BS Wheel Alignment: cite your references

[Bill Space]

This is to be an educational question rather than a debate so please try to keep it on topic.


It seems like there are three camps related to how bandsaw wheels should be positioned with respect to one another. In all cases the top wheel has tilt adjustment so we can ignore that feature with respect to this discussion.


What I see are three possibilities, in no particular order:




It doesn’t matter if the wheels are coplaner or not
Wheels should be offset by some amount, definitely NOT coplaner
Wheels should be set coplaner



So what do your manuals/other sources say?


Please cite specific sources. Manuals, publications, theses or whatever.


In other threads many opinions have been expressed. Hopefully this thread may list sources that back up those opinions. We all have our opinions. Let’s try not to post them here and rather defer to published directives or scientific studies, if such animals exist. Of course, a summary of what the reference says is welcomed!


Perhaps this will be the rare one post thread! Hope not!


For a start, here are a couple references that support the coplaner relationship.


In a different thread Tom M King referenced the following instructions which call for coplaner wheels


http://www.northfieldwoodworking.com/TechTips/FieldLevelRetargetingLowerWheel-QuillAssembly.pdf


John TenEyck in another thread pointed out that in “the owner's manual for my G0636X 17" bandsaw. There is a whole section about "Wheel Alignment" which starts out "Wheel alignment is one of the most critical factors for optimal performance from your bandsaw. Heat, vibration, wandering, blade wear, tire wear and overall bandsaw wear are considerably decreased when the wheels are properly aligned, or "coplaner".


https://cdn0.grizzly.com/manuals/g0636x_m.pdf


I don’t recall seeing any references supporting the other two possibilities but with age my memory may be growing shorter...


There is no doubt in my mind that a bandsaw can be made to perform satisfactorily without the wheels being coplaner. But that is not the question here.


Above are two references that indicate coplaner position of the wheels is desirable.


Can anyone provide references that support the other possible wheel relationships listed above?


Remember...not opinions...but rather published references such as manufacture’s manuals or other documented sources.


Just trying to solidify what I have come to believe, and think this subject could be of interest to others now and in the future.


You know what you believe. Can you post a reference that supports it?


Bill

[John TenEyck]

Bill, as I recall, after at least one person in a prior post said that some Asian manufacturers purposely set the wheels some amount out of coplaner, I asked the question if anyone could show a reference supporting that statement. No one responded.

John

[Van Huskey]

Take a couple of seconds to think about the issue of coplanar as it relates to bandsaw wheels.

If the proper operating state for bandsaw wheels is supposed to be exactly coplanar then why do bandsaws have a mechanism to adjust the plane relationship between the wheels which you are supposed to use each time to put on a new blade? The word "tracking" would not be in the lexicon of bandsaws if coplanar was the proper way to orient the wheels. They would be adjusted to coplanar and never moved.

So why does the coplanar "myth" exist? It exists because the wheels of a bandsaw have to be within a certain tolerance of coplanar to operate. This will vary with the width of the tire, the width of the blade and distance between the wheels. Consider the venerable Delta 14" saw, you can't have one wheel offset by 3" and have it function nor can you have one wheel canted 45* in relation to the other. So "everyone" talks about coplanar because you need to have the wheels near coplanar.

So why is it that truly coplanar is bad. If the wheels are perfectly coplanar then the blade is very twitchy and tracking it is a huge pain, this is where the smallest adjustments to tracking have the largest impact on blade position*. The offset doesn't need to be much at all, probably lower than most peoples tolerance of what they call coplanar. Keep in mind the methods I have seen on how to check and adjust to coplanar all use the incorrect reference surface. The rim of the wheel is NOT the proper reference surface, the actual top of the crown is the proper reference.

The reason I hate the coplanar mantra is far more people have screwed up their saw by futzing with the lower wheel. I have only seen one bandsaw so far out of coplanar that it would not track blades correctly. It was a PM140 that had the upper shaft so beat up the upper wheel would not seat and was sitting about an inch forward of its proper position.

