Bandsaw wheels with non shouldered bores

[Ttrees]

Hello folks
Bit of a head scratching moment.
Hopefully this will be the end of my Centaurolization attempt on my old Italian bandsaw.

After tracking down the cause of upper wheel wobble to this, it seems I need to address the spacer issue I'm having.
This is the rear of the wheel, and that bearing has some space to wander until it butts against the retaining clip.

A clue might have been that the bolt never cinched down on the washer holding the wheel/bearing in place.
As in the inner race was free to move about, and the washer does not have any say in the matter.

Noting that the Centauro's of old, have a big washer which looks to capture both races of the wheel, I wonder what kind of spacer is in those wheels.
That is.. if those wheels have a non shouldered bore?
If so, I question if things are still the same with new machines made today, using a non shouldered bore...
Is there a better way of doing things, as that orange spacer seemingly isn't up to the job.

Some Centauro machines of old have washers that seemingly might compress or at least align with both inner and outer race,
with possible a thou more contact with the inner race?

Compared to my machine where the washer which would only have contact with the inner race...if the spacer was wider, that is.

Looking at Jack Forsberg's videos earlier of work done to the Poitras (non shouldered bore) spacers and bearings.
I couldn't find recent activity on his local forum to question him about it.
Here is a look at the bore

I'll skip to the more important aspect of the spacers which Jack covers


I see a cast hub with a raised ring to press against the outer race,
Seems he has two spacers made of cast iron and the inner spacer is a thou wider.

I wonder what would be the best solution for me, as I don't see any wear on this orange plastic/rubber spacer,
and I guess things could be improved.

Love to hear some suggestions, especially anyone who possibly might have worked on Centauro's which possibly has a better system,
as I've not read anything about this before, nor can I find anything but Jack's posts on the subject.

Thanks
Tom

 

[Ttrees]

Been looking at more machines
Here's a Centauro CO 600 from 2001

And the SCM formula

As one can see the retaining washers seemingly look to cover both races.
I'd love to know if these machines also have a non shouldered bore, and if so
what kind of spacers are in these wheels.
Not exclusively referring to European saws, just would like to know what other solutions regarding spacers are done, for non shouldered bores.

Just trying to figure out if I can make something from some steel pipes, as I don't have solid lumps of metal that size.

Love to know if this would be adequate.

Thanks
Tom

 

[clogs]

In the past I've repaired/replaced worn out bearings and spacers.....even at times having to re machine the bearing bore due to a spinning bearings....on all kinds of machines.....
I now use this kinda bearing where poss.....
these are for the auto trade, note that the inner race is split and the big nut tightened down tight....often 100lb/ft of torque.....this compresses the inner races for the correct fit....IE, free to rotate and no wobble....
those bearings are available in many different sizes so plenty to choose from....specs are available to get a bearings near enough to original sizes.....
they are also fully lubed for life....I've seen them go over 250,000 miles and still in perfect condition....totally sealed...these bearings will carry extreme loads and at high speeds on vehicles and so the job in a bandsaw is well within spec.....
with careful spacing to get the wheels in line they are a better job than the original....
there is a little machining needed, spindles and bores etc....but done once they will last the life of the machine...
those bearings are for a Nissan Note at £16 each bearing....
so as cheap as chips...
this style of bearing are used on small trucks weighing over 3.5 tons...they have now replaced the adjustable taper roller bearings of old......
I've used these bearings on home made machines as well as line shafting etc....
I had intended to build my own h/d wood lathe for turning wood root balls up to a ton in weight using these but bigger bearings in the headstock, that job would require 2 bearings...but have now bought a super h/d wood lathe....
just saying....

 

[Ttrees]

Thanks Clogs
I've not known of those super wide bearings before, but it appears that I'd still be faced with a spacer issue to suit the wheel.

From looking around so far, it seems like near everyone else making a European(ish) saw bar SCM and Centauro are using the same smaller washer.

Including this SNAC machine, slightly heavier duty than mine, has the small ones,
but seemingly might use the twin spacer idea like in Jacks Poitras machine.
Seems like it might be from the upper wheel too, since it's running without a blade.


EDIT: That wasn't a spacer, it is just a roll of tape on the table! Lol

 

[Ttrees]

So I've at least tracked down a manual for the Centauro CO machines
You would have to go to page 35 to view it, as I cannot copy a PDF
Anyway it appears that the CO models also have a non shouldered bore,
although I can't be certain from the drawings.

There looks to be some subtle differences which might be worth some further pondering.

Mainly hoping someone with a Centauro or SCM machine would be able to help me regarding the spacers, and be able to tell me what material it is made from.
Whether it is tight on the shaft like a slip fit, or loose, and if it's as thick or thicker than my spacer or say the inner race.

Asking on the Creek also, so hopefully some Minimax/Formula folks will be along to answer my queries.

Thanks
Tom

 

[Ttrees]

Hello again folks
I found a piccy of a spacer on a Centauro CO800
https://www.owwm.org/viewtopic.php?f=1&t=180094&start=15
Nice to see the innards of the machine

Should this wheel be firmly seated onto the shaft, then it would mean that the washer compresses on the inner race, instead of the shaft being proud which it was on my top wheel.

