bandsaw blunder w pics

[Tim Reagan]

I am new to resawing and have read quite a bit here about proper setup. Here is my most recent attempt to resaw 10" mahogany (previous stair tread given to me). The first pic is the entrance cut, but still shows it is not parallel. The second cut, well, enough said. At the very end of the second cut the side guide got loose thats why there is an abrupt curve at the end.
I am using a grizzly 0513p with a 1/2" 3tpi bimetal blade, that has very little use on it. It is tensioned by the flutter method, and on the scale on the saw is at almost 6 (on the 1-8 scale). I'm obviously very afraid to try to resaw again with any wood, especially something expensive.
Also when I attempt to correct for drift, my fence doesn't have enough adjustment in it, it is pointing more the the right that can be adjusted for (see pic with sliding bevel). I'm clearly doing something quite wrong, and would love to hear correction advice.
thanks.

[Jeff Bartley]

Tim,
I'd suggest looking into or making a 'resaw' guide. It's basically a 't' shaped thingy that gets clamped to your fence and it's job is to provide a single point of contact to the workpiece directly in front of the blade. It allows you to adjust the workpiece for drift as you cut. I made on out of two pieces of plywood, the two pieces are screwed together to make a 't' then the bottom of the 't' gets a slight radius. In use the center of this radius is positioned just in front of the blade.
Hope this helps! Jeff

[Kevin W Johnson]

Is the blade he's using proper for the work he has?

Edit: I missed it's a 1/2" 3TPI, in the picture it looks like a 1/4" 5-6TPI.

[Van Huskey]

Some people like Jeff have good luck with point fences, I don't, especially with a long havey board like this. Also if one looks at the cut following the center on the top of the board which you could see would still leave an poor cut since the the cut deviated within the board.

There could be a bunch of things wrong here and without more attempts to see the results it is hard to say. My first inclination (as usual) is tension is on the low side. I am not a fan of the flutter method since I usually find it is low for carbon blade and even farther off for bi-metal. I would try more tension, I know it is "high" on the saws scale but that blade needs a lot of tension. The final veer may well be from the wood itself but I can't see anything in the grain in the picture to indicate this. I do have concerns about the blade itself when you say you can not compensate for the drift completely. What brand of blade is it...

[glenn bradley]

This is the sort of thing that can get analyzed to death and by all means, if that's your thing, proceed. I should add that I am aware that hearing how someone doesn't have your problem is not a fix, it just adds credence to the possibility that there is a fix . As Van points out the two pics don't give a lot to work with. Compound that with the fact that different people re-saw successfully with different methods and its game-on. I am not clear when you say "the side guide got loose". Was this due to it not being tightened down or did the blade jump the bearing? If the blade jumped I would tend to think there is a material control issue.

I see you have solid roller stands which often prove a problem for me on bandsaws (I prefer casters but some folks use roller-balls). I do not want anything influencing the path of the material and unless the solid roller is truly perpendicular to the path and remains that way, you can track poorly. I also do not see any featherboards (I prefer them stacked when resawing) to maintain pressure against the fence. I cannot see the bottom edge of the board but, if it is as irregular as the top (not jointed) you are again introducing influences that can foul a true feed path.

I have your saw's cousin; the no longer made G0513X. Assuming that there are no mechanical problems with the saw or blade, I think you can get much better results. I do not bother with trying to adjust for drift. I set the blade to track true, adjust the table to that path by using the miter slot as a guide (parallel to the feed path). I adjust the fence true to this same path. I run Timberwolf or Highland Hardware's Woodslicer blades so I am not sure about tensioning a bi-metal; I use the flutter method. With this setup I cut 1/16" veneer pretty reliably.

[John Lanciani]

One word, tension. The flutter method is dubious at best, even with "low tension" blades. Every bi-metal blade that I've ever used begged for high tension; Lenox reccomends around 30k psi for best performance and life. The side guides are like training wheels, if everything is working correctly you don't even need them so the fact that they moved out of alignment means that something else was wrong. (Most of the time when I'm cutting veneer I don't even have the guides in play on my MM20)

Crank up the tension, square the fence to the blade vertically and determine the feed rate that the blade wants and you'll have much more success.

