Semi-emergency, need tips for straight lumber

[canopy]

I am getting some teak logs milled into lumber for a house frame in Thailand. I don't know much about milling, but I notice the boards coming out of the mill are not straight. By that I mean they vary in thickness and straightness along the length. Below is a video of their process making a board. Any suggestions on anything that could be incorporated into their mill that would straighten things out? The longest lumber will be 20'.

http://youtu.be/pGUTWl4bCQ8

[mikeb1079]

i can't get the video to work.   :(

[POSTON WIDEHEAD]

i can't get the video to work.   :(

You're right. It says VIDEO UNAVAILABLE.

[drobertson]

It looks like to me the log is floating through the cut too much, some things need to be added to hold the log fixed while going through the blade for at least a straighter cut,   almost looks like a carraige will be needed to hold the log.   

[ElectricAl]

They need a longer fence to put the flat face against.
Real easy to get Thick & Thin lumber the way they are doing it.

[Chuck White]

Longer fence and longer bed.

It's the only way I can visualize any improvement.

The log has to be fed straight through the blade.

Welcome to the Forestry Forum, Canopy.

[Magicman]

Lowering that top blade guide may help, and the blade's sharpness is only a guess.

[mikeb1079]

of course they're getting thin and thick lumber.  they're feeding the log thru mostly by hand, like how you use a shop bandsaw, only they're trying to do it with logs.  as has been said if it's gotta be done this way improve the fence drastically and/or add some type of adjustable hold down to keep the log tight to the fence.  it really needs a proper carriage tho...

[Ianab]

Not really sure how you are going to get straight boards out of that set up  ???

Any real sawmill relies on some sort of rails to either move the log past the saw, or the saw head past the stationary log. The rails provide your straight reference point to get straight boards. With that mill the only thing providing straight boards is the eye of the guys pushing the log though. They have a small fence to set the width of the board, but if you feed a banana in, you will get 2 bananas out. Likewise if the log drifts away from the fence due to grain, tension, knotsm dull blade etc, there is nothing to stop this.

What it really needs is a major redesign to incorporate some sort of carriage and clamp system to hold the log and guide it though the saw. Then you can worry about blade guides, sharp bands, feed rates etc to get the cut perfect.

But if you look at ANY proper sawmill system, there is some reference "rail" there some place. Even if it's a chainsaw mill running on a 2x4, that 2x4 is the straight edge that lets you create a straight board.

Ian

Edit Mike bet me too it with the comment about needing a proper carriage to hold the log.

[beenthere]

I wouldn't be surprised if they are not fighting a dull saw as well as one with teeth that need setting.

[canopy]

Sorry the video took a while to get squared away and thanks for all the quick replies. I've got one more day before I go back there and have the chance to propose a better strategy. Are there any photos / videos or even just a good description of a fence that might be practical to construct for this? How long a fence would be needed to support up to 20' long logs up to 20" in diameter on the input & output sides? Will be making 3 sizes of lumber: 6x6, 6x7 and 6x8".

[5quarter]

Are those your logs in the video? aside from all the good advice above I would add that there is nothing that they can "fix" on that set up to improve their quality. Get your logs out of there if you can and find another mill. Perhaps even buy your own? BTW...Teak is hard on blades even with a good setup.

[barbender]

How in the world are they going to mill a 20' 20" log using that method ? And I don't care how good of a blade you put on there, you just can't saw lumber like that. If you had some straight boards, you could make a sled to fasten the logs to.

[Ianab]

This is probably the sort of thing that could be fabricated locally. It's actually an old wooden framed sash sawmill, with a reciprocating blade in a frame. But the thing to look at is the carriage. The log sits on a wooden frame on rollers and can be fed through the saw nice and straight. Blade runs in the slot down the centre of the carriage. Length of the carriage is a couple of feet more than the max long length, and the rails 2X that. It's a principle that could be adapted to work with a band mill in just the same way. This was fabricated 100 years ago using locally sourced lumber and some simple hardware, so it's something that could be built by the locals in Thailand too.

