Saw wobble

beenthere · February 12, 2016, 05:59:43 PM

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 · February 12, 2016, 06:20:21 PM

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 · February 12, 2016, 06:44:24 PM

Quote from: dgdrls on February 12, 2016, 06:20:21 PM
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 · February 12, 2016, 07:37:43 PM

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 · February 12, 2016, 07:41:21 PM

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

beenthere · February 12, 2016, 07:47:45 PM

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 · February 12, 2016, 07:55:16 PM

Quote from: CX3 on February 12, 2016, 07:37:43 PM
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 · February 12, 2016, 08:02:01 PM

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

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

CX3 · February 12, 2016, 08:16:14 PM

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 · February 12, 2016, 11:03:33 PM

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 · February 12, 2016, 11:46:31 PM

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 · February 12, 2016, 11:51:27 PM

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 · February 13, 2016, 08:24:08 AM

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 · February 13, 2016, 09:43:06 AM

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 · February 14, 2016, 12:53:52 AM

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 · February 14, 2016, 09:36:51 AM

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 · February 14, 2016, 04:52:46 PM

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 · February 14, 2016, 06:02:28 PM

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 · February 14, 2016, 06:47:17 PM

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 · February 14, 2016, 10:06:26 PM

What about engine governer?

CX3 · February 15, 2016, 11:29:50 AM

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

CX3 · February 15, 2016, 01:40:18 PM

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 · February 15, 2016, 02:57:23 PM

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

Kbeitz · February 15, 2016, 03:36:44 PM

Quote from: hackberry jake on February 15, 2016, 02:57:23 PM
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 · February 15, 2016, 04:03:55 PM

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