Circle saw headrig problems

[Robert.schade]

I am having problems with my circle saw at a new job and the problem is when the saw is running it "flutters". As it rotates the saw flutters and bounces of both of my front guides. The saw still cuts but the boards are coming out thick and saws don't last long at all. Any help would be great! https://youtube.com/shorts/an1Jin7WqAI?si=UTBG550B8D8LbQ9B

[mudfarmer]

Nice looking setup.

Wrong speed, something bent, needs hammered, someone that knows stuff will likely be along soon to help. I see back in August you were having problems with the saw heating up, did you get that resolved and if so what was the problem? Was the fluttering happening back then too?

[Robert.schade]

That was a complete different set up in Wisconsin and they still have not figured it out. My current setup is in North Carolina and is a lot more simple of a setup. Same thing happens with multiple saws. I was figuring it was something on the setup. Thanks for a quick response!

[longtime lurker]

That type of fault with one saw is probably a saw issue.
That fault with multiple saws is probably a shaft bearing going, less likely a bent shaft or the mandrel is out of alignment. A laser level or straight edge along the shaft, saw off and spun by hand, would be a quick fault diagnosis tool.

[Gearbox]

saw speed is the main cause of wobble . if your diesel powered speed it up until it stands up. I ran one that everyone insisted it was hammered for 500 it didn't stand up until 600 . I had a 4 71 Detroit on that one it wood produce some lumber 

[moodnacreek]

So if all the saws do it... where they all hammered by the same guy? Probably not the saws.  Turn the mandrel by hand with a dial indicator rubbing the outer contact area of the tight collar. Should not be more than .002 wobble.  Something out of balance on the mandrel or drive can do this or something loose. Does it flutter at slow speed when coasting down to a stop? How about cold versus been run for awhile. How about if the guides are pulled back so they don,t touch the saw.  I had 3 saws do this and they where all bent from big slabs hitting them. When did this start and what happened to cause it?

[DanielW]

Dialing the collar would be the first step. It's a little hard to tell from the video, but that looks like an unusually thin-gauge saw. Not the typical 7/8 or 8/9 you see on conventional headrigs. We've done a few circular headrigs with thin-gauge saws, sometimes with carbide brazed teeth. It's possible to get them to work, but always a bit of a struggle. Until you go with a full guide system (water-oil pressurized guides), those thin saws can be hard to stabilize. If it's a conventional hammerman doing the tensioning, he might not be familiar with how strugglesome these ones can be to get right. Is that flutter happening after it's cut a few boards, or is it like that right from the get-go? If you collars are ok and it's like that (or gets worse) after cutting, it looks like a tension problem.

The hammering/tensioning of a saw is primarily to counteract the strain when the saw enters the cut: The rim stretches due to cutting forces. The metal is still within its elastic zone so you don't get permanent deformation, but it certainly does stretch. A smaller (much smaller) proportion of the tensioning is to counteract the centrifugal forces from running at speed, but these forces are minimal compared to the cut forces. Back in the day, folks assumed the centrifugal force was the primary concern, but this isn't true. The hammerman needs to apply residual stresses to counteract the cutting stretch and make sure the plate stays in-plane. Speed and feed make a difference in hammering: Higher rpm with the same feed will result in less rim strain. Lower rpm with faster feed will result in higher rim strain. Gullets improperly sized can lead to a boat-load of strain (and many other problems). A lot of hammermen only ask for RPM and right/left hand, because feed rate often doesn't vary too much in most headrigs. There are several exceptions however: One exception is sharp-chain and canter systems which can really boogey. Another exception is the old handset farmer mills like the Belsaws which have a very slow feed rate. Good hammermen will take these factors into account in addition to RPM.

