Minimax MM20 upper bearings

[Brian Holcombe]

My upper wheel bearings sound like they are in need of replacement. Just checking in to see if abyone knows the bearing number? The number is facing in on
mine. I’d like to get a new set before I pull the wheel off.

I tried to order through SCM but they sent me guide bearings.....

[Tom Trees]

My acm saw had the same size sets of bearings on both wheels.
If it is the same as my saw, then the top wheel shaft is movable in the cast carriage and there is a bolt for adjustment.
If the saw was running prefect then I would suggest measuring wheel position/protrusion from the cabinet.
Might be necessary to get wheel plum first, so might be worth measuring the tracking knob distance before you start. if there is a fair of adjustment.

The top wheel might slide of without pullers, but you may need bearing pullers for removal of the shaft of the lower wheel.
As again if it was perfect before, If taking off the lower wheel, then leave one of the east or west jacking bolts alone.
Easier to align the north south ones. take a snap of the position when you remove the bolt and washer.

You also need some tool for removing the retaining clip, i'm sure you could get one cheap.
I bought SKF ones for the job, I think it was about 25 quid for the four, but I've recently read that SKF can be a loose fit on shafts, compared to other brands.
Don't know if that's true or not?
I heated my bearings, and froze the shafts, two great youtube videos by Jack Forsberg on bearings worth watching.
I think I used a dowel for knocking the old ones out, but would think there's a much better way to remove them using the pullers and some ingenious way
of getting a plate inside.
Eager to see

Tom

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[Brian Holcombe]

Thanks, Tom. Appreciate the insights.

I spoke with Patrick Walsh and he had the bearing numbers. The number is 6207-2RS i
decided to get the Abec 3 version which is rated for higher stress since I run a carbide blade all the time. The current set lasted about five years, which seems a bit low to me.

I do have the necessary snap ring pliers and a bearing splitter for pulling the shaft.

[Erik Loza]

Brian, all good info so far. I will add that pounding the upper wheel back onto the arbor shaft is murder. I used the heaviest dead-blow mallet I own and still had to take a break halfway through. I would coat the arbor shaft with a little grease and also, a dab of anti-seize on the main bolt threads. Hope this helps,

Erik

[Jacques Gagnon]

I will add that pounding the upper wheel back onto the arbor shaft is murder. I used the heaviest dead-blow mallet I own and still had to take a break halfway through.
Erik

...This might explain why woodworkers stay in shape without ever having to go to the gym.:D

[Brian Holcombe]

Here is my plan so far, please feel free to shoot holes in it.

planning to remove the shaft support assembly, shown here. Press out the shaft and install new bearings using the hot bearings cold shaft method or a press (or both).

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[Bill Dufour]

Do not heat the bearing over 300F or so. I grind down the outer diameter on the old bearing and use it to press in the new one. You may have to disasemble it in two so only the outer races touch. If you heat it red hot and let it cool the inner race can be drilled out a little bigger and also used to press on the new bearing. You only need to take off 5/1000" or so to get enough clearance.
Bill D.

[Erik Loza]

There shouldn't be any need to superheat parts for this project. I've rebuilt many MM's from a bare chassis, up. Maybe put the bearings in a ziploc bag in some hot water but that's it. All things being equal, I would rather have a large puller and mallet than be boiling parts. You can't really hurt anything in this machine. Brian, is that sound deadener in there?

Erik

[Tom Trees]

Has getting them out of the wheels been addressed yet?
I presume there's fancy pullers with exchangeable arms so the ends can get inside the inner race somehow,
or some expandable round plate to do the job.


Was thinking it could be done with stacks of shaped sheet metal thin enough to get in there.

Pity I didn't think ahead and take more notes, I would want to know I done the best job I did now, as there's a slight hint of a thud, when the upper wheel is spun
without a blade installed.
Not sure if it always was there, and I can slide my upper wheel off the shaft without all that sweat,
again not sure if it would have been an easy job with the old bearings. (a few things were a bit ceased when I got my old machine)
Might have a look at presumably original Koyo's again as there was nothing wrong with them, probably battered now though from my dowel shenanigans.

