Bandsaw CoPlanar vs Proper Tracking?

[Ken Casser]

I'm still working on my new/old Delta 28-203 bandsaw. I added new tires last night and a new tracking arm from Iturra, and now the blade is perfectly aligned with the guidepost.

At this point, I've put a shim behind the top wheel and reset my tracking adjustment so that both wheels are coplanar. When I put the blade on (3/4" 2-3 tpi TimberWolf), the teeth seem to want to ride flush with the front edge of both wheels. If I screw in the tracking, I can get the blade centered on the top wheel, but at the bottom wheel, the blade is still forward with the teeth riding close to the inside edge of the rim, and then the wheels are no longer coplanar - the top rim of the top wheel has been shifted back due to the tracking adjustment.

So, is there something else wrong that I can't figure out? Or, once I get the wheels coplanar, does it matter that the top wheel shifts when I track the blade? Or, is my goal to get the blade centered on both wheels regardless of whether they are coplanar or not? Finally, am I trying to get the whole blade centered on the tire? or should the TEETH be centered on the tire?:confused:

Or, another possibility, am I overthinking this thing? The saw cuts great, but I don't mind spending the time setting it up, and I would like it to be perfect if possible.

Thanks!

[Tom Veatch]

OK, I'll be the heretic.

I think too much is made of the coplanar/parallel idea. The important thing is that the blade contact surfaces on the wheels be parallel to each other and both be perpendicular to the plane of the blade travel.

If, and only if, the wheel rims are flat does that require them to be on parallel axes. But they still don't have to be coplanar. If they aren't, the blade will ride farther farward on one wheel than it does on the other. The wheels need to be coplanar only if it's required that the blade ride in the same position on both wheels. That might be the case if the wheels are hard and the teeth need to sit proud of the rim. That is the case with my metal cutting band saw, but not with my soft tired wood cutter.

If the rims are crowned, the wheels being exactly coplanar is unnecessary since the crown allows the blade to seek the position on each wheel where the contact surfaces are parallel and perpendicular as described above. Of course there is a limit to how far out the wheels can be, but if the blade position on the wheels is stable, i.e.,tracks consistantly without wandering, it has found the location on the crowned surfaces that meets the parallel/perpendicular requirements.

Summing up:

If your wheel surfaces are flat, the wheels need to be parallel. If the blade needs to ride on a specific spot on the flat wheel, then the wheels need to be coplanar.

If you wheel surfaces are crowned, and the blade track is stable, you're as good as you can be.

[Gary McKown]

I'm no expert but here is my take on the subject. First, I think a 3/4" blade (even a Timberwolf) on that saw will never track or operate properly because of tight bends at the wheels and too little tension. Second, I have found that narrower TW blades (maybe others, too) tend to ride with the SPINE closer to the center of the domed tires when everything is aligned and tensioned correctly. For a wide blade that would place the teeth near the outer edge of the wheels. Also I would think that wide blade, riding on the edge of the tires and probably with too little tension, would show a severe drift angle in the cut.

[Lee Schierer]

When I put the blade on (3/4" 2-3 tpi TimberWolf), the teeth seem to want to ride flush with the front edge of both wheels.

The 14" saw may not be able to tension a 3/4" blade, particularly with the factory spring. You may need a stronger spring. My Delta seems to track just fine with a 1/2" blade, which rides on teh center of the upper and lower wheels. The only problem is the band is a bit short so it is hard to get it on both wheels when teh adjustment is bottomed out.

[Ken Casser]

Thank you for the answers! I hadn't considered the difference between flat rims and crowned rims. I guess I'll just work towards getting the blade centered on both wheels while running at correct tension. BTW, TimberWolf told me that their 3/4" blade would be fine on my 3/4hp saw, but maybe I'll just save that one for the super wide boards, or sizing up my turning blanks. Maybe a 1/2" 3tpi would be more accurate for general ripping. At least now I can put my credit card back in my wallet, and start making sawdust again.;)

[Ray Dockrey]

Thank you for the answers! I hadn't considered the difference between flat rims and crowned rims. I guess I'll just work towards getting the blade centered on both wheels while running at correct tension. BTW, TimberWolf told me that their 3/4" blade would be fine on my 3/4hp saw, but maybe I'll just save that one for the super wide boards, or sizing up my turning blanks. Maybe a 1/2" 3tpi would be more accurate for general ripping. At least now I can put my credit card back in my wallet, and start making sawdust again.;)Timberwolf told me the same thing when I was buying blades for my Grizz G0555 so I bought one but it just didn't work very good. I called them and told them the issues I was having and they replaced it with a 1/2" blade. The 1/2" blade is awesome.

[Tom Veatch]

... The saw cuts great, ...


That's the whole point. If you're there, then you're where you need to be.

[bob hertle]

Ken,

I'll be the heretic now and tell you there's nothing wrong with running that 3/4 2-3 pitch blade on your saw. That's a .025 thick body blade, not .035 or .032 like most other 3/4 blades. Just tension it the max your saw shows on it's tension scale if you have the stock spring and it will be fine. Tensioned the same (load in lbs.) as a 1/2 inch blade, it will still provide a lot more beam strength than the 1/2. Don't use it for your turning blanks unless they are dry. Green and wet wood require a heavier set blade.

