I'm frustrated! How long do you run your bands before resharpening?

[scsmith42]

I'll say up front that I'm frustrated about this and need some advice.

Mill Specifics:  Tom's Baker 3638D band mill, 38 hp Kubota Diesel, sawing a mixture of oak and SYP.  Bands are Woodmizer Turbo 7/29's .055 x 1-1/2".  Band tension is set right on Baker's recommendation (and also Woodmizers who recommended that we max out tension on the bands.

I just received a shipment of Turbo 7's back from Woodmizers resharpening service, and out of 14 bands sent in for their very first resharpening 6 were rejected (over $250.00 investment loss).

Initially we had a problem with breaking bands, and were advised that we were running them too long and that the gullets were cracking.  OK.... So based upon advice from others we idle the mill down if we're not going right back into another cut (reduce the number of rotations on the bands), and are not running the bands more than 2 to 2-1/2 hours before changing them. Our logs are cleaned in advance of milling and we also have a debarker on the mill.  The darn bands are still sharp when they come off the mill, but we're pulling them off anyway to try to prevent the cracking.  Yet we are still experiencing almost 50% rejects at Resharp.

What should we be doing different?

[Gary_C]

I always had trouble with .055's breaking early. I mostly do not use them any more than I have to. Can you get by with the thinner bands?

[Rachiano]

Buy your own sharpener and setter and sharpen your own bands...use turbo 7 silvertip .045...you should at least get 3 sharpenings out of them...maybe you can also ask the reason why they were rejected..the .045 have more flex life and should stay alive longer.

[terrifictimbersllc]

Not going to know anything about 55's but wondering what is the wheel diameter?

[Dave Shepard]

Baker runs big wheels, at least 24", I think, U wouldn't you would be having a flex life issue if you are only running a couple of hours. I have 19" bandwheels, and I run probably too long and I go about 4-5 sharpenings. I've only had them rejected for being bent, which I usually catch them and don't send them back. I wonder if there is an issue with your guide rollers. I hate to comment too much on a Baker machine not having experience with how they are aligned, but the WM has different amounts of clearance to the flange on the back of the roller. If the band is flexing too far back in the horizontal plane, that will chew up a band, too. The guide roller closer to the drivewheel has 1/16" clearance, and the outer has 1/8".

[backwoods sawyer]

Track down the root cause of the bands braking.
Vibration and wheel build up both cause cracking along with back presure on the guides and alignment issues.

It dose not sound like you are pushing the mill.

Yes sharpening your own saws will save you when diagnosing an issue. Problem becomes you don't know if the issue you are solving is with the mill or with sharpening.   

Ask for a detailed list as to the reason for each saw being rejected on your next batch, may point you to the issue.

[Foxtrapper]

I think it points to something out of alianment on your mill.  I had a homemade rig for awhile, and was running cook's super sharp blades.  They never made a resharp, they'd always break first.  If anyone can help you, it would be cook's.  Of course they will want you to run their blades, but it might be worth it if it helps solve the problem..

[Chuck White]

I use W-M .045-1¼-10° set at .030 and I routinely run them for half a day before pulling them off.

I average around 500-800 bf per blade change.

With the bigger band wheels on the Baker you shouldn't be losing blades at the rate you are now!

I think if it continued, I'd switch to .045 thickness!

[isawlogs]

 I also beleive that you would get better milage with the .45th blades. Are they being rejected because of gullet cracking  ???

[giant splinter]

I have experienced the same results with the .055's and I do not think the flex life is as good as the .045's ..... the thicker blades do cut faster and hold truer to straight in the cut, when my reject percentage hit the same level that yours did I found a local sawshop that could re-sharpen my bandsaw blades and have been having better luck with the results. I did have a run of bad luck with the lube/coolant not being consistent and between heat buildup and sawdust/pitch buildup on the bandwheel belts i lost a few blades cutting very large ponderosa pine. I agree it is very frustrating and wood-mizers blades seem as good as any of the blades out there so I sure dont know how to solve the problem.
I suspect that Custom Sawyer might be the one to shed some light on this issue as he does his own sharpening and has good results. I will be interested in hearing his view on this as he uses .055 regularly, like many others running the bigger mills.

