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Author Topic: Blade coming off the drive wheel  (Read 10683 times)

Offline furu

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Blade coming off the drive wheel
« on: February 19, 2017, 04:12:50 PM »
I have a TK that I have had more than my share of issues with. 
It however has, for the last several months, actually had no real issues for the first time since I bought it. 
I finally have begun to not regret purchasing this particular mill.

I was sawing through a DF log that was about 26" at the butt end.  I had already turned it into a nice cant and was taking off boards that I am putting on as siding on my DH kiln.  Blade was pretty new, not yet dull in any way.
As I am making the cut, bang, and sparks fly down at the mill head.  Shut it down and another blade break I figure. (another story)
When I get to the mill head (halfway down the log) the blade is off the drive wheel.  No other real obvious thing wrong other than the blade is in a knot in the cant.

Put the blade back on after getting it out of the cut and try again. Bang, same thing, same place in the log.  Repeat, but this time as I get to the knot I go to about 1 inch every 15 seconds until I am through the knot.  I then saw for another hour or so with no issue.
Blade tension was on the high side of what TK now recommends for tension.  I found that I get better cuts after they bumped their tension recommendations up 200 psi or so about a year ago.

My belt on the drive side is a bit more worn than the idler side but the blade is not on the metal rim yet (close but not yet).  I know that I will sooner rather than later need to replace that belt but to be honest the videos of that are making me think that will be a bear so have put it off.  Other than the belt starting to get thin any other ideas as to why the blade might have jumped off the drive wheel?  The belt has a nice texture to it and is not shiny/slippery.
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Offline TnAndy

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Re: Blade coming off the drive wheel
« Reply #1 on: February 19, 2017, 05:51:02 PM »
Blade tension, blade guides, and feed speed in that order.   Never had the problem on my Woodmizer, so I can't relate too much.

If you're sure you have the tension enough, do your blade guide rollers (not familiar with your mill) have a back flange on them, and is it running just slightly in back of the band with no load ?

Offline furu

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Re: Blade coming off the drive wheel
« Reply #2 on: February 20, 2017, 05:36:50 PM »
Blade tension, blade guides, and feed speed in that order.   Never had the problem on my Woodmizer, so I can't relate too much.

If you're sure you have the tension enough, do your blade guide rollers (not familiar with your mill) have a back flange on them, and is it running just slightly in back of the band with no load ?

have a back flange on them     Yes
is it running just slightly in back of the band with no load   Yes

I have never had this problem before either.   :)
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Integrity is not just doing the right thing when no one is looking.
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Offline TnAndy

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Re: Blade coming off the drive wheel
« Reply #3 on: February 20, 2017, 07:03:41 PM »
Hmmm...dunno.  Personally, I'd try uping the tension some more.

The tires on your wheels....I take it they are real snug to the wheel groove ?   Woodmizer uses a standard Browning belt that runs real loose....when running, you can actually see it out from the wheel on the inside....it slips on/off real easy.  I bought a pair of those supposedly GREAT polyeurathane orange tires from Grizzly (i think), and never could get them on the wheel right....they keep running out of round for me....thump..thump...thump.....

What size is your wheel ?  Could you try a set of the same belt WM uses ?

Offline mountainlake

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Re: Blade coming off the drive wheel
« Reply #4 on: February 21, 2017, 04:59:06 AM »
   A couple of things that make the blade come off on my TK.

 Running a worn v belt using a little too much diesel for lube, new belts fix that.

 Check all of the drive side and idle side bearings good, the outside bore like too get loose in the wheel. The best fix is to take the wheel to a machine shop get it bored out and put a steel sleeve in the wheel with tight tolerance. I have 10000 hours on mine after I did that and would get less than 500 hours on the orginal wheel, just the idle side on my B20
  Seems like the cast iron wheels don't hold up to the pressure and wallow out which causes the blade to come off and also break way too soon.

