Disengaging blade between cuts

[toolman18]

I've noticed some guys (in videos) disengage their blades between cuts and some don't.  What is the purpose of disengaging between cuts?  Thanks in advance for your answers!

[VictorH]

Disengaging the blade reduces the number of times it run around the wheels thus extending it's potential life.

[Qweaver]

Woodmizer says that the only time the blade should be moving is when it's cutting.  But if I'm making a series of cuts with out off-bearing the boards, then I keep the blade moving.  I don't like the idea of my helper being close to a moving blade.

[POSTON WIDEHEAD]

I only disengage the blade when I'm turning my log or removing a slab. Once I get my cant the right dimension.....The blade runs until I saw the last board on the bottom.

But like Victor said, a blade will only go around so many time, however, the disengage switch will only flip on and off so many times.

So I guess its a sawyers preference.

[Bandmill Bandit]

SAFETY
Blade life!
Noise level
Fuel consumption
Belt wear both on the drive and tire belts.
SAFETY
guide/roller wear
and I am sure there are as many more as I have listed.
Did i mention SAFETY?

A switch is about 12 bucks and I would guess will last for a few hundred blades switching on and off between cuts. Baldes are 20 ish and up each and I would guess you will shorten your blade life by 40ish% per blade. You tell me which you'd rather buy more of.

My blade ALWAYS stops with in a second or 2 of completing a cut and starts when I am lined up for the next cut. That is the primary reason I added auto clutch to my mill. The right arming for a manual clutch was a bit painful to my bursitis in my right shoulder at the time and SAFETY was my main concern. Pain can cause you to do thing that are unsafe so I had the auto clutch installed. 

[T Welsh]

I disengage while busting the log down into a cant,but once I have a cant it runs until I am down to the last cut. Tim

[Magicman]

Personal preference I guess, and I have just completed my 10th year of sawing.  I always disengage the clutch and I have a manual clutch.  That is a lot of "right arming" every saw day.   :-\

OK reasons:  Any blade will only travel around the band wheels so many times before they break.   Disengaging the clutch stops this unnecessary blade travel.

Sometimes, especially when removing a slab, I may not raise the saw head quite high enough to clear a knot or something.  If the blade is turning on this return, it would probably be knocked off of the blade guides.

I may accidentally reverse the power feed leaver before the blade quite clears a cant or stack of lumber.  Again, if the band is turning, I probably just knocked it off.

When I am sawing, there are things that my hands and fingers just automatically do.  Disengaging the clutch is one of them.

[petefrom bearswamp]

I'm not sure what the tradeoff is between keeping the blade running and using the electric stuff to dis engage re engage  the blade.
Bandmill Bandit The switch may be 10 bucks, but i am willing to bet there is a lot more more involved than a switch.
Manual is a different story causing carpal tunnel sore arm etc as Magic man says
I dis- engage when cutting long stuff of 12' and longer and keep running on the shorter stuff.
Maybe we can find somebody in academia to do a study to resolve this issue (of course at taxpayer expense)
my 2 c

[Bandmill Bandit]

Bandmill Bandit The switch may be 10 bucks, but i am willing to bet there is a lot more more involved than a switch.

Yes there is the little cam motor but I have yet to hear of any one changing one of those out and if they have i will bet it had several thousand hours on it at change time.

Maybe we can find somebody in academia to do a study to resolve this issue (of course at taxpayer expense)
my 2 c

A study would would only in crease that cost of sawing cause our taxes would all go up and at the end of the day the study would get filed in the congress library of completely useless information.

If you increase blade costs by 30 per cent minimum that would be equal to paying $31 a blade instead of $24 based on my last box of blades. I am pretty sure that number would be closer to 50% in reality, so closer to $35.

It dont take a forensic accountant to figure out which is the most economical and SAFE answer to this question.

[Brad_S.]

