a new one that's very stiff.
The blade is pulling the wood down in the hole.
Ive had that happen with Ebony and a flimsy throat plate.
Good luck it's a nice blade I have two of them.

[Aaron Wingert]

I see what you're saying but the throat plate was removed after the first catches and just wasn't replaced when I took the video. The catch happened first on a log with a jointed face that is a heck of a lot wider than the plate.

[Jamie Buxton]

Do you have the blade tension set right? Sometimes if the tension is wrong, the blade flutters in the kerf. It'll flutter a while, then cut straight, then flutter some, and on. Perhaps you're not getting a catch, but a sudden onset of flutter.

[Geoff Crimmins]

It looks like you have a 14" cast iron bandsaw with a riser block. If that's the case, it's my understanding that such a saw can't even come close to properly tensioning a carbide blade. I don't know what the effect of that would be, or if it could be contributing to your problem, but I thought I'd mention it just in case. From the video, it looks like the force of the cut is causing the board to tilt down into the throat, which would force the top of the board into the blade and cause a catch. But I don't see how that could happen with the 8" log you mentioned, so there must be more to the problem. You also mention cutting turning blanks. It's my understanding that carbide blades aren't the best choice for cutting curves like you would do when cutting a bowl blank. So if that's what you're planning to cut, you might do more research before attempting such a cut.

--Geoff

[Andrew Hughes]

Sorry I overlooked the part with the log.That would be a shame if your saw won't tension the blade for tall Resawing.
One more thing to check.Is the table flat from front to back a hollow won't hurt as much as a hump.

[Bradley Gray]

Maybe the harder woods are stalling the power transfer from the motor. A blade this wide and thick will really challenge a saw of any size and yours is on the edge (or maybe just shy of) not enough power.

Another thing to check is the thrust bearing. If it is only engaging in the harder wood and not turning freely it could be a cause.

[andy bessette]

Check the adjustment on roller guides, especially the one which supports the rear of the blade. Make sure the guide's support is locked down tightly. Increase blade tension and reduce feed pressure.

[Aaron Wingert]

Thanks for the ideas thus far guys. To be clear, I'm not cutting curves. I'm cutting square turning blanks...Like 2x2x12", etc.

[Van Huskey]

Even at 1/4 speed on the viseo I can't work out what the actually mechanism is but it looks to be catching on the wood itself since the wood bucks up in the back. What size blade is it? I hope it isn't a 1" but it is hard to tell. Where do you have the tension set on the scale?

[Aaron Wingert]

It is a 3/4" blade, tension is nearly maxed out, which for that saw is the 3/4" tick mark.

I just hung a 3/4" 3TPI brand new Timberwolf on it and it had no problems at all cutting a few green mud-cured hedge logs into 1-1/2" turning squares. No catches, no hiccups. I feel very confident that the catches with the Laguna blade are attributable to the blade, not the saw.

[Van Huskey]

How close is the thrust bearing to the back of the blade?

[Robert Hayward]

For what it is worth I had the same problem with the same setup. Maybe three ~ four years ago. Same blade and same 14" Powermatic. I finally got a catch so bad it stalled the bandsaw, kinked the blade and pushed the end of the piece of wood down into the plastic throat plate ruining the throat plate. I straightened the kinked blade but it was not like new by any means. I hung the blade up on the pegboard and went back to using Supercut blades with no more catches. I had had minor catches with the blade prior to this incident. Ended up selling the bandsaw, throwing the blade in the trash and bought a bigger bandsaw.

[John K Jordan]

... Barring any revelations, I'll be on the phone with Laguna on Monday.

Before calling them you might check the actual tension with a borrowed a tension gauge or use the caliper technique given here:

http://www.sawmillcreek.org/showthread.php?250388-Bandsaw-blade-tension&p=2640833#post2640833

They might be able to better advise if you can give them a number. BTW, I and others have found out that the tension marks on at least some saws are not accurate.

JKJ

[Aaron Wingert]

VanHuskey my thrust bearings are about 1/32" behind the blade, and are spinning freely.

Here's video of the Timberwolf cutting hedge today. https://www.youtube.com/watch?v=sx_dsyciEZI

[Van Huskey]

I am trying to figure out what exactly is happening and honestly I am not sure. It seems a tooth is catching on the upper edge of the cut, but based on how it did on the mahogany it wouldn't seem to be an odd tooth, which you inspected for anyway. You can't do anything about tension since you are maxed out but if it were me I would try it with the thrust bearing much closer to the blade just a "micron" off the blade and make sure the side guides are VERY close as well. When I slowed the video down I saw the blade moving rearward more than I would like.

Do you have any pictures of the top of the kerf from either piece that the saw "bucked" on? They may give an indication whether the teeth were hitting outside the expected kerf, maybe a chunk out of the side of the kerf at the top. The only time I have ever had anything like this happen was hitting a hidden nail or rock but that obviously is not the case here.

