Help - Why am I Breaking Bands.

[warren46]

Help!

I would like some help to figure out why I am breaking bands.  I am running my new to me Timberharvester with 25" band wheels.  I have reduced the tension on the bands but still broke a band and the saw was out of the log.  Is it possible that I need to adjust the roller guides?

Warren

[beenthere]

For sure you need to determine that the guides are right, whether they need adjusting or not you will find out.

Loosening tension may be the wrong direction and might need more tension. More expert advice forthcoming to help you out.

[chickenchaser]

I am running my new to me Timberharvester with 25" band wheels.

Do you have a manual to refer to the troubleshooting section? What is the recommended tension? I would worry about too little tension  more than too much unless your mill's design allows you to tighten way above recommended. Are the blades new?

Wiser, more experienced men will no doubt be along shortly...

CC

[Magicman]

New to you sawmill probably indicates that you are using older blades.  If so, they may have been on their last leg.  New blades would not break without something very seriously being wrong, such as the blade being strongly pressed against the blade guide.

[YellowHammer]

One way to start troubleshooting is to take a good hard look at the broken bands, even using a magnifying glass.  Look for any very small cracks, either in the gullet or on the back of the band.  Cracks on different sides of the band, including the weld, indicate different causes.

Once (if) you can identify where the little micro cracks are, then you can maybe figure out what might be causing them. 
YH

 

[taw6243]

When blades start breaking check for pitch or buildup in the v of the drive pulley or driven blade wheel.
tim

[thecfarm]

How many have you broke and how much are you sawing before they break?

[warren46]

How many have you broke and how much are you sawing before they break?

I broke three resharpened blades each with less than one hour.  I will check the wheel alignment and roller guide adjustments on Monday.

Timberharvester made a good mill but the owner's manual not so much.

[drobertson]

Mill alignment is in order,  and start with  new blades, and some practice material,  they should not be breaking, this fast,  david

[ladylake]

The 2 fastest ways to break bands are worn v belts if your mill has them and the guide rollers flange too close to the blade,  the guide roller flange needs to be at least 3/16  to 1/4" behind the blade when fully tensioned and if you have v belts they have to be high enough to keep the blade from contacting the metal on the wheel.  . Keep in mind even if you fix the problem you will still break more blades that were already damaged.  Steve

[dgdrls]

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&ved=0CFQQFjAF&url=https%3A%2F%2Fwww.sawmillmag.com%2Ffeatured_article%2Fissue_106%2F897%2FIssue_106_Featured_Article_3.pdf&ei=nga1UqCyOYi0kQe2zoHgCw&usg=AFQjCNG_YCutKSWx44ImskEvQjcw57AqDw&cad=rja

The Good Doctor has some information to help you here.

DGDrls

[bandmiller2]

Warren, chances are your using the resharpened bands you got with the mill.They have a flex life and its close to predictable,a group of bands used and sharpened togather will have failure times close.Alignment is important as belts and guide rollers.Put a new band/bands on the mill and run them I think you will get normal life from a mill like yours.I would estimate 5 or 6 sharpenings if your carefull mayby more. Frank C.

[warren46]

Thanks for all of the suggestions.  I will adjust guides and wheels (making sure the wheels are clean) on Monday and let you all know how it works.

Warren

[warren46]

I went to the mill this morning to make some adjustments.  I believe I found the problem.  The Timber Harvester mills measure blade tension by aligning an indicator rod with a mark on the mill frame.  The indicator is attached to the tension spring nut and the mark on the mill is stationary.  The arrangement indicates the length of the spring when compressed.

I believe my problem was that the indicator rod had moved relative to the tension spring nut so that when I aligned the mark on the rod with the mark on the mill the blade was significantly over tensioned.  The owners manual does give the correct length of the tension spring when the blade is properly tensioned.  I tensioned the blade until the spring was compressed to the specified length and then reset the indicator rod.

I also adjusted the roller guides so there is one eighth to three sixteenths inch clearance behind the back of the blade.

I sawed one small log and everything seemed good.  I did not saw more today because I did not have any additional logs at the mill and I did not want to create any more mud in the yard today.  Besides, I need to get my wife's Christmas present this afternoon.

[ladylake]

Good to hear , nothing as aggravating as breaking bands way to often..   How far behind the blade was the flange set at, if too close that will break blades fast.  I keep mine at least 3/16 to 1/4" behind with excellent blade life.  Thanks for reporting back.   Steve