I never disengage the blade.
Starting the blade from a dead stop puts stress on it too and, I believe, negates any saved life.
I often throw blades out long before they break because they have lost a good portion of their width due to repeated sharpenings so I don't buy into that "save blade life" reason for disengaging.
Starting/stopping the blade eats up time.

[POSTON WIDEHEAD]

OOOOOOOOOOOOK......now we are getting technical. I can dance.....

When I first got my mill in Feb. the REP told me to always turn the blade off when not cutting. So I did, which resulted in me engaging and disengaging about 100 times a day. ( Just a guess ). Well at less than 150 hours, my auto clutch went out. Had to install a new one. Then my 2 sensors went out on the auto clutch, had to replace them.
All this was due to the engaging and disengaging everyday, 6 days a week since Feb. Not to count how many times the drive belt is stressed getting the blade up to high speed.

Someone add it up......$$$$$$$

Like I said before and what Twelch said, I turn my blade off while busting down my log, but once I get my cant.....My blade DOES NOT turn off until I saw that last board.

It is my belief that leaving the blade running in the manner I do, I will come out way ahead when I cut my last board at 101 years old.

This is my way and I'm sticking to it. 8)

[WH_Conley]

I do like Magicman. I put a new drive belt on that came with the new motor. That was at 1400 hours on the meter, it now has over 4000. Can't see belt stress as being a factor. Saves a lo of RPM's on the bearings, that big one on the drive is not cheap. I guess it is like the old Ford vs Chevy argument. Pretty much what each person want's to do.

[Dave Shepard]

When I was trained on our mill I was told to leave the blade engaged when gigging back for the next cut. This was to save wear and tear on the belts and other mechanisms, and that the start up forces were stressful on the band. Later, I was told not to, as it reduces band flex life, which I already knew. That's why the LT70 has bigger wheels. I pretty much shut off all the time now, unless I'm making multiple cuts on 8' or 10' logs. I don't see any safety issue leaving it running, nobody is supposed to be near the heasd when it's running, whether it's in the log or not.

[cypresskayaksllc]

I disengage. I like a little peace and quiet every now and then

[Banjo picker]

I would suggest you wear hearing protetction.  I did not start in time.  Banjo

[bandmiller2]

My bandmill has an over center belt idler, at the end of the cut I just flip the lever up and stop the band wile leaving the electric motor running.I've had the same belts on the mill for years no sign of ware.If I'am cutting a series of boards off a cant I leave the band turning then shut down and pull them off. Frank  C.

[Chuck White]

               smiley_argue01                                ;D     

[POSTON WIDEHEAD]

Good one CHUCK........Good one! :D

[cypresskayaksllc]

I would suggest you wear hearing protetction.  I did not start in time.  Banjo

What :D

[WH_Conley]

HUNH??? Did somebody say something?

[POSTON WIDEHEAD]

 smiley_whacko Not me....I'm finished with this subject. 2 deep.

[TGS]

What about TK owners? Do you guys disengage? I'm honestly afraid of burning a flat spot on my belt. I run a B20 and it just doesn't seem like a good idea.

[Paper Maker]

What about TK owners? Do you guys disengage? I'm honestly afraid of burning a flat spot on my belt. I run a B20 and it just doesn't seem like a good idea.

I run a B20 and right or wrong I just bring the motor down to a idle. I rarely ever disengage the band. If I'm not going to make a cut anytime soon, for whatever the reason may be, I shut the motor down. I usually keep the hydraulics motor running all the time about 1/2 throttle or a little more. I also never run either one without earplugs.

[redbeard]

I disengage alot if Iam by myself pulling flitches off. Cutting stacks out of cants its running full throttle.

[Brucer]

I always disengage at the end of a cut. 300,311 BF since I installed the autoclutch and no failures or signs of wear. I've heard of the odd problem with autoclutch components but it's usually a faulty part and is covered by warranty.

I might do things differently if I had a different mill and was making a different product.

