Bandsaw vibration - how much is normal?
- Thread starter GraemeD
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GraemeD
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Thinking back, I once had to make some accurate rubber rollers for an engineering project I was involved in. We turned them roughly on a metal lathe with very sharp tools, but to finish them I remember putting the rubber in a freezer for a while to make it harder. Then we used a small grindstone fitted into an electric drill rotating against the direction of the rubber roller (back in the lathe), to get a higher effective cutting speed. The results were fantastic. I wonder if something similar might work here? A grindstone in a drill would certainly be a bit safer than using a turning gauge!
Graeme
Graeme
Digit":3177l0ys said:
No doubt that is the most immediate danger, but I don't see why not take that 30 second precaution in case the unexpected happens - given that you are running a bandsaw completely unguarded - like maybe f'rinstance the sanding stick jamming and then you losing your footing or something and sticking some part of you against the blade. One way, you have a friction burn or small cut, the other way, you could be seriously damaged.
I call it common sense, but it's probably nanny softie thinking or something really.
At least tell me you stick on a 14tpi or something rather than a serious rip blade :lol:
GraemeD
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Not had a chance to try this yet.....it will probably have to wait until next weekend now, as it sounds quite involved.
Graeme
Graeme
Scott
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Graeme
I put a clock gauge on the tyre of the top bandwheel on my machine and there is zero runout on the tyre.
There is 0.55mm axial play on the top wheel but that shouldn't make any difference. It moves axially but it doesn't rock on the shaft.
The wheel is definitely in balance because if I clean all the dust off it and spin it by hand it never stops in the same place.
There's no discernable vibration with the machine running (5/8" Dure-Edge blade). I can put a 1 Euro coin on edge on the table and it just slowly turns round. Certainly in no danger of falling over and definitely no visible vibration.
The tensioning mechanism is supposed to be a bag of bolts when the tension is off and it does make it harder to figure out what's going on. I have a Heath Robinson modification on mine with a Scania valve spring and an old lathe handwheel on top for adjusting tension. My original spring was well goosed and I couldn't find another.
My tyres have 1.5mm at the edge and are obviously crowned in the centre.
Dunno if any of that is any help but give's a shout if you want to know/compare anything else
Cheers
I put a clock gauge on the tyre of the top bandwheel on my machine and there is zero runout on the tyre.
There is 0.55mm axial play on the top wheel but that shouldn't make any difference. It moves axially but it doesn't rock on the shaft.
The wheel is definitely in balance because if I clean all the dust off it and spin it by hand it never stops in the same place.
There's no discernable vibration with the machine running (5/8" Dure-Edge blade). I can put a 1 Euro coin on edge on the table and it just slowly turns round. Certainly in no danger of falling over and definitely no visible vibration.
The tensioning mechanism is supposed to be a bag of bolts when the tension is off and it does make it harder to figure out what's going on. I have a Heath Robinson modification on mine with a Scania valve spring and an old lathe handwheel on top for adjusting tension. My original spring was well goosed and I couldn't find another.
My tyres have 1.5mm at the edge and are obviously crowned in the centre.
Dunno if any of that is any help but give's a shout if you want to know/compare anything else
Cheers
GraemeD
Established Member
Scott, this is brilliant information....thank you for going to all this trouble!
I tried a "one pound coin test", and found that it fell over after a couple of seconds of wobbling, so I think I have a definite problem.
As I mentioned before, I tried to measure the runout on the tyre edge, but couldn't get a good reading. I'll have to persevere, but one of my two DTI gauges seems to be broken, and the second is slightly dubious now I look at it.
Interesting about the tyre thickness.....mine are obviously more worn than yours, though not completely unusable. I think I have margin to clean them up, but would need to do more than hold a bit of abrasive against hem in my hand (which is what I did previously). Assuming I have runout, I need to re-establish a reference as Roy suggested. That will have to wait until the weekend though.
Nice bit of work for your tension mechanism! Mine struggles to tension a 1/2" DureEdge....seems to be maxed out yet still not as tight as I'd like. The knob becomes too hard to turn before the tension is really high. Maybe I need a better tension setting wheel like yours....or maybe my spring is tired too? Should I go see a Scania dealer!!?
Graeme
I tried a "one pound coin test", and found that it fell over after a couple of seconds of wobbling, so I think I have a definite problem.
As I mentioned before, I tried to measure the runout on the tyre edge, but couldn't get a good reading. I'll have to persevere, but one of my two DTI gauges seems to be broken, and the second is slightly dubious now I look at it.
Interesting about the tyre thickness.....mine are obviously more worn than yours, though not completely unusable. I think I have margin to clean them up, but would need to do more than hold a bit of abrasive against hem in my hand (which is what I did previously). Assuming I have runout, I need to re-establish a reference as Roy suggested. That will have to wait until the weekend though.
