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New member with long story already.

Started by kajtek1, March 18, 2010, 09:53:04 PM

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kajtek1

Hi everyone.
I am new to milling and it is side job or hobby for me at the time. I am in process of building new structure in San Francisco Bay Area mountains. To make space for the structure I had to cut 120' tall redwood.
So having the very nice log I tried to mill it with Alaskan mill attached to Stihl chain saw.
Very fast I realized that milling whole log with this equipment would take me about 1/2 a year, so I bought old sawmill mounted on  trailer.
So far nobody can figure out what sawmill it is. It could be home made, but it does have industrial quality 2-speed electric feed. It is using Lucas double blades, so it could be very old Lucas.
Anyway, in my other life I was working as industrial mechanic, so fixing bearings and switches is not a problem for me.
After few try by errors control runs, I was able to mill about 1 ton of very nice 1x8" siding and than the disaster strike. Right in the center of 40"dia log, the saw hit steel. It cut 1/4" round stock couple of times with me not noticing it, than chunk of heavier steel destroy the blade. I start chiseling the steel from the log and was quite surprised to dig out 8" dia rope pulley. Picture below. So my guess is, that couple generations ago the residents at the property had a cloth rope hand between the house and the tree and they put heavy spikes into the young tree. Over the years the wood grew up around the spikes and attached pulley.
Now comes my real headache. I got new blade and can't make the mill working again.
Any change in wood consistency will kick the blade out of balance and make it dive.
Don't laugh if I don't use the right description. I was born Polish and this is new trade for me, so I don't know proper names for all the stuff I have.
So far I think the main difference was, that the log I was cutting so nicely was pretty wet and consistent, that what made it easier. Now I have dry wood with very hard knots. If I run the mill on low speed cutting 6" and put lot of water on clean blade -it will go straight most of the time, but any knot will make the blade overheat, than dive and start burning the wood.
Can anybody help me with tips how to set the thing right?





stonebroke

Welcome to the Forestry Forum.
Stonebroke

PineNut

Welcome to the forum Kajtek1. Beautiful lumber except for the bad spot that did you in. I wish I could help you with you mill problems but that is out of my area. But I am sure that there are members here that can supply you with help. There is a lot of experience here and many people ready to help.

fishpharmer

Kajtek1, welcome to forestry forum.  You have come to the right place for answers.  Although I really don't know for sure, I will give a pure guess based upon my table saw experiences.  It almost sounds like a dull blade or the arbor has a misalignment.  Maybe shock of the metal collision altered the arbor or the bearings or gearbox that holds the arbor.  It may be ever so slight that it only gets out of balance under a very heavy load. Just a guess. 

And nice lumber and neat looking mill too.
Built my own band mill with the help of Forestry Forum. 
Lucas 618 with 50" slabber
WoodmizerLT-40 Super Hydraulic
Deere 5065E mfwd w/553 loader

The reason a lot of people do not recognize opportunity is because it usually goes around wearing overalls looking like hard work. --Tom A. Edison

kajtek1

Thanks for the welcome. I do have minimal play on the bearing, but I remember having some before. Can't say for sure if it got worse.
Could minimal play in the bearing have such big effect? Per my observation it is the blade that twists out of flat and dances off the cut line.
I have 1 new blade and 1 repaired in proffesional shop. Both do the same.

Tom

Welcome to the forum.

Too bad about the metal in the log, but that is the heartache that comes with saw-milling.  I've cried over it too.

If this is a bandmill:

What you describe about the problem with your band is what would happen with a thin kerf band that didn't have enough "set". That is, it wasn't cutting enough wood to allow for the passage of the band.  When you do this, the band rubs and heats and also tends to follow the grain.

The Kerf is controlled by the set (bending teeth from one side to the other), or swaging (spreading the face of the tooth so that it is wider than the band body)  

The other thing that will cause this problem is band tension.  too loose of a band and it will wander and do all kinds of unpredictable things.

I wish I could see a picture of your saw.  It sounds a bit like a Povlsen, made in British Columbia.  I don't know if Paul Povlesn is still in business or has sold out. He was making mills in 2000 that used a 3", double edged band and was basically a hydraulic mill. http://www.timber-pro.com/products.html

You mention that it might be an old Lucas.   So, it's a swing mill, or double bladed mill, like a mobile dimension?

