Interesting Band Saw sharpening video.. Brand new blade is dull compared to sharpened blade

Pretty good vid... watched it at 2 times speed..

I ran into a problem resawing yesterday, my first piece 9" maple was true... my second one drifted and was hard to push. I realized my blade must have dulled after a few years. I haven't drifted off my fence for a long time... I'm going to give this a try b4 I need the resaw again..

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Reply to
woodchucker
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Well, I decided to do it the way Mathias Wandel does it, with a dremel, and a cutting wheel. Much easier I figured.. maybe , maybe not.

But wow does it cut now. Holly crap. If I were employed, I would have just bought a new blade, probably a wood slicer instead of the timber wolf just to give the wood slicer a try. But man that is cutting like new.. better than new??? I don't know. But it just sliced through 6 inch maple taking ribbons off. I even cut by hand, just turning the wheel just to see if I had any high spots... freaking awesome.

A 105" blade took about 15-20 minutes... well worth the time for me.

Reply to
woodchucker

Wouldn't it be even easier to put the blade on the saw backwards so it runs with the teeth pointing up and let it run gently against a hand held stone?

Reply to
dadiOH

I don't believe so. I think it would round the teeth.

Not willing to take that chance.

Reply to
woodchucker

Well maybe don't sharpen your blade...!!! I just had the bandsaw kick back and it bent the blade and lodged into a piece of wood.

I imagine I did something wrong when sharpening.

Never had that happen b4.

Destroyed the wood and blade.

Reply to
woodchucker

Interesting....

I kind of suspect that non-carbide bandsaw blades are not actually sharpened after they are stamped out... so sharpening them improves them.

If the face, rather than the back of the teeth was sharpened they could probably be sharpened more times... up to the point where the blade is work hardened and breaks. Sharpening the back at the angle shown in the video decreases the clearance behind the cutting edge more and more with each sharpening so at some point there is basically no clearance and they don't cut well.

I'd think that a thinner and finer grinding wheel would allow grinding the face of the teeth with no more effort than grinding the backs.

It's got me thinking about making some fixtures for one of my grinders to give this a try. I also need a fixture for grinding long blades (e.g., lawn mower, machete) in a similar manner to a surface grinder... Would make for a productive diversion!

John

Reply to
John Grossbohlin

Well pics once you come up with a jig. I ruined my blade, I think I must have dulled a few teeth and caused it to grab while resawing. I tried an old olson (don't like them), definetly sharper, but same. Maybe doing the gullet side would be better.

Reply to
woodchucker

Certainly better. While it is important to back grind and deepen the gullet, the face grins is what gives you the lasting resharpening job.

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Reply to
Leon

Nice.. But I don't think I need that... Would be nice, but no room. I would think if I did milling, it would be a no brainer.

Reply to
woodchucker

Agreed. Unless you were sawing several hours every day these type mills would not be cost efficient, probably.

The guy grinding from the back side was only putting a temporary sharp, almost microscopic, point on the extreme end of the cutting surface. None of the rest of the cutting surface of the hook was being sharpened.

Reply to
Leon

True but apparently you don't need all that much. The results he's produced (before and after) were pretty damn dramatic. Almost 4X faster cut.

The extreme end is, pretty much, THE cutting surface. Everything else is clearing the chips.

Reply to
Unquestionably Confused

Yes he did sharpen the blade and he did cut more quickly. This will however be extremely short lived. Only the extreme point of the tooth is being pointed. The sides of the face of the tooth are still dull.

Once he dulls the almost microscopic point of each tooth he is back where he started. He is not sharpening all of the cutting surfaces.

Reply to
Leon

To expand on the extreme end being the cutting surface, yes it is but the more of the tooth that is sharpened the more the rest of the tooth shares the cutting load. While it seems that only the point is doing the cutting that in fact is not true. The point is involved in all of the cutting but more of the tooth surface past the point gets used with the increase of feed rate. With a slower feed rate less of the tooth surface is used.

Reply to
Leon

And by my 2 attempts, you can screw up a blade pretty damn good. You have to be very precise, no rushing, no mis touches.

I am thankful my hands were away, but I did get hurt and cut by the wood being jerked up on my end... it broke the throat plate and the blade was wrapped into the wood. I have to resurface my cool blocks too.

Reply to
woodchucker

Yes.

I have only had one blade break on my BS and oddly my wife was using it at the time. She broke the blade while cutting cardboard removed from the back of a note pad....

Reply to
Leon

I sharpen mine with a flex shaft tool using a long stone similar to the ones you can buy to sharpen chainsaws. I never touch the back of the tooth.

Reply to
G. Ross

Have you ever had the problem I did, where the bandsaw grabbed? So you are using round stone, not a circular disc?

Reply to
woodchucker

There must be one helluva back story on that, Leon.

Care to share? Like, did she wrap the cardboard around a piece of angle iron to stabilize it first?

What happened? Piece get carried down into the lower blocks and jam?

Reply to
Unquestionably Confused

I really really don't know what the heck she did. LOL I set her up and let her go. Next thing I hear is the bang. You might be on to something with the cardboard possibly tearing and getting jamed in the lower ceramic guides.

Reply to
Leon

Never grabbed. Yes, a stone about 1/8" diameter and 1' long. It fits into the gullet and down the underside of the tooth. Have to be careful that it doesn't go around the tip and dull the point.

Reply to
G. Ross

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