Sorry if the above is already sorted,
Thanks
Tom

[Brian Holcombe]

There shouldn't be any need to superheat parts for this project. I've rebuilt many MM's from a bare chassis, up. Maybe put the bearings in a ziploc bag in some hot water but that's it. All things being equal, I would rather have a large puller and mallet than be boiling parts. You can't really hurt anything in this machine. Brian, is that sound deadener in there?

Erik

I think I’ll press in the bearings at room temp and install the shaft frozen. Heating a bearing above boiling is poorly advised as Bill mentions, so I don’t do that.

Anywho, forgive my ignorance since I have not broken down this machine before, but I assume the shaft support can be removed if the spring pressure knob is totally backed off. Is that accurate?

Very much Appreciate your guidance!

Tom and Bill, thanks for your thoughts as well.

[Bill Dufour]

Make sure the new bearing are rubber sealed on both sides.
Bill D

[Bill Dufour]

I recommend everyone buy a small bearing splitter say around 2". Buy it used on the bay before you need one and get a good price.
Bill D

[Brian Holcombe]

I have a bearing splitter, one of the best purchases I made for working on cars. I went totally overboard on snap ring pliers and bought the full lineup of knipex recently after having dealt with one crappy pair or junky adjustables for the last twenty years or so.

[Tom Trees]

Here is one video of a few on Jacks channel, which demonstrates heating the bearing on a light bulb.
https://www.youtube.com/watch?v=ocsnUBYEyuM

I don't recall my bearings being this easy of a fit when I did it.
https://www.youtube.com/watch?v=Bza0WiKMckE

Hope to see some clever way to take the bearings out of the wheel, if things are tight.

[Brian Holcombe]

Roger on the bearings, I’m good to go on those. I’m more curious if that whole carrier can come out easily. I’ll find out in a few days I suppose but knowing would help my planning a bit.

[Tom M King]

This is the best money I've spent on cheap, Chinese tools. I'd be rigging up a way to use a press, but have been known to use a big hammer with one of these dies, and the handle that can fit in it.

https://www.amazon.com/ABN-Bearing-Driver-50-Piece-Carrying/dp/B073ZMFV38/ref=sr_1_1_sspa?dchild=1&keywords=bearing+press+set&qid=1620412278&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyMFBJQlNaRlpDQVBSJ mVuY3J5cHRlZElkPUEwMTA1MjQ1MzdKOTZVQzNXRjFVTyZlbmN yeXB0ZWRBZElkPUEwMjE4MDU3M0tVSk1UTzlKSElDMSZ3aWRnZ XROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05 vdExvZ0NsaWNrPXRydWU=

I have used a hydraulic jack, under an 18,000 pound tractor, for something that wouldn't fit in the press.

edited to add: With that press die set, you can even put two on the handle. One that fits the bearing ID, and another for the pressing of the OD.

[Bill Dufour]

I bought the channlelock snap ring pliers with replaceable tips. Not noticeably less solid then a one piece pair for the size. Nice when i can grind a tip to fit and still use them with stock tips.
I have to play with them every time I use them to remember how to switch from expand and contract when squeezed.
Bill D.

https://channellock.com/product/rt-3/

[Tom Trees]

Not that I'm that fimiliar with the Centauro's, but I have studied them as good as I could find on Google searches,
seeing if I could match the design when rebuilding my saw.
It appears the design is similar.
I don't think you need to go near the plate which the bowden tension cable is attached to,
nor need remove the screw or anything like that, TBH I was unaware that there was a spring for a long time!

(someone before me was at this saw, the parts weren't in the correct order, and it had a big fall at some point too, I learned a real hard lesson about removing a split pin that
was damaged, don't ever try to get them out without a proper tool, made a rough punch with locating pin but it didn't cut the mustard, couldn't get it out after a lotta wallops with a big hammer.
Testament to the casting that it didn't break!
The other pin came out fine... for a split pin.
Just fair warning if wanting to delve further!

Back to your query
Should be a simple procedure.
Still unaware of the best way to remove the bearings with a tool that will fit inside the inner race.
Would love to get a term to search or link for the procedure.

