Saw wobble

[CX3]

Guys I am having a time getting my saw to fly straight. It leads in bad about the third log. Teeth are good. Guides good. Lead is good. When it comes out of the log it is pulled in so hard it literally wobbles. Then of course it is warm and won't settle down for awhile. I feel like I have tried everything. ??? Besides having it hammered

[beenthere]

"All" is not good.. need to find out what it is that "isn't good". 

Maybe you have this document... if not, it is a good read.

http://www.fpl.fs.fed.us/documnts/misc/circsaw.pdf

What mill do you have?

[CX3]

Yes I have that thanks.

My mill is a JA Vance handset 3 headlock. Cummins power. 52 in saw.

[ETSawyer]

I would start by checking the teeth in the saw against new ones. Make sure your angle is correct and the teeth are not too narrow and that the tooth is square not filed leading the saw in or your log side is not wider that the board side of the tooth. Side clearance issues can make a saw do alot of strange things. Was the saw hammered recently?  If the saw is a known good and the bits are good I would look deeper into the husk. Sounds like if everything else checks out it could be lead or collars. Also where is the saw heating up  around the eye near the collars or on the rim near the guides? 
Some of the more knowledgable circular saw guys will chime in I'm sure but this info will help to narrow down where your problem may lie.  Hopefully this helps and good luck!

[Ron Wenrich]

When was the last time the saw was hammered?  I had a saw that was cracked that gave me fits.  I assume you haven't changed shanks lately.  If you are sure it is okay and the teeth are new, that should take care of the issues of the saw. 

Next thing is to make sure the rpm is where it is supposed to be.  If you run too slow or too fast for the hammered speed, you can get wobble.  When you saw, are you maintaining those rpms through the cut?  Feeding too fast will slow your saw, and it will lay over.  Rpm can drop if the belts aren't tight enough.

How cold is it in your area?  You may be running frozen logs or half frozen ones.  Half frozen is the worst, since you're sawing 2 different types of wood in one cut.  If you're gullets aren't up to snuff, you can get spillage and sawdust will freeze to the sides of the log.  That usually pushes the saw out of the cut. 

Lead can be tricky, especially this time of year.  Although you say lead is good, I have never been able to say that a certain amount of lead is optimum for every saw and every situation.  With frozen logs, you need less lead.  If you swap saws, you may need to adjust lead.  I'd try to dial back the lead to see if that makes any difference. 

We had one a few months ago, here on the forum, where we couldn't figure out why a saw had wobble.  Turned out that the front bearing holder was loose on the husk.  Make sure they are solid.  Do you have 2 or 3 bearings?  If you have 3, then make sure you loosen the middle bearing when you adjust your lead.  Tighten it last.  If you don't, you'll put spring in your mandrel. 

Then, you have your collars.  How tight do you make your saw nut?  You shouldn't be putting too much pressure on it, or you'll smash your collars.  When mounting the saw, you should pull back the saw on the shear pins (you did check those?), then tighten the nut.  I always got mine tight, then kicked it twice to get it snug.  That's tight enough. 

You can also check your collars with a flat edge to see if they're within tolerance.  Another check for mandrel and collars is to check how the saw is running between your guides.  It shouldn't be moving back and forth.  Take your saw and put it where it is in the middle of your guides.  Take a crayon or marker and make an "o" on that tooth.  You're going to map out your saw.  As you advance to each tooth, you will mark either an "o" for center, a "+" as it moves to one side, or a "-" as it moves to the opposite side.  The more it moves, add a + or -.  When you're done, you'll be able to see which side is high and which is low.  Now you have to figure out if it's the collars or the mandrel.

Take the loose collar and turn it 180°.  If nothing changed, it's probably not that collar.  Rotate the saw 180°, if nothing changed its probably not the fast collar or the mandrel.  Its probably in the saw and it needs hammered.  Old timers will tell you that you can use a paper shim to bring your saw back into balance.  Its not optimum, but I've used it on old mills.

After that, you have to start looking if you're getting any movement in the carriage.  Track needs to be straight and level.  Carriage trucks can't have much play in them.  Your headblocks can't be sloppy.  You also want to look at your board splitter.  If that is moved too far beyond the saw, you'll be pushing against your log as you're feeding past it.  You'll be able to see that when you gig back.  If you move your log beyond the splitter, then gig back, your log shouldn't be hitting the splitter. 