When you get into thinner gauge saw plates and different teeth, the conventional rules go out the window. Brazed teeth don't impart the same stresses in the rim that conventional inserted shanks do (this is important if you're running conventional inserted teeth - make sure you have a full set of shanks. Some folks remove every other bit to save power on slower feeding units, but you need to still have the shanks and dummy bits in there).  Smaller tooth pitch and gullets will really change the rim stresses. Some of the thin kerf units really wind up the RPM vs. feed ratio, which may lower the rim stretch when in the cut, but exacerbate the centrifugal strain. When you get into thinner plates, getting rid of any ridges is much more critical. All hammermen get rid of ridges/lumps, but few get it absolutely perfect. It's no fault of theirs: most of the time it's not necessary to get it 100% perfect. You can put a fair pit of hammering/rolling into a thicker plate to account for high cutting stresses before you start influencing its free-running condition. With a thinner plate, every little bit of tension you add is going to influence the free-running condition to some degree. It takes a good hammerman and a lot of trial/error to account for all these factors in an unconventional saw plate.

So: Start with dialing the collars, but if that all looks good, let us know a few more spec's: Plate thickness, RPM, tooth type/profile, collar condition/profile/taper, who/how it was tensioned, etc.

Also, after you shut down (assuming you're able to cut with it), feel the saw. See if it's hot towards the rim, hot towards the eye, hot all over, or not hot at all. That'll tell you a lot about how the tension's behaving.

Good luck with it. I hate circle headrigs next to clearing belts like you have there. A tiny bit of wobble and suddenly you've hit the belt frame and send shrapnel everywhere. If you don't have a rear guide on there to prevent contact with the belt when the saw goes snaky, you should really add one. Just make sure it doesn't influence the saw during normal operation - set it a good 1/8" away from the saw's nominal running position. Because it's not there to guide the saw it doesn't have to be phenolic - you can use UHMW (or even wood).

As a final note: It doesn't hurt to put a tach on the arbor. You'd be surprised at what a little belt slip can do, or what can happen if some maintenance chap on night shift swapped out one of the belt sheaves to one that was 'almost' the same size.

[Robert.schade]

So if all the saws do it... where they all hammered by the same guy? Probably not the saws.  Turn the mandrel by hand with a dial indicator rubbing the outer contact area of the tight collar. Should not be more than .002 wobble.  Something out of balance on the mandrel or drive can do this or something loose. Does it flutter at slow speed when coasting down to a stop? How about cold versus been run for awhile. How about if the guides are pulled back so they don,t touch the saw.  I had 3 saws do this and they were all bent from big slabs hitting them. When did this start and what happened to cause it?

It flutters way worse when slowing down especially the back of the saw. It will do it first thing in the morning and constantly flutter like that. The guides are spaced as well as I can because it bouncing off both of them. All my saws come from one guy hammering.

[melezefarmer]

snip

Thank you DanielW. Your post is why the internet is awesome; sometimes one stumble onto nuggets of priceless knowledge and the lifetime and experience required to acquire said knowledge.
cheers

[beenthere]

 All my saws come from one guy hammering.

Have you talked with your hammering guy about the problem? Have you changed rpm to see if higher or lower makes a positive correction? 

[Don P]

Also unbolt the saw, turn the arbor 180° and put the saw back on. Is the problem identical?

[moodnacreek]

Is it running too slow? If engine driven this would be easy to check. One time i was so frustrated  i took the saw to another mill to test it there. Those point and click thermometers are great. The saw bearing has to warm some after running awhile and that warmth can migrate into the collar and in turn warm the saw plate in that collar area. Many times this happens after the bearing has been greased. Saws can be hammered for this but less and thinner grease is the thing to try. Some saw will go into a fit with a 5 degree difference between the collar area and the rim just below the guide line.

[moodnacreek]

Dialing the collar would be the first step. It's a little hard to tell from the video, but that looks like an unusually thin-gauge saw. Not the typical 7/8 or 8/9 you see on conventional headrigs. We've done a few circular headrigs with thin-gauge saws, sometimes with carbide brazed teeth. It's possible to get them to work, but always a bit of a struggle. Until you go with a full guide system (water-oil pressurized guides), those thin saws can be hard to stabilize. If it's a conventional hammerman doing the tensioning, he might not be familiar with how strugglesome these ones can be to get right. Is that flutter happening after it's cut a few boards, or is it like that right from the get-go? If you collars are ok and it's like that (or gets worse) after cutting, it looks like a tension problem.