One doesn't need a higher authority to understand the sole function of the tracking mechanism on a bandsaw is to adjust the wheels in relation to coplanar.

[Edwin Santos]

If the proper operating state for bandsaw wheels is supposed to be exactly coplanar then why do bandsaws have a mechanism to adjust the plane relationship between the wheels which you are supposed to use each time to put on a new blade? The word "tracking" would not be in the lexicon of bandsaws if coplanar was the proper way to orient the wheels. They would be adjusted to coplanar and never moved.



This just makes too much sense.

[Mike Cutler]

Bill

I think a separate questions is generated by your initial question.

I would ask how many band saw instruction manuals do not advocate, or even address, setting the wheels to coplanar? If they're not addressing it, or detailing the methodology to set them coplanar, than that also is a data point.Regardless though, the answer is in the material coming off the backend of the bandsaw. It's either working, or it's not.

As for personal opinion, I still believe, and always will, that a 14" bandsaw, (Delta clone type), is not suitable for resawing on a consistent, repetitive, longterm, basis.

[Bill Space]

I was really hoping to get specific references stating how manufacturers recommend setting up their bandsaws, and to avoid debating the merits or weaknesses of one over the other.

The two references listed above do indicate coplaner position as at least the starting point. Do other manufacturers suggest something different?

I was hoping members here could show us manufacturers’ recommendations differing from those references listed above, as lots of opinions have been expressed here and elsewhere on this subject, but references backing them up have been rare.

Bill

[Bill Space]

Bill

I think a separate questions is generated by your initial question.

I would ask how many band saw instruction manuals do not advocate, or even address, setting the wheels to coplanar? If they're not addressing it, or detailing the methodology to set them coplanar, than that also is a data point...[ snip]



Mike I understand your point and think that falls within possibility 1) above.

Bill

[Zachary Hoyt]

I never considered the question of being coplanar or not till I started spending time on this site. When I have set up band saws I put the blade on the wheels, tension it and then see if it stays somewhere near the middle of the tire while I spin it over by hand. If it does I am happy, and I set the guides and try cutting a piece of wood. If it doesn't I twiddle with the tracking knob till it does. I had an old Montgomery Wards 10" saw that I couldn't get to run right because the upper wheel ran on a bronze bushing that was worn out so it wobbled, and it also vibrated, so I eventually sold that saw for $25, which was only a bit less than I had in it. "Unencumbered by the thought process" is a state of mind I learned about from listening to Car Talk and it usually works for me.
Zach

[Tom M King]

What problem are we trying to solve? While I am quoted with providing one of the references (the "M" is in my name because there was already another Tom King registered as a member back when I first joined these forums), I don't remember ever checking whether the wheels on any of my 3 bandsaws are coplanar, or not. I just remembered seeing a picture of them using fishing line in some Northfield video.

I do this for a living. I just need to produce work. The tracking is adjusted to where it works, and work produced. Or as someone quoted: "Too much to do...Not enough time...life it too short!

[Robert Engel]

I'm with Van.

Bill I don't know what the point really is, because machines are different. What a lot of guys seem so miss is that no all machines are made to have coplanar wheels. The issue I have is with Snodgrass and his disciples is to make a definitive statement across all brands of machines. I believe this has caused a lot of grief and frustration.

So, I'll cite my manual which has nothing in it about adjusting the bottom wheel.

My saw (Rikon 10-345) has adjustment screws for the bottom wheel. The wheels on this machine are definitely notco-planar. In fact, they seem a bit more out than I thought they should be. So I called tech support and their reply was the wheels are set to factory specs and they were emphatic in saying DO NOT change the settings. So this particular machine is set at the factory with non-coplanar wheels.

ASFAI the only reason to set wheels coplanar is to achieve the nirvana of the Snodgrass "No Drift" machine. But if a particular machine is set with non-coplanar wheels, its not going to be fruitful or as Van alluded, you may mess up your machine.

Instead, I adjusted the table (not the fence) for drift and I set the tracking to match, not the fence. I think this is a better way to go.