[5quarter]

I think excessive tension, not dressing the gullet and dirty logs do more to shorten blade life than the # of revolutions around the wheel. I've only broken 4 bands...2 fairly new broke at the weld. the other 2 jumping off the wheels due to operator stupidity.

[5quarter]

Having said that, I do disengage between cuts to save wear on the guide and bandwheel bearings.

[ladylake]

What about TK owners? Do you guys disengage? I'm honestly afraid of burning a flat spot on my belt. I run a B20 and it just doesn't seem like a good idea.

I run a B20 and right or wrong I just bring the motor down to a idle. I rarely ever disengage the band. If I'm not going to make a cut anytime soon, for whatever the reason may be, I shut the motor down. I usually keep the hydraulics motor running all the time about 1/2 throttle or a little more. I also never run either one without earplugs.

Same here, with the setworks, a offbeareer and the fast head speed  on the B20 it would be foolish to disengage the clutch on up to 14' logs, 16 and longer I may slow the engine down, remote throttle sure is nice for that.  Even sawing by myself with a little time between cuts I'll just slow the engine as I think it's just as hard on everything kicking the belt in and out as it is leaving it idle. I'm getting excellent band life .     Steve

[tcsmpsi]

At the end of each cut, I throttle down, which disengages the clutch.  Knocking off a band while dragging back due to any myriad reason, is a shock enough to the mill and meself to inherently make that decision.  Then I go to fuel, wear, etc.   I used to like to leave it running as I drag back.  The personal set up then takes place, as well.  I am the sole hp (human power) at the mill.  All in all, I have found that my blades do last longer. 

Alas, I know I may wear out the throttle one day.  A catastrophe I am willing to chance.   ;D

In the end, each person has their own mill and develops their own way. 

[Cedarman]

We saw a lot of 8,10,12' logs  10" and up of ERC.  I disengage manually our electric mill just as the blade is about to leave the cut. I stop the forward movement just as the teeth clear the end of the log, but before the body of the blade exits.  I leave the board on and bring the blade straight back.  I do this leaving all the boards on the cant.  I like to leave the boards on the cant to keep the cant from springing up making thick and thin boards.
It is extremely rare that I will knock a blade off.  For me it is much faster than exiting the cut, raising the blade, then lowering it back down to start the next cut.
Started this way in '83 with all manual mill and forward step switch and 3 sizes of pulleys.   It would be tough to change my habits now.  Don't make my way the best way, it is just my way. 
My gut reaction is that blades can only go so many times around the mill.  But we all know guts stink.

[ladylake]

Don't know how you can bring the blade back through the cut, if I have to back up in the cut I get about 4" and it's stuck.    Steve

[toolman18]

Thanks guys for all the input, this is one of the few topics I've ever seen where everyone agrees with everybody. :D I run a TK B-20 and don't disengage unless I'm loading another log onto the mill.  Unlike a lot of you guys however mine is just a hobby mill and I don't go through anywhere near as many blades as you'll.  Thanks again for all the feedback!

[Cedarman]

If the cut is not completed, then you must raise the slab on top to get the blade to back up.  Sometimes it takes a wedge driven in to get the needed lift.  But if the cut is completed, the  blade should  slide back with minimal difficulty.  Splinters that catch the blade is the only time I have problems.

[paul case]

cedarman,
what mill and what size blades are you using? My saw will not come back in the cut with a board on either. There must be some big difference here.

Noone has taken into account some mills have a brake that stops the band when the motor is disenguaged and some don't. My mill doesnt and if I disenguage the blade, It is usually still turning when I am back and ready for the next cut. That can't save much blade life.
I get good blade life. Very seldom do I break one before it has been sharpened 6 or 8 times. If I only get 300 bdft per sharpening(which is low) my blade cost is around a penny/bdft. Thats cheap. I usually get more bdft per sharpening than 300 bdft.
Just saying. PC

[ladylake]

Mine will come back if I raise the slab-board but cant imagine doing that all the time.    I've done that cutting over length logs.    Steve

[5quarter]

Cedarman...ERC might be the exception. The wood is relatively dry and sawdust probably clears the cut better than wetter or more resinous woods. Still, it seems physically impossible unless you release just enough tension with each board to lift it just enough to slip the blade back through the cut. I'll try it tomorrow on some small walnut I need to cut and see what happens.

