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Thread: True coplaner bandsaw wheel adjustment?

  1. #1
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    True coplaner bandsaw wheel adjustment?

    Hi,

    It seems that having bandsaw wheels coplaner is something bandsaw owners strive for. Makes sense to me.

    But what I wonder about is the method for checking if the wheels truly coplaner. I could be wrong, but it seems like every procedure I read only checks the wheels on one side if the axles. So while the straight edge might contact the wheels at four points, the wheels could still have some twist, that would not be apparent unless the straight edge was also used on the wheels at the opposite side of the axles.

    With my particular bandsaw, a Davis and Wells 20”, it is possible to adjust things so the wheels are showing coplaner when the straight edge is positioned both in front and behind the axles.

    But I understand many bandsaws do not have this adjustability.

    So, is it the common procedure just to check for coplaner just on one side of the axles?

    Just curious more than anything really. Do you guys check the wheels on both sides of the axles when setting the wheels coplaner? I believe I read that if there is some twist, the fix in most bandsaws would require machining.

    I do know that crowing the tires will cause the blade to run well even if the wheels are not coplaner. I know this because I changed the bearings on my saw, and the blade ran very well before I set the wheels coplaner. But I think using the crown on the tires, or wheel tilt, probably stresses the blade a bit and may shorten its life.

    This is is an educational question on my behalf.

    All experience and opinions greatly appreciated!
    Too much to do...Not enough time...life is too short!

  2. #2
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    Quote Originally Posted by Bill Space View Post
    Hi,

    It seems that having bandsaw wheels coplaner is something bandsaw owners strive for. Makes sense to me.
    The need for coplanar bandsaws wheels is a myth.
    Of all the laws Brandolini's may be the most universally true.

    Deep thought for the day:

    Your bandsaw weighs more when you leave the spring compressed instead of relieving the tension.

  3. #3
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    Interesting, but if not coplaner wouldn’t stresses be introduced into the blade which would not be beneficial to blade longevity?

    What could the advantage be of not having the wheels coplaner?

    This is is a learning experience for me.

    Please explain more as to why the perceived need for having the wheels the wheels coplaner is a myth.

    Having wheels coplaner seems seems logical to me. But the again, I am not Valcan...😀

    (Not being Valcan I might not have spelled that right...ROFL)
    Too much to do...Not enough time...life is too short!

  4. #4
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    These comments apply to bandsaws with crowned wheels, flat tired wheels are a different discussion.

    The forces introduced are so low compared to the other stresses and strains on a bandsaw blade that it makes no material difference in blade longevity.

    If you check how far out of coplanar several new examples of the same bandsaw are you will find they are curiously very similar in their apparent misalignment and beyond curious it is indeed by design, verified by two Taiwanese engineers that actually design bandsaws (and other machines) for the largest Taiwanese manufacturer of woodworking machines and echoed by Alex Snodgrass (though I don't always agree with him).

    The two non-coplanar wheels produce an opposing force which prevents the tracking adjustment from being too touchy and helps hold the band in the proper position while it has to fight the pressures applied to it by sawing. If you spin the wheels and move the tracking on the upper wheel back and forth and watch the lower wheel you will see it move ever so slightly so as to be in constant opposition to the upper wheel, it takes very little movement to accomplish this so it can be mistaken for not moving. If you make the wheels perfectly coplanar the blade has to move much further on the lower wheel to provide the necessary opposing force, the tracking becomes much more touchy and easier to push the blade off-kilter which forces the saw to rely more on the guides just to keep the blade on the wheels.

    When one moves the wheels into coplanar alignment they experience an increase in control and responsiveness of the tracking adjustment BUT what they have also done is reduce the saws ability to control the blade. It is like setting a cars camber and toe-in to zero simply because it is "logical" for a cars front wheels to be coplaner, trust me you don't want to try to drive that car at highway speeds.
    Last edited by Van Huskey; 10-09-2018 at 7:27 AM.
    Of all the laws Brandolini's may be the most universally true.

    Deep thought for the day:

    Your bandsaw weighs more when you leave the spring compressed instead of relieving the tension.

  5. #5
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    That's a good explanation Van. Makes sense but I have never quite seen it articulated. I once pulled out all of the stops on my old Rikon 10" saw and got the wheels perfectly coplanar, and it really did get very difficult to track. If perfectly positioned it would stay put, but if it was a little off it would gradually start to come off the wheel unless the guides were set. Much more tedious to track than when the wheels were in the factory setting (decidedly not coplanar).

