Defects in material or workmanship can take a long time to appear

I've got a nice little Rikon 14" bandsaw - the 10-325 - about a dozen years old. It's a nice saw, for a mid-range import (I think I paid $800 for it new), and has served me well. It runs incredibly quietly, when properly tuned. But it's been getting noisier over time, and the other day the offending drive wheel bearing, as I now know to be the problem, seized and broke a blade with a bang. I decided to replace both top and bottom wheel bearings since I had to take the saw apart anyway. The wheels, as it turns out are on two standard sealed bearings each. I removed the bearings from the bottom wheel, and found that one of the bearings has no seal on the inner side of the race, and a gap between the bearings. Ouch on the seal, right? Then I took the bearings out of the top wheel and discovered that there is a 7mm bushing between the two bearings. Looked it up in the parts book and sure enough, there is supposed to be a bushing on both wheels.

So, this saw was assembled with a bad bearing (no way for a seal to get out of where this one was missing, and there were no seal remnants there), and no bushing. The bearing was bound to fail in an environment as dirty as the bottom cabinet of a bandsaw. I'm surprised it ran for a dozen years. The consequences of the missing bushing? I'm not certain there were any, as both bearings were in their proper position when I removed them. But this saw has always had a strange quirk that when you put a blade on it, even an identical one to the one you've just removed, the blade would on occasion track WAY off the center of the upper tire, to the point of running off the back of the wheel. You'd have to push the wheel tracking camber to it's very limit to get it to track, and then at some point, it'd flop over to the other side, I'd have to adjust the camber to something more normal, and it'd run that way until the next blade change. This annoyed me, but I could never figure out what caused it, and the saw ran fine in either adjustment. Was the bottom wheel moving on bearings that weren't held in the proper spacing on the shaft, and I was not seeing it? I guess time will tell. I made a proper bushing, and reassembled the saw with 4 good bearings and 2 good bushings, so if the problem goes away, I guess that's a puzzle solved.

But sheesh - a bad bearing and a missing part, that's really bad quality control at the factory.

Interesting. I'm going to check mine for the wheel bearings, as it has never run like I think it should. Mine absolutely eats the bottom blade guide bearings - which are simply cheap roller skate bearings. I've been sorely tempted to replace them with cool blocks or something similar.

On sealed bearings... It is standard machinery practice to only use seals on the "Outside" when you've got two bearings back to back like that. I would guess they are tapered roller bearings to keep the wheels tracking right.

Typically, you squirt a bit of grease inside through the middle, and it works its way into the bearing.

12-years of use doesn't seem like much of a "Defect in Design and Workmanship" as much as lack of maintenance... I myself am guilty, as I've had mine since soon after they came out and have never even checked the wheel bearings. They are probably due, at a minimum, for some grease.

John - Everything you say makes sense, except that it doesn't apply to this situation . 3 of the 4 bearings I replaced had seals on the "inside", and the part numbers on the bearings are for double sealed bearings. They are deep groove ball bearings, not tapered roller bearings, and there is absolutely no way to get grease into them once installed.

The "defect in design an workmanship" to which I refer is simply that someone assembled the saw with a damaged bearing (seal missing), and without the bushing between the bearing that is clearly shown on the parts diagram for the saw. So, the saw was assembled "defective" at the factory. That it held up for as long as it did testifies that the bearings used were quality components, and adequately sized for the load they take.

Y'all should know by now, bandsaws have been designed to fail since 1996. ...
unless perhaps, you're looking for an 800mm wheeled machine like this CML/Sagitario from 2002,
which is probably the last Italian manufacturer to have made a fully adjustable bandsaw.

Not really something you can readily move compared to a Centauro CO,
The SC 800 @400kg
Attachment 517741
Perhaps someone else could find a smaller CML/Sagitario which has the same adjustability as the above?

There is however, another machine which was made in Taiwan, a 600mm wheeled saw @340kg, and they don't make it any longer,
(I had to dig out my old magazine to find accurate specs)
However, one could possibly argue that both of these are re-saws, rather than bandsaws...(I thought the saw below was 100kg heavier)

Attachment 517742

Because the bearings share a common bore, seals aren't necessary. Only way for dust to get in there ism thru outer seal on bearings. Bought a bench grinder once, and same set up, bearings only sealed on outer ends. Motor was a TEFC motor, but it was sealed.

Bruce - that's true, if the machine is designed that way, in which case the common bore between the bearings would be grease filled, and the whole assembly would work as a single, twin race, grease-filled bearing. As I explained to Tom, this machine was designed with two separate, sealed-on-both side bearings with a significant gap between them. The gap was not grease filled, and was never intended to be, and of the four bearings on the two wheels, 3 were intact, sealed-on-both-side bearings. One was missing it's second seal, and because of the gap between the two, was also dry - the grease having been slung out into the gap over operation of the saw - and consequently seized.

But you're right, dust couldn't get in there, and that part of my initial description was a bit off the mark. The bearing failed from being dry, not because it was full of dust.