Would make the sawing process 10X more accurate, and then you can worry about fine tuning the other things.


Others might have some different ideas, but this is something that would turn that bandsaw into an actual sawmill.

Ian

[Jay C. White Cloud]

Hi Canopy,

I'm not going to repeat all the advice you've gotten thus far.  Every point I would have made has all ready been stated.  The only thing I would stress, is what 5quarter wrote.  You need to get your logs out of there and find a real saw mill for milling.  That is an industrial ship wrights saw in the video, and most of the time used for cutting curves not re-sawing.  It definitely is not for milling logs.  Could a boat or timber wright, with a modicum of experience re-saw some board stock with it, yes, but not at that feed rate, nor that set up as seen in the video.

I can see some really large logs there.  How are they working with those?  Do they cut them up with a chain saw, then feed them through the saw in the video? 

I do know that there are many operations like this one, so it is not that unusual.  If your structure is going to be built by local timber wrights in a traditional fashion, they can effectively use timber sawn this way because of the layout methods they use.  The traditional Thai carpenter can build their timber structures with full log or live edge and crocked timbers and it does not effect the tightness of the joints. The traditional timber home styles of Thailand seem to fall into four regional categories, of post and lintel timber frames.

Are you having one of these or a version of them built? 

If you contact WoodMizer's rep for Thailand, they should be able to help.

PANASA CO LTD
59/503-504 Rama 2 Road,
Samaedam, Bangkhuntien
Bangkok 10150
Thailand
Tel: +66 (2) 4168965
Fax: +66 (2) 4168967
Email: panasa@ksc.th.com
Mr. Thanongsak Rata-aporn

[bandmiller2]

Canopy,when you go to live in a third world type country sometimes you just have to suck it up and go native.Its tough on everyone to impose our standards on their facilities.Have the lads cut oversize and find someone with a planer and jointer.Time for a cold one. Don't mean to offend. Frank C.

[canopy]

I couldn't have asked for more helpful replies. You guys really know your stuff. Finding another mill does sound like the best answer however the reality is the only proper mill with a carriage I know of is limited to 10' lumber. I would imagine purchasing a wood-mizer mill would be cost prohibitive, but I will check with them. What I plan to do is bring this guy who runs the mill to the proper mill that does 10' with a carriage and tell him he needs something like that. But building even a makeshift carriage might be outside their capabilities and even for me would be a large project in an unfamiliar area so results might not be ideal.

What about just chalk lining the wood and having them push following the line?


To answer Jay C.'s questions, I will be making a traditional square rule frame like those found in the US & Europe and do the framing myself. So the wood should not wander over half an inch and should have two adjacent perfectly straight & perpendicular surfaces. As far as how they process the bigger stock I am not totally sure. They have a lift on a truck they park nearby for moving the logs around.

By the way there is another "mill" that makes the first cut with a chain saw then uses a circular saw (see below photos) but I am not sure this is going the right direction...



 


 

[justallan1]

I don't know how plentiful wood is there and what it's costing you to get it, but I would defintely stop them from sawing another single log until you figure out something better.
Allan

[Meadows Miller]

Gday

I am with Frank on his opinion  ;) they are doing what they can with what they have got .

OK Tuning Issues .

The Top Guide and Saw maint as Lynn stated .

Gauge length you can go longer by bolting a piece of timber to the face of the gauge .

Looks like they are also getting slippage on the feed rollers and you can rough them up but if the band is not upto scratch that can cause issues to but the feed looks variable thats what the lever man is there for  .

tell them to add/bolt timber blocks to the top of the trolleys so they do not get the extreme drop or lift on the piece been sawn as that also causes issues with sizing you want it to clear the trolley by about 1/4 of an inch the easy way is to place a long piece centered on the machine table and bolt your pice of timber onto the trolly then plane of what you dont want untill the trolley rolls freely under the piece of timber  ;) 

