The Forestry Forum

General Forestry => Sawmills and Milling => Topic started by: Cypress Man on October 13, 2006, 11:07:03 PM

Title: Sharpening .055 x 1 1/4 bandsaw blades
Post by: Cypress Man on October 13, 2006, 11:07:03 PM
     Can anyone actually sharpen a .055 thick x 1 1/4 wide blade on a Wood Mizer sharpener.  They are never anywhere close to being as sharp as when they are new.  I can only sharpen them one time and then they will break.  Is this normal?  The .045 would get sharp and could sharpen them 3,4, or 5 times before they would break.  Any suggestions. :-[
Title: Re: Sharpening .055 x 1 1/4 bandsaw blades
Post by: Tom on October 13, 2006, 11:13:54 PM
Don't know if it would help but, if it were me, I would 1. slow down the sharpener with the speed control  2. pour the water to it  3.  create a longer transition area between the face and gullet (dress the left side of the stone more)

If This works, then slowly speed up the sharpener on the next blade until you find that the tooth isn't getting sharp.  That will help you find the optimum speed.

There is no reason that yo can't sharpen it. Take little bites and multiple passes.  It helps to keep from stressing the band or burning the tooth.
Title: Re: Sharpening .055 x 1 1/4 bandsaw blades
Post by: Fla._Deadheader on October 13, 2006, 11:21:33 PM

  I have 2---.055 X 1½" WM blades that I sharpen on a WM Sharpener. Just have to adjust the stone higher to clear the tooth tip. Go slower and lots of water. Tom is right on .  8)
Title: Re: Sharpening .055 x 1 1/4 bandsaw blades
Post by: WH_Conley on October 13, 2006, 11:22:57 PM
I am not a very good one to give advise on this one. Set everthing up the same as with .45, next thing the hook did not look right, wrong hook angle. Only thing I could think of was too much steel for the stone to take off. Kinda eat the stone to. Slowed waaay down on the feed rate worked better. As far as number of sharpenings , not sure. I would guess that because of the thicker steel they will break in less revolutions. I could not run them on my mill. More HP would probably work fine.

Title: Re: Sharpening .055 x 1 1/4 bandsaw blades
Post by: Tom on October 13, 2006, 11:27:58 PM
It's a good idea to check the sharpener clamp for dirt too.  If it gets debris down in the blade path, it won't clamp the blade tight and action of grinding the face will move the band forward. That will produce a shallower hook and could even produce a negative hook.

It helps to dismantle the clamp and clean it good every now and again.
Title: Re: Sharpening .055 x 1 1/4 bandsaw blades
Post by: Cypress Man on October 13, 2006, 11:40:02 PM
    Thanks for the info.  I have been setting the speed to 4.5 - 5, so I am probably going too fast.  I'll slow down and see if it helps.
Title: Re: Sharpening .055 x 1 1/4 bandsaw blades
Post by: Fla._Deadheader on October 13, 2006, 11:48:54 PM

The first grind kinda straightens out any deformities in the face and tip of the teeth. I let it go twice without adjusting on the second pass. That should be a VERY light touch. That's where the sharp comes from.  ;D
Title: Re: Sharpening .055 x 1 1/4 bandsaw blades
Post by: logwalker on October 13, 2006, 11:56:24 PM
IMHO, your problem is with the .055 bandbody. I don't know why woodmizer sells this blade for a lt40. I guess it does have a place for the person who wants to push hard and throws the blade away at the end of the shift. Let me stress this: The wheels are too small to run this blade. It will consistantly break ahead of woodmizer's other blades.

I have good luck with a .045 x 1.5". 6 or more sharpenings before breakage. I had to go to a 1.5 guide rollers but am very happy with performance on blade life.

How are you setting. My experience is it takes a lot of pressure to set a blade that thick. Good luck with this problem. LW
Title: Re: Sharpening .055 x 1 1/4 bandsaw blades
Post by: gmmills on October 14, 2006, 02:56:58 AM
   I sharpen .055's every day with a WM  sharpener. How many times around are you sharpening a new blade for the first time?  If you are only grinding twice they are not sharp. The first time I sharpen a new .055 it may take as many as 5 times around to be sharp. :o :o :o  The problem being you are not actually grinding enough off the back of tooth to sharpen the outside edge of it only grinding two times around. When WM manufactures their blades they sharpen the coil stock, which is flat teeth have no set, then the teeth are set. They are set out to around .027 thou. This makes the black angle of the tooth not 90 degs too the blade body. The inside of the set tooth actually is taller, higher, than the outside edge of the tooth. Sight down a new WM blade from the back side of the teeth. Look at the set teeth in relation to the straight raker teeth to see what I'm explaining. Look closely at the set teeth of a new blade that you have ground only 2 to 3 times around and you will see only the inside of the tooth was sharpened. The second and succeding sharpenings should be able to get by grinding around 2 -3 times.

   I tried .055's on my old LT 40 and the best I ever got was 5 Sharpenings before breaking. i finally settled on .045's  1 1/2" as logwalker and got better flex life. On my LT 70  I use  .055's  and average around 9 sharpenings. I just retired one blade this week with 13 sharpenings too narrow. Bigger band wheels really do get you more flex life. 