[Myk Rian]

Show a pic of the cut itself. That will truly show what was going on.

[Alan Schwabacher]

The guide block should be gently restricting the movement of the blade. If a force is pushing the blade hard to the side, there's a problem. I'd start by pulling the guides, as well as the thrust bearings, away from the blade above and below the table. Make sure the blade is running smoothly, set tracking to run the blade just behind the teeth in the center of the tire to minimize drift, and adjust the table square. Then bring the guide blocks and thrust bearings close to the blade without deflecting it.

I suspect the speed of the cut might be a problem: you must cut more slowly when you resaw than when you rip thinner stock, and not just because of power limitations. What limits the speed of your cut is that sawdust quickly fills the gullets between the teeth, and when that happens the only way the blade can cut is to deflect to the side. When you cut thick stock, you need to make sure that there is still space for sawdust in the gullets near the bottom of the cut. Consequently, when you cut 10" of wood, your maximum speed is about 13 times slower than when you rip 3/4" stock with the same blade.

Your problem is the blade deflecting, and I've mentioned things that diminish the lateral force that causes deflection. Tension helps the blade resist that force, so increased tension can also help. If the bandsaw frame deflects at all with increased tension, you'll need to reset guideblocks and table after changing the tension.

[Myk Rian]

If the bandsaw frame deflects at all with increased tension, you'll need to reset guideblocks and table after changing the tension.

All so true. As the frame flexes, the upper wheel moves further from the spine centerline. If the frame twists under tension, then all bets are off.

You can check frame deflection by attaching a thin dowel to the upper wheel cover, and have the end just above the table. Put a piece of tape on the table, and mark where the dowel is located. Now tension the blade, and see how the stick moves.
If it moves from right to left, the frame is flexing.
If it moves front-to-back, or back-to-front, the frame is twisting.

[Tim Reagan]

great thanks. I will try to get another pic of the cut up today. Van, the blade is actually from the company you recommend somewhere in the midwest (spectrum supply, dont know actual blade brand), where they custom make it for you. The side guides on the grizzly are the round metal type, not bearings or blocks. The thumbscrew that I tightened came loose on the left one and it moved away. But there was obviously alot of pressure on it. I actually saw sparks a few times. Sounds like more tension is necessary amongst other things. The 1/13 slower suggestions opened my eyes, I'm also probably going too fast.

I lied. I just found out on the spectrum website it is the flexback carbon blade, not bimetal. Does that change anything, the blade is almost new.

[Andrew Joiner]

I actually saw sparks a few times.

That explains it . The blade got dull on one side so the cut wandered at the end of the pass.

It's even recommended to use your resaw blade only for resawing. Even gradual curve cutting can wear the teeth more on one side and cause drift.

[glenn bradley]

I actually saw sparks a few times.

Ouch. Like Tim points out; at the number of teeth passing a given point in space per second, if you got into something that sparks, the blade is probably done.

[Tim Reagan]

here are some cut pictures. The spark was toward the end of the cut, but duly noted about it being likely done.securedownload-5.jpgsecuredownload-4.jpg

[Myk Rian]

The rough cuts indicate where the blade got clogged, and started wandering around the un-cleared saw dust. Trying to cut too fast will do that.

[Jim Matthews]

My first two (or six, but who's counting?) attempts to resaw looked like this.

I followed Michael Fortune's treatise on setting up the saw to cut straight, with no drift.
I replaced the blade, to be factory sharp - and used an auxiliary fence.

I'm now comfortable resawing up to about 8" stock, with little deviation.

The only variant I employ is a Rockler gizmo - a thin rip jig, to allow for multiple plies without jointing each time.
The same jointed face is kept against the fence, the fence is moved each time to reach the wheel on the jig.