I think that covers about everything that could be wrong.  I often had problems with winter sawing, and dreaded it on logs that had been laying on the ground. 

[dgdrls]

Guys I am having a time getting my saw to fly straight. It leads in bad about the third log. Teeth are good. Guides good. Lead is good. When it comes out of the log it is pulled in so hard it literally wobbles. Then of course it is warm and won't settle down for awhile. I feel like I have tried everything. ??? Besides having it hammered

The first and second log saw OK?  Is the blade already getting too warm by then??
Where is it getting warm,  in the eye or on the rim?

As others have pointed out check the teeth and be certain they are  true and square
as well as the shanks, 

Dan

[CX3]

Ok thanks for the replies. I had a guy come over and check my sharpening job (novice) he sharpened the teeth square. Same thing happened when sawing.

I have a meeting Sunday morning with the head sawyer at another mil . He is going to hang my saw on his mill and check my saw.

I am certain it has to be the saw. I have checked and triple checked all other possibilities. I have literally went mad setting my track level and sturdy. I have it blocked up just like the pamphlet says. 4 ft cross ties every 6 ft. It doesn't wiggle.

Hopefully this guy can line out my saw.

[Gearbox]

Did the mill saw good and then go bad ? Saw speed if to slow will cause wobble . does the saw stand up befor the first cut ? Are you checking lead on only one tooth and turning the saw with the guides backed out ?

[CX3]

Yes gearbox I was checking lead on the first headblock, and with the same tooth.

I called the local mill where I sell my good logs lol, and the head sawyer came over this morning before church. A few whacks with a 2 lb hammer and my saw was standing up good. He said it was dished toward the log. Soooo sinful me couldn't stop thinking about my saw while sitting in church....and just got done sawing a log and man he worked magic on this thing. What a great deal. Problem solved, and now I know what to look for when my saw gets warm. He said he'd help me anytime and told me after a few times I could hammer my own saw hanging on the mandrel. He said he hasn't had a saw hammered off the mandrel by someone else in 20 yrs. I am fortunate to be learning from this guy.

[CX3]

And I was also watching saw speed very carefully while in the cut, I have a tachometer on the power unit. I am going to move it closer to me so I can watch it without turning my head. Thanks for all the inputs guys, I have learned alot this week

[Ron Wenrich]

Nothing like a good mentor.  If you listen to your saw, it will act as good as any tach.  Keep the same pitch all the way through the cut.

[CX3]

Ron, I will soon enough learn the sound of my saw, but I have only sawn about 10 logs with it so my ears aren't perked up yet. Lol

[Gearbox]

Faster may be some better , mine stands up at 600 I try to run 625 . Have run it up to 650 . any faster it will heat .

[CX3]

Hey all I have been making some ties and good lumber since I had my saw hammered. I guess I sawed too long with dull teeth, it got warn and laid back down on me. I really didn't think the teeth were dull though, but they were. I shoulda checked. Post your valuable life lessons learned at the circle head rig here. I'd be glad to hear them before I pull my hair out here in southern missouri.

[beenthere]

I'm puzzled that you started a new thread here, when your "saw wobble" thread contained some great information and explanation. Plus included the comment that you have a good neighbor who is experienced and helped you sharpen your saw, and "hammered" it back into cutting good again.

https://forestryforum.com/board/index.php/topic,88534.msg1359163.html#msg1359163

What's up?

[Jeff]

There are valuable circle saw tips through out the Forestry Forum. No need to try and regather them here. I'm going to merge this with your original topic.

[CX3]

Well everything was running along fine, then it just quit sawing good. My buddy came over to check it out again, and he thinks the collars are bad?? He says it is super tight in the middle. So I am headed to a guy in the morning and he says he can roll the saw and flatten it.

I guess my point is I am getting frustrated at this mill. I have literally checked, and rechecked every piece and it still heats.  My rpm is correct. Teeth sharp. Track plumb. Clean logs. Guides ok. Lead good. I don't know what else unless it's just me.

[CX3]

I originally thought the teeth were dull but he said they were fine

[Gearbox]

What are you running for lead . I run 1/8 if i get out to 1/4 it will saw good for a while [ 2 or 3 logs] then start to heat . stay with it we will figuer it out . If you are running  belt drive you sure you arn't pulling the lead out of the saw with too tight a belt?

[dgdrls]

Well everything was running along fine, then it just quit sawing good. My buddy came over to check it out again, and he thinks the collars are bad?? He says it is super tight in the middle. So I am headed to a guy in the morning and he says he can roll the saw and flatten it.

