I doubt the blade flutter you mentioned was due to worn bearings. Most likely the tension you had on it resulted in a harmonic.
John
Contributor
I doubt the blade flutter you mentioned was due to worn bearings. Most likely the tension you had on it resulted in a harmonic.
John
Contributor
I just looked at the bearing on my lower wheel and it’s just a cheap Chinese bearing. Unless there’s another behind it it must of been changed when I had the saw in for service. So I retract yesterday’s post
My experience with bandsaws is the blade and tires make the most difference.
Good Luck
Aj
Member
I've often read of this, and watched various flutter methods before, and I can't say that I'm convinced of this being a thing with a properly set up machine.Originally Posted by John TenEyck
Having experienced this, mainly plonking away dressing tires with inconsistent results years before, it seemed I was getting a better impression of how the machine would
run, whilst not being tensioned fully.
Eager to do some experiments regarding this, so I'll be keeping that in mind.
As it happens, I can't recall what the general consensus is, in regards to this phenomenon being most apparent...
I guess some sort'a rule of thumb being the wider the more apparent?
Not sure I can recall this discussion with carbide blades, but that's possibly more understandable, as the suggestion is to use thereabouts around 25000 PSI tension.
Also worth noting if you look at Andrew's other video, you can see the blade on this machine being fairly cranked up.
Last edited by Tom Trees; 10-17-2023 at 12:01 PM.
[OP]
Contributor
Cranked up enough that I could hardly move the wheel anymore.
[OP]
Contributor
Alright, I ordered some SKF branded 6207-2RS's from Zoro.
Grainger prices are always crazy to me. Zoro is so much cheaper.
Contributor
I'm not sure what you mean by a properly set up machine, Tom. If it includes adjusting blade tension to eliminate any flutter that occurs when the blade is rough tensioned, then, yeah, that's a properly set up machine.
Narrow blades tend to flutter more easily because they will resonate at more frequencies than wider (stiffer) blades. In any case, if you follow the blade installation instructions, at least those with my Grizzly bandsaw, you rough tension the blade with the guides away from the blade, turn on the saw and look for flutter, and increase tension if any is observed, until it is eliminated. Pretty simple stuff.
John
Member
It'll be interesting to see if I can achieve any flutter going from rough tensioned to apt, is what I meant.
I'm just a bit sceptical of this being a frequency thing, and more partial to believe this, as a sign of mis-alignment, or tire issues,
as I've eliminated that before under the actual unchanged blade tension whilst dressing tires, (note the blood smear on the chassis waist)
way back when I didn't know anything about bandsaws,
I've went back and fourth on that, as you probably know, and can mention I experienced eliminating flutter more than once during that time,
whilst being especially curious regarding how things might tip the upper wheel, so left the tension unchanged,
as I was getting the impression of mad variables, and being too thick to question if the faces of the wheels were actually true,
so spent way too much time going back and fourth, as the beam is very sensitive.
Be interesting to see how things go, and surely a test also for my tire dressing job, which I just about got away with...for the umpteenth time, that is...
as silly me believed there were such a thing as true flat tires, and went on a bit of a quest for a red herring on that one !
Seemingly there might be others who might think the same, as in..I wouldn't attempt cutting if I seen flutter, as the set would compress,
although some videos exist of this seemingly not being an issue...
(Not reckoning fluttering is blade tension related, that is?..)
Take that Stockroom supply's bandsaw sled guy for instance,
slicing veneers using a wee saw, with a blade intentionally woefully inadequately tensioned, yet he still ends up with results!.
I must watch again to see if he actually does mention this.
My take on why that/those sleds work so well is, they might well be splitting the difference between wheels out of alignment.
Not that that'll be a problem for those with a foot mounted motor like the CO, but for others without such adjustments available,
I'd guess you just got a good one, and someone has gotta have a lemon seeing as most anything else out ain't built as such,
and whoever got the worst one, found an correlation with such a phenomenon, and coined that whole flutter = blade resonance thing.
I'd take a pot shot it, was a lot less hefty than your extra thick welded steel framed machine too.
Though I could be just talking out my hat, I'll find that one out fairly quickly,
In my defence, crowned tires are a bit new to me, as in lots of experiments I can do yet,
as when I had flat tires, hand turning the wheels whilst blade at least half or more tensioned, wasn't allowed, (blade dives hard into thrust guide)
so perhaps that might explain so, and it'll be interesting to see how much less tension I need for the above, not to happen.
Good to have two reasons to have a wee narrow blade, use for occasional curves and for testing the flutter.
I spent waay too much time on my machine, and I haven't used it since but for an emergency bird house, so more experiments can wait for me.
Cheers
Tom
Truing bandsaw tires.jpgTrueing tires.jpg
Last edited by Tom Trees; 10-17-2023 at 10:07 PM.
Contributor
Nachi makes a great bearing. C3 is the internal clearance between the races of the bearing, 2NSE is their double rubber sealed version. Brian
Brian
Contributor
Zoro is grainger. Grainger is industrial discounted per account, zoro retail discount. Brian
Brian
[OP]
Contributor
I understand, but you'd have to have one heck of an account to make Grainger prices work out when they start out at 2x to 3x their "retail brand" prices.
