Small bandsaw eating through sawblades

[mattthemuppet2]

cracking between the teeth is a strong symptom of overtensioning the blade - had quite a few of mine do that before I eased off on the tension. I tighten the knob to the point where I might need to put some effort into it and stop. The only ones I've had crack at the weld are the ones I've silver brazed together myself. I just braze them back together

 

[MrCrankyface]

That's a lot of weight on the blade. As someone else mentioned I would bring the guide in to reduce the span.

I think looks are a bit deceiving.
The sliding mechanism is hollow tubes and aluminium.
With the two blocks of steel in it, coupled with the spring-loaded hinge it's only applying up to 1.8kg of force into the cut
Surely that can't be considered too much?

Testrig:
Bar suspended across two points, not clamped in vice.
Blade lands in the middle, equal distances out to the outwards points.
Any load exerted from the blade should be split roughly 50/50 between the side with the scale and the pivoting side.
With the weight slighly behind the handle the scale registers ~300g, so 600g "downforce" on the blade.
With the weight extended all the wayout the scale registers ~900g, so 1800g downforce on the blade.
I guess it's possible that 1.8kg / ~18N is too much but to me it sounds like a rather small number.
Looking at the chips it's basically producing dust, not shavings, at anything less than 600g downforce.
At 1800g it's cutting beautifully until it starts acting all "harmonicy" and eventually throws the blade.


I have moved the support out more but when I'm cutting larger things I will be back to the same 'bad stability' I assume.
Some ideas I had were to also add a oil-piston to the setup to dampen the harmonics and keep the cutting pace more uniform.
Another was to reinforce the structure with some more material but then it's gonna look real frankenstein-y.

 

[MrCrankyface]

Ditched the idea of making an oil dampener. Too much work and not enough time.
Found a cheap death-wobble dampener on amazon instead, adjustable and everything.
Moved the weight a tiny bit further out and then increased resistance on the dampener so it moves pretty slowly.
Seems to work great now no matter how much of the blade is engaged.

 

[mattthemuppet2]

I just realised what you meant by death-wobble damper - a motorcycle steering damper! What a great idea, they're only $35 or so on Amazon. I might have to seriously think about that instead of a DIY option, thanks

 

[Gnpenning]

I know this was asked and may have missed the answer, have you tried adjusting motor speed?

 

[MrCrankyface]

I know this was asked and may have missed the answer, have you tried adjusting motor speed?

Yes! Motor is now running at it's lowest, around 35m/s.
Seems to have helped some. The cut is quite hot at that speed so I imagine running faster is wearing the teeth out.
A lubrication system would probably help tons.

mattthemuppet2: Ah, yes, that definitely sounds more like the correct term for it.

 

[Ultradog MN]

Giving the blade a bit of oil will help.
I have a water based coolant system on my bandsaw but it is in an unheated area of my shop so I don't use it in the winter.
It was only 20°f yesterday and I wanted to cut a couple of heavy pieces of steel. I used an oil can and gave it a squirt now and then.
I could hear the machine wasn't working as hard as it did on a dry cut.

 

[Charles scozzari]

Giving the blade a bit of oil will help.
I have a water based coolant system on my bandsaw but it is in an unheated area of my shop so I don't use it in the winter.
It was only 20°f yesterday and I wanted to cut a couple of heavy pieces of steel. I used an oil can and gave it a squirt now and then.
I could hear the machine wasn't working as hard as it did on a dry cut.

Nice chunk of steel. Looks like it was once a hydro piston. I have some short pieces left if that's what it is. looks like 1 1/4" wall.

 

[MrCrankyface]

Giving the blade a bit of oil will help.
I have a water based coolant system on my bandsaw but it is in an unheated area of my shop so I don't use it in the winter.
It was only 20°f yesterday and I wanted to cut a couple of heavy pieces of steel. I used an oil can and gave it a squirt now and then.
I could hear the machine wasn't working as hard as it did on a dry cut.

Will give that a try once I've set up brushes or something to clean the blade after it passes through the cut.
My previous experience is that the chips get stuck to the blade and then onto the wheels/guides etc.