Tom

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[Dave Cav]

Regarding heating bearings, my go to method for years has been to put them on top of a 60 watt incandescent light bulb for a couple of minutes on each side, until they are just too hot to handle.

I'll be watching this thread because I have a 4 year old MM20 with a 1" Woodmaster CT that I never de-tension......I hope Brian takes lots of pictures.

[Edwin Santos]

The number is 6207-2RS i
decided to get the Abec 3 version which is rated for higher stress since I run a carbide blade all the time. The current set lasted about five years, which seems a bit low to me.



Do you keep your blade under tension all the time, or most of the time?

[Brian Holcombe]

Thanks Tom, sounds like the upper wheel mount can be spun off and removed from the top. It looks to be the case on mine, I’ll find out soon.
E
My saw’s wheels have no access points for a standard puller so I have assumed there to be another method of removal.

Seems you all are bound and determined to discuss snap ring pliers, so here:

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[Brian Holcombe]

I never de-tension, I assume the bearings have died because of the level of tension rather than the fact that it is constant.

[Tom M King]

Your relative percentages of Knipex, and Klein, look very similar to mine.

I have used a slide hammer for bearings that can only be pulled from the inside. Search Pilot bearing puller .

Speaking of retaining ring pliers, I had to get a pair of these to get the external retaining ring off the King Pin in one of the tractors front ends: https://www.ebay.com/itm/254709719314?hash=item3b4de1e112:g:OTIAAOSwaS9fUp-C

[Tom Trees]

Thanks Tom, good to know the tool for the job :)

[Edwin Santos]

I never de-tension, I assume the bearings have died because of the level of tension rather than the fact that it is constant.

Thank you! I'm interested because I own the same saw, about 3 1//2 years old.
Looking forward to hearing how the replacement operation goes. Wishing you smooth sailing.

[Erik Loza]

E, My saw’s wheels have no access points for a standard puller so I have assumed there to be another method of removal…

Brian, I am sure that I used a large 3-jaw puller to remove those flywheels. It was a large puller and you inverted the jaws to go through the cutouts in the flywheel.

Erik

[Rod Sheridan]

If my slide hammer puller is too big, I drive them out with a punch, they’re going in the garbage...Rod

[Tom Trees]

On closer inspection with problem in mind referring to my comment about the SKF bearings, it appears that it does seem a bit loose on the shaft!
I'm thinking I might see if a pair of the original Koyo's might be put back to use.

With this in mind that they might be toast, I am eager to know if Erik can remember which brand bearings were a tight fit to get onto the shaft?

So glad I read this, Brian, I'd see if your wheel slides off easily without need for taking the carriage assembly off, or spin the wheel without a blade
and listen for anything.
If so, might be worth seeing if Erik can recall a good brand.

Thanks
Tom

[Erik Loza]

On closer inspection with problem in mind referring to my comment about the SKF bearings, it appears that it does seem a bit loose on the shaft!
I'm thinking I might see if a pair of the original Koyo's might be put back to use.

With this in mind that they might be toast, I am eager to know if Erik can remember which brand bearings were a tight fit to get onto the shaft?

So glad I read this, Brian, I'd see if your wheel slides off easily without need for taking the carriage assembly off, or spin the wheel without a blade
and listen for anything.
If so, might be worth seeing if Erik can recall a good brand.

Thanks
Tom

Tom, I honestly never checked. One time I looked (brand new machine) and the bearings were made in Korea! I’m sure Centauro sourced out bearings from any number of different vendors over the life of those machines.

Erik

[Brian Holcombe]

The original bearings are not impressing me much, they look
like a low cost choice. One was crunchy was just plain worn and spins loose.

I sourced SKF explorer, to replace them.

I had suspected the wheel assembly could be removed, I was correct about this. I drifted out the pin holding on the hand wheel along with a few bolts in the upper part of the assembly. After this I was able to lift out the wheel.

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Pressed out the old bearings. Pressed in the new.

I plan to clean and reapply grease. One thing I think SCM could really improve upon here is the dust collection. This saw is constantly loaded with dust after any resawing.