And finally the spacer, looks to be made of mild steel, and seems a snuggish,
or even a slip fit onto the shaft?

Quite a bit of difference it appears from a glance, hoping to get a better idea.

With that rough shape in me head, I set about searching for some suitable pipe, all of which were to large of an internal diameter, not as thick as the mushrooming would make out it is.
I have this lump of steel which would do one wheel, so immediately went to check if this were necessary with the lower wheel also, but luckily it isn't and I'm not able to move that washer which presses on the inner race.

So I measured the orange plastic spacer and found about half a mm in variance,
although I did not check if it sat square, so it could be off by more than that.
Also thinking there's likely some play in the snap rings and the slots for them.

Have some old bearings to check with, and sneak up on the fit.
Seems I've got some work to do.
Hopefully that's all there is to it, fingers crossed.

Thanks

Tom

 

[Ttrees]

Just wanted to give an update on this, as a new spacer was made for it.
Now the wheel is solid.

Tried making a metal spacer, but the lump of metal was case hardened and it eat my bench grinder wheel for breakfest, as quickly as one of the super aggressive wheel devices one can get, a wheel down but a tool up.

Carbide tile bit wouldn't touch it either, likely the wrong geometry but should cut,
asking a bit much on this wood lathe.
Quick poor mans cross slide rigged up, and turned on a mandrel like in Jacks video.
(Thanks Jack)

I got some sharpening tips for making cutters from, this old Tony, and Abom79
and some inspiration from others making cutters from old drill bits.

Didn't get this part drilled as accurately as I could have due to the plastic deforming in the vice.
Might be making another pair of these, but holding off on that until I do some testing with my machine.
Very easy to use, wee taps for advancment makes it very relaxing and pleasing tool to use.
Chamfered the part to reduce down to the inner races, by shifting the bed to it's maximum skew,
The tail stock and motor gives one a rough reference.

Sneaking up on the fit, got quite comfortable with things going back and fourth to the lathe.

Now the wheel retaining washer can actually clamp down on the inner race like the Centauro shown earlier.

Going to attempt cleaning the older and more than likely original Koyo bearings and reinstalling them,
As you can see there is more surface area of the race compared.
There's also a heavy chamfer on the inner race on these SKF's, which won't have as much contact with the snap ring.

Should some wear be the case, things are thankfully, seemingly nice and tight,
then these seem to me to have that little bit more insurance with the greater surface area in contact with the bore.

Need info about cleaning bearings to progress with that,
but have other things to test seeing as the wheel is now shifted forwards a bit, and not going in and out on the shaft.

Combined with a heavy chamfer on the bottom wheel tire, due to damage,
the top wheel tire which hasn't had the edge addressed yet,
makes for some interesting experiments to try out some queries I've asked on various forums.
As I got the impression that the edges play a part in running a quieter machine.
Important to have that for me, seeing as it's my most used thing when I'm woodworking,
and wish to hear whats goin on around me.

 

[deema]

Just seen your thread Tom, anyway, my two penny’s worth, spacers are normally seated on either the outer or inner races only, any diameter of spacer will do, as long as it’s not touching the other race. Anything metal will do. When clamped up, ideally you want the spacer locked against the two bearings so that it won’t spin independently, so good faces that make contact with the bearings is what your aiming for.

Well done and very ingenious solution for turning up the spacers.

The circlips are only there to retain the wheel on the shaft, so as long as the outer race makes contact with the circlip no real worries. Personally I would replace the bearings with new, if they are metric they won’t be that expensive I wouldn’t have thought. The greater risk is that they seize and then either scrub the shaft or wheel journals which is a much bigger and more expensive job to rectify.

The the bearings are not a press fit you need to use some form of bearing lock otherwise they will wear the journals.

The clamp washer must inky touch the race that the spacer is also supporting, otherwise you are applying pressure through the bearing it’s not designed for and it will wear out quickly. You’ve got a good solution, well done

 

[Ttrees]

Cheers Deema
Nothing much ingenious on my part, thanks to Jack Forsberg making the video, as I doubt I could get things as good by hand or whatever method which would likely have been a grinder.
Hopefully the solution will work out and that will be the end of that,
don't mind a bit of other stuff, I'll just be glad if I don't get some more surprises/lessons
along the way.
Went to the agri shop for some fuel, and found where they keep the grease.
I was a bit confused about the differing types, so rang herself's da,
don't get the blue one, as its too stiff for the job, just the regular stuff will do.
Seemed the brown and cheapest was the way to go, 3 euros!couldn't say no, was expecting it to be 5 times the price.

So will give these bearings a go, well at least a pair,
should I be able to take the seal off.
I see folks have commented about all this, so it's likely better to use that thread
about cleaning bearings.

I'll be keeping an eye on these bearings should they be acceptable,
with the intention of changing them at a later stage without the machine doing too much work.

All the best

Tom