I guess my point is I am getting frustrated at this mill. I have literally checked, and rechecked every piece and it still heats.  My rpm is correct. Teeth sharp. Track plumb. Clean logs. Guides ok. Lead good. I don't know what else unless it's just me.

How is the saw acting (what happened specifically) when it quit sawing good, what messages is it sending?
as @Gearbox indicated you'll get it
Dan

[JSNH]

Well when I was new to a circle saw. I just ran it and it ran well but the foundation I had it on was temp one. I screwed up and heated the saw a bit too much and the saw lost it's tension. I leveled the mill checked the alignment the lead everything twice. I even moved the mill onto a good foundation. It just would not cut straight and the saw would lay over. It almost had a floppy feel to it. I brought the saw to a saw doc. He did his magic and tensioned the blade and it has cut perfectly for the last 8 years. 
You might be in a similar place. Stick with it you will overcome it. This site has some of the best people on it and it is a great place to learn from.

[CX3]

Ok I just got back to the mill after a 6 hr road trip with a saw doc. He hammered my saw and rolled it. I got back to the mill, hung the saw and it still wobbles. I rotated saw until it touched the guide. Unscrewed mandrel nut and removed collar. Rotated saw 180 degrees and clamped it back down. Nothing really changed at the guides, maybe a ten thousandth but hardly noticeable. I checked lead and it is a 1/4"  the track is flat as a pancake and on a concrete slab.

My power pulley is 8" the mandrel pulley is 24"  with 1800 engine speed I should ha e 600 saw rpm. Just sitting there running at 1800, the saw still wobbles and chatters at guides. I checked the bearings they are not warm and seem tight.

[CX3]

The only thing I haven't really confirmed is my belt tension,  maybe it is pulling on the arbor. I don't think so though because the pamphlet says the belt should be hard to roll with fingers. My belt is not that tight but it isn't slipping either.

I also did the collar check, I set the guides pretty close to saw then clamped it down. It never moved.

[Kbeitz]

What about the back collar or is that part of your shaft ?

[CX3]

It is part of the shaft, or at least would be rather hard to get off. The saw doc told me to watch the guide clearance as I tightened the nut. The saw never moved.

I just got done sawing 4 logs. No heat anywhere. Seemed like it sawed ok, but it is leaving a belly in the ties. They are 7 and 9 near the head blocks, but 6 5/8 and 8 3/4 thru the middle. The lumber came off 1 1/8 or very close. I did not measure the middle of the boards.

On the gig there is over 1/2 inch between the log and the saw.

When the saw comes out of the log it looks like the board breaks off instead of being sawn off.

[beenthere]

Smacks of too much lead.

Don't know where to suggest you start, but I'd start with a straight 2x6 laying on the carriage, and begin making a lot of measurements to find out what the carriage is doing with respect to the saw blade.
If all good, then work with the relationship of the sawblade with respect to the board on the carriage.
This being done without the blade moving other than by hand.
Something is out of alignment and you need to find out what it is before moving on to firing up the saw. IMO and admit knowing but little.

[dgdrls]

CX3 
I would also suggest you actually measure the fast collars
and check the mandrel run-out, as you indicated the saw wobbles and
chatters on the guides.

Dan

[Kbeitz]

CX3 
I would also suggest you actually measure the fast collars
and check the mandrel run-out, as you indicated the saw wobbles and
chatters on the guides.

Dan

I agree with 100%. And if it's out I would find a cross slide off a metal lathe and bolt it fast to the floor
and mill it right.

[CX3]

Well I can assume the problem is collars, mandrel, or bearings. Because the saw wobbles and chatters at running speed.

I have done the test to check for a sprung arbor. And also to check for bad collars. Both seemed to be ok...

Should I put the lead at 1/8" and see what happens?  If it saws better could I live with the chatter?

[CX3]

What is the tool called that I need to check the mandrel?

[beenthere]

Dial indicator.

Such as
http://www.harborfreight.com/1-inch-travel-machinists-dial-indicator-623.html

and a way to hold it steady... some have a magnetic base.

[beenthere]

Well I can assume the problem is collars, mandrel, or bearings. Because the saw wobbles and chatters at running speed.

I have done the test to check for a sprung arbor. And also to check for bad collars. Both seemed to be ok...

