uneven cut from top to bottom when resawing
I just added a riser block , new tires, 3/4″ timberwolf blade and cool blocks to my 1975 3/4 hp Delta band saw. Prior to the additions, I was able to resaw 3-4″ hard woods as thin as 1/16″th. My problem with the new set-up is the cut seems to wander from side to side but more importantly, the difference in the cut from top to bottom, (narrower at the top) is driving me nuts. I tried to adjust the blade tension using the Timberwolf method; start with a lose blade that will show a flutter and tighten until the flutter stops, add a 1/4 turn and that’s it. The process workded fine on a 1/4″ blade but not on the 3/4″. I tightened the new blade as much as I dared and still get a thin top cut and wider bottom. I’m open for suggestions,different blade,etc.
Replies
The first thing I'd check is that the wheels are coplaner. You made a lot of changes all at once, but my hunch is the riser block is causing the problem. I had a similar problem with a Jet saw, the culprit was the wheels not being coplaner.
riser block as the culprit
You may be on to something. I did have a problelm getting the blade to ride on the wheels. I was able to solve the problem by starting with the blade as far back as possible and cranking the thumb screw to adjust the wheel angle. I have to turn the screw all the way to where the shaft hinge begins to hit the wheel. I never feel comfortablle when any adjustment is maxed out. Also the blade now rides too far to the center of the top and bottom bearings. The brearings are also adjusted to the outermost cam setting ...If it is the riser block, I see two problems. One, it sits too far back and two, it is too far to the left, bringing the blade to the inside of the bearing.
Consider the blade
It could be the blade, especially when you say the 1/4" blade works fine. My Delta is a mere child compared to yours (circa 1986) but I put the riser block on mine several years ago and have not had any significant problems. Though I've not used a Timberwolf blade, I did pick up a 1/2" Delta blade a few years back that was terrible. I didn't use it to resaw, but in general cuts it wandered terribly. I took it back for exchange and was much happier.
resaw problem
I lucked out, It was not a riser block problem. I started back further on the wheel and brought it forward slowley as I increased the tension. Also I had the lower bearing to tight which bowed the blade.
So far I am able to resaw 6 1/2" mahogany smoothly and evenly. I will try some white oak as I work up my courage . Thanks for your interest. I love the Timbre wolf blade. Its claim to fame is that it doesn't need a high degree of tension. And they are not expensive.
according to much of what I read, a 1/2" blade is adiquate. Next time
Sounds like you are figuring it out, is there enough or too much tension on the blade? I found that the tension guide, based on the blade width, on my bandsaw is inaccurate. I found that my blade won't track properly if my tension is too little or too much.
If it was good before the riser, perhaps their are some burrs that are causing the problem or the the riser itself is not square.
the adjoining faces
of the riser block may not be true to one another causing a shift in alignment. turn the riser 180 degrees and see what happens. cast can warp sometimes. you perhaps have a pice of crap between the mounting surfaces or a nick and a bump in the surfaces. one of those process by elimination things
when I first bought my general 260 lathe 30 years ago the tailstock to headstock relationship was off .090"; so things happen. seen a .050" variance in a t/saw top. general again. the table on my 14" Rockwell b/saw had a wow in it.
you will just have to check it out
ron
My problem
I added a riser to my 14" jet and found the alignment pin was cocking the upper wheel. I had to remove the pin and work from there. I also had to add some shim stock to one corner of the riser to to get it right.
Been there
If I'm understanding you correctly, i've been there but not due to a riser block. When I first set up my 17" BS with the 3/4 timberwolfe blade I had a similar problem. After reading "The bandsaw book", I made sure the blade was perpendicular to the table and I adjusted for blade drift most of my problem dissapeared. I increased the height of my fence to provide more support and slowed down the feed a bit, and it was resolved. I have since switched to a laguna carbide tipped blade and use that saw just for resaw and its night and day difference. If you can swing it the laguna blade is unreal in quality of cut. Good luck.
It sounds like way too much blade for your saw. The frame isn't designed to tension that wide of a blade properly. I've gone as wide as 1/2 inch on my Delta saw, but have had better success sticking with 3/8 in. blades.
Good luck, Mike
3/4" blade
l am inclined to agree with you. I ordered a 1/2" today. No doubt it will give me a little more latitude in adjustment. I have a habit of thinking if x amount is good, 2x must be better . I'll let ya all know how it works out. Stay tuned. I used the saw today to resaw mahogany to make a tiller on a sail boat. If I knew how to post photos on this site,,,,, Oh well, all in due time
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