   I've been experimenting with grinding wheels also. Been using Cook's 46 grit black wheel. Seems to cut the thicker blades better. The WM wheels are harder with less agressive grit 60 or 80.They cut 045's and 050's well.  With the WM wheels you have more tendency to burn the teeth.  Must grind lighter .
Title: Re: Sharpening .055 x 1 1/4 bandsaw blades
Post by: Cypress Man on October 17, 2006, 06:12:21 PM
    I,ve tried slowing the grinder speed way down, pouring on the water,  and grinding 4 - 5 times and dont see any difference.  They are just not as sharp as when they are new.  Not even close.  I could'nt imagine a .055 lasting for 9-13 sharpenings.  I had a brand new blade out of the box break today after cutting 1,000 bf.  I have a brand new 2006 Wood Mizer Super HD with a 25hp electric motor.  It only has 156hrs. on it.  Does anyone else have this kind of results with blades on this type of mill or could my luck really be this bad?  The only wood I cut is cypress, which is soft and it would seem I would have better results than cutting mixed hardwoods.  Does anyone have any suggestions.
Title: Re: Sharpening .055 x 1 1/4 bandsaw blades
Post by: logwalker on October 17, 2006, 06:15:22 PM
I know I am repeating myself but, don't use .055's on a 19" wheel. Tell woodmizer they aren,t working and get .045's exchanged. And go to a cooksaw grinding wheel. I get great results with mine.  LW
Title: Re: Sharpening .055 x 1 1/4 bandsaw blades
Post by: amberwood on October 17, 2006, 07:34:02 PM
Slight off topic, but any thoughts on tracking blade life/sharpening? I was thinking of engraving a ser# on each one as they enter service and keep a log of the number of sharpenings.

DTR
Title: Re: Sharpening .055 x 1 1/4 bandsaw blades
Post by: Cypress Man on October 17, 2006, 07:43:48 PM
     I do keep track of how many board feet I cut before I change blades but the blade always breaks between 300-800bf after the first sharpening.  I'd like to know if this is common when using .055 x 1 1/4 on a LT40SuperE25.
Title: Re: Sharpening .055 x 1 1/4 bandsaw blades
Post by: Bibbyman on October 18, 2006, 10:30:53 PM
We're not getting near the life out of .055 blades as we were with the .045s.  But they are cutting faster and straighter longer.  I think that's one of the problems.  Because they tend to cut longer, we tend to push them more.

As for sharpening,  you may want to try speeding up the grind instead of slowing it down.  Years ago I found that if I ground slow,  it would tend to burn the tooth and cause more burrs.  I found a couple of light fast grinds produced a sharper blade without burn.

With only 156 hours on your mill,  have you checked and adjusted your main belt tension?  I've found I've had to adjust the main belt a couple of times in the first couple hundred hours – when it was new and when we changed belts.

At 158 hours your B57 belts should still be in good shape.  Check your tracking.  The older Wood-Mizer mills had a built-in handle on the tracking bolt.  I checked the tracking and twinked it just a little on every blade change.  But the newer models (like our 2002) does not have a handle so I got out of the habit of checking.  For a while we were having a rash of broken blades.  I checked out everything, did some adjustments,  but nothing helped.  Then I thought to check the tracking.  It was pretty far out.  I adjusted it in and – so far, knock on wood – we've not had a blade brake.

Another time we had a rash of blade brakage that went on for awhile until I noted the outer blade guide tilt just a little when the blade was engaged.  Turned out the blade guide was just a little loose and as the blade slipped through, it'd pull the lower guide block over and work like a break against the blade.  This caused it to heat and abrade the blade that lead to their failure.
Title: Re: Sharpening .055 x 1 1/4 bandsaw blades
Post by: Cypress Man on October 19, 2006, 05:34:09 PM
Bibbyman,

I also agree that grinding faster reduces the likelyhood of burning the teeth and it also seems that light grinds do not affect the set as much as heavy grinds do allowing for better performance.

I have not adjusted the main belt tension yet but I can tell it is time to do so. 

Do you sharpen your oun blades or send them back to WoodMizer?  If you do sharpen do you always set the teeth?
How many BF do you get before they are dull?  How many sharpenings before they break?  being we have the same mill we should have simular results.
Title: Re: Sharpening .055 x 1 1/4 bandsaw blades
Post by: Bibbyman on October 19, 2006, 10:24:05 PM
Quote from: Cypress Man on October 19, 2006, 05:34:09 PM
Bibbyman,

Do you sharpen your oun blades or send them back to WoodMizer?  If you do sharpen do you always set the teeth?
How many BF do you get before they are dull?  How many sharpenings before they break?  being we have the same mill we should have simular results.

We started out sharpening our own blades.  But we started using WM Resharp about 6 years ago and sold our shapener.

The number of board feet very from type of wood to sawing conditions.  When sawing soft maple and cherry,  we'd saw a 1,000 bf and then pull the blade.  But we would not always get that many board feet when sawing walnut or hickory.  Even though we have and use the debarker,  there is still a lot of grit and junk stuck down in the thick bark on walnut logs. 

I've not kept count of the times we have had .055 blades resharpened but I suspect two resharps would be an average.

I'd think sawing conditions, technique, and type of logs would be more of a factor than having the same mill.  For example,  do you stop the blade at the end of each cut or do you keep the blade moving at all times?  I know people with electric mills that do it both ways.  We do a combination.  We keep the blade moving when cutting on one face of the log – that is,  we don't clutch the blade when making the gagback to cut the next board.  But we do stop the blade when turning the log or loading the next log, etc.   

Not clutching may be a factor in short blade life because of all the additional turns the blade is making.  But clutching also shortens the main belt life on an electric mill (because an electric motor don't slow down to an idle like an engine – so it's spinning at something like 3200 RPMs when it clutched).