One case is particular involved turbo 7 1 1/2" blades .... both where resharpened (one by Wood-Mizer Resharp and the other by CSW)  The first blade was removed halfway through the second cut in a large red fir log after hitting a chunk of metal that looked like fence wire, after removing the wire and replacing the blade that just had a few teeth out of whack I put on the blade that was resharpened by CSW ran the mill back just short of where the metal had been removed and fired it up again ...... interestingly enough the new blade took off through that log very quickly without making any strange noises or straining at all ( I could have sped up my feed ) and had to look at the cut to see if the blade was still in the cut, it was and was moving effortlesly through the log. hitting a piece of wire or fencing can happen but why would a bandsaw blade slide through a cut twice as easy as the previous one in the same spot on a log. Im not sure that CSW even inspects the blades for cracks but at this point im not concerned if they do or not because I have three of the ones Wood-Mizer resharp inspected that didnt last more than a few passes before they broke and got stuck in the log and wadded up on the sawdust outlet ....... all three where still very sharp and may not have had over ten minuets cutting time before they broke in the gullet and got tangled up in the mill. I am not placing any blame on anyone here and stuff happens that we cant explain in very much detail because we get so busy at times its difficult to recall the entire situation.

[kelLOGg]

Scott, use less tension. I tension until the band begins to flutter. Once it enters the log it of course settles down. This lessened my breakage rate. (Simonds 0.042, 1.25", 19" wheels).
IMO the number of sharpenings (and arguably the board feet) between sharpenings is a useless statistic. It so dependent on the species sawn, tramp metal, size of lumber cut, etc. For whatever it's worth, I get about 7-8 sharpenings before the band breaks.
Bob

[FarmingSawyer]

It's been a long time since I've had bands rejected from gullet cracking--usually from pushing too hard. And I haven't (fingers crossed) broken any bands since I change sharpening services--couldn't stand loosing a band on the 1st or 2nd sharp.

But....I have had numerous bands rejected from the current service I was using....too many 1st time sharpening candidates to take it laying down..... The bands were either flexed out of a flat loop by 1/4" or had bent into a hard right angle when the came off the rollers, and slammed into the shield--usually from trying to back out of a cut, or if there was too much lube on the drive wheel. I haven't figured out the flex part--why they won't lay flat in a loop, but I have a feeling it was due to an alignment issue I've since fixed.

Are these blades ruined? No way. They just take a human being there to watch and help them through the sharpening process...... The automated machine the sharpening service I was using can't handle the slightest deviation from normal or it won't work and will grind funny. A missing tooth will throw it into fits. I've watched.

Now that I've got a Cats Claw on the way I am hoping to save the 20 rejected bands and get back *some* of my money on them...... Needless to say they are all marked and identified as to the issues they're having so I can pay attention when I attempt to sharpen them myself. They will be among the 1st bands on my new toy......

[bandmiller2]

Good news FS on your Cats claw you should be able to nurse many of your bands back to health. Theirs no one that cares more about your bands and wallet than you. You will need a setter, the single tooth models work well but are slow. Keep a small adjustable wrench handy for really  tramp bent teeth. Frank C.

[drobertson]

this is going to sound like a bash, and it's not meant to be at all,, When I first started sawing I used strictly wmz bands.  I suffered through many broken blades.  The Resharp (tm) was what I used.  very costly for me. Just me, but knowing what the blades were made of at the time, it made sense.  These bands work hardened more than others of differing compositions.  'This said, I still have some originals that I still use from 05' .045,1-1/4 x158" so something has to be said about this.   I deep down believe after watching and  being around different mills, that several factors come into play.  Band wheel bearings, proper adjustments(alignments) which can deceive the best of us, and debris.   Band tension is another factor,  I say that the least amount of tension that delivers an acceptable product is the best.  They all don't have to be maxed out.  It only takes a few tweeks, and a board or two to find this range.

[boardmaker]

Scott,
A guy not too far from me has a Baker head saw.  His biggest trouble was cracks on the rear of the blade.  They really push the limits of the saw.  I have the specifics written down in my office.  I'll check it out tomorrow and let you know what bands he runs.

[pineywoods]

Probably not your problem, but I'll toss this out here anyway. A while back I got what I think was a bad batch of new blades from one of the major blade suppliers. Every blade broke after 3 or 4 sharpenings, where I normally get 10-12 or more. Nothing else changed, same mill, same syp, same setter and sharpener (mine). I think what happened was that some machine operator got a little carried away and induction hardend the whole tooth and down into the body of the band. The hardened part won't bend, forcing the adjacent metal to bend more than normal, resulting in premature cracks and breakage. Next batch from the same supplier was fine..

