Centauro 600

[Tom Trees]

Getting a bit confused now...but thankyou again.
The current blade in use has a bad weld so it has a bit of a hump along its spine.Accounting for that the blade appears to stay perfectly in place on the wheels under rotation.
I also have again hung the teeth off the tyre as Centauro suggest.
So again I will ask how will any east/west alignment issues of the flywheels manifest when cutting.

I'd be very surprised if the blade stayed put at the very top where I've pointed, without the wheels being in alignment.
If you've got genuine Centauro tires for your CO 600, the camber will dictate where the blade goes, (so the blade will have to shift if wheels are misaligned)
and since you're no stranger to bandsaws and threads of such, you'll likely have came across the never ending threads regarding drift,
and tracking of such blades to point the blade in a favourable direction.

Also worth mentioning tracking blades on the crown, if using a narrow blade, (with misaligned wheels) makes a great recipe for nibbling off the camber apex,
resulting in a flat profile on the tires,
like you'll likely have seen on any Italian bandsaw troubleshooting publication, hence why you'd have read it in the first place.
The previous Far Eastern saw I had, one could hear the nibbles and see the rubber dust, on that terribly running saw which the company expert, nor the retailer could sort.
Keith Rucker's Diresta bandsaw series demonstrates a very clear example of a blade walking about on those huge wheels,
so if you've happened to test those new blades with the old tires, it might give explanation of why you've got drift issues, as the set could likely be damaged as mentioned above.

So we're trying to measure if the motor shaft and top wheel shaft are lying in the same planes in both x and y axes but the x axis specifically, and how to do this in straightforward way as only one of them is adjustable left to right.
I did put a dial guage on both wheels and each seemed to have a variance of about 5/100 mm,given the vagaries of a cast iron surface.
But no comparison to each other.
It would seem that to be relevant any variation needs to be measured at the horizontal mid line.
Given the relatively small diameters of the shafts this feels difficult to achieve in a meaningful way in a woodshop.
If I set the saw level and then shot a vertical laser line I'd possibly pick up some variation?

Using the 25mm blade and cranking up the tension a bit more has helped with the blade wandering.Currently wanting to rip 300mm.
The most significant issue now is the work piece drifting off the fence.
I've tried the free hand cut allowing the blade to take its course and then setting the fence to that but no joy there...?
Thankyou to all who bother to read this.

My response concerning taking any measurements, would be related to the bottom wheel and motor, not the upper wheel
since it's a datum. (be it done with wheels made accurate, or the laser mounted on the shaft)
since you didn't mention which Centauro 600 saw it was, I mentioned all three of differing builds,
then responded when asked how to align wheels, which might not be the most pleasing answer for those without the specific foolproof Centauro.

Saying that, the datum doesn't change regardless IMO, as I could have skewed the carriage to suit the motor if I wished,
when repairing damage of the fixing points, a nitty gritty job to fill, drill and tap for those bolts either side...
SAM_4491.jpg
https://i.postimg.cc/PrTTxBLr/SAM-4491.jpg
but that wouldn't be pleasing whatsoever, as the guidepost and table would need be skewed to suit...
so the wheels needs to be accurate to get some reference from, if not making a tool mentioned.

Mentioning axis would likely be misleading, as there's adjustments on the upper wheel on most Italian saws to account for differing tire thickness,
to suit the parallel guidepost, which would be an axis adjustment.
Plane as you mentioned, lateral rotation or tilt is a separate thing, and that's why I'm mentioning east/west, as it concerns the jacking screw adjustments which tilt the wheel shaft at the back of the lower wheel.
What might indeed be confusing matters was me mentioning anything else but sureworthy methods, and that's getting an accurate reference/datum line from the upper wheel,
as the scribing beam proved the wheels aren't to be trusted without checking/making accurate to use this method,
hence the laser mounted onto the shaft is quite likely a more sensible approach.

(I could mention I didn't find any difference getting this datum line without a blade, (for interests sake) pressing well down on the lower portion of the wheel,
so it probably isn't necessary to make up a shaft extension,
but I've read from Eric's posts that the carriage might not be quite as snug as on my ACM, so couldn't advise for surety)

Not having a groove in the wheels on my Italian machine, making the edges/lips/rims accurate, simplifies matters for me down the road should a blade snap and rip off a tire,
then I can simply line up a spare with the edge of the wheel.
Centauro or some Meber owners obviously wouldn't need to do this, if they bought a genuine replacement tire.
Scribing datum 2.jpeg
https://i.postimg.cc/MG7XN1N9/Scribing-datum-2.jpg

I could post some other miserable pictures of motor disassembly for fair warning if intending to compromise, if not having a loose drive belt, or belts to test,
but that would likely confuse matters, and besides it's a pure lottery whether the chassis behind the lower wheel might be somewhat in line with the upper wheel.
This might be a more helpful picture instead
The right shim.jpg
https://i.postimg.cc/63xQtcFk/The-right-shim.jpg
All the best
Tom