I am attempting to resaw 8″ cherry on a jet 14″ bandsaw with a riser block. I am using a 3 tooth/in skip tooth carbide blade and have tried various tensions up to 15000 psi. The problem is when I feed the stock the blade chatters and jumps violently. I have checked the clearances on the guides on top and bottom and just can’t figure out what the problem is.
Any ideas?
Replies
If all is lined up properly, inspect your blade for kinks. Had a similar problem and found a small kink. I replaced the blade and all is fine.
Bob
Scott,
Are your wheels co-planar? Like have you checked them to make sure that they are balanced and in-line with each other?
What kind of blade guides are you using? I'd assume that they are tuned to the blade properly? What size blade are you using? 1/2" or less?
Rod
I have not checked coplaner but I will look into this. I am using replacement rollers from Iturra along with their 1/2" 3 tooth/in carbide blade. If the wheels are out of line how would I fix this? Do you know physically what is happening when it jumps violently?Thanks
The chatter sounds like the band is vibrating. I'm not sure what you mean by "jumps violently". Can you describe in more detail?Make sure the guides are set just behind the gullets of the teeth and the thrust bearing is properly adjusted to about 1/64th behind the band. I've never used roller guides but I understand they want very close clearances (1-2 thousandths). This is less than the thickness of a sheet of paper.I hate to mention it after you've shelled out for all that Iturra stuff, but if the adjustments don't help, you might want to back off on the mods a bit. This is a pretty straightforward resaw and you're using a lot of add-on gear that I wouldn't think would be necessary. A 1/2" 3PC Timberwolf would be fine. You might also want to experiment with your original guide blocks. There's a lot of "wisdom" out there about steel blocks, but the fact is they work.Pete
"If the wheels are out of line how would I fix this?"Tension the blade to the proper tension and see if the wheels are in line with one another. If not then you may need to move the bottom shaft by shimming under the mount or sliding the wheel on the shaft. It is tedious but is well worth it. The blade should be perpendicular to the surface of the table all the way around.
"If the wheels are out of line how would I fix this?"A useful tool is a 4' straightedge. A 4' level is a good choice, because depending on the design of the cabinet, you may have to tape two equal pices of 1X or similar to the ends to touch the wheels.Pete
I checked my wheels and they are coplanar and not twisted. I changed the blade to an old 1/2" wood slicer from highland hardware that I had the problem went away although I still have significant drift.
If you draw a line parallel to the straight edge of a board and try and saw that line that is the angle you need to set the fence at. That will be your drift angle.
Don't be offended by this suggestion if you already checked, but this bit me once and I never forgot it. Make sure your blade isnt reversed. If the blade is "inside out" the teeth will be running upside down and will basically be trying to batter their way through the wood.
I bought a nice timberwold blade for my bandsaw to replace the stock blade. I put it on and got incredible amounts of chatter and drift. Finally I took a good look at the blade and realized that the teeth were oriented upside down! I didn't think this was possible, but I pulled the blade off the saw, "inverted it" and put it back on. Worked great after that.I wonder if someone over at timberwolf decided to have a little fun when they packaged up that blade....
Happened to me once--uh -- I mean to someone I know. Seems "he" was showing a friend how easy it was to change out blades on his new saw and his mind was not all there. (Some would say it still isn't!) I think this situation was worse because there was a witness. Embarrassing to say the least!
I didn't even know the blade could be inverted like that! It certainly didnt happen *after* I took it out of the package.
I checked my wheels and they are coplanar and not twisted. I changed the blade to an old 1/2" wood slicer from highland hardware that I had the problem went away although I still have significant drift.... scott
Perhaps a bad weld on the other blade. You've done quite a bit of checking on the wheels, guides, belt, etc. and all seem OK. The jolting went away with a blade change, but you still get significant drift!
Is the older blade sharp? Have you checked the crown on your tires for chunks missing or worn tire causing un-even crown?
Regards...
SARGE..
The blade should run smooth without any guides. If it does not then you have another problem.
Have you checked the wheels to make sure they are balanced?
The blade I prefer to use is hook tooth with a raker. Normally I use a 1/2" blade for resawing.
Edited 9/15/2006 1:47 am by gb93433
another thing to check is the belt from the motor to the pulley. on my saw the tension had gotten loose and when the torque of cutting was applied it was not grabbing consistantly and there was lots of chatter and "lurching."
jerry
I just ran into a similar problem. I am resawing 8/4 hard maple 10" wide rough cutting for 1/2" thick finished. using the same saw with a 3/4" blade. I was down to the last cut (out of 10). I had absolutly no problems so far. I started the last cut, about an 1/8" into the cut the blade started jumping around and chattering. I shut everything down and checked the saw out but couldn't find anything. same thing happened when I started back up. This time when I shut down, I checked the wood. A nice size wood shaving had stuck to the bottom and it wouldn't allow the wood to sit flat against the table. The wood was still flat aginst the fence but it allowed the wood to move when the blade started to load up. I had been checking every peice and blowing off the table between cuts but missed this one. After I cleaned it off, no problems.
Magnus
"Remember, a bad carpenter always blames his tools" -Joe Conti-
Another way to correct the drift problem is to change how the blade is centered on the wheels. Try moving the center of the blade a little forward - does the drift get worse? If so, try moving the center of the blade a little back - improvement? You may be able to completely eliminate drift by shifting where the blade runs on the wheels - within reason, of course.
Mike D
OK - you're not the only one then. I was going to suggest something earlier, but it just seemed much too obvious. I had similar problems a couple of times when resawing longer boards. I found that due to the weight of the longer boards, I just wasn't keeping the first 10-12" of so down tight (and I mean TIGHT) to the table. Once I got enough of the board on the table that it's own weight kept it down, the problem went away. Now for anything longer than 4-5' I pull an extra roller stand for infeed support.
If you build it he will come.
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