Blade Tension when not using mill

123maxbars · March 25, 2012, 12:33:43 AM

I have been doing this practice since I have had my WM. I am now just wondering if there are any cons to doing this or what you guys do when you shut your sawmill down for the day. After I get done sawing I leave the tension on my blade and do not release it. Sometimes its a week or a few days between sawing. Should I be releasing the tension everytime I close the mill down? Does leaving the tension on take away from the life of the blade? Thanks for any suggestions.

Okrafarmer · March 25, 2012, 12:37:34 AM

I would be more concerned about the bearings, I think. I leave mine tensioned because there is no quick and easy way to detension it and instantly bring it back again. But I am certainly no expert.

WDH · March 25, 2012, 12:40:35 AM

I always de-tension the blade on my LT15 if the engine is turned off and I am done sawing for the day.

Okrafarmer · March 25, 2012, 12:49:17 AM

I should have mentioned, mine isn't a WM.

MHineman · March 25, 2012, 12:51:22 AM

When I'm done sawing for at least a couple hours, I back off the tension, but then put back just a little (about 200 on the quage) to keep the blade from chattering if it gets moved before next use.
In theory the blade can stretch, but I've left the tension on unintentionally and never noticed any difference. The bearings could fail earlier, but it seems they are built for near constant use. Probably the most likely is a flat spot on the V-belts the blade ride on. That may result in a slight chatter when sawing.

Brucer · March 25, 2012, 02:18:40 AM

I always slack mine off to about 500 pounds (20% of sawing tension) overnight or when I shut down for lunch. In these parts the temperature change from early morning to afternoon will cause the fluid in the tensioner to expand. I've seen the tension go right off the gauge when I forgot to back off the tension during lunch.

bandmiller2 · March 25, 2012, 07:18:22 AM

Its pretty much standard procedure to detension bands when your done for the day.It does more harm to the bandwheel belts than anything else.Its kinda like a vehicle sitting on tires a long time they thump for a wile.May be an interesting experiment try it boath ways,possibly a sawmill myth. Frank C.

customsawyer · March 25, 2012, 07:23:14 AM

I try to remember to detention mine when through for the day but have forgotten many times and have saw no ill effect.

Larry · March 25, 2012, 07:35:14 AM

At the end of the day I pull the blade and clean all the wet sawdust from around the wheels, guides, and housing. Clean crud off the wheel belts. Put the band on the next time I saw. I figure its just good house keeping with all that wet sawdust.

The shop bandsaw has bigger wheels than the mill. It can run just as big of bands also. It has been tensioned for the last 15 years and shows no ill effects.

medic · March 25, 2012, 08:16:14 AM

"The shop bandsaw has bigger wheels than the mill. It can run just as big of bands also."

Wow. Now I have shop bandsaw envy too.

Magicman · March 25, 2012, 09:01:28 AM

I am with Larry. I de-tension at lunch time, but at the end of a sawing day I always remove the blade and do a cleanup. The blade will quickly rust between the blade and belt.

WM's manual says to remove the tension, and I always try to follow the manufacturer's recommendations.

Dave VH · March 25, 2012, 09:45:28 AM

I thought about the same question yesterday when I was done milling. Mine is not too easy to tension, and release. When I got my mill it had been sitting for untold years, and it had full tension on it, so that gave me piece of mind that it'll be okay. I look forward to following this post to hear some of the pros and cons of tension or not.
I just got done milling about 4k bd ft of cherry last week, so I think that it's still doing okay.

dgdrls · March 25, 2012, 10:11:47 AM

Suffolk Machine has a nice guide with "The 6 Rules of Sawing"

They recommend removing tension every day.

http://www.suffolkmachinery.com/

Best
DGDrls

Norm · March 25, 2012, 10:54:35 AM

I turn it down to 500lbs if I'm not going to saw for an hour or so and do the same at the end of the day. I don't turn it all the way down as I've been known to not retension then trying to saw. :D

Chuck White · March 25, 2012, 02:52:17 PM

I back the tension off, even if I'm only taking a 15 minute break.

The blade comes off at the end of the day, period!

As MM said, the blade will rust between the blade and the belts.

I hate rusty blades!