[Bruce Whitaker]

Bill Space, to reply to your original post asking what do the manufacturers recommend: The 1947 Delta 20” manual states that the wheels are set up at the factory and only tracking adjustments when changing blades should be needed. However, the manual goes on to state that due to abuse during shipping or if a wheel has been removed, the upper and low r wheels must be brought into alignment.

”Use of the 3-point mounting feature previously men* tioned provides a simple correction for such cases. Two hexagon head cap screws SP-628 fasten the left edge of the mounting plate CBS-68, Fig. 8, to the band saw frame. A third screw SP-617 passes through a steel bushing CBS-84. By releasing this screw and turning the bushing in the frame the mounting plate may be adjusted toward or away from the frame, thus shifting the upper wheel shaft through a small horizontal angle. The hexagon head cap screw SP-617 should be tight* ened when the wheels have been made parallel.Similar adjustment for alignment of the lower wheel is provided by the bushing CBS-Ill in the mounting plate CBS-70, Fig. 10. The lower wheel shaft may be shifted through a small vertical angle by turning this bushing.
If either wheel has been removed it must be brought into line with the other wheel when it is remounted, by locking it in proper position on the shaft. A straight* edge built to span the cabinet will be helpful for this.”

[John Sincerbeaux]

Are we planing a lunar landing mission here or cutting wood? Geez!

[glenn bradley]

I was really hoping to get specific references stating how manufacturers recommend setting up their bandsaws, and to avoid debating the merits or weaknesses of one over the other.

I hear you. This topic is second only to chip breakers, Saw Stop and Festool discussions.

My manual dedicates two pages and four diagrams to adjusting wheels for coplaner.

I think we all know that the wheels will probably not be coplaner in operation due to tracking adjustments of the upper wheel. The point of discussion, believe, is the starting point from where that tracking is adjusted.

[Bill Space]

What problem are we trying to solve? While I am quoted with providing one of the references (the "M" is in my name because there was already another Tom King registered as a member back when I first joined these forums)....

Tom, I checked to be sure I did not misquote you. I was referring to post #50 in this thread:

https://sawmillcreek.org/showthread.php?268379-True-coplaner-bandsaw-wheel-adjustment/page2

Not really trying to solve a problem. In my case I have come to believe one thing, and always try to keep an open mind, and see where I may have come to an erroneous conclusion.

So I was hoping to find references related to the three possibilities i listed above, to either cause me to adjust my thinking or reinforce it.

So far we have four manufacturers indicating that coplaner wheel position is desirable. And Robert Engel, in his post above, indicates that Rikon tech support told him that he should not adjust wheel position even if they are not coplaner.

It is not clear what the Rikon factory specs are for the wheels on Robert's saw. It would be interesting to know what they are. For me it would be disturbing to be told something is good the way it is, without being told the way it is supposed to be, so I could verify it was set to spec.

If I read Bruce Whitaker's post correctly, it looks like Delta is calling for coplaner wheels on the 20" bandsaw, and lists a procedure for making them so if the need arises.

Glen Bradley states his manual says the Wheels should be coplaner. Not sure what saw Glen has. If it is a Grizzly then the number of manufacturers supporting coplaner wheel position would reduce to three at this point.

Glen also has made me realize this subject is " second only to chip breakers, Saw Stop and Festool discussions." :eek:

[ChrisA Edwards]

I found this informative

https://www.youtube.com/watch?v=rxfZphxj2eM

[Jeff Heath]

I can share my experience. I cannot give credence to my thoughts while referring to any manual. I currently have 4 bandsaws in my shop. The oldest was built in 1905, and the newest was built in 1947. The two in the middle were built in 1936, and 1939, respectively. These machines do not come with manuals, and all of the manuals available regarding vintage industrial bandsaws at the vintage machinery website, that I have read, do not discuss this issue.

I have restored quite a few bandsaws. When you do that, you get to know a machine fairly well. Here's what I have learned, based on my own experiences setting them up. BTW, I am speaking of industrial, cast iron C-frame saws.

