How to decide when a blade is garbage.

[ChadH]

Hey guys,

So this may be a stupid question to some but something I need some major help on.

I know the basics about when to call a blade garbage but I was wondering if any of you sawmill wizards who have helped me out so many times in the past have any tricks or tips?

I was going through my blades tonight, anything from brand new, to sharpened once, sharpened 3 times etc. Now maybe I've lost tracked of a few of them and they haven't been sharpened as much as I thought or maybe they have. Is there a way to measure the blade to tell when it no longer should be re sharpened? I measured them all, and they were all the same. Now I was only using a tape measure and I know it's not as accurate as a micrometer but if a blade has been sharpened a few times wouldn't it be a noticeable size variation? I'm using 1 1/4" blades on my LT35 and blade I thought were back from their 3rd sharpening are still measuring the same as a new blade....

I also had a box of 15 blades sent out for sharpening and when I got them back I had also got my brand new warranty replaced sawmill.... I got about 200 2x6 and struggled with wavy cuts and wandering blades that I blamed the blades that they were finished and were all garbage. I thought they must be to thin to stay straight. But that doesn't seem to be the case. Now I'm convinced it was the sawmill that was never trued up from the dealer in the rush and chaos to get it to me. ( yes I was nieve to think I didn't need to check it over. Lesson learnt)

Any how I have digressed, so is there a way to measure or how do you guys no when to stop getting them resharpened and just throw them out?

Thanks again guys!

[ChadH]

Oh yeah and about 2 months ago I broke my first blade. Although not my fault, I changed out a dull blade for a brand new blade, to start a new log. It was about 16' in length and I cutting the first flitch off. As the blade exited the log, there was a loud bang followed by screeching and a blade in a particularly balled up mess in the cutting throat. I was not at all impressed with how little bdft I got out of that blade.

Any ways just thought I would share that I had officially joined the club. Not sure why I shared that....

[Stuart Caruk]

I just send them to resharp. They tell me when they are no longer resharpenable and I replace them and keep on going.

[Kbeitz]

I run my blades until they come apart. I use them up.

[ladylake]

 
Sharpening take off 10 to 12 thousands on my sharpener so 3 sharpening's or so would be hard to measure with a tape measure, when my blades get down to 1 1/8 wide or about 10 sharpening's they did good.  Steve

[bandmiller2]

My results are close to Ladylake Steve's. I sharpen and set my own. Mine start off 1 1/2" after about a dozen grindings they are down to 1 1/4 and start to wave and dive. I have never had one snap in service. Most have a long fruitful life and I can't complain about the service. Over tension is a killer of bands. Frank C.

[petefrom bearswamp]

When they break or I hit something hard such as a side support, but of course I have never done this.

[Ga Mtn Man]

Once you've sharpened below the tip hardness it's time to retire the blade.  One of our members up in the NE re-hardens his...I forget who it was.

[ChadH]

Thanks for the input guys!

So what this has told me is that I should have a longer life out of my blades then I thought.
This is great news because I have 60 blades and was worried I was needing to get rid of about 30 due to wearing then out.

Where would you recommend taking a measurement in the future, from the back of blade to the tip of the tooth or the gullet?

Just out of curiosity, any of you guys who use the resharp program through wood mizer, what does that cost you per blade?

Up here the dealer (who started out as a company who sharpens everything and anything for wood workers to cabenit shops to high production sawmills) charges $15 per blade and that includes setting the teeth. They have local pickup and drop off spot near me and charge me $10 to pick up my blade at the drop point and drop them off a week later. I find it to be very easy and convenient.

Also I'm running a 10 degree set on my teeth, any one have any advice on if I should switch to a 7 or 4? I find the 10 leaves a lot of sawdust on the wood it self, maybe that's normal not matter what?

[Ox]

I'm close to ladylake and bandmiller2's results.  I still have a bunch of "thin-in-the-skin" blades I'm hanging on to for real cruddy or questionable logs.  I'd sure hate to wreck one of my prized Kasco 4s. 

I remember trying a blade that's around 1" wide now.  It made a bit of noise as the gullet bottoms hammered across the guide rollers... I don't expect it to last too long... ;)

[paul case]

I have a little different take on it as I use simonds red streaks and they are cheap. $13 each so we use them and sharpen once and use them and throw them away. I could go more, but the more you sharpen,hardness goes away, and they dont last as long. If it gets to where you can only cut 200 bdft per band, you would have to change 9 times a day to cut 1800 ft. I also got tired of using them till they break it is usually a train wreck and you have a mess to get them out of the log or the guards. That is a waste of sawing time.

I also learned that when you hit something and the band wont finish the cut, to cut it on each side of the log and pull the piece out and put a good band on and start again. Much faster than trying to back out and generally that band is trash anyway. Tin snips work well to cut the band.

PC

[terrifictimbersllc]

My sharpening removes between 6 and 10 thousandths usually.   I measure from gullet to back of blade, with a  micrometer, narrowest point.  So new blades start out abut 1.00 inches (speaking of 4 degree) and 0.98 inches (7 degree, non turbo), 1-1/4" woodmizer double hard blades.  I just keep re sharpening them.  They tend to break at some point but most always before they get to 0.900 inches.  If a blade hits metal and I decide it is worth fixing part of my decision is how wide it is, so if it is 0.95 still I might save it but 0.92, forget it, it gets stepped on. 

[irvi00]

This is all great info!

[Magicman]

On the opposite side of the coin, I use Wood-Mizer ReSharp.  They determine whether a blade will be rejected, and if so, they replace it with a new blade at a discounted rate.  My blade inventory stays the same.

[Brucer]

Resharp isn't available in Canada :(.

I've had as many as 13 sharpenings out of a blade, and as few as one. My average is about 8 (not including damaged blades). About half my blades break before I can wear them out.

When I damage a blade, I write myself a message on it with a felt pen. When it comes time to sharpen the blade, I examine it and decide whether it's worth trying to salvage it. If it is, I reproduce the message after I sharpen the blade. Then if the salvaged blade gives me trouble as soon as I use it, I trash it.

[losttheplot]

As has been said already, once the hardened tip of the tooth is gone they dont stay sharp very long.
If your paying to get them sharpened you might want to replace them once the tip has been ground off.
I sharpen my own and keep going till they break.

It only takes a couple of wavy boards to offset the savings of pushing a blade for too long.

I might be mistaken but when I used to get them to sharpen my bands (same place your using) I thought they changed them out when they were due.
You might want to give them a call and check.

[drobertson]

I used my own resharp, and the blades pretty much let me know,, I would say know logs, wood types and the condition of the logs in regards to hardness and dirt and such,, I never relied on someone else telling me my blade was of no more good,,it was easy enough to see for my self,

[YellowHammer]

I'm more of the the run 'me till they drop kind of thing.  I sharpen in batches of 10, and they will all gradually wear down and start to fail at about the same time.  So when one starts getting fatigue cracks or wavy cuts, or the many other thing that indicate excessive blade wear, they will all start dropping out pretty quick.  I'll just keep whittling the batch down until they are gone.

[JustinW_NZ]

My results are close to Ladylake Steve's. I sharpen and set my own. Mine start off 1 1/2" after about a dozen grindings they are down to 1 1/4 and start to wave and dive. I have never had one snap in service. Most have a long fruitful life and I can't complain about the service. Over tension is a killer of bands. Frank C.

Ditto!