Circle mill blade heating

ddcuning · February 08, 2014, 08:05:03 PM

I wasn't pushing the feed speed and while cool it fed through with no effort.

Dave C

lyle niemi · February 08, 2014, 08:08:46 PM

Quote from: ddcuning on February 08, 2014, 08:03:17 PM
My mill only has two. I didn't think about stressing he shaft. The blade stands up at speed when it is cool. It just overheats almost instantly as you enter the cut.

Dave C

You said you have new teeth but what are your shanks like?? they are just as important as your teeth

ddcuning · February 08, 2014, 08:10:38 PM

Lyle, they are not new but the saw shop checked them out and didn't report any issues.

Dave C

lyle niemi · February 08, 2014, 08:16:16 PM

Quote from: ddcuning on February 08, 2014, 08:10:38 PM
Lyle, they are not new but the saw shop checked them out and didn't report any issues.

Dave C

Im guessing its a blade problem because you said it starts to go kitty wonka as soon as you start to go into the log???We gots ta figure this out tonight or I wont be able to sleep..lol

b dukes · February 08, 2014, 08:22:01 PM

I had somewhat the same problem after having my blade hammered. I had the saw shop replace the bits and shanks when it was hammered. It would cut about 15 minutes and then start heating up. I changed all the bits and the problem went away. After inspecting the bits we took out , I had four bits the angle was off from the others. Have you tried changing the bits again ?

ddcuning · February 08, 2014, 08:22:36 PM

I have a 48" style 3 blade and a 54" 2-1/2 7 gauge that I can throw on the mill. The 2-1/2 blade is new in the crate and I think has only been sawed with once or twice. It is probably my best bet. I am just stumped. I have been all through this mill from bottom to top and now this is driving me crazy. I can change out the blade tomorrow and see how that goes.

Dave C

ddcuning · February 08, 2014, 08:25:02 PM

I didn't change the teeth but I did hit them with the jockey grinder. It didn't seem to make any difference though.

Dave C

lyle niemi · February 08, 2014, 08:27:14 PM

Quote from: ddcuning on February 08, 2014, 08:22:36 PM
I have a 48" style 3 blade and a 54" 2-1/2 7 gauge that I can throw on the mill. The 2-1/2 blade is new in the crate and I think has only been sawed with once or twice. It is probably my best bet. I am just stumped. I have been all through this mill from bottom to top and now this is driving me crazy. I can change out the blade tomorrow and see how that goes.

Dave C

You dnt havta be crazy to mess with this kinda stuff but it does help

bandmiller2 · February 08, 2014, 08:57:54 PM

Dave, I would recheck the level of the tracks and carriage near the saw, if their not real close it can cause the log to cramp the saw. Also check with a heavy log on the carriage. I know you would have leveled it well but possibly something has shifted. Frank C.

bandmiller2 · February 08, 2014, 09:37:06 PM

Another thing that's very important is to be sure even a small splinter or piece of bark is not rubbing agenst the saw plate. A painful lesson ($$$) on my first mill a piece of bark wedged between the saw plate and the wood deck and heated the saw, had to have it rehammered. Now I have a hinged section next to the saw that I can flip up in a moments notice if I see something agenst the saw. Frank C.

Jeff · February 08, 2014, 10:21:36 PM

Check your bearings. An inboard arbor bearing close to the mandrel that is failing can heat the arbor and the saw quickly. When your saw gets hot, shut it down and check the bearing. The bearing will transmit heat to the saw, but the saw will not transmit heat to the bearing. If the bearing is hot, there is a problem. Its easy to over look when trouble shooting a hot saw. You just think it is the saw.

beenthere · February 08, 2014, 10:45:15 PM

If still looking,....
Might toss a reasonably straight 2x10 or so on the carriage, and run it by the saw when the sawblade is up to speed.
Not sawing at first, but just pass by.
Then advance the carriage knees a quarter or half inch at a pass and make some sawing cuts that hopefully will not heat the blade. Measure on the gig back to check clearances with the blade to see that the carriage isn't causing the piece to be pushed against and rub, and thus heating the saw.

I'd assume that with all the work you have done, these clearances should be good. But something is heating your blade, you say.

Ron Wenrich · February 08, 2014, 11:05:01 PM

You need more lead. Don't ever get swayed with the idea that the lead has to be 1/32". The lead needs to be set to where the saw runs right. I had one saw that needed 3/8" to run. Every saw will run differently.

I had one mentor that told me he didn't care how much a saw wobbled, its that it didn't wobble in the cut.

If its not lead, its in the collars. Of course partially frozen logs will cause fits.

GeneWengert-WoodDoc · February 08, 2014, 11:07:22 PM

Maybe it is too obvious, but are the new shear pin(s) long enough?

Jeff · February 08, 2014, 11:12:14 PM

Quote from: Ron Wenrich on February 08, 2014, 11:05:01 PM

I had one mentor that told me he didn't care how much a saw wobbled, its that it didn't wobble in the cut.