My objective is to get them as co-planer as possible, without stressing over it once the upper and lower wheels are close. The critical factor in a bandsaw blade tracking well is the crown on the wheels. If the crown is perfectly dead center, chances are, the wheels could be perfectly co-planer and the blade will track quite well. However, it is practically impossible to manually crown a bandsaw tire and get it EXACTLY centered on a new crowning job. Because of this (and the manufacturers knew this), the tracking adjuster of the saw allows for slight variances. Each saw will have a different tracking adjustment based on the crowns on the tires.

I have owned two saws, however, where the upper and lower tires were not very co-planer. A 1942 Northfield 36" saw, and a 1939 Yates American Y20 saw. Both were out by around 1/2". They both still worked perfectly, once the new rubber tires were crowned. Without the crown, however, neither saw would keep the blade on the upper wheel. It would always fall off. Once crowned properly, the saws worked perfectly, as long as the guides were adjusted to where the blade was tracking.

The closer you get your wheels to co-planer, and the better job you do at crowning the tires, the better the saw will run true. If you put in the time and effort, you can get a good bandsaw to cut and resaw without any allowance for drift. Is it worth all the effort......depends on how anally retentive you are and wish to be.

[Chris Parks]

Jeff brings up another point, European saws do not have crowned wheels so how do they maintain tracking without the band leaving the wheels. For such a simple machine the hobbyist has a very poor understanding of it due to lack of proper information. Someone has to sit down and design these things but the thinking never seems to escape to the users. I am with Van, I hate the term coplaner and only came across it here to begin with but it seems to have escaped to the wider WW community now.

[Bill Space]

Jeff brings up another point, European saws do not have crowned wheels so how do they maintain tracking without the band leaving the wheels.....

FACTORS AFFECTING BANDSAW TRACKING BEHAVIOR AND STABILITY, a thesis
by DARRELL C. WONG, goes into great detail about bandsaw tracking theory.

He explains two modes of blade tracking. With crowned tires the crown affects blade tracking. With flat tires the blade hangs out over the edge of the tire, and the tire edge performs the same function as a crown.

Read all about it here:

https://open.library.ubc.ca/media/download/pdf/831/1.0080858/1

It has been a while since I visited this thesis. I will have to take a look and see if coplaner vs non coplaner wheel positions are addressed by the author.

[John TenEyck]

I haven't seen anyone post a reference to a manufacturer issued Owner's Manual, repair manual, engineering drawing, whatever, that shows the wheels should specifically be set to something other than coplaner. There were several references that they should be set coplanar. Seems pretty clear to me. Would I adjust mine if the saw cut fine but I found the wheels were not coplanar? Of course not, but I would and have when I had a saw that wouldn't cut straight until I did.

The teeth on a bandsaw blade result in that side riding differently on crowned tires than the back side. To compensate for that you have to tilt the upper wheel back a little. Different blade, different amount of tilt. It would completely unreasonable to expect that the wheels could be set in any particular alignment, coplanar or otherwise, and never have to adjust them.


I use my bandsaws for lots of things, one of them being cutting joinery on thick stock, think dovetails on something 4" thick for example. If the wheels are not pretty close to coplaner the blade will not sit perpendicular to the table. This presents two problems. First, the guides, including the thrust bearing, will ride closer or further from the rear of the blade as you move the assembly up and down. Second, the end of a stopped cut won't be square. Neither of these issues may be important to some folks. They are to me.

John

[Chris Parks]

FACTORS AFFECTING BANDSAW TRACKING BEHAVIOR AND STABILITY, a thesis
by DARRELL C. WONG, goes into great detail about bandsaw tracking theory.

He explains two modes of blade tracking. With crowned tires the crown affects blade tracking. With flat tires the blade hangs out over the edge of the tire, and the tire edge performs the same function as a crown.

Read all about it here:

https://open.library.ubc.ca/media/download/pdf/831/1.0080858/1

It has been a while since I visited this thesis. I will have to take a look and see if coplaner vs non coplaner wheel positions are addressed by the author.