 I think your running a 2200 which has a different setup than my B20 on the drive side, check the 6 bolts on the drive side wheel, make sure they're tight  and not wallowed out.  Others have drilled those bolts out and used 5/16 bolts.  Also keep the flange on the guide wheel 1/4" behind the blade, your blade wont break as soon.
Steve
« Last Edit: February 21, 2017, 05:41:45 AM by mountainlake »

Offline Stevem

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Re: Blade coming off the drive wheel
« Reply #5 on: February 22, 2017, 01:08:07 AM »
My mill is the 1600:
Changing the belts on the drive wheels is not that hard or at least it wasn't on the second one!  You need to take the wheels off (left hand thread on the nuts) and use a vise to hold the wheel and about 2 or 3 C clamps and a small ball peen hammer.  Old belt off with a knife and new belt(s) on using the "C" clamps, screw driver and the hammer to tap the belt in place as your go.  Keep moving the clamps as you pry the belt on with a flat blade screw driver and tap tap the belt into the groove.  I tried it without moving the clamps very much not tapping and kept rolling the belt into the grove and no way to unroll it after it was on.  TK recommends about 300 hours or so on the belts. Belts are cheap if you don't buy them from TK.

The only time I've had the blade jump off the drive wheels is when I put too much sawing pressure on it or the blade guides were out of alignment (as received).

Make sure the saw bed is leveled.
Check that the blade under tension is level side to side and for and aft without any down pressure.  Apply the spec down pressure.  Check the blade again for level.  Adjust the rollers to get it level.  Might have to move the brackets holding the wheels on the frame like I did to get the proper down pressure.
When I got my mill the blade was tipped up so it entered the log going up but straightened out once the blade was all the way into the wood. Delivery guy didn't catch it.  When sawing it wasn't riding on the rollers just the log.  The rollers were not shinny and didn't stay clean.  When I got that right blade breakage went way down and I was using about half the fuel.
Blade pressure:
I have the third hydraulic blade pressure gauge on the mill (300 hrs on the mill).  First one went bad (internal leakage) and to get to pressure I was way too tight. Second one the needle came off.  I learned from TK that the spring length should be about 1 7/8".  That spring length gives me a 1000 reading on the gauge where the book says run the gauge at ~1200.  I'm thinking about bumping up to that figure again but right now I'm using the 1000 number and it seems to be running pretty true.
Of course this is all for what it's worth
 
« Last Edit: February 22, 2017, 01:19:03 AM by Stevem »
Stevem
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Offline bandmiller2

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Re: Blade coming off the drive wheel
« Reply #6 on: February 25, 2017, 06:03:18 AM »
Sounds like a bandwheel alignment or bearing issue. Band is barely stable tracking and the least thing such as a knot will upset it. Frank C.

Offline furu

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Re: Blade coming off the drive wheel
« Reply #7 on: February 27, 2017, 01:49:04 PM »
Thanks for the inputs.
I certainly hope my mill does not yet have a bearing issue with the relatively few hours I have been able to keep it in operation but I will look at it anyway. 
With my luck I have a bad set of initial bearings and they are already shot. 

I backed the guide wheel flange off to 1/4 inch soon after I got the mill despite TK's insistence on 1/8 inch. 
Found that it helped as well to have more down pressure/deflection with the guide wheels than TK numbers and that really helped.

Think I will have to swap the belts for new belts if it happens again.

Question for Stevem (think the 1600 has a similar wheel setup to mine) and and to anyone else as well

I know the video of the belt swap has Jason pulling the wheels off and you said the same. 
What did you do to remove that center nut and not have the wheel rotate?  I know an impact wrench will do it without blocking the wheel from turning but don't like that idea very much.  The sheet metal in the area is light weight enough that I am afraid to put a block in and brace it against any of the sheet metal as it will bend.  I have heard of folks doing it on the mill but that has the same issue as you have to stop the wheel from turning as you pry the new belt on.
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Offline Stevem

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Re: Blade coming off the drive wheel
« Reply #8 on: February 27, 2017, 03:31:51 PM »
I used a large wrench (16" crescent) and a hammer.  I don't have that big of anything else.  Only needed about a quarter to a half of a turn and the nut just screwed off.  Then the wheel just pulled off.