I think I’ll do the bottom wheel also given the quality of the original bearings leaves much to be desired in my opinion. This is a higher quality saw and they can’t spare $20 for higher quality bearings? The Ulmia, Maka, Wadkin and Omga machines I have are all top quality parts soup to nuts.

[Brian Holcombe]

This saw is actually pretty quiet now, I have wondered why this saw is so loud for the entire time I have owned it. I’m not sure the bearings were ever very good but glad now to have some better grade bearings in. I’m definitely replacing the lowers now with the hope that it will get quieter still.

[Tom Trees]

Thanks for your replies Erik and Brian.
I believe it was the same bearings I bought, curious to know if the older ones were a tight fit, compared to the new ones.
Sounds like the wheel wasn't sliding off the shaft without a fight.

Cheers for the update
Tom

[Brian Holcombe]

It felt like a .00025” interference fit, so very light but removing the previous bearings they felt about the same. There is positive retention so I’m not particularly concerned there.

[Tom Trees]

Thanks again Brian.
I'll be keeping an eye on this thread, I wonder if the lower wheel will be more difficult.
All the best
Tom

[Erik Loza]

Thanks again Brian.
I'll be keeping an eye on this thread, I wonder if the lower wheel will be more difficult.
All the best
Tom

The lower wheel is about a MILLION times easier.

Erik

[Brian Holcombe]

Good to know, the upper wasn’t bad once I figured out how to get it out of the saw without a puller. If you run the screw all the way before removing the tension handle you can tip the assembly forward after taking the bolts out and lift it out.

Changing the belt to while I’m at it. The belt squeals on startup.

[Brian Holcombe]

Swapped the lower bearings and belt. The lowers were fine so while it was nice to upgrade there is no noticeable improvement.

One of the things that really bugs me about this saw is the belt tensioner, it’s pretty lousy so I plan to replace it. The belt squeal is not from the belt being bad but rather from not enough tension. This is clear when I watch the saw run and the belt flops pretty badly. I can max out the adjuster and the belt still does not have appropriate tension but finally stops flopping wildly and stops squealing.

While I’m at it I think I’ll make some sort of basic isolation between saw body and motor with high durometer rubber abs rubber washers for the bolts.

I suspect there is something to the idea that the wheels should be parallel with one another. I have never checked that but was told to disregard by Sam’s notes. I checked today and they are not parallel. I suspect that aided in the demise of the previous bearings so I think I will attend to that.

[Erik Loza]

The belt squeal is not from the belt being bad but rather from not enough tension. This is clear when I watch the saw run and the belt flops pretty badly. I can max out the adjuster and the belt still does not have appropriate tension but finally stops flopping wildly and stops squealing.

You could get a longer bolt but I never experienced a case where belt remained too slack. Is the new belt too long?.


...While I’m at it I think I’ll make some sort of basic isolation between saw body and motor with high durometer rubber abs rubber washers for the bolts. I wouldn't do that. You will probably create more issues as far pulley arbor yaw, once the assembly is under tension.



I suspect there is something to the idea that the wheels should be parallel with one another. I have never checked that but was told to disregard by Sam’s notes. Sam is correct.



...I checked today and they are not parallel. I suspect that aided in the demise of the previous bearings... Unlikely.

Brian, with all due respect, I think that you are thinking that you need to treat this like a 14" bandsaw. Trust me: You run a much higher risk of getting poor results by trying to out-think this machine. If anything, I would maybe try a shorter belt and see where that gets you. The rest, I just wouldn't worry about. Good luck with it.

Erik

[Edwin Santos]

Swapped the lower bearings and belt. The lowers were fine so while it was nice to upgrade there is no noticeable improvement.

One of the things that really bugs me about this saw is the belt tensioner, it’s pretty lousy so I plan to replace it. The belt squeal is not from the belt being bad but rather from not enough tension. This is clear when I watch the saw run and the belt flops pretty badly. I can max out the adjuster and the belt still does not have appropriate tension but finally stops flopping wildly and stops squealing.

While I’m at it I think I’ll make some sort of basic isolation between saw body and motor with high durometer rubber abs rubber washers for the bolts.