The hammering/tensioning of a saw is primarily to counteract the strain when the saw enters the cut: The rim stretches due to cutting forces. The metal is still within its elastic zone so you don't get permanent deformation, but it certainly does stretch. A smaller (much smaller) proportion of the tensioning is to counteract the centrifugal forces from running at speed, but these forces are minimal compared to the cut forces. Back in the day, folks assumed the centrifugal force was the primary concern, but this isn't true. The hammerman needs to apply residual stresses to counteract the cutting stretch and make sure the plate stays in-plane. Speed and feed make a difference in hammering: Higher rpm with the same feed will result in less rim strain. Lower rpm with faster feed will result in higher rim strain. Gullets improperly sized can lead to a boat-load of strain (and many other problems). A lot of hammermen only ask for RPM and right/left hand, because feed rate often doesn't vary too much in most headrigs. There are several exceptions however: One exception is sharp-chain and canter systems which can really boogey. Another exception is the old handset farmer mills like the Belsaws which have a very slow feed rate. Good hammermen will take these factors into account in addition to RPM.

When you get into thinner gauge saw plates and different teeth, the conventional rules go out the window. Brazed teeth don't impart the same stresses in the rim that conventional inserted shanks do (this is important if you're running conventional inserted teeth - make sure you have a full set of shanks. Some folks remove every other bit to save power on slower feeding units, but you need to still have the shanks and dummy bits in there).  Smaller tooth pitch and gullets will really change the rim stresses. Some of the thin kerf units really wind up the RPM vs. feed ratio, which may lower the rim stretch when in the cut, but exacerbate the centrifugal strain. When you get into thinner plates, getting rid of any ridges is much more critical. All hammermen get rid of ridges/lumps, but few get it absolutely perfect. It's no fault of theirs: most of the time it's not necessary to get it 100% perfect. You can put a fair pit of hammering/rolling into a thicker plate to account for high cutting stresses before you start influencing its free-running condition. With a thinner plate, every little bit of tension you add is going to influence the free-running condition to some degree. It takes a good hammerman and a lot of trial/error to account for all these factors in an unconventional saw plate.

So: Start with dialing the collars, but if that all looks good, let us know a few more spec's: Plate thickness, RPM, tooth type/profile, collar condition/profile/taper, who/how it was tensioned, etc.

Also, after you shut down (assuming you're able to cut with it), feel the saw. See if it's hot towards the rim, hot towards the eye, hot all over, or not hot at all. That'll tell you a lot about how the tension's behaving.

Good luck with it. I hate circle headrigs next to clearing belts like you have there. A tiny bit of wobble and suddenly you've hit the belt frame and send shrapnel everywhere. If you don't have a rear guide on there to prevent contact with the belt when the saw goes snaky, you should really add one. Just make sure it doesn't influence the saw during normal operation - set it a good 1/8" away from the saw's nominal running position. Because it's not there to guide the saw it doesn't have to be phenolic - you can use UHMW (or even wood).

As a final note: It doesn't hurt to put a tach on the arbor. You'd be surprised at what a little belt slip can do, or what can happen if some maintenance chap on night shift swapped out one of the belt sheaves to one that was 'almost' the same size.

I cut a notch in the steel on the off bearer so the saw teeth will miss the steel in a wreck, the saw plate could rub however.

[moodnacreek]

Went back and looked at the video. That is such a common problem. It seems to me that most saws do that although that one is a little too much.  The thing is that once you run a saw that stays flat and does not bounce in the guides you hate the others. I had one hammer man that could fix that most times but he has passed. The man was a hardwood sawyer who retired into saw hammering. He only had an anvil, hammers and straight edges. He welded shoulders with a torch. A real craftsman.

[Gearbox]

Your not that far from Rice Blacksmith in Rice MN just west of St Cloud . Those guys been hammering saws for at least 2 generations . They can help over the phone . 320 393 2169 tell them Bob Pittack says helo

[beenthere]

And Menominee Saw is a Forestry Forum sponsor.. helping to keep this forum alive. Lest we not forget.  Please.

It's 100 miles closer than Rice, MN, just sayin...