As for the tracking issue, did you set the "coplaner/parallel" under load? If not, you may want to revisit the setting. The wheels should be set to be at least parallel under the max tension you are going to run. Now if you say the guidepost is parallel to the blade, and you change the position that the blade tracks on one wheel or the other, you'll lose paralellism of the guidepost front to back. If the saw runs good, and cuts good, I'd leave it alone. If you have drift issues, you'll need to do some further work!

Enjoy your saw!
Bob

[Perry Underwood]

Ken, the information below is from an earlier thread I started about having the wheels coplaner . It might be helpful to you.

I read in Duginske's book that blades 1/2 inch and larger have difficulty tracking in the center of the wheels. I probably have forgotten some of the information, but I remember this can be due, in part, to the making of the blade in which the tooth area becomes a little shorter during the manufacturing process.

Another reason mentioned in the book is that the crown on the tire is only about 1/4 inch wide. There's little surface to support a 1/2 inch and larger blade. These size blades find their own equilibrium, which tends to be toward the front on the wheels. I've noticed that my 3/8 inch blade tracks closer to the center with the wheels coplanar than the 1/2 does. Seems to make sense now.

I was also interested to read about coplanar tracking, which is where the wheels are coplanar but the blade is not centered on the tires. I would assume it is better for the wheels to be coplanar than to have the blade track in the center. I'd like to have both, though.

[Wilbur Pan]

My take on this is, I don't really care where the blade is on the wheel, or if the wheels are coplanar, as long as it's tracking evenly, and the drift is minimal.

The rationale that's often given for keeping the wheels coplanar is that it results in less strain and wear on the bearings and the blade. I have yet to see such wear really be significant on the bearings. After all, how many times have you heard of a woodworker changing the bearings on their bandsaw? As for the blade, the teeth will dull long before anything happens to the body of the blade with this issue.

Mark Duginske emphasizes having the wheels coplanar. I think that what is missed, even by him, is that coplanar wheels is a starting point for setting up your bandsaw, not the goal. On my old Walker-Turner bandsaw, my wheels are nowhere near coplanar, and due to the construction of my bandsaw, they can't be without doing something drastic like remachining one of the axles, yet I get perfectly square cuts without drift. As Tom has already mentioned, I'm able to accomplish this because my wheels are crowned.

[Stephen Edwards]

On my G0555X I have much better results re-sawing with the Timber Wolf 3/4" 3tpi than I did with the TW 1/2" 3tpi. Sounds as if the consensus is that there's no consensus!

[Ken Casser]

So many variables! Ray, it's possible you just got a 3/4 blade that wasn't perfect. Or me, for that matter. That's why I need to go through this with all my blades if I really want to get crazy.

Tom - I agree fully and am going to pretend the saw is perfect.:D If I lose my straight edge and feeler gauges, I'm much happier.

Bob, the 3/4 2-3 does cut fine. TM told me this blade would be fine for wet wood - the tooth pattern is different than the others - it's a 'VPC'. I don't do that much of that anyway. And yes, I set up the coplanarity with full tension on the blade but I was concerned when the teeth were riding even with the front of the wheel rims. I don't want them to chew up the metal rims, or dull the blade, so I'll adjust my tracking to get the blade closer to the center. It occurs to me that to correct this (if centering the blade is considered a 'correction'), I turn in my tracking adjustment. As soon as I do this, I'm no longer coplanar, am I? In this scenario, the top of the upper wheel will no longer touch the straight edge that rests on the lower wheel rims.

Perry, thank you. That makes sense. Each width of blade must react differently.

Wilbur - that makes sense, too. Coplanarity as a starting point, and then adjusting tracking from there if necessary. But I would think that if all the blades were tracking in the middle, drift would be non-existent because the blades would be parallel to the rims of the wheels. I would think that drift would only be induced when the blade was either farther forward on the wheel, or farther back.

Stephen - you're right! Of course what I'm trying to do is to get answers for my saw without spending time and money on trial and error, but I guess the bottom line is that every setup is different, and there's really no way around testing different blades to get the result you want. At least now I know a bit more about what to look for, and what is important and what is not.:)

[Chip Lindley]

Or, another possibility, am I overthinking this thing? The saw cuts great,...

YES Ken, IMO you are overthinking this thing. The saw cuts FINE! No further adjustment is needed.

As one contributor added, CO-PLANER is a place to *start!* With both wheels co-planer vertically and horizontally, you are good to begin fine-tuning a BS. Any tracking of the top wheel (even 1 degree) destroys *co-planer*! It's just common sense!

IF your saw is cutting repeatably, and the blade is not running off the tires, and the tracking keeps the blade in one spot....ENJOY using your BS, instead of obsessing! And forget all *this BS*!

[Ken Casser]

Ah, the voice of reason. Clearly I have too much time on my hands. :D:D (Now where were those feeler gauges?:eek:)

[Wilbur Pan]

Wilbur - that makes sense, too. Coplanarity as a starting point, and then adjusting tracking from there if necessary. But I would think that if all the blades were tracking in the middle, drift would be non-existent because the blades would be parallel to the rims of the wheels. I would think that drift would only be induced when the blade was either farther forward on the wheel, or farther back.

That is true, but many other things can lead to blade drift as well, and that's why it's good to adjust the upper wheel tilt to compensate for that.

Again, I'd rather have a drift-free square-cutting blade that tracks off center of the bandsaw wheel than a blade that tracks in the center of the wheel where I have to adjust, say, my fence to account for blade drift.