burnt teeth?

[coastlogger]

So when I sharpen my bands(WM 042/10*) with my Dinasaw sharpener,and for that matter with my old Norwood, I have to  go very light to avoid a bit of a blue tip.Of course I know burnt teeth are bad,but I wonder if Im being too fussy. The burn I m talking about is likely only 3-4 thou back from tip,and I can get rid of it by running another light pass on the back of tooth only.In other words its not going very far or deep. Is this the dreaded burnt tooth or is this just something immaterial.I suppose the teeth will dull faster if thy are burnt?I dont always get rid of all the blue and the band seems to cut ok. Wonder what wisdom others have?
I have experimented with a squirt bottle of water,dampening teeth before they get to grinder,it does help prevent the blue from occurring.

[Brian_Rhoad]

I use Dinasaw sharpeners. If the teeth are turning blue you are grinding off more than you should. I take 2 light passes and that is usually enough to get a sharp tooth and get the gullet and back of tooth. If you are using the hand crank sharpener, crank a little faster. Light grinding will make the grinding wheel keep its shape longer. Is the tooth turning blue when sharpening the tooth face or the back? You may be taking a light grind on the face but heavy on the back. I don't use any coolant and don't have any bluing unless the sharpener is out of adjustment.

[Nomad]

     Make sure your grinding rock is clean and not loaded up or glazed.  That will cause it to not cut properly and build up heat.

[bandmiller2]

As far as blue tooth my jury is still out. I try not to but if theirs a little blue I don't fret I can't tell ether way cutting or band life. Avoid it if possible. Frank C.

[Chuck White]

If the tip of the tooth is turning blue after sharpening, you are grinding too heavy!

When that happens, you have removed some of the temper from the tooth and it is "softer" than it's supposed to be, so it will get dull a little sooner than it normally should!

If the tooth is turning blue, adjust your sharpener so that it doesn't take off quite so much metal, and then make another light pass!.

[bandmiller2]

A lot depends if band steel is air hardening or not. When they manufacture bands they induction harden the tips of the teeth wile leaving the band body soft for flex life. This is the time for someone in the industry to jump in, after induction hardening are the band teeth quenched with oil, water, or air.??? Frank C. If chainsaw teeth are ground blue. it seems to harden them.

[barbender]

I have a real bugger of a time not burning teeth with my Cook's sharpener, I set it so it just BARELY touches the face of the tooth, but it will still grind  some teeth to heavy on the face, and others not at all. I don't know what is causing the inconsistency, but if I set it so that all the faces get ground some will be burned a touch. I do a light grind in the gullet, too.

[bandmiller2]

Bender, try clamping the band a little tighter. If not enough clamping force after the pall advances the next tooth it will slip back intermittently, and you will get a light and a hard grind. Frank C.

[Chuck White]

I was just about to write that same suggestion Frank!

If the blade is not tightly clamped it can (and will) move as the rock contacts the tooth!

[barbender]

Actually,  that was the first thing I tried. I kept turning it tighter and tighter, until the gear motor actually spit a seal out I wish I could figure it out, it drives me nuts.

[coastlogger]

(quote)A lot depends if band steel is air hardening or not. When they manufacture bands they induction harden the tips of the teeth wile leaving the band body soft for flex life. This is the time for someone in the industry to jump in, after induction hardening are the band teeth quenched with oil, water, or air.??? Frank C. If chainsaw teeth are ground blue. it seems to harden them.

My thoughts too. Guess one could do some kind of experiment with a file on an old blade to see how much different the hardness on a burnt tooth is. Will try this     sometime.Meanwhile glad to hear others burn the odd toothtoo
clgr

[coastlogger]

My Dina is powered I run it on  fastest speed. Seems like the blue occurs when the stone goes down the face   like it got the tooth pretty hot going up the back of tooth and when it does the face(same tooth of course)the added heat is just too much. I will look into the stone dressing thing. Its the only stone Ive used;   came with grinder(used). I have a new stone Ill try that.From what Im reading here Im probably just grinding a bit heavy.
Thanks all for the replies.clgr

[bandmiller2]

Bender, another thing to check is the support of the band wile it being ground. Watch the two small sealed bearings that the band rides on near the grinding wheel, do they both turn together, and does the band stay firmly on them.? If not the outer conduits that supports the band needs adjusting. What hook angle are you grinding, does the advance pawl look like its hitting the tooth the same each time. Does it misbehave with new bands or old or all of them and do you keep adjusting as you go. Take the offending band and set the machine to take a real light cut and keep running  the band around adjusting a little at a time. You should reach a point where the grind and spacing is even. If none of this helps call Tim Cook. Frank C.