[customsawyer]

I bet the blades are 7/39 turbos not 7/29s. ;) I know I have fat fingers sometimes also.
I doubt if the fact that the blades are .055s has anything to do with it. If that was the case then I wouldn't be able to do what I do with the same blades. I have not ran very many of the 7/39 blades as of yet but I am gearing up to run some. I also have never ran a Baker mill before so keep this in mind.
When the blades is spinning and not in the cut is there any vibration in the blade? When the blade exits the cut does it pop up or down? How much trouble is it to remove the blade guide rollers and run the blade a little with them off (not in a cut) and see what the blade is doing? Is there any build up on the band wheels? Are the blades cracking at the leading edge of the blade or the back of the blade? How far does your blades run off the flange of your rollers?  With all of this being said it might be just a bad batch of blades and nothing to do with you or your mill. I would double check my alignment and start from there. Pay really close attention to what the blade is doing while in the cut.   I know when you are running a Baker you are at the wrong end of the mill to watch the blade exit the cut but maybe you can get someone to run the mill while you go down to the other end and watch. I know I didn't offer much advice just lots of questions.

[Ivey]

Scott,
I have never used a resharp service,  (I bought a sharpener and setter in the beginning).Sure seems
  like a waste, I think that I can understand you're fustration. I have taken some pretty beat up bands
  and made them saw good again.
It's about time to take a road trip to see you, (my turn ;D) be glad to bring a few of those rejected
  bands back w/ me and see what I can do. Would like to see that Baker saw anyway. Maybe a new set
  eyes on the situation.

By the way I have been using Cooks .050 1 1/2" xcel black for a while now with good service. Flexable
enough to last a while, yet stiff enough to push on through the wood.

Ivey

[customsawyer]

Has that mill got steel or belted wheels?

[Ivey]

Jake,
Don't hold me to it but I beleive that they are bare steel like mine..

Ivey

[Nate379]

6 bands cost you $250?!  The wood mixer bands we run are about $15 each.

[Dave Shepard]

The Baker bands are much longer than an LT30/40/50 band. I pay about $28 for a box of ten .055"x1.25"x158" bands. What are you running that is only $15? Are the Silvertips that much cheaper?

[scsmith42]

Many thanks to everybody that has responded and sent PM's.  I spoke with the WM rep yesterday and apparently what we know so far of the problem is a potential mix of adjustments on my mill as well as what may be a little too strict requirements by the guy that is doing the actual resharpening.  Not all of the bands were rejected this time for cracking (although some were, this was a bad assumption on my part).  At least one had cracks that were adjacent to the weld (but not through the weld).  Additionally, apparently we messed up on my end and included some non 7/39 bands for resharpening (which were rejected by the sharpening tech).  So not all my problems are due to gullet cracking, which is a bit of a relief. 

One of my rejected bands showed what appeared to be wear related to excessive tightness of the guides.  Baker does not use rollers; rather they use a bullet type of guide that is comprised of a pair of 3/8" steel dowels that guide the blade.  Their adjustment process recommended in my manual is to loosen the guides, then fully tension the band, next to allow the top guide pins to drop down until they contact the band with gravity alone, tighten them and then push the bottom guide pins up until they contact the band, and then tighten.

The WM Rep mentioned that if the band heats up it will expand and cause a lot of drag on the pins.  Some of my bands have noticeable marks where the guide pins contact it, so this may be part of the problem.  I've switched over to some experimental ceramic guides (a future post will be made about them once I have more time on them) that so far look like they will have much less wear than the steel pins.  My next step is to set the guides so that there is .003 or so of clearance on both sides of the band to see if this helps prevent problems.

The WM rep will also return my old bands for review.  In the future I will include a note to the person doing the sharpening asking them to return my rejects for analysis (or use on possible metal logs).

The WM tech rejected 3 of the bands due to excessive set.....  This really confused me because they were brand new bands that were run one time on the mill and then returned for sharpening.  WM kindly offered to replace these bands, and they are sending me three replacements out at no charge.

The bands exit the log even; I don't hear any "singing" in the cut nor do they appear to be fluttering at exit.  I'm tensioning to 1600 - 1700 psi on the hydraulic gauge per Baker's recommendation (although after cracking so many bands I reduced the tension a bit). 

I think that my next step - after adjusting the guides for more clearance is to double check all of the band alignment adjustments on the mill. I reset it recently when I switched over to the 1-1/2" wide bands but it would behoove me to check again.

The Baker mill has steel wheels - no rubber strip on them, and the 1-1/2" bands are supposed to be adjusted so that they are even with the back of the wheels. 

I don't recall noticing any vibration or harmonics in the band, but will pay very close attention to this next week. 