Well, it could well have failed from the lack of seal. While I haven't dug too deeply into my Rikon, I once got a Grizzly "Belt powered buffer" arbor. It had the grooved sheave on one side and the clamp bolt on the other for a buffer mop or grind stone. Presumably, you would run it off the motor off of an old dryer or something.... Anyway, the whole casting was still full of sand from end to end. They just poked the shaft through and stuffed bearings into the ends, but I swear close to a pound of casting sand came out when I disassembled it and cleaned it out.

Stray metal shavings, grit, or trash could have gotten inside the unsealed end of the bearing during assembly, especially since those unsealed units are designed to be greased after assembly, so they typically only have a little light machine oil on them from the factory.

Quote:

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Originally Posted by Tom Trees

Y'all should know by now, bandsaws have been designed to fail since 1996. ...

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Why do you say that? Not arguing with you... I just don't know the "history of bandsaws".
What happened in 1996 to Bandsaw designers/manufactures?

Quote:

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Originally Posted by Patty Hann

Why do you say that? Not arguing with you... I just don't know the "history of bandsaws".
What happened in 1996 to Bandsaw designers/manufactures?

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What happened in 1996?....
This is all speculation, but fairly evident IMO, if one looks up some old posts here by Van Huskey, a prominent bandsaw aficionado
they might get the same impression.
i.e here's an old thread which might suggest something along those lines..."Every time I talk to one of the insiders I get a different story"
stuff like that to start with....
https://sawmillcreek.org/showthread....alian-Bandsaws
I can try digging up some other thread about the old man at Centauro being displeased about something, if not in that one...
I contend that was in 1995/1996 (pure guess n my part) :rolleyes:

Now let's examine the machines instead, and put the conspiracies aside for the moment...
The leaders of the pack, an Italian company, Centauro who made the blueprint in regards to modern design... (look up their website for the story)
decided to change tack, because their flagship model, the second gen of "lightweight" bandsaws, the CO was just too good.
That would be sometime during the 1980's until mentioned, when the fully adjustable machine was done away with, and as such the deception entered a new level.

Here's the first seemingly non adjustable one, though the same thing regarding the lower wheel, as with some of the older small Mebers,

Attachment 517762
and the second gen CO
Attachment 517759
one could speculate it was made to outclass the local competitors.. namely ACM,
though not to omit the fully adjustable Meber, some of which are very similar to the Centauro machines in many ways, grooved wheels for one.
Attachment 517764
and the tables for example, very similarly machined,
Attachment 517763

Here's some old ACM saws (with non adjustable motors) which I assume was some time around that, difficult to get dates though...
Attachment 517760Attachment 517761

I can post some links to the user manuals of the CO, of which there are many,
but yet, no mention the cambered tire profile in the troubleshooting, like what's in the older SP manual....
https://owwm.org/viewtopic.php?f=1&t...anual#p1805193

Here's a photo of a replacement CO tire, just to show the camber, as it's very important regarding all this.
Attachment 517765

No more space for pictures

Attachment 517766

Aligning the wheels...i.e not to have one wheel facing east, whilst the other wheel facing west, isn't quite as simple as it may seem,
which I've explained in recent enough posts, but to get there, a quick photo or two of things, the way I've done it,
Attachment 517767
And the datum to get there, seeing as my machine was made fully adjustable, (with no compromises)
Attachment 517768

Lots in between, which I won't get into, but to mention, I had to fix damage of the wheel bore
which is the most important reason for alignment, and retaining the camber the second.
Both extremely important in regards to longevity of a bandsaw, and a complete lottery if ignored.

No need explain that all the machines made today don't have such adjustments,
whilst some unscrupulous far Eastern manufacturers taking things one step further in regards to "jobs for the boys"
regarding no hub for adjustment of the lower wheel.

Best get a Centauro, instead of anything else really, and get a tin o'paint if one of the newer ones, or other nice Italian saw,
or at least something else which is a closeish copy of such like the Rikon,
and plan for the future, unless you wish to repair those wheel bore journals.

That's just the way things are these days, and thus concludes the modern history of bandsaws.:D

Sceptical perhaps?... just look on the bay and see for yourself!

All the best now

Tom

Bearing need spacers between the inner races., otherwise tightening force will push on the race. It's surprising even on industrial machinery, that spacer is missing. Ideally the inner seals are popped off and the cavity 1/3 filled with grease. 6200 series bearing are fine for that use.

The good news is that it is an easy fix and not expensive. When I replace bearings I tend to buy an extra set. They are only a few bucks and I wire tie them in a zippy bag to the machine in some out of the way place for next time should it appear. I do tend to upgrade the bearings when I replace. Like a lot of factory blades the bearings are what is reasonable for the price point. A sealed (versus shielded) upgrade doesn't hurt. I am still working on a tube of guide bearings that I bought for one of my bandsaws over 15 years ago. They were sure cheaper then and I have them when I need them.