Reinstalled the same way.  Just remember it's a left handed thread.  TK calls for a whole bunch of torque but I just used the hammer 'till it was just right.  lol   The torque issue made me reluctant to take the wheels off but the left hand thread keeps the nuts snug if initially tight.
Stevem
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Offline mountainlake

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Re: Blade coming off the drive wheel
« Reply #9 on: February 28, 2017, 05:55:14 AM »
 When changing belts with the wheels on my B20 I just clamp a pair of vice grips on the wheel to keep it from turning.   Steve

Offline bandmiller2

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Re: Blade coming off the drive wheel
« Reply #10 on: February 28, 2017, 06:51:10 AM »
For years I've been wanting to make a belt installer kinda shaped like the tool that mounts the bead on a tire machine. Have a tee handle for traction and put a vice grip on the pulley so you won't be chasing the belt around, been too lazy. I've had good luck with vice grips and a couple of old screwdrivers. If you have trouble with the belt twisting, start by twisting it in the opposite way then when it twists it will be right. Frank C.

Offline furu

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Re: Blade coming off the drive wheel
« Reply #11 on: February 28, 2017, 09:15:36 AM »
When changing belts with the wheels on my B20 I just clamp a pair of vice grips on the wheel to keep it from turning.   Steve

Maybe I am missing something here but unless you use that pair of vice grips to clamp the wheel to some other object to keep the wheel from turning then it takes two hands to hold the vice grips to keep it form turning and two hands to install the belt. 
I am two hands short on that deal.
What am I missing?
Integrity is not just doing the right thing.
Integrity is not just doing the right thing when no one is looking.
Integrity is doing the right thing when no one else will ever even know.

Offline HaroldCR - AKA Fla.-Deadheader

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Re: Blade coming off the drive wheel
« Reply #12 on: February 28, 2017, 03:39:22 PM »

 I believe he is using the vise grips as a tool against the frame or whatever, as a blocking device so it can't turn.

 Use liquid soap on the belt, same as on tire beads to work the belt on. Soap on a squeaking fan belt will stop the squeak. Funny how it works as a slippery and then a sticky substance.

Offline 4x4American

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Re: Blade coming off the drive wheel
« Reply #13 on: March 09, 2017, 08:29:07 PM »
Furu you gotta change them belts!  I've had blades pop off from something getting stuck underneath the B57 belt.  I would change the bandwheel belts first.  And once your blade pops off, in my eyes, that blade is going back to the saw shop to get touched up, I'm not gonna put it back on, unless I had wood or some material inside my blade guards that wouldn't damage the blade.  I tried the B56's thinking that it would help, but you break one blade and then theres a chunk of rubber missing and I change the belt.  Just quicker/easier with the B57.  When I was sawing pine I'd have troubles with sawdust building up underneath them.  But I don't hardly saw pine anymore and almost every blade change or so I just pull the bandwheel belts off and scrap the crud off the tops of them with a stout putty knife and run my finger inside the bandwheel groove to make sure it's clean. 

So my opinion, forget the B56, get the B57 and make life easier.  Have you had any problems since?  Was the bark loose?  It's possible that a piece of bark, or maybe just a piece of wood (esp if there was shake in the log) came off and wedged itself in between the blade and the bandwheel and spit the blade off.  And if it happen around the same spot maybe it could have happened 2x in a row.  Not saying it's probable, but it's definitely possible. 

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Offline mountainlake

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Re: Blade coming off the drive wheel
« Reply #14 on: March 24, 2017, 10:53:57 AM »

 Furu
 
 Did you find the reason why your blade was coming off yet, always good to know the results.  Steve

Offline furu

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Re: Blade coming off the drive wheel
« Reply #15 on: March 26, 2017, 07:25:20 PM »
Steve
No I have not found any reason--- as of yet. 
It has not reoccurred however.
I still have not replaced the belts on the wheels as I can measure a definite gap (small) between the blade and the wheel rim so I know that the blades are riding on the belts and are not riding on the metal rim. 
I will have to do it at some point in the somewhat near future but just have not done so yet.

Since it has not reoccurred I am thinking that there was something weird about that specific log/knot in that log that made it "special".

Thanks for asking

Off the thread topic but..................
I am still swamped with trying to finish my late winter planting.  This is the result 3 hours later after planting 400 seedlings one day.
I will get back to more sawing after planting season is up.




From one Steve to another
Integrity is not just doing the right thing.
Integrity is not just doing the right thing when no one is looking.
Integrity is doing the right thing when no one else will ever even know.