I suspect there is something to the idea that the wheels should be parallel with one another. I have never checked that but was told to disregard by Sam’s notes. I checked today and they are not parallel. I suspect that aided in the demise of the previous bearings so I think I will attend to that.

I have the same experience with the same saw with the same belt issue. I have added tension twice, both times eliminating the start-up squeal. Then after some time, it comes back. My assumption has been that the belt is not a super high quality and is simply stretching. I've just been keeping an eye on it to see if it gets to the point of slipping under load. This has not been the case thus far, so I just consider it a minor annoyance. I figured at some point I would replace the belt and see if my thesis is correct.

I do not know enough to know what you mean by replacing the tension adjuster. Mine is just a long bolt feeding through a welded on block, and the bolt pushes against the motor flange.
Which is better than my other bandsaw where the tensioner is one guy levering the motor up with a pry bar and the other guy tightening the mounting bolts when the belt seems tight enough.

[Brian Holcombe]

You could get a longer bolt but I never experienced a case where belt remained too slack. Is the new belt too long?.

I wouldn't do that. You will probably create more issues as far pulley arbor yaw, once the assembly is under tension.


Sam is correct.


Unlikely.

Brian, with all due respect, I think that you are thinking that you need to treat this like a 14" bandsaw. Trust me: You run a much higher risk of getting poor results by trying to out-think this machine. If anything, I would maybe try a shorter belt and see where that gets you. The rest, I just wouldn't worry about. Good luck with it.

Erik

Ok, perhaps I will remove the isolation ideas but I can’t imagine 1/8” of 80 durometer adding any yaw issues.

The longer bolt isn’t fixing anything, the bolt is plenty long enough it works against the plate at an angle and at some point the angle becomes too extreme. Belt us identical to that which the factory provided. 3VX475 is what I had and have again. Not opposed to putting a shorter belt on.

Please explain your reasoning/logic behind the parallel issue rather than simply writing off my ideas. If my ideas do not have merit, I can certainly accept that but I’d like to understand why you think what you think. My thought is that putting a normal bearing at an angle shortens it’s Life because the bearings are running against the sides of the tracks. I suspect my ideas do have merit since the upper bearings died and the lowers did not.

I took bearings out of the Maka that were still running clean after 40 years of daily use, these died after 6 years of easy use in my one-man shop.

[Tom Trees]

I've only just replaced the bearings in my motor after fitting a new belt to the saw (same brand and size, bought locally, so wondering now if it is OEM or spec)
as well as having the bottom wheel misaligned, this caused a massive vibration issue which toasted them.
Wouldn't have been a problem with the old belt, as there is looooooads of stretch compared with none on the new one, not even sure if I have enough space for the new one
with the hub being so close to the pulley, might need a bit of working streching out (if that's a done thing?)

I assumed that the bottom wheel would be in line with the cabinet, not so with my machine!!!
I found out the hard way this is not the way to go about it :o457843
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I only uploaded a video yesterday on setting up my saw after doing a bit of work to it.
Having heard reference about a beam for getting coplanar on the wood whisperers channel
I'm guessing that its along the same lines as what he was on about.

Maybe not the same thing, but some useful info I think, as I haven't seen any demonstrations for this.
There is a Rikon guide for the lower wheel that has some info, be interesting to observe if it correlates with what the beam says,
even though its for cambered tires, it might be the same.

https://youtu.be/VQ9dmP9yF8E

[Brian Holcombe]

Tom, thanks for the update. The wheels are now co-planar on mine and this saw sounds a lot happier. I’m going to go out on a limb here and suggest that getting the wheels co-planar had some merit.

This saw sounded like a box of rocks a week or so ago, now with better bearings and a finer degree of tuning it’s starting to sound a little closer to what I expected of a nicer saw.

Frankly, I was expecting whisper quiet given that most nice bandsaw are, I recognize that the steel frame amplifies vibration noise but it has been pretty irksome to have it both be louder than expected and deal with that awful squeal.

[Bill Dufour]

Did it end up the upper and lower bearings were the same size or different?
Bill D

[Brian Holcombe]

They’re the same.

