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General Forestry => Sawmills and Milling => Topic started by: WStringer2 on August 15, 2020, 03:25:50 PM

Title: HM126 popping blades - balance question
Post by: WStringer2 on August 15, 2020, 03:25:50 PM
I've lurked on this forum quite a bit while deciding on which hobby mill to get.  I wound up with the Woodland Mills HM126 10th Anniversary edition, and have a couple of questions about "what is normal".  I followed the manual for tracking, setting the guide blocks, etc.  I was able to cut up 2 10' cants smooth as butter, but then the blade bit into the yellow safety rail (that runs along the adjustable guide arm) and popped off.

I removed the safety rail, reset the blade, filed the teeth that were damaged, and fired it up again.  I can make almost 2 passes before it pops off again.  Called WM who recommended re-seating the orange belt on the follower wheel.  I did this, but then it still pops off.  I was hoping to work (play) some more this weekend and was hoping you gents might could help.

I'm not familiar with what is "normal" and would like to ask y'all about a few things.  The 1st is whether or not the tension pulley belt should change location on the pulley when I reverse direction by hand.  This is hard to explain so I took a video:
Belt movement - YouTube (https://youtu.be/5i9KS6JPrYU)

My other question is whether or not it's a problem for the follower wheel to be slightly off balance?  When I rotate it by hand and let go, it slowly rotates back.  A video of that:
Unbalanced? - YouTube (https://youtu.be/ogd3bGtmF2I)

Finally, after my blade popped of the last time the follower wheel was still spinning at a high RPM.  I was resting my head on the mill, frustrated with life, and I felt the mill shaking.  I videoed the wheel and could see a slight wobble.  Is this enough to throw blades, or normal?
A little wobble - YouTube (https://youtu.be/XikIC-zW9ts)

Any advice would be appreciated!
Title: Re: HM126 popping blades - balance question
Post by: Chuck White on August 15, 2020, 03:38:37 PM
I think I would try spinning and the balancing part with the belt OFF, and make sure there's no sawdust buildup under the belt!
Title: Re: HM126 popping blades - balance question
Post by: Nebraska on August 15, 2020, 03:43:20 PM
Try a new band as well. Start over with set up, deep breath, all sorts of unseen growing pains await. Congrats on the new mill.
Title: Re: HM126 popping blades - balance question
Post by: cutterboy on August 15, 2020, 04:55:29 PM

I have been there before and I think everyone on this forum has too. Sometimes you run into a problem and nothing you do seems to work. Very frustrating! But you stay with it or maybe you walk away from it and go back later and figure out the problem. Then life is good again. Don't get too discouraged.
As Nebraska said, changing the blade is a good idea. When a blade pops off it can get damaged, it can get bent.
Good luck with your mill. You will work this out and you'll have fun with it.
Title: Re: HM126 popping blades - balance question
Post by: WStringer2 on August 16, 2020, 01:42:20 PM
Thanks for the replies Gents!

I did take the belt off follower wheel and it's still off balance a bit and rotating in the same way.  Is that little bit of off balance enough to cause problems?

I checked the drive wheel and it was slightly out of alignment at the 12 o'clock and 6 o'clock so I adjusted that. 

However, there's one more adjustment that is off.  According to WM tech support if I put a straight edge across the drive wheel over to the clutch pulley face it should have a gap of no more than 1/16", but mine is 3/16".  How would that be adjusted?
Title: Re: HM126 popping blades - balance question
Post by: btulloh on August 16, 2020, 02:20:18 PM
I would not want anything out of balance, follower or drive wheels included. Out of balance means vibration and vibration means bad everything. 

I have never had to align the clutch with the wheel so you need to check with woodland mills tomorrow on that. They are certainly off and need some attention. 

I would ask about that balance on the follower also. Unless there’s some kind of debris causing it, it would be a manufacturing defect. 
Title: Re: HM126 popping blades - balance question
Post by: Patrick NC on August 16, 2020, 04:29:13 PM
Try a new band as well. Start over with set up, deep breath, all sorts of unseen growing pains await. Congrats on the new mill.
X2. I got a 5 pack of blades from Timbery (Woodmizer silvertips) that would not stay on no matter what I did. Switched back to doublehards and no problems. 
Title: Re: HM126 popping blades - balance question
Post by: luap on August 16, 2020, 05:38:25 PM
From a machinist prospective your balance test needs to be done with a clean pulley ( I see sawdust buildup on the spokes), the belt removed as said and  marking a spot and repeating from several starting locations. On the belt moving back and forth when you change rotation tells you nothing because that is not how it operates- It only goes one direction. In a perfect world it would not wander regardless of rotation but you only need to concern yourself with operating condition. Mostly this indicates the idler is not parrallel with the driving pulley. But it doesn't have to be to operate. You would like it to ride in the middle of the idler and not all the way to one side.

Your last video  on the wobble- Look at and compare the machined surface of the outer rim and the bore where the bearing is. Looks fine in the video. Castings are imperfect and choices have to be made in the machining process in dealing with imperfections which may be what you are seeing. On one side or the other of the rim of the pulley may be a few very shallow drill holes that are made in the balancing process. A dial indicator is really the only way to detect  wobble and runout. That said manufacturing defects do happen so if in doubt get some one with a dial indicator to help.
Title: Re: HM126 popping blades - balance question
Post by: WStringer2 on August 29, 2020, 09:22:51 PM
Quick update - I contacted WM and they sent a spacer for the clutch pulley.  I installed that and the spacing is what it should be now.  However, the ribs of the drive belt still rub a bit.  I haven't tried cutting again (was on vacation) and I wanted to check with y'all one more time before doing so.

Ok or not? - YouTube (https://youtu.be/6rrU0DjYqMM?t=14)

From this video, does my blade position (tracking) look OK?  I see from luap's reply that reversing direction and seeing a change isn't a big deal.  What about the drive belt rubbing...does that look normal to y'all?
Title: Re: HM126 popping blades - balance question
Post by: kelLOGg on August 30, 2020, 12:10:04 PM
In your 2nd video (Unbalanced?) the magnitude of unbalance looks very small to me. The idle wheel on my MP32 does just about the same thing which bothered me too, but there was no effect from it for 18 years now. My mill has exceptionally low vibration so I got over worrying about it. I think you should look elsewhere for your problem's solution. Good luck and congrats on your purchase.
Title: Re: HM126 popping blades - balance question
Post by: btulloh on August 30, 2020, 12:27:53 PM
It looks like the belt does not have enough tension to me. 
Title: Re: HM126 popping blades - balance question
Post by: KenMac on August 30, 2020, 02:44:53 PM
No expert on your mill by any stretch, but I have been around a few belts during my life as a commercial HVAC tech. I have never seen one follow the wheel past the exit like yours was on the video. Does the belt fit the wheel groove properly?  Even slack belts do not stay in the groove like that from what I've seen. Good luck on your venture!