bandmill blade questions

[fluidpowerpro]

I still consider myself a novice when it comes to sharpening and setting so I say this only to solicite feedback from others.
Regarding setting. What i have been doing lately is I set the teeth, trying to get each tooth "close" erroring on the high side. I then run the blade through some rollers i built to bend the tooth back a little.  The goal being that all end up the same. That way I dont have to be too concerned about what I'm setting it to because once I pull it through the rollers, they all end up the same.
I can't claim this is the best way. Only that I can make a dull blade cut good again, so as far as that goes, it seems to work for me.
I know a few others use rollers/de-setters but not sure if they use them the same way.
Looking forward to comments from others.

[customsawyer]

One other thing I'd like to point out. It is best if you're cam and push rod is indexing on the tooth to be sharpened. The teeth on these blades are stamped/pressed into the blade. I've heard it does 3 at a time, but I don't know that for sure. However, as that machine is advancing the blade you will get some slight variance from time to time. By having your sharpener indexing on any tooth, other than the one that the stone is coming down the face of, can through things out of whack by a few thousandths from time to time. Remember, the more constancy you can get out of this sharpener/setter the better your blades are going to do.   

[trimguy]

fluid, running your blade through after it is sharpened and set seems like it would mess the corner of the tooth up, ( round over, flatten ). I guess your not finding this to be so ?

[fluidpowerpro]

Thats a very good point. I can't imagine that its not doing what you describe. 
Even though my blades cut again, they are not as good as new.
I'll have to rethink my method.

[jpassardi]

My personal approach (not saying I'm an expert) is to not de-set blades. A blade should not increase in set unless there is a metal strike in which case I send it to the recycle bin.
During normal use/sharpening a blade should only decrease in set - wear, grinding & fatigue. Based on this I find I can sharpen once or twice before I need to re-set (increase only). I shoot for 0.023 and that has worked well for me.

[Stephen1]

The best advice is you need a straight edge and pointed outside corner on the tip of the tooth. If a blade is over set, I run it and keep sharpening until the set reduces or the blade breaks. 
A tooth mark on my lumber is not the end of the world. I am trying to promote the bandsaw marks versus the circle saw marks that people like. It seems like it okay for the circle saw to leave marks but not the band saw. After all it is rough sawn lumber.

[YellowHammer]

These are obviously 2 different profiles. @YellowHammer the left corner of my grinding wheel wears off before I get around the blade and gives me the rounding at the bottom of the tooth instead of a "corner " is this what you are referring to when you say don't fight the grindstone ?

Yes, if the profile of the grind changes on one band then that's a problem.  Ideally, you should be able to do several bands, several passes and not worry about it changing profile.  So if the factory profile you have seems to cause excessive wear or "hotspots" on your grinding wheel, let it find it's happy place.  I also switched to Ruby stones, they lasted longer. 

Also, the lighter the pass, the less stone wear. 

I notice the one band in your picture seems to have a much shallower gullet than the other, and the depth of the gullet is what determines how much sawdust the band can carry out of the kerf, and sawdust spillage out of the gullet during a cut is a major cause of poor cuts.  So it's important to match angle and gullet depth, when sharpening.  It's also counter intuitive, but the faster a cut, the more sawdust the band will carry out and the straighter the cut, as the gullet shape creates a vortex with the air, and suspends the sawdust like in a snow globe, and ejects it cleanly.  If the vortex can't form, and the sawdust spills out of the gullet, or the gullet isn't deep enough then sawdust will spill out into the kerf, and if that residual spillage is greater than than the set to that side of the tooth, then there is negative clearance between the body of the band and the saw kerf.  That jamming of the saddest into the body of the band  will create all kinds of cut quality problems.  I did a fairly lengthy experimental video on the subject, with a factory WM band, and you can see how sawing slow is a disaster, the sawdust spillage is horrendous, and as I sped up, the cuts got better and better as more and more sawdust stayed in the vortex and got ejected.  So a sharp band is a necessity to allow you every possible advantage to cutting faster (and flat), where an improperly sharpened and set band, or with an improper gullet, will force you to cut slower. 

I always sharpen, then set, although others do it the opposite.  I feel can get a much more accurate set off a properly formed tooth corner straight off the grinder than a slightly rounded one that hasn't been sharpened yet.  But I think that may be a personal preference, because other have good success doing it the opposite way.  Also, I generally will regrind and reshape the setting anvils to ease the angle to not impact the tooth corners so hard, and not damage them when setting.  On both my Cooks and WM setters, the grind on the anvils was not normal to the side planes of the anvils, so the amount of set would change based on where the tooth touched the anvil.  That was intolerable and would result is inaccurately set teeth.  I have long since sold my Cooks, and switched to a WM CBM.

As others have said, a properly sharpened and set band with cut better than new one, or at least as good.

As an FYI, I had a Cooks drag sharper, decent machine, for several years, it took 7 minutes per grind around, two passes per band, so 14 minutes per band, and so 4 band per hour.  I went to a WM CBN, now I can do 3 minutes per band, most times only 1 pass, so for sake of argument, overall average is 5 minutes per band to account for the messed up ones, so 20 bands per hour and all come out perfect and no fiddling with re profiling the stone.

What you are going through is normal for a drag grinder, they seem easy but there is a lot of learning curve and fiddling to get them dialed in.  That's also why it is SO Difficult to buy resharpened bands that are any good.  As Coach Saban says, "It is a process".     

[barbender]

That's a very good summary, YH. Especially the finickiness of drag grinders. People think that they can just unbox one, and sharpen blades. It don't work that way. I'd wager that at least half of people that get a drag grinder, never will learn to sharpen a blade correctly (and 50% of that number, will start to offer their services to the public😂). 

Its easier to learn to run a sawmill, than it is to learn to sharpen with a drag grinder. And probably even a CBN grinder. 

Just a general observation of mine, but when it comes to sharpening, whether it be band blades, chainsaw chains, knives, or whatever- it takes a certain "knack" for it, and I'd guess less than 20% have it. 

Back to drag grinders- I've seen some that are physically not able to make an accurate grind. Total wastes of time. Flexible mounts, bad clamps, underpowered motors. 

I have a Cooks, it is among the better drag grinders and will do a good job. It is built like a tank, kinda looks like it was built by a caveman. There are many on the market that I question if an experienced grinder operator could get passable results out of them. They're just too light, and underpowered.

[Stephen1]

I went thru the aggravation of a drag sharpener for 7 years. I would get so p!@#$ that I would just buy more blades. At one time I had over 100 blades , I was one of those % that could not really master the drag sharpener, I didn't have the patience. The grinding wheel would maybe sharpen 30 blades before it was time for another wheel, then reshape it....  The single tooth setter was something else, I used to get Cathy to do that and she did a Wonderfull job. when I finally switched to the CBN grinding wheel my life changed. I bought the BMS sharpener and dual tooth setter and never looked back. it is the best money I spent in this hobby/business 

[SawyerTed]

Lay people aka customers and beginners in sawmilling want to know how to get blades sharpened.  

Often a customer will ask if I sharpen my own blades.   Then if the blade strikes metal I often get, "You can resharpen that, right?"  

Well no.  I don't even try any more.

Here's why. 



This blade hit a 16d nail in an oak log.  My customer wanted to protest the blade charge, I went over this blade with him.  He changed his tune.