Okrafarmer · March 25, 2012, 03:24:13 PM

What are these belts you are talking about? How would a belt be in contact with the blade?

Magicman · March 25, 2012, 03:42:43 PM

Okra, on WM (and some other) bandmills the tires that the blade rides on on the bandwheel is a V-belt.

When I de-tension a blade at lunchtime, etc. I always hang my leather apron on the tensioner as a reminder to re-tension before engaging the clutch.

thecfarm · March 25, 2012, 04:16:02 PM

I have a Thomas that has a rubber v belt in the band wheels too. I don't back off at all. Proably I should but kinda of a bother on my to release it. I have 2 big bolts to adjust it with. Which works very good.

Okrafarmer · March 25, 2012, 04:31:51 PM

ok, that makes sense. Just couldn't picture it. I was thinking of a drive belt of some kind.

Wintergreen Mountain · March 25, 2012, 04:44:20 PM

I back the tension off my Turner Mill when i shut it down. The band wheels are regular trailer tires and start off with a jumping action if i don't back the tension off. I think i broke a few blades because i didn't back it off when i first got the mill.
It makes for a lot smoother start-up anyway.
LEON

Okrafarmer · March 25, 2012, 04:48:52 PM

Quote from: Wintergreen Mountain on March 25, 2012, 04:44:20 PM
I back the tension off my Turner Mill when i shut it down. The band wheels are regular trailer tires and start off with a jumping action if i don't back the tension off. I think i broke a few blades because i didn't back it off when i first got the mill.
It makes for a lot smoother start-up anyway.
LEON

Good to see another Turner user! The one I use is about 12 years old +/-, anyway, the tension adjustment is a bolt and nut setup, and of course there is no gauge to show how much tension there is-- they told me it's not an exact science. So far I have only ever broken one blade, and that was when I left the blade engaged while leaving the engine idling. (after a cut). It was just sitting there ticking over and all at once the blade broke.

red pine · March 25, 2012, 04:52:25 PM

I am new to sawing but have de-tensioned at end of day. I find springs lose tension over time and relaxing them is as good for them as it is for me. I will have to get a leather apron like Majicman and hang it on the tensioner handle so as not to forget to tension-up before re 8)starting. Redpine 8)

cutterboy · March 25, 2012, 09:05:15 PM

I know it is common practice to back off the tension on the blade when done sawing for the day. But I don't know why. In all these posts in this thread there is not one with a good reason why we do it. Woodmiser must have a reason why they recommend it. But what is the reason? Sometimes I de-tension and sometimes I don't and I don't notice any difference.

never finished · March 25, 2012, 09:44:16 PM

I let mine off at the end of the day. It might be tomorrow, or next month before I saw again. Okra I bought a pawn shop torque wrench to solve tightness problem. That was after a major problem of a broken shaft. The biggest part of the problem was figuring out what the problem was.

dgdrls · March 25, 2012, 09:56:22 PM

Cutterboy,

See the link I posted from Suffolk Machine in this thread,

Item 3 page 6 of the online catalog answer's your question(s).

Best DGDrls

Cutting Edge · March 25, 2012, 10:36:25 PM

Quote from: never finished on March 25, 2012, 09:44:16 PM
I let mine off at the end of the day. It might be tomorrow, or next month before I saw again. Okra I bought a pawn shop torque wrench to solve tightness problem. That was after a major problem of a broken shaft. The biggest part of the problem was figuring out what the problem was.

Excellent/Simple solution for us with non-hydro tensioners!!! 8) That would take all the guess work and "fluttering" outta the equation...I will be adding this to the mill tools for sure!! Just have to remember to back off the torque wrench now :

Brucer · March 25, 2012, 11:49:26 PM

Quote from: cutterboy on March 25, 2012, 09:05:15 PM
I know it is common practice to back off the tension on the blade when done sawing for the day. But I don't know why. In all these posts in this thread there is not one with a good reason why we do it. ...

Here's the one you missed ;D.

Quote from: Brucer on March 25, 2012, 02:18:40 AM
... In these parts the temperature change from early morning to afternoon will cause the fluid in the tensioner to expand. I've seen the tension go right off the gauge when I forgot to back off the tension during lunch.