Should I put the lead at 1/8" and see what happens?  If it saws better could I live with the chatter?

You may get by with some shortcuts. But seems you would want to know why you have a sawblade 1/2" away from the cut face on gig back. To me (and I'm an amateur), that indicates carriage or track out of kilter with your sawblade.  Diving into your mandrel first may work, may not.
Just trying to help here, not hinder. But you seem quick to jump to conclusions.

[Kbeitz]

You can screw down a small metal plate to stick the Dial indicator on.

https://www.youtube.com/watch?v=JILP_4GJJH0

[CX3]

Ya I'm not usually quick to conclude, but I am ready to solve this problem.

I will go to harbor freight in the morning. Thanks for the links and videos.

[ETSawyer]

You are right about the the board breaking or snapping off at the end of te cut. Tell tale sign a saw is running in and hard which your measuring of the ties shows.  Some saws hammered by a good saw doc will stand up to that kind of abuse but not for long. Four logs and not heating is understandable.
Would look into your collars with a dial indicator and also arbor runout.  A good machinist straight edge to check collars are not flat. You want the saw to be clamped only on the outer edge of the collar so with a straight edge and light you should see the the collar taper in as you look toward the center. Have been told 3-4 thousands taper is what they should be.  Some may say more I'm not claiming to be an expert just from experience finding worn collars.
On your lead I have had a few different saw docs say that lead is very subjective and can change from mill to mill.  If collars and arbor are good, saw is good and bits are good I might look into lead as too much will cause a saw to dive like yours.  Good luck

[beenthere]

CX3 said he had Stan Lunstrum's "Circular Sawmills" pub and such good info is also included in that .pdf

http://www.fpl.fs.fed.us/documnts/misc/circsaw.pdf

[Ron Wenrich]

It sounds like too much lead.  The reason for being 1/2" off on the gig back is that you cut into the log.  I'm assuming you have new teeth.  You can file lead into a saw, if you know how.  1/4" is probably way too much.  I've run at 1/8" or less.  It all depends on the mill or saw. 

How are you setting your guides?  I always set mine with the saw running, but you have to have a bit of experience under your belt to do it.  I had a split guide system where you can adjust either side.  Some mills can only adjust both guides at one time.  I always set my outside guide a bit snug.  If your guides are off, you can push or pull lead.  When you check lead, the guides should be pulled away from the saw.

You're saying that there is no movement in the saw between the guides when you spin by hand.  If I'm reading that right, then your wobble is coming when it is under power.  It wobbles at all rpms?  Have you tried to slow the saw rpm and it still wobbles?  It wobbles at start up?  Are your belts lined up with the power source?

[CX3]

My teeth are nearly new. A head sawyer and saw doc both said teeth and shanks looked good.

I set guides with saw running. Probably the most scary thing known to mankind. They are individually set.

The saw wobbles at any speed. When I near 600 saw  rpm it does stand a bit better but it still wobbles. I tried to video it but you couldn't see it. 

I have spun the saw by hand and cannot seem to find any area of the saw that touches the guides more than others. I mean it may barely touch the guide, but the guides are extremely close when I do this. I did this right after I got it hammered.

I untightened my belts, and ran the saw under no saw load. To make sure the mandrel wasn't being pulled. Saw looked no different.  I believe the belts are tensioned and straight

The saw doc took a straight edge and looked into a light at my outside collar. He showed me the gap and explained how they work. I have not confirmed the inside collar, I don't have a good straight edge.



I am going to harbor freight this morning to get a dial indicator to check runout.

[Ron Wenrich]

How bad is the wobble?  If its not too bad, it probably doesn't make much difference.  Does it wobble in the cut?  Some of this can be controlled with the guides.  I always had my board side guide pretty tight.  Basically, just a bit of light showing through.  Log side was looser.  But, my lead was a light tighter then yours and I had more of a tendency to lead out.  Your saw diving is probably lead or carriage alignment, and has little to do with wobble. 

How do your boards look?  If your saw is diving in, that extra material has to have gone somewhere.  If its consistent through the board, then your saw is cutting pretty good.

Another thing to think about is how far your guides are off the shanks.  I've seen guys that run their guides several inches away from the shanks.  That's too far.  I ran mine about ½" away.  You also don't want your guides touching your shanks. 

[CX3]

Ron, the boards look pretty decent actually. Besides snapping off from too much lead.

The wobble is around 1/4-1/2" each way it's hard to tell. I don't think it wobbles in cut.

