BS bottom wheel tracking?

[Wade Lippman]

I have a Rikon 10-345. It runs fine, but I noticed that the bottom wheel is tracking at the very front of the wheel. The manual gives instructions for aligning the top wheel, but doesn't mention the bottom.
I have an email into Rikon, but am not holding my breath for a reply.

Is this okay, or must it track in the middle?

The wheel axle stick out the back and there are 4 bolts to it, which I presume are for adjustment, but the manual does not refer to them.

[Erik Loza]

How does it cut?

Erik

[Phil Thien]

On crowned wheels, a band running center of the top wheel will always ride front of center on the bottom.

That is because the length of the band is less than the distance around the two wheels (otherwise we wouldn't be able to apply tension).

So we play with the camber of the top wheel until the blade is centered. But at this point, being of finite length, the blade can only ride so far back on the bottom wheel.

You can adjust the camber of the bottom wheel, which will influence where the blade rides down there. But I'd only make adjustments there if multiple blades of different sizes all were running way forward on the bottom wheel, and if the result was the blade wasn't cutting square to the table front to back.

Edit to add: I do think the camber of the bottom wheel has been an issue on some Rikon saws. I'm pretty sure I've seen threads where Rikon sent instructions to owners on making adjustments.

[Wade Lippman]

It cuts fine.
I couldn't find anything on the Rikon website, and didn't think to google.
But found this:
http://www.rikontools.com/Manuals/Lo...djustments.pdf

But the other part of my question, does running on the front part of the bottom wheel matter?

[Erik Loza]

Just my opinion, for what it is or isn't worth: If the machine is cutting the way you want, then I wouldn't worry about it.

Erik

[Phil Thien]

Just my opinion, for what it is or isn't worth: If the machine is cutting the way you want, then I wouldn't worry about it.

Erik

I agree w/ Erik.

All blades will run front of center on the bottom wheel, to varying degrees (and seeing as Erik is here we should point-out this is for saws with crowned wheels only).

It doesn't matter unless it is causing a problem. Like, too far forward and riding off the wheel when backing out of a cut. Or cuts that aren't square to the table.

[Mike Cutler]

Wade

I have the predecessor to your saw. I have the model 10-340.
The four bolts you are referring too correct the "pitch and yaw", for lack of better expression, of the lower wheel.
If your saw is running fine leave them alone. The adjustments are very sensitive. Yes, I needed to mess with mine. Turning one of those bolt heads a 1/4 of a flat has a dramatic impact at the outer wheel edge, and they have to be turned in pairs. If you should ever need to adjust them, you will need an ultra fine marker to match mark everything so that you can gauge your progress, and if necessary go backwards.

[Allan Speers]

Wade,

Check that the adjustments Mike mentioned are correct, then also check that both wheels are coplanar. (In other words,, all the edges line-up, and they do so at far left, far right, and center.) If not, no matter how you adjust everything else, then you might have to add or subtract a shim (washer) behind one of the wheels.

Like everyone else said, if the blade is just a LITTLE bit forward, but not hitting the cover and not interfering with the cut, then you're good.

[ian maybury]

Alignment of the lower wheel on bandsaws is an interesting matter - one that's probably best looked at in the context of the total set-up picture. Pardon my usual length.

We often casually tweak stuff while focused on achieving one effect - but don't realise that we're inadvertently disturbing other adjustments that matter too. The line in which the blade tracks on the wheels isn't for example a matter of free choice (at least not without other compensating adjustments), it's actually one of a number of interdependent (change one and you disturb others) settings on an accurately set up bandsaw. It's often hard to detect what's going on because these disturbances start out as minor, and their effects may surface only as a general inaccuracy or inconsistency in the saw. By multiple adjustments later who knows where it's all ended up.

I'm a big believer in initially working through the set up of machines up from the ground up so that we have baseline settings or alignments for everything - of doing the hands on work to get to the point where we truly understand what we're actually having an effect on when we make an adjustment.

One fundamental that sometimes gets missed in discussions about bandsaw set up is that the upper guide post needs to end up sliding up and down in the same line as that the blade is running in - otherwise every time it's raised or lowered the guides will need adjusting in and out to the correct distance from the blade - or they will end up deflecting it. The table can then squared in both directions to the line of the blade.

With cambered wheels it's important that the blade consistently tracks on the same line - because if it changes location (moves to a different point across what is a curved wheel surface) then the line in which it cuts will change. Which will likely lead to the saw not cutting in the line of the fence as it previously did, and may also move the blade out of alignment with the guide post.

Blade tracking changes (which may be caused by lower as well as upper wheel realignments) may lead to other issues too. The deal is complicated by the fact that it's the actual line of travel of the blade we're interested in (which is e.g. changed by said tracking adjustments) and not just the line of the plane of the wheels, and that there's two axes involved. i.e. coplanarity establishes a basic alignment of the wheels relative to each other, but doesn't entirely determine the actual line of the blade.

Most of the time when we set up saws we start from the presumption that certain basic alignments like that of the guidepost and wheels are correct, but this is not necessarily the case either. The possibility (apart from tracking changes) is that if we then make adjustments to realign/place both wheels in the same plane (set them to be coplanar - especially using the lower wheel adjustments) we could create a situation where the upper guide post is again moved out of the line of the blade, or in an extreme case the blade ends up moving into an unsuitable placement relative to the chassis leading to the possibility of it touching guards or even bits of structure, or not centering in the throat plate or whatever. (unlikely if the saw was pretty well set up in the first place)

There's actually a number of alignments that have to simultaneously end up set correctly, and depending on the design of the saw and the available adjustments the most effective sequence/set up procedure may vary a bit. They are reasonably self evident though if we move to thinking holistically and in 3D about alignment rather than getting sucked into focusing on single adjustments in isolation. Presuming that is a well built saw with an accurately fabricated chassis that places some of them correctly.

Bigger Italian saws for example often have the ability to adjust the line of the upper guide post, while smaller models may require shifting the line of the blade (using our lower wheel adjustment) to suit a fixed post. Luckily if we get the wheels correctly aligned and placed, and hence placement and line of the blade right there's normally enough adjustment range in the other settings available to sort out the rest - even if the final fine adjustments are likely to require a bit of iterative trial and error.

Seen in this light the lower wheel alignment adjustment is pretty much essential. The typical four bolt arrangement means that it can be tilted into any plane around the vertical, and it can also be moved in and out along the stub axle. So it's central in achieving coplanarity of the wheels, and in placing the blade in the correct line and location in the chassis...

[Wade Lippman]

With cambered wheels it's important that the blade consistently tracks on the same line - because if it changes location (moves to a different point across what is a curved wheel surface) then the line in which it cuts will change. Which will likely lead to the saw not cutting in the line of the fence as it previously did, and may also move the blade out of alignment with the guide post.

It took a couple of inquiries, but Rikon finally got back to me; assuring me that adjusting the bottom wheel wasn't a big dieal.

I had to turn the top and bottom adjusting bolts 1.5 turns, but it is now centered. Of course, the top wheel and the guides then had to be adjusted, but they are fine now also.

Before, the blade cut at a slight angle to the fence. I didn't use the fence much, so I lived with it. It seems to be better now; so maybe tracking on the bottom wheel is important. Or maybe I am imagining it.

[John Kananis]

Congrats on working it all out.

Question for you: When you center the blade on the top crown, are you centering the middle of the blade or the gullet of the teeth [the latter is much more effective (IMHO)]?

[Wade Lippman]

I centered the blade, because I thought that was proper. I am pretty ignorant about all this.