[YellowHammer]

You guys know how little time I've got on my Cooks and in that time I've certainly misground a "few"  ;D bands to the point where I was getting all kinds of erratic contact, heavy and light, on some bands.  So I tried an experiment where I didn't adjust anything and just kept sending the band around and around, many times.  I figured the band was already screwed up anyway, what's the worse that could happen?  So I just watched, and let it run and sure enough, after awhile the bands were nice and uniform again, and the grinding wheel stopped contacting metal so it was running but not grinding and I knew the band was uniform again.
YH

[36 coupe]

Blue teeth are caused by heavy grinding.The teeth will be hard.A file wont touch them.If you burn a chain saw tooth you cant file them.Same goes for circular saws and planer blades.Bluing looks bad but a light grind will clean it off.Hard steel needs a soft wheel.

[coastlogger]

Blue teeth are caused by heavy grinding.The teeth will be hard.A file wont touch them.If you burn a chain saw tooth you cant file them.Same goes for circular saws and planer blades.Bluing looks bad but a light grind will clean it off.Hard steel needs a soft wheel.

I will be conducting the aforementioned experiment tomorrow and will report back.If in fact a burnt tooth is harder wouldnt that be a really good thing for holding a sharp edge?

[36 coupe]

I have been sharpening tools as a business since 1970.A hard tooth on a chainsaw will keep you from filing it in the woods.A hard tooth on a cordwood saw will be impossible to touch up with a file.I have found some new chains that were too hard to file.Blued cutting tools are the sign of a poor workman..Bow saw blades are all induction hardened  now.They stay sharp a bit longer but are impossible  to resharpen with a file.The wrong grinding wheel can cause bluing.Photos Ive seen of band saw blades after sharpening prove the grind is too heavy and the wheels used are too coarse and hard.The bonding of the grit on a grinding wheel must match the type of steel being ground.A wheel that is out of balance will vibrate and do poor work.I am not talking about an out of round.These can be dressed.No need to experiment because I have given you information that took me many years to learn.

[coastlogger]

I have been sharpening tools as a business since 1970.A hard tooth on a chainsaw will keep you from filing it in the woods.A hard tooth on a cordwood saw will be impossible to touch up with a file.I have found some new chains that were too hard to file.Blued cutting tools are the sign of a poor workman..Bow saw blades are all induction hardened  now.They stay sharp a bit longer but are impossible  to resharpen with a file.The wrong grinding wheel can cause bluing.Photos Ive seen of band saw blades after sharpening prove the grind is too heavy and the wheels used are too coarse and hard.The bonding of the grit on a grinding wheel must match the type of steel being ground.A wheel that is out of balance will vibrate and do poor work.I am not talking about an out of round.These can be dressed.No need to experiment because I have given you information that took me many years to learn.

I hear you, but of course we are not going to touch up our bands with a file so extra hardness would be acceptable,or an improvement Id think.Given that ,in a bandsaw world,"staying sharp a bit longer" is what its all about. What am I missing here.??

[ladylake]

 
So which way is it, do burnt teeth get harder and stay sharper longer or do they get softer and not last as long.  Seems like my sharpened blades run just as long as new ones, once in a while I see some burnt teeth but most time not..  Yes a softer stone will not burn the teeth at all but wears off way to fast.   Steve

[36 coupe]

Read reply 16.A cutting edge that is too hard will chip .A grinding wheel has to wear to expose new grit and keep cutting.A hack saw blade is very hard but dulls and loses teeth.If band saw teeth are too hard you cant set them.Theres a good chance a too hard tooth will break when you set it.

[coastlogger]

Read reply 16.A cutting edge that is too hard will chip .A grinding wheel has to wear to expose new grit and keep cutting.A hack saw blade is very hard but dulls and loses teeth.If band saw teeth are too hard you cant set them.Theres a good chance a too hard tooth will break when you set it.
[/quoteI I wonder if this applies to bandsaws cutting wood. Maybe Im wrong but it seems to me we dont chip our teeth they gradually round off. As to setting,were talking maybe 4 thou at the most of blue metal right at the tip(for me anyhow)whereas the setting anvil pushes Im guessing 60 thou or so from tip. Im not sure Ive ever broken a tooth setting,burnt or unburnt.

I did a bit of experimenting today on a well worn WM doublehard band. Ground some teeth hard so a bit of burn showed up on tip,others a light grind,no blue. Put band in vise,ran a file over tip of both kinds of teeth,looked with magnifying glass at result.No noticeable difference. Tried file on back of tooth including point. Again no noticeable difference in apparent hardness..Likely a microscope would tell more as to whether one point got rounded off more by file, but my impression was the a little burn doesnt make much if any difference.

[coastlogger]

oops Ive meessed ip the quoting on prev. post. Sorry Coupe. The last 2/3 of post is mine not Coupe's

[beenthere]

coastlogger
Just FYI, you can go back to your post and correcting it by clicking on the "modify" button, upper right.
Just move the ending quote above your reply, rather than at the end.  ;)

[Magicman]

oops Ive meessed ip the quoting on prev. post.

Notice that the [/quote is missing the ] at the end.  Especially when making quotes, it's good to use the "Preview" and scroll up to see what your actual post will look like before posting. 

[thecfarm]

At least he got who he was quoting. Some leave that part out than I have to look through all the posts to understand what they are talking about.  : Sometimes I don't bother with it.