Contributor
A number of years ago I bought a band saw blade tension meter from a guy on eBay. He milled the body out of aluminum and then you installed your own dial indicator. Cost was about $100. I use it most of the time when I put a new blade on and it's amazing how much more it takes to get to 22,000 psi than you think. But if your machine can get you there then the blade is rock solid and will cut like a table saw. I have a Meber 600 which is probably the same machine as the Centauro 600 and can get a 1" Lenox Tri-Master tensioned to 22,000 psi. I just did a bunch of resawing with it and the blade with that tension looks like it's not moving. I can also peel off .080 veneer from 12" stock with little variation top to bottom. My personal experience is that most people under tension the blade either because the machine can't get there or they are afraid of breaking the blade. But be aware that metal band saws that ride with no rubber tires are tensioned to 40,000psi and the blades can take it.
Jay
Contributor
Agreed. Brian
Brian
Contributor
It'll be interesting to see if I can achieve any flutter going from rough tensioned to apt, is what I meant.
I'm just a bit sceptical of this being a frequency thing, and more partial to believe this, as a sign of mis-alignment, or tire issues,
as I've eliminated that before under the actual unchanged blade tension whilst dressing tires, (note the blood smear on the chassis waist
way back when I didn't know anything about bandsaws,
I've went back and fourth on that, as you probably know, and can mention I experienced eliminating flutter more than once during that time,
whilst being especially curious regarding how things might tip the upper wheel, so left the tension unchanged,
as I was getting the impression of mad variables, and being too thick to question if the faces of the wheels were actually true,
so spent way too much time going back and fourth, as the beam is very sensitive.
Be interesting to see how things go, and surely a test also for my tire dressing job, which I just about got away with...for the umpteenth time, that is...
as silly me believed there were such a thing as true flat tires, and went on a bit of a quest for a red herring on that one !
Seemingly there might be others who might think the same, as in..I wouldn't attempt cutting if I seen flutter, as the set would compress,
although some videos exist of this seemingly not being an issue...
(Not reckoning fluttering is blade tension related, that is?..)
Take that Stockroom supply's bandsaw sled guy for instance,
slicing veneers using a wee saw, with a blade intentionally woefully inadequately tensioned, yet he still ends up with results!.
I must watch again to see if he actually does mention this.
My take on why that/those sleds work so well is, they might well be splitting the difference between wheels out of alignment.
Not that that'll be a problem for those with a foot mounted motor like the CO, but for others without such adjustments available,
I'd guess you just got a good one, and someone has gotta have a lemon seeing as most anything else out ain't built as such,
and whoever got the worst one, found an correlation with such a phenomenon, and coined that whole flutter = blade resonance thing.
I'd take a pot shot it, was a lot less hefty than your extra thick welded steel framed machine too.
Though I could be just talking out my hat, I'll find that one out fairly quickly,
In my defence, crowned tires are a bit new to me, as in lots of experiments I can do yet,
as when I had flat tires, hand turning the wheels whilst blade at least half or more tensioned, wasn't allowed, (blade dives hard into thrust guide)
so perhaps that might explain so, and it'll be interesting to see how much less tension I need for the above, not to happen.
Good to have two reasons to have a wee narrow blade, use for occasional curves and for testing the flutter.
I spent waay too much time on my machine, and I haven't used it since but for an emergency bird house, so more experiments can wait for me.
Cheers
Tom
Truing bandsaw tires.jpgTrueing tires.jpg
I spent a lot of my engineering career challenging what some folks espoused as true. Never along the way, however, did I challenge basic, proven, engineering principles. It's not a matter of belief or disbelief. Engineering is pretty black or white. That's a lead in to say bandsaw blades flutter due to resonate frequencies induced in them as a result of the applied tension. Different blades will resonant at different frequencies, but the concept is the same. Solving flutter takes nothing more than adjusting the tension, higher or lower, to move the frequency out of the resonant zone. The saw itself is irrelevant to the problem.
John
[OP]
Contributor
It didn't matter what force I put on the blade. It was fluttering. One inch blade.
The only way I could go tighter would be to use a lever arm on the wheel.
My tension measure on the bandsaw doesn't seem accurate. But I was tightening until I couldn't anymore while the machine was on and thy flutter never went away. Maybe it passed thru a few frequencies getting better or worse but never became normal
Member
This makes for some very interesting reading, as I haven't experienced this atall, even when the wheels were likely still out of alignment,
differing blades and all.
Not as far as someone without a class blade tension indicator!The saw itself is irrelevant to the problem
Not being sure what the dimensions are of my ACME tension screw,nor the screw on your machine, but one could suggest that being quite relevant,
though for the curious, anything is better than nuffin....
It's a very vague question, I understand, but I'll ask it none the less.
Unsure of what your might deem a minimum amount of PSI might be starting at, guessing around 15Kpsi (say, for edging shingles, something thin)
By say turning the screw 90 degrees, or a quarter turn, how many times can one expect to experience this flutter?
A ping or deflection "white finger test" would have been good Andrew,
https://www.youtube.com/watch?v=HTWi9O13zu8
I'd guess the machine should be good in ballpark tension, that's if Andrew's...
A. Not been living under a rock, and actually looked some stuff to get some sort of idea, (note the smaller bandsaw at the back)
B. He's not too weak to turn the screw, doesn't seem the case to me either,
C .The blade being good, and not having a stress crack in the gullet, and is giving warning signs.
D. add to whatever other speculation their might be in regards to something not being mis-alignment.
That's if those tires are good, should be a no-brainer if they were the replaceable type with the offset groove.
I see paint on the upper one, so it's not new.
Erik has mentioned some of the CO's being vulcanized real rubber tires, and the thickness of them & the paint job would suggest it's an old one also,
so I'm guessing it likely needs a wee lick.
All the best
Tom
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