I'd agree to that to a point. If you are a production sawyer, you want to enter that cut as fast but as safely as you possibly can. Having a wobbly saw, even if it cuts good in the cut, will slow you down a bunch as I'm not going to cram a log into a wobbling saw.

chopperdr47 · February 08, 2014, 11:52:06 PM

You may already know this, but when I was having a lead problem, I laid a 2 x 10 down flat and dogged it. I removed the drive belts and and turned the drive pulley by hand. I advanced the carriage until the 2 x 10 was abeam the blade marking the tooth and the corresponding point on the board and measuring the distance. I advanced the carriage to the rear of the blade then lined up the marked tooth with the mark on the board. I loosened the bearing mounts (3 on mine), made the adjustment, tightened the bearing mounts and measured again. This part is left over from my helicopter days, but I rotated the blade several times before moving the carriage back to the front of the blade and measured again. If there would have been a difference in the 2 measurements, I would have looked for the reason before I moved on.

I brought the carriage back to the front and measured to find the lead. I had to repeat this several times to get it to a little more than 1/32". Don't forget to have the guide pins safely away from the blade while measuring, one of my lessons learned.

When resetting the pins, there should be a 1/8" total gap, 1/16" on each side of the blade when running. I say it that way since the blade will rest against the husk side pin when stopped and be centered when it stands up at cutting rpm.

I also had a time when the blade was heating up. There was evidence of contact with the log on the center of the blade, on the cant itself and the blade was walking out of the cut. Doing what I described, and cleaning the blade with a diesel/oil mix solved my problem. I've been cutting some 24" red oak logs and it's doing great now.

John

ddcuning · February 09, 2014, 06:08:23 AM

Thanks for all of the input guys. I am going back to the mill this afternoon and will go through it thoroughly. If I can't resolve the issue on this blade I may try changing it out but I will go through all of the advice here with the blade that I have on the mill now. I really appreciate all of the advice and help on this. I was so frustrated yesterday since we have worked 3 years to get this mill running and then out of the gate we have this issue.

Dave C

GeneWengert-WoodDoc · February 09, 2014, 07:58:09 AM

If it is not the bearings and if there is nothing rubbing against the saw near the eye, then where is the heat coming from? How about taking a piece of chalk and marking the collar and saw position. Then saw and see if the chalk line has moved.

ddcuning · February 09, 2014, 08:33:24 AM

After church today I am going to make a checklist from all of the input here and walk through all of the items on the list. I will update once I am done.

Dave C

dblair · February 09, 2014, 08:59:14 AM

just food for thought my old book says the top of the blade should lean in towards the log slightly so my mandrel is set a 3 thousands per foot letting the top of the blade closer . the guides should be as close as possible without touching .

Ron Wenrich · February 09, 2014, 10:44:02 AM

That's a good point, especially on longer mandrels. If the level is off even a little bit, the saw will be open at the eye, and all the alignment and lead won't work. You can put a level on the shaft, and if its off a bit, your eye will rub.

The difference on an 8/9 gauge saw is only 15 thousandths. On a 54" saw, that's 6 thousandths per ft. How far off of level do you need to be to offset that difference and open up your eye? My guess is not much.

I remember putting a plumb bob to the saw on one mill, and I ended up shimming the rear bearing to take care of the problem.

ddcuning · February 09, 2014, 08:01:14 PM

So here is the deal. Went to the mill this afternoon and was removing the log from the carriage when I noticed a lot of bluing on the bottom of the log like metal in the log. I assumed this was from rubbing on the blade. I checked the level on the carriage and all was good. I checked the square of the knee to the base and it was perfect. I then checked square between the headblock base and the blade and there it was. I put a 4 ft level against the LH side of the blade to flatten it and set a 12 inch machine square on the headblock base and against the blade. 12 inches up the blade, the saw was tilted 3/16 of an inch away from the carriage. I assume that if the square had reached the tip of the blade it would have been over a quarter inch off. So as the cut went, the base of the log was riding on the inner region of the saw blade causing it to heat.

I had forgotten a key piece of information that caused this issue. When we set the lead back at Christmas, we found that the adjusters for the mandrel bearing were completely loose to the point that the shaft was barely held to the husk. We were frightened by the prospects of this find and tightened the adjusters and set the lead. What we didn't realize was that tightening the adjustment studs raised the saw and thereby induced the error we found today. No telling how long the previous owner sawed with the mandrel bearing loose. Not sure how he sawed with it like that.

We found that the carriage was level but the husk was not. We leveled the husk and it took some of the error out of the saw blade. We also found that the shaft was not square with the husk which made us misalign the headblocks. We squared the shaft then shimmed the sheave side bearing up until the saw was square with the headblock base and the shaft was level. It then got dark on us so we called it a day. Since the shaft is now square to the husk, we can align the headblocks to the front tip of the saw and they will be square with the husk. We will then set the lead and we should be good to go......I think. We will hit it again next Sat and see how it goes but I think this will solve our problems. It was good to get away from it and think about it and then go back to it.

Dave C