In that case, you will have to wait on the circle saw guys.  I can't see the head of the mill's detail and honestly thought it was behind the camera somewhere.

Ah well. :-\

sgschwend

You changed the saw and it does cut right.

Sounds like a problem with the new saw.

Welcome to the forum, post some more pics of the machine, we would all enjoy seeing it. ;)
Steve Gschwend

sjgschwend@gmail.com

kajtek1

http://www.youtube.com/watch?v=fd4xeG9Hslo
Here is the video of the saw when it was cutting well. It is powered by 25 HP Kohler and is having gear box with shafts coming at 90 degrees. It is not a swing saw.
I am not sure how can I tell the bad blade? I could have doubts about the repaired one, but the new one looks pretty well, yet it dives on too many occasions.

Tom

Yep.  That's a double blade saw OK.   I was really out in right field.  We do have double blade owners here that might help though.   

jdrum

  check to see if the blade is parraell to the line of cut (front of blade and back of blade same higth above a previouse cut, then clamp a block on to the log and push the front of the blade against the block with some force and check again. if there is much deflection under load it could be pushing the back of the blade up aginst the top board and over heating the blade.
  what side was getting burned, the board or the log.
  a little bit of play in a short abor can add up to a lot at the rim of a saw blade.
  we had a similar porblem wit a 12" table saw and it took new berrins a nd realinement to fix it.
this may not help at all but it is a direction to look.

jim

DanG

Welcome Kajtec1!  I have a Mobile Dimension saw and have encountered somewhat similar problems in cutting dried out pine logs on occasions.  I've also had heating problems cutting Red Cedar, but that was attributed to dull teeth.  I can't watch the video so I haven't really seen your blade setup.  Are both blades the same size?  Are they both following the grain, or just the horizontal one?  Are your blades sharpened properly?  The edges need to be exactly perpindicular to the blade, and the corners of the teeth must be sharp and not rounded at all.  I'm going to guess that it is the horizontal blade giving the trouble, and suggest that you put a tiny bit of lead into it.  In other words, adjust the shaft such the the front or leading side of the blade is very slightly lower than the trailing side...like 1/64 of an inch.  Also, things just seem to work out better if you are entering the log from the small end.  That way, the grain of the wood, and the angle of the knots are tending to push the saw away from the log, while the natural tendency of the saw is to pull toward it.  As much as you can, try to orient the boards vertically rather than horizontally, if just to see if you have the same problem.

With all that being said, it could just be that particular log, and it might work differently on the next one, even if it's from the same tree.  Good luck, and keep us posted on your progress.  I'd really like to see some still pics of the saw itself.
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

ErikC

 I don't have a dimension mill, but the blade on swingmills is similar. I think 25 hp is a little underpowered for a twin blade saw, so if things are a little out of whack, it will really show. It takes so little lead in a sawblade to mess things up you won't believe it, so really make sure on that. If you had a problem that caused a blade to get hot, it may be that you got a wobble from that, and when you load it down it really shows. You are feeding slow, and that can cause excess heat buildup as well. It's a downward spiral :-\.  I have not seen a mill like yours before, I hope someone can id it for you. For all of us. ;D
Peterson 8" with 33' tracks, JCB 1550 4x4 loader backhoe, several stihl chainsaws

Captain

Which blade is the problematic one?  The horizontal or the vertical?

Captain

bandmiller2

KAJ,welcome,you were cutting fine before hitting the tramp metal, after problems.Sounds like you knocked the horizontal blade out of adjustment,as you say its diving.I don't recognize the mill brand probibly homemade hybred of a MD and Lucus.Anyone clever enough to build it would have an adjustment for the horiz. blade,if its diving the nose is down too much. Frank C.
A man armed with common sense is packing a big piece

thecfarm

kajtek1,welcome to the forum.Good pictures and good job explaining your problem.We won't laugh at you when you are trying.We may point you in the right directions and ask more questions.I would like to see more pictures of your sawmill too.We are a real helpful bunch here,as long as you don't try to change the place on your first day here.  :(
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

TwinCut

Well I'm no real expert, but here's what I have learned. Just because a saw is new doesn't mean it will run perfectly for your mill. I had the same kind of issues with our mill until I found a good saw shop. It turned out the saws needed to be hammered for true and for operating RPM. Without the right tension in the center and rim of the saw, centrifugal force can make it do funny things. The other thing to check is how its mounted, I assume you have counter sunk bolts attaching the blade. Make sure the bolt pattern is exact, if it's not, you could be putting unwanted tension in the blade.