[andy bessette]

Be certain you're correctly adjusting both upper and lower sets of blade guides.

[Aaron Wingert]

Van Huskey, here's a video showing the cuts where I got the same catch at about the same depth of cut on the cocobolo. Same piece of wood from the previous video. The green hedge has already been cut up with the new Timberwolf blade, so it isn't something I can show you. On the green hedge I made it maybe 1-1/2" to 2" before the first big bang. Thank you for the input on the roller guide thrust bearing placement. I'll get it a bit closer on the next round.
https://www.youtube.com/watch?v=LA6g2G8xs1Y


Andy, yep my upper and lower guides are adjusted.

Thanks again guys, appreciate all the ideas and time spent helping.

[Van Huskey]

OK that is different than I expected to see but it seems clear that the blade is going wonky somewhere around the middle of the cut and catching the side faces of the teeth. I have been afraid to pronounce it as lack of tension since that isn't something you can fix but I am leaning farther that way. That section is the farthest from the side guides where barreling is the worst and I think a bunch of teeth are grabbing the side. Since you are maxed out on tension get all the bearings right up to a whisper away from the blade and try again, but I am not sure if at will fix the issue.

Obviously, get in touch with Laguna, they may have seen the issue and have more insight, both videos should help them with the diagnosis.

Also, understand I am just guessing here since I have never had this issue and can't remember anyone mentioning a similar issue on any forum I read. I am going on the side of the teeth grabbing because the teeth on the TW blade are set so they have clearance behind the point so side pressure won't grab like the carbide teeth will. Again, this is all guess work. Hopefully Laguna will have a different view along with an easy solution.

[Andrew Hughes]

I'm still seeing a piece of wood that's getting pulled down into the throat plate.The coco bolo has not been jointed flat and your plastic throat plate is flexing.
I had the same thing happen to me when I ran a RK blade on a Laguna 16 inch.I was cutting Gaboon Ebony It as some years ago and I don't remember if I ever got it solved.
Try this lay a piece of 3/4 plywood on top of your table make the cut with a flat side down.
I think you be able to get the blade to cut but will find that the wood is out classing your saw.

[Van Huskey]

I'm still seeing a piece of wood that's getting pulled down into the throat plate.The coco bolo has not been jointed flat and your plastic throat plate is flexing.
I had the same thing happen to me when I ran a RK blade on a Laguna 16 inch.I was cutting Gaboon Ebony It as some years ago and I don't remember if I ever got it solved.
Try this lay a piece of 3/4 plywood on top of your table make the cut with a flat side down.
I think you be able to get the blade to cut but will find that the wood is out classing your saw.

I see what you are saying and it certainly is a (real) possibility. The secondary table would rule it in or out. While I may well be wrong the speed and violence of the catch indicates to me that even if a non-flexible throat plate was installed it might mitigate the symptom I don't think it is the root cause.

[Steve Demuth]

I've been watching this thread and I am with Van in leaning toward insufficient tension as the primary issue. A blade like that should be tensioned close to 25000 psi for the hardest wood and deep cuts, and you're not going to get anywhere near that with that saw. The blade is .024" thick, and .75" nominal depth, for a cross-section of .016 sq in. It's a bit less than that because of the gullet depth, but say it's .012 sq in. If your saw can put 100lbs on the blade, which is probably generous, that gives you roughly 8000psi tension. The blade lacks the beam strength at that tension to not distort in a hard or deep cut, and the big overhanging carbide teeth are probably gouging sideways into the kerf, causing the catch.

[John K Jordan]

I've been watching this thread and I am with Van in leaning toward insufficient tension as the primary issue....

That's the reason I suggested measuring the actual tension, either with a gauge or the free digital caliper method. If the actual tension is known it might eliminate some of the guesswork.

If the tension is low, the spring weak, and frame it strong enough it might be possible to install a stiffer spring and get some additional tension, but at the risk of warping the saw or the tensioning components. I did exactly the latter on a 14" Delta. I was trying to properly tension a large blade that Delta optimistically implied would work. That's when I bought a tension gauge.

JKJ

[Steve Demuth]

Yep, makes sense, and I'm not disagreeing - just pointing out that we and Laguna already know you can't properly tension those blades for really hard cuts on a 14" saw. The numbers just don't add up. I have the Resaw King for my own 14" saw. Great for the cuts it can handle, but with very definite limits.

[Andrew Hughes]

Laguna sells Rk blades with their 14/12 bandsaws.I though the powermatic would be as stout as the 14/12 maybe not.
I still stand by my first thoughts feeding rough sawn coco bollo.
The Rk blade is a fine blade for very precision cuts.But only if it's feed right.
The obvious solution is a 20 inch BS and a Woodmaster Ct.
I have not found anything more rugged then the Woodmaster Ct.Ive used it to Resaw Plywood,Hickory,Oak,Basswood, cedar.It just keep going.