Re the price for replacement bands, Tom uses 208" bands, which is about 30% longer than what most bandmills require.  The Turbo 7/39's are supposed to be one of the best production WM bands, which also drives the price up.

I switched from .045 1-1/4" to .055 1-1/2" because I did not feel that the production rate that we were obtaining was correlated with what the mill could produce.  If we increased the feed rate with the .045 bands, typically they would deflect upward.  Yet when they were cutting straight I felt that the mill was only using 25% or so of the available HP.  My logic in moving up to the .055  1-1/2" wide band was that they should deflect less and allow a higher speed through the cut.  Thus far that seems to be the case, but I still don't think that I have everything dialed in (mill adjustments plus the best band) to achieve the maximum potential of what Tom can delivery.

Here are some photo's of the Baker Guides with the experimental ceramic guide pins installed.  I took these photo's when the mill was shut down so the bands are not tensioned (we relieve the pressure at the end of the day).



 



 



 

[Dave Shepard]

It sounds like you are getting a much better understanding of the situation. What is Baker's spec for the distance from the back of the band to the roller? If those rollers are too far away, then that could be causing some of the cracking. On the partially cracked bands, does the crack start on the gullet side, or the back of the band?

[ladylake]

 That back roller looks way too close which will cause the gullet to crack fast, I run mine 1/4" back with excellent blade life.    Steve

[scsmith42]

I had the roller set so that it is almost touching the back of the band.  My logic on this is that if the band moves too far back in the guides they will start to hit the teeth, and also that the teeth could travel back on the wheels.

Is my logic faulty (wouldn't be the first time!  ;D)

(note - I just checked the manual and it appears that I may have the blade 1/4" too far to the front.  Baker recommends centering the 1-1/2" band on the wheels - it was the 1-1/4" band that was supposed to be set flush to the rear).  I'll make that correction next week.  Thanks guys!

[ladylake]

 
It looks like the whole guide system can be adjusted back at the same time leaving those white guides the same distance from the back roller, you can bet having the back rollers too close is causing the gullet to crack. Keep in mind the blades you ran like that will be damaged and break, when you get it adjusted right new blades should work good..   Steve

[Cypress Man]

I have been sawing on a woodmizer mill now for over 15yrs full time. I've been using 1.5x.055x10 degree with 1 1/8 tooth spacing for over 3 yr now. 2 yrs on a LT40 super with 25 hp electric and 1 yr on a LT70  with a 25 hp electric.  I would cut about 1000bf of cypress sharpen the blade and it would always break after the first sharpening.I sharpen my own blades with a woodmizer cbn sharpener. The LT70 will cut 3000 to 4000bf of cypress before it needs to be sharpened. It usually always breaks after the first sharpening. I've tried removing the blade sooner and seen little to no improvement in blade life. You only have to sharpen more within the same amount of bt cut. Hope this helps.

[bandmiller2]

The current trend with mills is to go to larger and more HP engines. I think we're over running the bands capacity which greatly reduces their usefull life. If someone is having breakage problems try slowing down the feed slightly and a tad less tension. I may be all wet on this but I believe if you sharpen your own on a good sharpener and some teeth don't get sharpened on the back its a sign of gullet stretching. Frank C.

[FarmingSawyer]

Good news FS on your Cats claw you should be able to nurse many of your bands back to health. Theirs no one that cares more about your bands and wallet than you. You will need a setter, the single tooth models work well but are slow. Keep a small adjustable wrench handy for really  tramp bent teeth. Frank C.

Thanks! It's getting closer! I was hoping to have the gear here on Friday so I could spend time over the weekend setting it up, but it's looking like it will be here on Monday sometime--which means I'll have to come out of the woods early.  >:( Still not sure how I'm getting it unloaded....ramps I guess. Then I have to lug everything upstairs into the warmer part of the barn.......

I got the single tooth setter. I figured for the price it couldn't be beat and if/when I can find a used dual tooth I can afford, I'll sell the single. I've got 30+ bands that need sharpened, so I've got plenty to practice on. And I've got some knotty spruce to test the newly sharpened bands on.......

When I ordered the sharpener & setter I went ahead and ordered a few more blades. Not enough for free shipping, but I asked Cooks if they would throw them on the pallet with the Cats claw. Aryup! Only $15 shipping instead of $55!  

I've been running a mix of 8˚ & 10˚s.....the Cooks are all 8˚ I think....sooooooo, it looks like I'm going to be sharpening everything I have to that......  I'll stick with the .022 set which has been working pretty good for the mix of woods I'm cutting, but will probably set some to .015-.019 for frozen logs. With the weird weather swings we're having right now, nothing is freezing solid fast....even the cedars I'm cutting out in the woods are only frozen in 1/2" on the shady side of the tree.