Nice bit of work for your tension mechanism! Mine struggles to tension a 1/2" DureEdge....seems to be maxed out yet still not as tight as I'd like. The knob becomes too hard to turn before the tension is really high. Maybe I need a better tension setting wheel like yours....or maybe my spring is tired too? Should I go see a Scania dealer!!?
Graeme
Scott
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GraemeD":31tl98wb said:
I doubt it would necessarily have to be Scania! Much to the Chief Engineer's disgust I just robbed a selction of likely looking candidates from the engineroom stores!
In all honesty it isn't perfect because it doesn't turn well under tension and gets a bit skew whiff but at least all the tensioning gubbins is now outside the casing so it's easily accessible. If ever get time I might upgrade the mod to put some form of bearing on it. The best thing is that the spring is now visible so I can see how closed up it is. The original square section one was very tired and wouldn't tension a 1/2" blade even when fully screwed up. Just as you describe. If I get a sec over the weekend I'll post a pic.
My tyres have several grooves in them BTW but that obviously makes no odds. I think my uncle (whom I inherited the machine from) ran his blades on the tyre whereas I tend to run mine with the tips just a fraction off the tyre.
You got yours on a metal stand or a wooden bench? I have the latter. It's inert rather than being "live" like a metal stand can be if it's not damped down or well bolted in. Just a thought.
Best o' luck!
GraemeD
Established Member
Sounds interesting....I'd definitely like to see a pic if you get a minute. I reckon my spring is almost fully compressed when I'm tensioning my 1/2" DureEdge, so maybe I need to take a look at this too.....I must admit I hadn't thought much of this previously, but now I'm wondering. Dunno if this is the cause of the vibration, but if the spring is fully compressed it might not be helping matters.
My saw is on the original metal box base (3 metal and one open side), and it is a bit "live" to be honest. I fitted adjustable feet to it so it nolonger wobbles at least. It isn't contributing the the vibration as far as I can tell, but probably amplifies the rumble!
I'm gonna try and play with the tyres this weekend.....at least have another go at measuring the runout. I will report back......
Graeme
My saw is on the original metal box base (3 metal and one open side), and it is a bit "live" to be honest. I fitted adjustable feet to it so it nolonger wobbles at least. It isn't contributing the the vibration as far as I can tell, but probably amplifies the rumble!
I'm gonna try and play with the tyres this weekend.....at least have another go at measuring the runout. I will report back......
Graeme
Scott
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Not the best mod in the world but it works. Like I say I should really tweak it a bit.
You got a manual for the machine Graeme? Think I have one somewhere if you want a scan although, if memory serves, I've a feeling it wasn't particularly in-depth.
GraemeD
Established Member
That's not too "Heath Robinson", Scott! Looks eminently reasonable to me. I bet you can get as much blade tension from that as you like, which is great. You mentioned that the spring (being a larger diameter) has a tendency to skew......would a bit of suitably sized tubing in between the spring and the rod help keep things straight?
Interestingly your wheels are a little different to mine.....mine are more "spoked" than yours with less iron in them, so presumably lighter. Maybe an economy measure?
Not had a chance yet to look at the tyres again today as we have had family stuff going on, but hopefully will have a crack tomorrow.
As for a manual, a scan would be fantastic if it's not too much trouble! I bought mine third hand off Ebay, so it came with nothing extra, so any info would be of interest.
Graeme
Interestingly your wheels are a little different to mine.....mine are more "spoked" than yours with less iron in them, so presumably lighter. Maybe an economy measure?
Not had a chance yet to look at the tyres again today as we have had family stuff going on, but hopefully will have a crack tomorrow.
As for a manual, a scan would be fantastic if it's not too much trouble! I bought mine third hand off Ebay, so it came with nothing extra, so any info would be of interest.
Graeme
Scott
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My apologies for possible big let down Graeme! It's not a manual at all but a brochure. Has the machine spec including band length on it though.
PM me your email. You on broadband? It's a 6Mb scan so I'll re-scan at lower resolution if you're on dial up
PM me your email. You on broadband? It's a 6Mb scan so I'll re-scan at lower resolution if you're on dial up
GraemeD
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Still sounds interesting! I'll PM you right away.
Had a play with the saw on Sunday, but had no joy. I really can't decide whether the tyres are at fault or not, and my measuring kit wasn't up to telling me either way, so I'm going to try and borrow some better kit from a metalworking friend. If it's not the tyres I can't think what it is....so I will persevere with that. Might take me a while before I can do this though....still the saw does work a treat, just annoying knowing it could be better!
Graeme
Had a play with the saw on Sunday, but had no joy. I really can't decide whether the tyres are at fault or not, and my measuring kit wasn't up to telling me either way, so I'm going to try and borrow some better kit from a metalworking friend. If it's not the tyres I can't think what it is....so I will persevere with that. Might take me a while before I can do this though....still the saw does work a treat, just annoying knowing it could be better!
Graeme