[Robert.schade]

Dialing the collar would be the first step. It's a little hard to tell from the video, but that looks like an unusually thin-gauge saw. Not the typical 7/8 or 8/9 you see on conventional headrigs. We've done a few circular headrigs with thin-gauge saws, sometimes with carbide brazed teeth. It's possible to get them to work, but always a bit of a struggle. Until you go with a full guide system (water-oil pressurized guides), those thin saws can be hard to stabilize. If it's a conventional hammerman doing the tensioning, he might not be familiar with how strugglesome these ones can be to get right. Is that flutter happening after it's cut a few boards, or is it like that right from the get-go? If you collars are ok and it's like that (or gets worse) after cutting, it looks like a tension problem.

The hammering/tensioning of a saw is primarily to counteract the strain when the saw enters the cut: The rim stretches due to cutting forces. The metal is still within its elastic zone so you don't get permanent deformation, but it certainly does stretch. A smaller (much smaller) proportion of the tensioning is to counteract the centrifugal forces from running at speed, but these forces are minimal compared to the cut forces. Back in the day, folks assumed the centrifugal force was the primary concern, but this isn't true. The hammerman needs to apply residual stresses to counteract the cutting stretch and make sure the plate stays in-plane. Speed and feed make a difference in hammering: Higher rpm with the same feed will result in less rim strain. Lower rpm with faster feed will result in higher rim strain. Gullets improperly sized can lead to a boat-load of strain (and many other problems). A lot of hammermen only ask for RPM and right/left hand, because feed rate often doesn't vary too much in most headrigs. There are several exceptions however: One exception is sharp-chain and canter systems which can really boogey. Another exception is the old handset farmer mills like the Belsaws which have a very slow feed rate. Good hammermen will take these factors into account in addition to RPM.

When you get into thinner gauge saw plates and different teeth, the conventional rules go out the window. Brazed teeth don't impart the same stresses in the rim that conventional inserted shanks do (this is important if you're running conventional inserted teeth - make sure you have a full set of shanks. Some folks remove every other bit to save power on slower feeding units, but you need to still have the shanks and dummy bits in there).  Smaller tooth pitch and gullets will really change the rim stresses. Some of the thin kerf units really wind up the RPM vs. feed ratio, which may lower the rim stretch when in the cut, but exacerbate the centrifugal strain. When you get into thinner plates, getting rid of any ridges is much more critical. All hammermen get rid of ridges/lumps, but few get it absolutely perfect. It's no fault of theirs: most of the time it's not necessary to get it 100% perfect. You can put a fair pit of hammering/rolling into a thicker plate to account for high cutting stresses before you start influencing its free-running condition. With a thinner plate, every little bit of tension you add is going to influence the free-running condition to some degree. It takes a good hammerman and a lot of trial/error to account for all these factors in an unconventional saw plate.

So: Start with dialing the collars, but if that all looks good, let us know a few more spec's: Plate thickness, RPM, tooth type/profile, collar condition/profile/taper, who/how it was tensioned, etc.

Also, after you shut down (assuming you're able to cut with it), feel the saw. See if it's hot towards the rim, hot towards the eye, hot all over, or not hot at all. That'll tell you a lot about how the tension's behaving.

Good luck with it. I hate circle headrigs next to clearing belts like you have there. A tiny bit of wobble and suddenly you've hit the belt frame and send shrapnel everywhere. If you don't have a rear guide on there to prevent contact with the belt when the saw goes snaky, you should really add one. Just make sure it doesn't influence the saw during normal operation - set it a good 1/8" away from the saw's nominal running position. Because it's not there to guide the saw it doesn't have to be phenolic - you can use UHMW (or even wood).

As a final note: It doesn't hurt to put a tach on the arbor. You'd be surprised at what a little belt slip can do, or what can happen if some maintenance chap on night shift swapped out one of the belt sheaves to one that was 'almost' the same size.

I will be able to answer this in full detail on Monday. But as of today we looked at the pins that go inside the collar and they keep getting worn within a month and are getting decent wear on them. Thanks for the super detailed response! Unfortunately I'm very busy sawing during the week but I'm going in early Monday to check as many of the things I can that you mentioned!