What am I doing wrong!?

[Stevenjohn21]

I’ve been frustrated for several weeks now because anything 12’ or longer that I try to mill, I end up with a hump in the wood in just one place (about 4’ into the cut)
I have adjusted the guides within a piece of paper away from the blade, the back wheel is the same however, whenever I get to this same spot on the mill, the blade wants to angle up and then a few inches later it starts to come back down and then levels off perfectly for the remaining cut.

If I move the guides any closer I can hear the blade rubbing on them, so I know I have them correct but somehow it’s still cutting a mountain every time. 
I have a torque wrench set at 24 ft lb for the blade tension so I’m good there. 
The mill is a 130max 
 

[Wlmedley]

Sounds like a problem with your bunks.I would get a piece of masonry string and stretch from back bunk to front bunk with a one inch spacer under it on both ends.Then go to each bunk and measure.If not one inch adjust legs under rails.Check both sides.If bunks are all in line rails should be too but you might want to string them also.Hump in rails will transfer to your logs.

[WV Sawmiller]

   Also how stable is your support? I am not familiar with your mill but could the weight shifting cause the change? Running the string might indicate the bunks are in line but are you getting some sag at that spot? Getting a hump doesn't sound like sag but check anyway. 

   How about the track? Is it clean or is there some kind of build up on the track causing the rollers to raise up which would raise the head at that spot?

[YellowHammer]

These can be pretty hard to figure out.  So it's always doing it at the same place?  Then it's time to take to log off and mark where the hump is and hand push the mill down the track and especially pay attention to the area of where the hump forms.  Pushing the head by hand (engine off) will let you feel what the mill head is doing as it travels up and down the rail to see if it's rocking inboard and outboard, is it hanging, is it staying dead flat through the trouble spot.  Sometimes the rails aren't welded and lined up correctly and, it will cause the head to rock back and forth.  Our there is some crud built up on the rails that the bearings may be riding on, or any numbers of things.      

[Old Greenhorn]

Those 3 posts above are rock solid things that any experienced bandsawyer would begin with. Likely you have already looked into them, but you need to get really picky and look very closely. In any event, I can't add to what they said.
 However, I would like to get some more detail on the problem that might help us find something. You said anything 12' or more gets this hump at the 4' mark. Does that mean an 8' log will have no hump?
 Also, you say it's in the same place (4' ) every time, but what happens if you move the head of the log forward or back, is it still 4' in on the log, or is it in the same place on the mill bed?
 It may sound like I am splitting hairs, but that's what you have to do sometimes to get a clue leading you to the solution.
 Don't get frustrated, focus on each detail as deep as you can. Write things down if you need to. Make no assumptions, check each thing completely. 
 Best of luck and we'll hang in with you until you figure it out. There is always an answer.

[Southside]

As much as this might not make sense a bad bearing may be the issue.  When I have had cam followers go out on a WM mill I have experienced bind up or other issues at the same travel point along the bed.  Would not bind up any other spot along the 20', but right at the same spot every time.  A cam follower is basically a bearing that laterally supports the mill head assembly and rotates plenty of times along the way, but likely due to tolerances, would only cause me issues in one spot.  

[bigblockyeti]

Is this happening even with a new blade?  I was cutting cherry last week and the new blade I started with was still cutting perfectly with zero signs of dulling after 400bdft.  Then I barely touched the second backstop with the blade and I knocked the tooth set from the entire bottom side of the blade.  It still cut well, just not straight, it wanted to go up like what you've shown.

[Stevenjohn21]

I have loosened the rail and tightened again making sure it was level with the rest of the bed. I also put a laser level on the bunks and lined up with the blade, moved the head down to each bunk and re-tested and all seems level since the laser was hitting the blade on each bunk. 
I have a woodmizer 7 degree blade in it at the moment which is brand new. 
I have only cut a few logs since owning the mill. I cut a small cherry about 14” in diameter and only 5’ long and didn’t notice any humps but I’m not sure where on the bed I cut it. 
I put a monster basswood 28” diameter x 14’ long on to cut stickers and I noticed immediately the hump. 
I went cut it again and as I slowly approached the hump I could see the blade starting deflect up wards and begin making that hump so I stopped. 

[customsawyer]

I know it is a pain with your mill but if you can take the log off and turn it around. Cut it from the other end and see if you still have the hump in the same spot on the log or the mill.

[Old Greenhorn]

I don't mean to nit-pick here, but that's what you have to do sometimes to find the root cause.
 How many logs over 12' have you seen this on? Were they all in the same spot?
 You mentioned at the end of August in another thread you were getting wavy cuts in 20" basswood, hw did that finally turn out? Did you solve it?
 This is a large log. Is it possible that the leveling jacks in that area are taking more of the load and sinking a bit with the weight?
 Lastly, have you only cut one face on this log, or have you tried the other faces?
  It could be that you can do opening cuts on 4 faces, then do a cleanup cut on any faces that have a wave. More flipping, but good troubleshooting and I bet you learn something about the problem's behavior.
 Based on what you said in your last post, I would change out that blade first, before I did anything. If the new blade cuts the same, it's not that and you can use that other blade next time you swap out. But it's too easy to have a tiny blade defect from a previous log that you can't detect.
 Don't forget, you've only had this mill a short time and this is a necessary (and frustrating) part of learning how it behaves, how hook angles relate, lube flow, HP, cutting head speed, all play a part and all the other stuff too. It's a dance, with a lot of steps to learn.   Keep yer chin up.