    With my current saw I haven't messed with the factory wheel alignment. I just center the blade on the upper wheel, ignore the bottom wheel (it sits a bit forward on the lower wheel), then align the table and fence to the blade.

    So to the OP I would recommend not going down the coplanar rabbit hole. On the other hand, crowned vs flat tires might be a more interesting topic if you want to run wide blades on the saw.

  6. #6
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    The first thing I did when I got my 14" Rikon was to get the wheels coplanar. Ugg, It took hours to get just right & then when I ran the saw it shredded the belt because the drive pulleys were then way out of alignment. More hours to get that sorted. The ordeal made me hate the saw & I didn't even want to look at it. The story has a happy ending though, because it now tracks well & rips wide stock without blade drift. But if I was to do it again, I'd not do anything to make those wheels coplanar.

    Van explained the physics of it very well, I just wish I'd read that a few years ago.

  7. #7
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    Always a contrarian I guess, but my 14" Delta would not track for beans until I adjusted the wheels to be coplaner. New blade, tilt adjustments, you name it, nothing would get that saw to cut straight and parallel with the miter slot until I adjusted the wheels to be coplaner. And to the OP's question, I had to pivot the upper frame casting a little in order to get the wheels to be in alignment on both sides of the axle. The saw cuts beautifully straight now. Changing blades couldn't be mush easier; just set them on the center of the upper wheel and they generally cut straight with only a minor tweak to the tilt so the cut line is parallel with the miter slot.

    Under tension the blade rides a little forward of center on the lower wheel. This is how it counteracts the tilting of the upper wheel and maintains stability. I've had no issues with the blade wanting to run off the wheels. My two cents.

    John

  8. #8
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    Quote Originally Posted by John TenEyck View Post
    Always a contrarian I guess, but my 14" Delta would not track for beans until I adjusted the wheels to be coplaner.
    Same here. I didn't love my 14" Delta with a riser block until I tuned it as per Duginske. I also bought a tension gauge to remove that variable from the guess list. (the digital caliper method you described here would also have worked: http://www.sawmillcreek.org/showthre...33#post2640833)

    Both of these subjects will always be controversial, possibly since different people have different experience with different saws. Those who preach otherwise often imply their gospel is universal. My experience is otherwise.

    In my case, the adjustments changed the saw from a frustration to a joy. I could consistently resaw 12" boards afterwards. I also checked my larger Rikon when new and it was almost perfect, needing only a minor adjustment of the lower wheel (a 4-bolt axle alignment mechanism is built in.)

    I'd say try the bandsaw as delivered, following all instructions in the manual. If unsatisfied, try adjusting it.

    JKJ

  9. #9
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    Quote Originally Posted by John TenEyck View Post
    Always a contrarian I guess, but my 14" Delta would not track for beans until I adjusted the wheels to be coplaner. New blade, tilt adjustments, you name it, nothing would get that saw to cut straight and parallel with the miter slot until I adjusted the wheels to be coplaner. And to the OP's question, I had to pivot the upper frame casting a little in order to get the wheels to be in alignment on both sides of the axle. The saw cuts beautifully straight now. Changing blades couldn't be mush easier; just set them on the center of the upper wheel and they generally cut straight with only a minor tweak to the tilt so the cut line is parallel with the miter slot.

    Under tension the blade rides a little forward of center on the lower wheel. This is how it counteracts the tilting of the upper wheel and maintains stability. I've had no issues with the blade wanting to run off the wheels. My two cents.

    John
    That's not being a contrarian unless you did it for the joy of disagreeing it is simply relaying your personal experience.

    The Delta 14" saws bear a little extra discussion here since I am pretty sure they are the genesis of the whole coplanar revolution. The Delta saws are notoriously hard to adjust to coplanar and part of the reason so many of them get jacked up in the hands of hobbyists that read an article and tried to fix things that likely weren't broke. Many of us seem to love to fix the unbroken, I know it is one of my favorite pass times. My point being it isn't uncommon to acquire one that has been "fixed upon". One of the actual misnomers which I have perpetuated here is talking about coplanar WHEELS which really isn't what is or at least should be discussed. It is coplanar crowns that are actually the salient issue. All crowns are exactly in the center of the wheel.

    So IME the Delta 14" saws due to the relatively high crown need about the least crown offset of any of the bandsaws. When the wheels are about as close to coplanar as one can reasonably get them there is still enough offset of the actual crowns to impart the necessary counterforces since the actual crowns almost always vary slightly from the top to bottom wheels.