[Magicman]

ERC would be the only species that I could drag the blade back through.

This thread goes to clearly illustrate that different sawyers develop sawing techniques that work for them.  Not necessarily right or wrong, just different.   

[Cedarman]

The mill I am using now is an electric with 25HP motor LT30.  It does have a band brake that stops the blade in about a second or two.  If I push forward on the engage handle, it will stop in a 1/2 second.  Cedar is dryer and the sawdust acts more like ball bearings I think.  I can tell by the drag back whether I am in danger of pulling the blade off.  Most boards are 6" to 12" wide. 
At end of cut, I flip the forward handle to neutral as I disengage the blade.  As soon as it forward handle hits neutral I pull back on the box with my left hand stopping all forward momentum.  Very seldom does the blade go off the end.  If it does, I slowly bring the mill back to make sure it enters the cut without catching.  Once in the cut it is full speed back.  As soon as it is out of the cut, then down, then up a fraction to get on the mark. (No accuset). Forward, repeat process.  It is amazing how fast I can cut a bunch of 1/2" lumber.

[Larry]

I was thinking...I know its dangerous.  I've never seen a circle mill disengage.  Guess there too busy making boards.

With my TK, left hand is on the feed and right on the up lever.  As soon as the blade clears the cant the carriage moves up, for maybe a second or two.  Pull reverse lever back and soon after hit the setworks down button with right hand to repeat sequence.

If I were to disengage that would add a four step sequence.  Slow engine, hit clutch off button at end of cut.  Hit clutch on button, and finally bring engine up to speed for the next cut.  I guess one could skip the slow engine part.  Seems to me this is gonna slow production, and wear out my clutch.  Maybe I can grow couple more hands to help but than I would need a faster brain. :D

[customsawyer]

I only disengage the blade if I am going to turn the log or something occurs that will slow me down on the return trip. Even if it is a 40' log. You have to remember that I am running the LT70 which has the larger blade wheels.

[Banjo picker]

I disengage the blade just after I turn the key off.. ;D.   I do idle it down when turning a cant .  Banjo

[Dave Shepard]

I used to slide back under the board like Cedarman. White pine, no problems. On the super mill it's so much faster up and down I don't have to.

[red oaks lumber]

i just can't see cutting air, i shut down between cuts

[ladylake]

 I can't see shutting it down for 5 seconds and extra strain on the blade starting and stopping it.   Steve

[Brucer]

I've done just what Cedarman does, with white pine, lodgepole pine, and grand fir. It doesn't work very well on Douglas-Fir, however. The saw drags back OK at first, then the sawdust piles up on top of the blade and it starts to drag the whole board back.

I only disengage the blade if I am going to turn the log or something occurs that will slow me down on the return trip. Even if it is a 40' log. You have to remember that I am running the LT70 which has the larger blade wheels.

It also returns faster than a regular LT40. That's one of the factors that would make me change my ways.

[ladylake]

You hit the nail on the head Brucer, time between cuts. On my B20 there is no time to disengage between cuts.   Steve

[Brucer]

I've tried leaving the blade running a couple of times. I was sawing short logs, making thin boards (3/4" as I recall), and I had a helper clearing the boards as the dragback pulled them back. I got a nice rhythm going but it took a lot of concentration to keep track of where to drop the head to on the next cut. Accuset would have been nice for that job.

[Magicman]

Actually disengaging/reengaging causes me no lost time.  I disengage when the blade clears the log/cant.  I reengage immediately after I hit the down lever (SetWorks).  The mill comes up to speed before the blade reaches it's next saw target.

It's a rhythm that each of us develop whether we disengage or not.  No right or wrong, just different.