[Stevenjohn21]

Thank you for your advice. I really enjoy this hobby when all is working as it should and I get a sense of accomplishment at the end of the day but man, it’s so frustrating when one tiny problem messes up everything! 

Yes, back in august I had wavy cuts. That was due to loose belt, loose blade and me messing with the drive side wheel which is all sorted now. The waves in this cut is around 4’ from the start of the bed. So anything I put in that area will create a curve. It’s like the bed isn’t level however when I’m cutting I can physically see the blade start tilting up which makes me think it’s the blade function. 
I’m not giving up and I know with everyone’s knowledge on here I will be able to fix it. 

I have turned the log and tried to cut a fresh side but the exact same thing happens. This is the 2nd 12’+ log this has happened on. I’m trying to cut the basswood to make stickers so I need this to cut straight. 

[JRWoodchuck]

Seems like I remember other members having similar issues on the same mill and it ended up being one of the bearings or bushings that was faulty from the manufacturer. 

[ljohnsaw]

Just trying to get a clearer picture.  You had troubles (that you noticed) on just the two logs?  Both were basswood?

Several years ago, my mill was cutting real good.  Put a fresh log on and just could not get it to cut straight.  It would dive in several places.  Take another slice and still dive in the same places.  I would back up (carefully!) the second I saw it diving and go slow to let the blade correct itself.  Made for some ugly wood.  Usually it would do it on one face and 180° as well but not at 90° - sort of tells me it's the grain of the log.  A couple logs later, same thing.  Only this time I tossed the log.  I've had a few logs that just don't want to be cut!  It happens.  Maybe too dry, maybe too stressed, maybe knots and cutting from "the wrong end".  I have 3 or 4 big logs with a couple faces opened sitting around.  Since they are pretty big, I make benches out of them - no need for legs - and no worries that someone will steal them since they weigh a few hundred pounds

[btulloh]

Looks like blade tension and maybe sawing just a bit too fast right there. 

24lbs on the torque wrench is not an absolute. Sometimes it needs a little more. Different band types need different tensions. How thick is that band? .042, .045?  The torque setting is convenient but the only way to truly know is to measure the actual blade tension. Short of that, observations like blade flutter when running free, or tweaking based on results work for a lot of us. There are a lot of little things that affect cut quality and it takes time and experience - and a little frustration- to learn all of them. You’re doing well and just going through the normal learning process. When everything is right the saw will make straight cuts. “Everything “ is a pretty long list. Hang in there and don’t be afraid to experiment. 

[jpassardi]

You may want to try a new blade on that same log in case the set or sharpness is greater on one side. If no change, then the new blade with more tension. If neither helps, flip the log endo to rule out grain.
If no change, it's likely a bed or carriage issue. If the carriage travels through the bed straight I'd check the guides. Do you have roller or pinch block guides?
Check one variable then the next. Hang in there - diagnostics can be a PITA but try to be patience and follow logic. Good luck.

[firefighter ontheside]

On my woodmizer the guides are meant to put down pressure on the blade and not just be adjusted to be close to the blade.  I guess that is not the case with woodland mills.

[Stevenjohn21]

You may want to try a new blade on that same log in case the set or sharpness is greater on one side. If no change, then the new blade with more tension. If neither helps, flip the log endo to rule out grain.
If no change, it's likely a bed or carriage issue. If the carriage travels through the bed straight I'd check the guides. Do you have roller or pinch block guides?
Check one variable then the next. Hang in there - diagnostics can be a PITA but try to be patience and follow logic. Good luck.

I have new 10 degree blade which I will try tonight (I’ve got a 7 degree on at the moment) 
My guides are the ceramic block style except the back one which is a roller. 

[Stevenjohn21]

I fixed the problem! 
Don’t know how but after changing the blade, re-adjusting the guide blocks (ziplock bag distance away from the blade) and tensioning the blade one more turn than my 24 ft lb I made a cut and it’s straight! 
I also learned that you can put a blade on wrong 🤦‍♂️ 

Thank you to everyone that gave me advice and gave me the patience to keep messing with it. 
I also apologize to my mill for calling it some pretty bad cuss words over the last few weeks! 

[bigblockyeti]

My bet is the tension probably helped out the most.

[jpassardi]

Good to hear you addressed the issue. Keep in mind, it's likely to reappear at some point.
It's another expense but you may want to upgrade to roller guides, Cook's sells them. When set properly they are 1/4" lower than the band wheels. This provides down pressure on the band closer (than the band wheels) to the cut.