    Finally, let's look at it at the very base level. A blade is tracked on a bandsaw by tilting the upper wheel farther in and out of coplanar with the bottom wheel. One will not be operating a bandsaw with the wheels (crowns) perfectly coplanar*, the blade just won't be stable under any cutting pressure. The wheels (crowns) simply have to be close enough to coplanar to be within the tracking adjustment range. In the end, a bandsaw can be so far out from coplanar that it simply will not track (shows up first with wide blades) but that is rare unless the saw has been abused or improperly "adjusted".

    *We can go off into the minutia of coplanar tracking where you are using the decreased radius on the tooth side of a wider blade (with set teeth)
    in order to produce the counter force in order to track on perfectly coplanar crowns. But in the end, bandsaws are NOT designed to be run like that.


    I do get that a LOT of people including a large contingent of authors and experts will disagree with me, however, everyone that claims this when I visited their shops they were running their blades with the wheels non-coplanar despite the fact they took the time to align the wheels at the vertical.
    Of all the laws Brandolini's may be the most universally true.

    Deep thought for the day:

    Your bandsaw weighs more when you leave the spring compressed instead of relieving the tension.

  10. #10
    Bill

    Your question was about the coplanarity of the back of the wheels. It looks like it got nullified and hijacked by a discussion of whether the faces should be coplanar. The actual mechanics of blade tracking, etc obviously depends on the rims of the wheels. Assuming the rim of each wheel is perpendicular to the face of the wheel, we use the faces as surrogates for the rims. We assume that the rims are "coplanar" (whatever the correct term would be) if the faces are coplanar. Therefore, to answer your question, the planarity of the backs of the wheels is irrelevant as long as we can use the front faces as a surrogate indicator for the rims.

    As to whether the wheels should be coplanar, this is a "sharpening" question with many expert and other opinions on both sides but (AFAIK) no objective studies. I belong to the "coplanar" camp. My BS is the main power saw in my shop. The blade is perpendicular to the table in both directions (F/B. L/R) it does not drift (< 1/32" over 16"), it cuts the same whether the guides are raised to 12" or lowered to 1/2" and the guides need very little adjustment when I change blade widths. It was not easy to adjust the wheels on my Laguna 14-12 but IMO it was well worth the bother.

    Doug

  11. #11
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    Quote Originally Posted by Doug Hepler View Post
    Bill

    Your question was about the coplanarity of the back of the wheels. It looks like it got nullified and hijacked by a discussion of whether the faces should be coplanar.

    Doug
    You are correct, I hijacked and didn't answer the question. The general instructions are to mount and tension the widest blade the saw will accept. Then use a straight edge placed near the center of the wheels and align the four edges.
    Of all the laws Brandolini's may be the most universally true.

    Deep thought for the day:

    Your bandsaw weighs more when you leave the spring compressed instead of relieving the tension.

  12. #12
    This video is from Carter Products with Alex Snodgrass conducting a bandsaw clinic and he covers co planar.
    BTW Carter is top shelf when it comes to bandsaw products.
    https://www.youtube.com/watch?v=wGbZqWac0jU

  13. #13
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    One of the "experts" on bandsaws that I trust completely, Alex Snodgrass from Carter, has stated for years that, He has always insisted that this particular issue is a non-issue and that it is not necessary (nor advisable) to attempt to significantly adjust the wheels. Further, he also says that, f you have to spend time making the wheels coplanar on a new bandsaw, there is something else wrong and the manufacturer should be contacted for warranty service. A long time ago I attempted to line up the wheels on my old Sears 12" saw. While it admittedly wasn't a good saw, the adjustments I made, although bringing the wheels closer to coplanar, made the saw perform worse. On my new Rikon, I have never even attempted it and the saw operates fine. There are other, more important adjustments to make to get good resaw results.

  14. #14
    Well, this is fun. I have had to refine my thinking a bit (not always a fun exercise). Van made me realize that I did not state (or think about) my experience precisely. I see some wisdom in what he says, BUT (1) if coplanarity is not essential, how much variance is acceptable for a saw to cut straight? (2) I adjusted the bottom wheel of my saw until it was coplanar with the top wheel. I'm sure that it improved the performance of my saw. But then I tweaked the tracking knob until the saw tracked perfectly. Surely, when I tweaked it I took the wheels slightly out of coplanarity. So maybe both "camps" are correct. Maybe it is a matter of trial and error using the tracking knob to take the wheels out of coplanarity. But it has to start somewhere, such as having the wheels coplanar or nearly so.