[Joe Calhoon]

Brian,
Getting the upper and lower wheels parallel is just good machine tuning. I have a couple 40 year old books on woodworking machinery maintenance, one US book and the other from the UK. Dated books, but still relevant to a lot of things on modern machines. They both suggest parallel and the US book goes into detail on how to accomplish this. It says to check parallel both left and right using a straight edge and level to make sure they are the same. I believe the level is accounting for any tilt in the upper wheel.

I checked the left side of the Hema and it is right on. I might have to tilt or remove the table to check the right side.
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[Brian Holcombe]

Thanks, Joe! Appreciate the insights.

[Mark e Kessler]

Tom, thanks for the update. The wheels are now co-planar on mine and this saw sounds a lot happier. I’m going to go out on a limb here and suggest that getting the wheels co-planar had some merit.

This saw sounded like a box of rocks a week or so ago, now with better bearings and a finer degree of tuning it’s starting to sound a little closer to what I expected of a nicer saw.

Frankly, I was expecting whisper quiet given that most nice bandsaw are, I recognize that the steel frame amplifies vibration noise but it has been pretty irksome to have it both be louder than expected and deal with that awful squeal.


Hi Brian, assume you saw the 2003 MM16 I picked up recently. I have the belt squeal as well I was able to tighten it up and most of it if not all went away, probably due for a new belt anyways.

On the wheels being co-planer, when we are talking co-planer do we mean top to bottom wheel plumb in line with each other (i think this is what is typically talked about with bandsaws) or/and right to left + the lower wheel has the upper and lower bolt to tilt in and out, I think the manual says to never adjust the right and left bolt on the lower wheel and that they adjust it for the largest blade at the factory.

I didn't check co-planer on mine (damnit, should have when I had the table off...), the tracking was pretty darn close with a 1/2" blade (teeth hanging off a hair top/ a little more than a hair on bottom wheel) so I thought I was good until I put the 1" Woodmaster CT on and tensioned it (ballpark 25-27k using the ol' clamp caliper on blade...) and found that the blade at the top wheel was about right (teeth barely hanging off but the bottom the blade was like almost 1/2" hanging off so I adjusted the lower wheel (top/bottom bolts) and got it darn close. I went back to the 1/2'' and I think I had to tweak the wheel again (stupid me, I can't actually remember if I readjusted for the 1/2"...duh).

Honestly I have never bothered or thought it was important to check for co-planer but the CT on the lower wheel hanging a good 1/2" off so something needed adjustment, and this thread got me thinking I need to do some more investigation. I also had some (in my opinion) excessive vibration which I thought was bearings until I found that the bolt on the top wheel seemed a little loose, got almost a full turn and definitely removed most of the vibration.

Thanks, Mark

[Brian Holcombe]

Mark,

Yes, that is a good description. I might spin the upper wheel and see what it sounds like also.

[Tom Trees]

I've since done a few minute adjustments since my last video working on my particular Italian saw.
Just a lot of faffing around with plumb lines,
Must go searching for some good woven cord, as the accurate one takes an age to settle.

Seems I've hit a bit of a snag that is that the wheels seem to be wanting to be closer to the column than before.
so much so that the guides has ran out of adjustment in regards to the left, so it seems I need make a part.

From studying other models of my seemingly discontinued machine, it appears that all these saws are positioned the way I have adjusted mine,
and the guides have a different mount or type.

Getting to the point, I must check if my upper wheel makes any groaning, since the wheel is level now.
I haven't noticed that, not to say its not there anymore.
The wheel doesn't appear loose either, as in not coming off the shaft compared to the last time where I removed the wheel,
Relieved I can count that out and see if it was just a case of it being so skewed before my adjustments.

Interesting to read the comment Mark about the left and right being adjusted for the largest blade.
Seems like a 3/4" is about the sweet spot for my tires with a worn/rounded edge, and using the level.
Be interested to see a demo of some other or similar method.

Tom

[Brian Holcombe]

The smaller belt does not fit on this machine, so anyone following along don’t bother doing that.

I decided just to tension the motor like I normally do with a couple blocks and a lever. Nice and tight, the squeal is gone.