To give you an idea of what can happen, my friend John bought a new hydraulic Wood-Mizer 3 years ago. A few days after he fired it up he noticed the blade was losing tension. Wood-Mizer told him to check the fluid level in the tensioner -- it was full. They had him try a couple of other troubleshooting tricks -- nothing.

Finally they told him to just keep tightening it. There must be a fluid leak somewhere and it would eventually show up. Well John was sawing and the pressure kept falling off so he just kept winding up the adjuster. Suddenly in the middle of a cut there was a loud bang and fluid sprayed straight up in the air from the tensioner. It turned out the guage was faulty and he had the pressure up around 4500 PSI. It blew the top right off the guage.

The point here is that rising air temperature or direct sunlight pushes the pressure up 'till you're off the guage, you really don't know how high it's gone.

ely · March 26, 2012, 12:24:43 AM

i take the pressure off my norwood each day or if i stop for lunch.
i also turn of the water and run the band until dry before i let it off.
i have been squirting oil on the blade guides too after the bands dries.seems to help the bearings.

Okrafarmer · March 26, 2012, 01:38:13 AM

I oil the bearings. They're too expensive not to. >:(

Chuck White · March 26, 2012, 06:26:29 AM

It's also been said that in hot weather, that if you don't back the tension off when shutting down, that due to the heat, the band could snap.

tcsmpsi · March 26, 2012, 01:41:27 PM

I release all tension on my band at the end of the sawing day. The torque wrench (for those to whom it might apply) works if you use the same type of blade. Different bands work most efficiently with different tensions.

bandmiller2 · March 28, 2012, 10:07:36 PM

When I'am done sawing at the end of the day I usally remove the band for sharpening and install a sharp one might as well leave it slack til the next running.Prehaps theirs no real damage from leaving the band tensioned but it can't help it, bearings,springs and belts. Frank C.

fat olde elf · March 29, 2012, 04:05:46 AM

Cook's manual says to detension at the end of the day. I rarely forget. Not worried about flatttening any belts on the mill as I have solid steel band wheels. Just trying to follow directions.........Say your prayers

starrtraveler · March 29, 2012, 03:54:00 PM

Quote from: dgdrls on March 25, 2012, 09:56:22 PM
Cutterboy,

See the link I posted from Suffolk Machine in this thread,

Item 3 page 6 of the online catalog answer's your question(s).

Best DGDrls

Just printing out your reference to Suffolks recommendations for de-tensioning blades after cutting.
ALWAYS DETENSION YOUR BANDS
When you are done cutting for the day, take the tension off your blade. Band saw blades, when warmed up from cutting, always stretch; and upon cooling shrink by tens of thousandths of an inch each cooling period. Therefore, blades, when left on the saw over tension themselves and leave the memory of the two wheels in the steel of the band, which will cause cracking in the gullet. When you leave the band on your saw under tension, not only do you distort the crown and flatten out the tires (which makes them very hard), but you also place undue stress on your bearings and shafts. Believe it or not; you can, and will damage your wheel geometry sooner or later and considerably shorten bearing life. You are also crushing your tires or V-belts.

Figured this would be a nice link to throw in: http://www.suffolkmachinery.com/six-rules-of-sawing/

Knute · March 30, 2012, 09:57:35 PM

I have had my LT28 for 18 months and have never released the tension except when changing blades. Have never had any problems, but maybe should start to release when not in use. I don't remember seeing anything in the instructions regarding this, but I could have missed it.

cutterboy · March 30, 2012, 10:08:27 PM

Quote from: dgdrls on March 25, 2012, 09:56:22 PM
Cutterboy,

See the link I posted from Suffolk Machine in this thread,

Item 3 page 6 of the online catalog answer's your question(s).

Best DGDrls

Thanks dgdrls, that was very interesting. I guess I'll be more careful about backing of tension.

cutterboy · March 30, 2012, 10:24:09 PM

Brucer, my Norwood has a different tensioner than your Woodmiser. There's no fluid in it. It has a large spring. However, thanks for your post..... there are so many woodmiser owners out there.

Starrtravler, thanks for posting the info that dgdrls brought to our attention. There is good information in there.