Bill, interesting but flat wheels get a few pars and that is it with no real attempt to explain them. It is pretty obvious how a flat wheel works and I suspect that the flat wheel pre-dated the crown wheel but I might be wrong. I haven't read the entire thing but I will. The bibliography might be useful as well. Thanks.

[Pat Barry]

With flat wheels the blade teeth should overhang the wheels? Never heard of this before. Is that right?

[Chris Parks]

With flat wheels the blade teeth should overhang the wheels? Never heard of this before. Is that right?

That is the recommendation of the manufacturers of the saws that I have used and owned. What must happen is by tensioning the blade the overhang acts like a clawed hand and starts to fold or clench over the edge of the wheel and this action defines the tracking on the top wheel. Other theories or knowledge welcome as that is only my take on it.

[Bill Space]

....The teeth on a bandsaw blade result in that side riding differently on crowned tires than the back side. To compensate for that you have to tilt the upper wheel back a little. Different blade, different amount of tilt....


John, are you sure about this?

For example, when calculating blade tension the teeth material that extends beyond the gullet is ignored.

I do not know, but it seems to me a blade that had the teeth removed would track on the bandsaw the same as an identical blade which had the original teeth. At least for the most part, since the with the teeth missing the weight and balance of the blade would change somewhat.

Bill

[Chris Parks]

My thoughts on this is we are getting into an area of engineering that no one has facts to prove and anything said is speculation. Assumptions never made anything a fact unfortunately. Bill's statement that teeth affect weight and balance do not ring true to me but I can't disprove it so I won't comment and leave it at that.

[Alan Schwabacher]

My thoughts on this is we are getting into an area of engineering that no one has facts to prove and anything said is speculation.

I disagree.

Take a look at the Masters thesis in mechanical engineering provided earlier in this thread. There are specific facts listed, sources for those facts, and theoretical treatments that allow behaviors to be understood. There are careful checks that the predictions of the theoretical model well match the behavior of actual machines. The things you are claiming to be speculation are mostly summary statements from that work.

[Chris Parks]

We agree to disagree, I have looked at the thesis and I could drive a truck through the holes it leaves, as I mentioned above flat wheels get about two pars.

[Bill Space]

We agree to disagree, I have looked at the thesis and I could drive a truck through the holes it leaves, as I mentioned above flat wheels get about two pars.

Could you list some of those "holes" in that thesis?

Appreciate specifics as I am doing my best to understand the intricacies of bandsaws, and have a lot to learn.

Thanks... Bill

[Chris Parks]

Bill, I still haven't read the whole thing and I don't know if I will because the whole point of the document in the author's words was that it was a reference to the workings of bandsaw mills and not bandsaws per se that a hobbyist such as you and I would operate. You may say and I certainly can't contradict you because I simply don't know that the two machines are in essence the same animal but what very little I think I know about bandsaws tells me that they most probably aren't, two wheels and a band being the only common thing between them but operating and setting them up being worlds apart. If anyone has direct knowledge of the two machines I would defer to them. The reference to cutting logs makes me back away from any comparisons.

[Van Huskey]

Mr. Wong references both the tern bandsaw and bandmill in his thesis. Most current scientific papers will be bandmill facing since the bandsaw (vertical woodcutting) is essentially dead in industry. The highspeed bandmill use is actually growing though since the preferred residential flooring has shifted back to wood in the US over the last 20 years. A bandmill is essentially nothing but a horizontal bandsaw on steroids. It does not produce a paradigm shift on the level of Newtonian to quantum physics, most everything that applies to one applies to the other in a general way.

I just made it a few pages into the paper last night, partly because making sure I completely understood all the terms in the nomenclature section took a little more time than most of the scientific papers I have read on bandsaws/bandmills.

Since I have just started digesting the information I can't say for sure but nothing I have seen so far suggests to me that it would not be applicable to bandsaws that we use. The last thesis I read in this arena was one on the causes of band breakage (again industry facing) and pretty much confirmed with data my opinions as well as conventional wisdom. This paper does list an expansive number of variables that impact tracking, my guess is most of them will have very limited impact on the hobbyist sized saws.