Chuck White

Kajtek1, welcome to the Forestry Forum.
Lots of good people here, good info too.

I don't know much about the type of mill that you have.
I do have a question though.  You said that the blade dives.
Now, the blade cuts while going either direction, but,
does the blade dive in either direction, or just while going in one specific direction?

Might not be much info, but it could help too!
Good luck getting the mill going again.
~Chuck~  Cooks Cat Claw sharpener and single tooth setter.  2018 Chevy Silverado and 2021 Subaru Ascent.
With basic mechanical skills and the ability to read you can maintain a Woodmizer  LT40!

Magicman

I know nothing about your mill, but I know about Metal.....Welcome to The Forestry Forum..... 8)
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

kajtek1

Yeah. I spend way more years working with metals than with the wood as well.  8)
Thanks for all new info that come.
To answer new questions. The bigger horizontal blade is 21.5" while the vertical blade is about 14' although I never had a problem with this one and didn't really measure it.
The horizontal blade has countersink bolts, so it can be moved sideways over cut log. Bot blades cut along the grain, but right now I am cutting 1x8 siding, so the vertical blade doesn't work much.
I did play with adjusting the lead tens of times and it is no use. With the same setup the blade can once go down and another time up. Most of the time it is bottom of the blade that touches the wood and overheats, but occasionally it happens to the top as well.
Bottom line it is very unpredictable. One blade is new and the other is professionally repaired, so I am pretty sure they are not the problem here, although I will double check it.
At this point from all the replies I take that the bearing play might be the issue here.
Time to use my mechanical skills and take the gearbox apart.
Thanks for the help.

Captain

don't discount the blade tilt left and right as well as front and back.  the blade should be 1 to 1.5 mm lower on the right than the left.  this to properly clear the previously cut face.

kajtek1

So we have different opinions already.
1/64" lead =0.4 mm
second opinion is 1-1.5mm.
http://www.senecasaw.com/docs/0310forum.pdf I found link on parallel topic saying 1/32 to 3/32".
I am still trying to determinate how critical is bearing play. There is no way to avoid some play even with new bearing and I keep the bearing well lubricated, so the steel incident not likely transferred to bearing wear out. Still I am planning to take the gear box apart this coming week.
The article also uses a term I don't understand.
What is "gig back"?

ErikC

 No difference of opinion really.DanG mentioned lead-front to back adjustment. Captain mentioned left to right adjustment. Ideally my saw will lead a slight amount as well as be slightly canted to the right. So the lowest point on the blade is the right front quadrant. This is very slight obviously, as they both indicated. Looking at the video and what your cutting pattern is, your horizontal blade should be the same.  :)
Peterson 8" with 33' tracks, JCB 1550 4x4 loader backhoe, several stihl chainsaws

DanG

Also, my horizontal blade is only 12.5" dia.   Your 21" probably needs a little more. ;)  I don't know that left/right lead would affect climbing and diving.  I'm still unclear if all this problem is on one log or different logs.  How thick is your blade, and what is your kerf width?  Mine is a 12.5" diameter, 10ga. blade with ΒΌ" inserted teeth.
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

ARKANSAWYER

  I would not be surprised to find the new blade not hammered right.  The blade you trashed may have been hammered for the mill while the new one is not right.  My WM edger got a board hung in it and the blade got a burnt spot on it.  After it was freed up it would not saw right so I sent the blade out to be sharpened.  It did not cut right when it got back.  I had to send it off and have it rehammered to 3000rpm and it now cuts fine.  Any circle blade needs to be hammered to the right tension for the rpm it will be running to run true.
  Welcome to the forum and maybe you will get that saw cutting true and get some lumber made.
ARKANSAWYER

kajtek1

So I gave it one more try and set the lead at 1/16" I have no side to side adjustment.
Both big  blades dove when I swap them. They would go straight till they hit hard knot, than blade starts vibrate, deflect and all goes out of line.
I measure the bearing play and it come to less than 1/32" at the end of the blade, so I don't think it is a big problem. I took the bearing out and will get a new one.
The blade has tooth less than 1/4" wide
Here is a picture of the blades and gear box. More in my album.


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