[Dave Shepard]

The current trend with mills is to go to larger and more HP engines. I think we're over running the bands capacity which greatly reduces their usefull life. If someone is having breakage problems try slowing down the feed slightly and a tad less tension. I may be all wet on this but I believe if you sharpen your own on a good sharpener and some teeth don't get sharpened on the back its a sign of gullet stretching. Frank C.

The Baker 3638D is "only" 38 hp, and with those big bandwheels, one should get good life out of a band.

[ladylake]

 Those back bearing were way to close, every time mine gets out of  adjustment and the flange gets to close to the back of the band I break blades like crazy. High HP mills with lower hook angles and high feed rates  need 1/4" back as the blade will push hard against the flange or bearing and flex around it causing the gullet to crack. As Dave said that mill should have good blade life.    Steve

[boardmaker]

Scott, the guy I was talking about earlier runs WM doublehards.  10* on standard hardwood, and 4* on hickory and frozen logs.  Set is .025.  For some reason I didn't write down the width or thickness, but I think they may have been 2".  He gets 4hrs on new bands, and only 2hrs on sharpened.

Lucas

[Dave Shepard]

For best flex life, you don't want to run them until they are dull. It's a compromise. You can have higher production and cut quality, or you can have higher flex life and more sharpenings, but not both.

[Foxtrapper]

I ordered the dual tooth setter from Cooks on Monday, doesn't look like it has been shipped yet though.  I wanted the sharpener too, but couldn't swing both.. :'(

[bandmiller2]

Smith42, Have you checked your wheels for round and a slight crown.?? I have read after long service they need recrowning. They are also sensitive to runout as they don't have the forgiving rubber belt. A friend of mine, I sharpen bands for, runs large steel wheels. I love the way crowned steel handles the bands, smooth and even cuts. If I wasen't so DanGed cheap I'd put steel on my mill. Frank C.

[scsmith42]

Smith42, Have you checked your wheels for round and a slight crown.?? I have read after long service they need recrowning. They are also sensitive to runout as they don't have the forgiving rubber belt. A friend of mine, I sharpen bands for, runs large steel wheels. I love the way crowned steel handles the bands, smooth and even cuts. If I wasen't so DanGed cheap I'd put steel on my mill. Frank C.

Hi Frank - thanks for chiming in.  Yes, I've checked for crown and they run straight.  Tom only put around 120 hours on the mill before I got it so it's practically new (save for sitting out in the FL weather).

[kelLOGg]

Smith42, Have you checked your wheels for round and a slight crown.?? I have read after long service they need recrowning. They are also sensitive to runout as they don't have the forgiving rubber belt. A friend of mine, I sharpen bands for, runs large steel wheels. I love the way crowned steel handles the bands, smooth and even cuts. If I wasen't so DanGed cheap I'd put steel on my mill. Frank C.

After 12 years my wheels began to lose tracking ability so I sent them to Cooks for recrowning. Made a big difference. Just for fun, I put a dial indicator on the wheel face and spun the wheel. They were round to within less than 0.001" - both of them. That variation includes the difference in mounting on their lathe and my bearing shafts.
Bob

[kelLOGg]

The Baker bands are much longer than an LT30/40/50 band. I pay about $28 for a box of ten .055"x1.25"x158" bands. What are you running that is only $15? Are the Silvertips that much cheaper?

Scott, is that a typo! My bands are 168" and that is with small 19" wheels and "Tom" is is
huge mill.

OOPS!. That was Dave Shepherd's reply, not Scott's.

Bob

[Banjo picker]

Scott I am glad you asked that question, as I have enjoyed reading the responses.  Many ways to look at things.  Hope you get it all figured out.  I have thought about going from the .50 to the .55 myself, but since I run the mill by myself now probably 95 % of the time I probably should go back to the even thinner blades, as I am not able to maximize the mill's full ability. Banjo

[Dave Shepard]

The Baker bands are much longer than an LT30/40/50 band. I pay about $28 for a box of ten .055"x1.25"x158" bands. What are you running that is only $15? Are the Silvertips that much cheaper?

Scott, is that a typo! My bands are 168" and that is with small 19" wheels and "Tom" is is
huge mill.

OOPS!. That was Dave Shepherd's reply, not Scott's.

Bob

That should have said $28 each in boxes of ten.