I sped the rpm to 2000 on power unit and it made a better difference in the cut. The saw sounded better when cutting. Alot better actually.

My guides may be an inch from shanks.

I got a dial indicator today. But had to push snow tonight for the state so no sawmilling today.

I will check runout, and I am setting the lead at 1/8 and gonna see what happens

[Jeff]

You need to know the rpm at the saw and run it at the speed the saw is hammered for and with the lead set correctly with correctly sharpened teeth or you will always be fighting it.

[CX3]

Jeff what I found was if I started at 2000 rpm on the power, it would drop to a steady 1800 in the cut. This would also allow me to feed properly.

If I start at 1800, I have to feed slower in larger logs, or else my power is at 1500 in the cut.

1800 rpm puts me at 600 on the saw.

Is it ok to saw like this.

[Jeff]

You need to maintain power. If you can't maintain power due to the reason of being under powered, you can't ever make a circle saw cut the way it is designed to. If you are losing power because your saw is not running efficient, then you need to fix what is wrong.

[Ron Wenrich]

You will lose rpm if you're digging into the log because of too much lead.  You will also loose rpm through belt slippage or through feeding to fast.  For example, when your teeth get dull, you'll have to slow down your feed rate.  Feeding too fast will also cause your saw to go off the line of cut.

[Sawmill Man]

 What about engine governer?

[CX3]

 yes it is governed.   I believe its kinda like an old truck it needs a little fire built under it

[CX3]

I just checked the mandrel.  It is within tolerance.

The pillow block bearing nearest the saw is very sloppy. Over 20 thousandths either way. I took all tension off the belts too.

???

[hackberry jake]

Mine started wobbling pretty good last week, but I think we are talking about different animals.


 

[Kbeitz]

Mine started wobbling pretty good last week, but I think we are talking about different animals.


 

You need some silver solder in that crack...

[lewis]

sounds to me that you have too much lead in your saw, also your bearing having slop. I cant remember but I think we used 3/16" lead on a 700 rpm saw or it could have been a starting point

[Jeff]

I would start at 1/32 and move a a 32nd at a time. If you are not sure how to set the lead properly, we can give that info, or point to an old post that has it.

[Jeff]

Here is another topic of the same title.
https://forestryforum.com/board/index.php/topic,70562.0.html

[Gearbox]

I think Jeff is right on also if you can get a hand tach run it on the arbor . engine tach may not be that accurate . What kind of a power unit are you running that drops that much in the cut . If it is a cummins with a PT pump you need to add a MVS governer . Mack is the only road diesel that you operate a PTO without changing anything .

[CX3]

Thanks for all the info guys.

Jeff, I will set lead as shown in the older topic. Thanks.

My power unit is a cummins. Honestly I don't know what engine it is, it's military. The Vin plate is intact and I need to run the numbers to see what I have.

[CX3]

Nobody really said anything about the bearing. Should it be replaced ?  I had to use a 6ft bar to get it to move 25 thou. It is going to be a chore to remove it, someone has welded the collar on the mandrel. So it has to come off the other end 6 rusty feet away lol

[Kbeitz]

Crank up the engine without the blade on the shaft.
Get a roll of plumbers sand paper and get to sanding.

[CX3]

That is exactly what I did. The mandrel is shiny new.

Headed to town now to get new bearings. Hopefully they can press new ones in my blocks.

[beenthere]

CX3
All been very interesting, and hope for the best for you.

Time to put up some pics of your setup, and fixes so we can get a better "picture" (no pun intended) of your mill. Hope that is possible for you to do.

[CX3]

Well the new bearings worked miracles !! It was a decent chore removing the pulley and bearings but we have it up and running.

I cannot figure out how to post pics with my phone. I will get things up and running and put some on here with my wife's computer

[Gearbox]

I have seen 250 cummins in 5 ton crane . I won't even try to explane the govener it is a great gov but not simple .

[CX3]

This engine came out of a military crane

[Gearbox]

That is what I thought . It is a combo of a road speed and crane speed gov. What ever you do to adjust mark where you start so if it doesn't work you can go back to where you started . Also don't let just anyone work on it . That is how I found out about them . This guy got his fingers in it and messed it up then walked saying the pump was bad . Took me 4 hours just to get it to run some what right . There is a plunger on left side top that has 2 nuts that I had to adjust to get it to idle 

[paul case]

Glad to hear you got it up and running.

PC