I am at my wits end

Ernie · June 16, 2009, 11:09:20 PM

This is my mill

It has performed beautifully for a couple of years now. Today while milling 2 X 6 X 16 footers out of Radiata pine the bottom blade started diving down about 3/8 " when I got about 4 feet from the end of the cut and I can't figure out why. I am cutting the boards with the 6 inch dimension flat and the 2 inch vertical when I get the problem. Cutting the other way around everything seems to go OK. What have I missed? >:( Or is my Altzheimers just workin overtime?

Radar67 · June 16, 2009, 11:28:02 PM

Blade heating up from lack of lubricant? Blade not sharp enough? Set off a little?

Just some guesses, sure someone will come along with better info.

Ernie · June 16, 2009, 11:33:16 PM

Good suggestions thanks

Brand new blade got it made up by the local saw doctor who is very good with a great reputation (we exchange a lot of email jokes so I can safely add fantastic sense of humour to his list of attributes) , plenty of water and it cuts the first 12 feet perfectly ??? ???

I see that your age is shown as 143 and here I thought that I was getting old.

fishpharmer · June 16, 2009, 11:39:51 PM

I don't know anything about your type of mill. Or any type for that matter.

It may just be me but it looks like the last couple of feet of the backside rail (guess thats what you call it, near the ground), is elevated a inch or so. Maybe that is causing it.

Just a guess.

My next guess is something heating and expanding.

Does the vertical blade dive too and intersect with the cut of the diving horizontal blade?

Ernie · June 16, 2009, 11:44:16 PM

Thanks fishpharmer

Both blades are very well located relative to each other so they move/dive as a unit. The tracks seem Ok, I have had the mill in the same place for the last year with no problems but, I guess that I'd better go out with my level, if I can find where my sons have hidden / stored/ put it away and check it out.

DanG · June 16, 2009, 11:45:32 PM

Well Ernie, we already knew you were at your wit's end, but we didn't know you were having trouble with the mill, too!

;D :D

The first thing that comes to mind is, how well is the log supported? If there is a pretty good span between supports and it is getting a bit thin, it could be the log moving instead of the blade.

Tom · June 16, 2009, 11:48:43 PM

Ernie,
The blind is leading the blind here. My experience being only with bandmills, I'm quick to put a blade problem in the back seat if the diving is taking place in one place. It might be a band following the grain, but I don't know if a circle mill does that.

Before I attacked a problem with the mill, Iwould look into the possibility of the cant moving. If you are relieving stress the cant might rise, giving the impression that the blade is diving. I've had gummed bands do that too. They will actually lift the cant off of the bed of the mill.

John Woodworth · June 17, 2009, 12:07:58 AM

How is your lead adjustment? you might be too flat and by the time you get part way through your blad is starting to heat up.

Ernie · June 17, 2009, 12:10:37 AM

Thanks DanG and Tom

I passed my wits end years ago, I just forgot that oops that's another problem.

I was just taking the first cuts off the top of the log which is sitting, well blocked, on the ground. it is the butt log end of an 80 foot log with the rings nicely centered at both ends and dead straight about 3 feet in diameter. I get a lot of stresses in the Eucalyptus logs but have never had any in my pines, they grow nice and straight-- I'm really spoiled there ;D

Ernie · June 17, 2009, 12:13:47 AM

Quote from: John Woodworth on June 17, 2009, 12:07:58 AM
How is your lead adjustment? you might be too flat and by the time you get part way through your blad is starting to heat up.

Lead adjustment?????? Too flat????? these are terms that I have never come across or maybe it's my memory. Do these terms apply to a twin saw circle mill?

DanG · June 17, 2009, 12:35:55 AM

I do have to adjust the lead in my edger blades from time to time, Ernie. If I don't have about 1/64" lead, it will tend to climb. However, it is over the whole length of the log. What you're describing though, sounds more like the log rather than the mill causing the problem. From what I've seen, your Radiata is much like an open-grown Loblolly Pine, with widely spread growth rings, and vast difference in hardness between the early and late wood. I frequently find a different grain pattern in the bottom few feet of a butt log, which can play havoc with the sawing, or in the drying. If there is a bit of flare at the butt end, that sweep in the hard late wood is sometimes enough to lift the saw and cause a miscut board. It always seems to happen when making a wide horizontal cut, with only gravity holding the saw down.

boardum · June 17, 2009, 03:35:14 AM

Ernie,
Everyone here is giving good advice, yes lead is everything in circle saw milling. But also try a different blade and see what it does. There are many times even with the best shops that a saw may still have a problem. This is at least an easy elimination.
Secondly, are you sure your bearing are in good shape. Not yours, the ones on the mill.

just_sawing · June 17, 2009, 07:07:23 AM

Been there and found that the Saw Shop had used a slightly thinner Carbide tooth. It was also wide enough. Changed teeth and all was well.
It totally amased me that thousands of an inch made a difference.

Fla._Deadheader · June 17, 2009, 08:05:56 AM

When I have that problem, it's nearly always the log relieving the stress. Everything I saw grows on hillsides, and it is ALL stress.

First I would check the rails for parallel-ness. Is that a proper term ???

Then, after I push-backup, push-backup. however many times it takes, to get the board loose from the log, I immediately go back for a skim cut, without moving the sawhead in either direction. That shows me if it is the log or something else has gone wacky.

beenthere · June 17, 2009, 10:24:21 AM

Quote from: just_sawing on June 17, 2009, 07:07:23 AM
Been there and found that the Saw Shop had used a slightly thinner Carbide tooth. It was also wide enough. ............

Missed what was meant here. ??

John Woodworth · June 17, 2009, 11:53:29 AM

Ernie, lead is the tipping of the blade into the wood. With 0" at the leading edge measure the distance between the bottom of trailing edge. I'd check the adjustments first before changing blades or teeth on a system that worked before.

DanG · June 17, 2009, 11:58:16 AM

I agree with checking the adjustments first, but I would try a different log before changing anything.

Fla._Deadheader · June 17, 2009, 03:03:03 PM

Quotelead is the tipping of the blade into the wood

He said it cuts good for 10' or so, then starts going south ???

My Peterson has very minimal lead. None going forward and minimal going side to side.

Jeff · June 17, 2009, 03:37:10 PM

I don't think lead is such an issue with a swingmill like it is with the typical circle mill. Sounds like a log problem to me, not a mill problem.

Ernie · June 17, 2009, 03:54:31 PM

Thanks for all the advice guys. Once the sun comes up and my lubricating water thaws out I think that I will change the log and see what happens. I still haven't found where my boys have hidden/left/forgotten my level but a skim cut stays level and gives me a good true surface for the next cut. ???

Fla._Deadheader · June 17, 2009, 06:17:33 PM

How about if you just flip the log. Is that possible ?? You may have already relieved the stress, IF that was the cause.

karl · June 18, 2009, 07:48:16 PM

I vote for stress in the log, assuming that the bits are good.
I usually encounter that in the butt end of log. I'm using an MD, but I think the systems must have the same issues when the saw is in the log....