    Story: My new Laguna 14-12 saw would not track, The blade was not perpendicular to the table, front to back. I could not adjust the top wheel to make it so. My studies made me consider adjusting the planarity of the wheels. I had to make a special "U" shaped gauge to bridge the hardware that was in the way, There might have been a bit of error in that gauge. However, according to it the wheels were initially far from co-planar. I adjusted the top and bottom bolts on the bottom wheel until it was coplanar with the top wheel. I do not think I gave any thought to what plane the top wheel was in. (!?) It must have been nearly neutral.

    I put a blade on it and adjusted the tracking knob until the gullets were just a hair in front of the crown. I did a few test cuts and tweaked the tracking knob until the saw cut straight. I have tweaked the tracking knob slightly when I have changed blades to a different width. The saw cuts straight.

    Doug

  15. #15
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    Hello again!


    Van replied: “The forces introduced are so low compared to the other stresses and strains on a bandsaw blade that it makes no material difference in blade longevity. “


    I can see how this could be true, BUT wouldn’t the small twisting and bending forces also be constantly varying, which might over time “work harden” the blade, leading to a greater opportunity for breakage? Perhaps only a concern on expensive long life blades.


    It seems to me that as the wheels move away from being coplaner (offset and tilt) the blade would feel more twist and bending action. I am certain the magnitude of these stresses would be much smaller than blade tension, but they would be continuous as long as the wheels were turning...


    Van also mentioned that at least one manufacturer purposely offsets the wheels by design on their bandsaws. By chance I was looking at an old PDF copy of the Iturra Design catalog (2010) yesterday (lots of time on my hands being away from home) and happened to remember Mr. Iturra mentioning that several callers reporting that JET does this, and his disputing the desirability of doing this. Couldn’t help but think Van might have been one of the callers. :-)


    The following insight by Van is especially interesting:


    “When one moves the wheels into coplanar alignment they experience an increase in control and responsiveness of the tracking adjustment BUT what they have also done is reduce the saws ability to control the blade.”


    I will have to digest this thought a bit. We accept increased tire wear from toe in on our automobiles as the price we pay for increases stability. Perhaps moving out of coplaner is a similar trade off...as Van suggests.


    John T is the first person that has specifically commented on measuring for coplaner on both the front and back of the wheels.


    “And to the OP's question, I had to pivot the upper frame casting a little in order to get the wheels to be in alignment on both sides of the axle.”


    My saw is different but the net result is similar to John’s. In a post below Van verifies what I have seen written in procedures in various places, that one normally checks coplaner at the center of the wheels near the axles. I cannot see how doing this could give an indication of having, or not having, wheel twist. If there is twist by definition the wheels are not coplaner.


    John also mentions that his blade runs slightly different on the bottom wheel with the wheels truly coplaner (or I guess very close to being so). Perhaps the wheel crowns are slightly offset, which would provide an affect similar to what Van describes that Taiwanese manufacturer doing.


    I see in a following post Van mentions coplaner crowns.


    In post #9 Van points out the following:


    “One will not be operating a bandsaw with the wheels (crowns) perfectly coplanar*, the blade just won't be stable under any cutting pressure.”


    This puzzles me. I believe John T above indicated that he gets good performance from his saw with the wheels running coplaner, without tilting the top wheel. Is this correct John?


    Even if the top wheel is tilted, isn’t tracking still being determined by the wheel crowns? Granted tilting the top wheel can cause offset between the crowns, which Van says increases blade stability, due to the crowns setting up opposing forces(my words, not Van’s)


    Doug H, I think you misunderstood my question. I meant measuring the same side of the wheels on both sides of the axle.


    George M, I have watched the Snodgrass video several times. I remember he doesn’t care about blade position on the bottom wheel much, just adjusts tilt of the top wheel to get the bottom of the gullets on at the crown, more or less. I see Randy H explains this in more detail...


    Doug H, what you did in post 14 sounds exactly like the Snodgrass method.


    “I put a blade on it and adjusted the tracking knob until the gullets were just a hair in front of the crown. I did a few test cuts and tweaked the tracking knob until the saw cut straight. I have tweaked the tracking knob slightly when I have changed blades to a different width. The saw cuts straight. “


    Thanks to all for the input so far, and especially to Van for sharing his vast knowledge and experience.


    This is giving me plenty to think about in the extra free time I have, not being at home where the work is!


    Bill





    Too much to do...Not enough time...life is too short!

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