Operation of benches and band resaws w/o hobs requires a fair bit of skill from both sawyer and tailer out or you will get thick and thin or you can be as bloody accurate as you want with them too 1/16th of an inch accuracy  I have sawn afew Million bft on a breast bench like this day in day out

http://www.youtube.com/watch?v=vhXjqW6idIU

I hope this helps if i had the spare time and the cash id jump on a plane and come over to help you out Mate

Regards Chris 

[mikeb1079]

AHA! 

i just had a sweet idea.  instead of buying a woodmizer or similar, why not buy an alaskan sawmill for that fellow who rips his lumber free hand?  in exchange for milling your timbers he gets a tool for life that will provide for much straighter (and safer) timbers.  you'd have a low investment and probably get much better results!   8) 8)

[Seaman]

I like the way Mike thinks!
My 10 year old daughter saw the video and said " They need to make a sleeve to hold the log straight."
I love kids!

Frank

[Jay C. White Cloud]

Hi Canopy,

I had a feeling you intended to cut your own frame.  I wanted you to call Wood-Mizer to see if they knew of a sawyer close to you, not for you to buy a mill, (not that it wouldn't be a good idea for you, or maybe rent it?) 

Frank C. has brought up a point that I was too tired to get into last night.  The saw mill operation you are showing in the photos, (thanks for those by the way,  ;D) are typical of what you find throughout Southeast Asia, and many tropical regions of the world.  Chainsaw mills can be found in Thailand, but without carbide ripping chains and/or someone that really knows how to sharpen a ripping chain, it is often not the mill for tropical hardwoods.  They are there, and you might find one you could use or buy.

Now please take what I'm about to say in good spirit, and as an observation, not a criticism. You have heard the expression, "When in Rome...," why would you try and build and Anglo European timber frame in a region that has a timber frame culture that is three times as old and suited for the tropical environment of Thailand? 

So the wood should not wander over half an inch and should have two adjacent perfectly straight & perpendicular surfaces.

You are in Thailand, this is going to be a real burden to achieve.  Is it doable?  Absolutely, anything is, but you will pay in time and material waste through the process, as well as, money.  Is it necessary, absolutely not.  I have 10,00 board feet of beams setting on the job I am writing you from, few are square, more than half are "live edged," and none are "edge ruled."

You have to ask yourself Canopy, do I try and make what I know and want happen here, or do I learn what the local timber wright knows and adapt that to my needs.  You are there, and you have great craftsman all around you.  When I was in your place, I learned to build using their methods.  If you want to adjust certain aspects to fit your since of space do so, but within reason and respect to the craft.

I think if you embrace the local methodologies of timber framing, you will get your frame cut, with much less effort, will be very pleased with the outcome and love what you learn.

Regards,  jay

[barbender]

Why not use smaller logs that would provide the size timbers you need and chalkline and hew them? Most traditional timber frames were made without sawmills, the sawmill kind of.put them out of existance for a time if I understand it right. Anywways, if you need a 6x6, go out and find a 9" or so log and get to hewing, it looks like you should have plenty of local labor you could train to do it, too.

[canopy]

Hewing oversize logs is a good idea which is in line with Frank's good oversize advice. That's why I wondered aloud if I get oversize timber and reduce to a chalk line, why not just have the mill follow a chalk line instead? I guess there is a good reason you can't have a mill follow a chalk line otherwise someone would have recommended it. I just am curious what the issue would be.

Jay C. good comments as always but since that is going off topic we can explore those ideas offline.

I gave the mill recommendations made here. They were eager about some of them  as it seemed they really want to fix problems they are having, but don't want to make a carriage. They think of it as some sort of high tech modernity not suited to their small operation. By the way the band saw blades are diamond and I've also attached a 20 sec clip below of a better look at them.

They began sawing my lumber having never done anything as big or long before. I expected the worst, but after a cursory check with string line, tape measure and square I noted substantial wane in some cases but they somehow came out reasonably straight and square buy maybe they are hiding the bad ones on the bottom. The one on the right has over an inch of bow and they said no problem, they'll make it into boards and cut a new one for any that don't pass my inspection. Teak has very little shrinkage, but they are cutting them about a half inch oversize in the hopes I can compensate for issues better.

The end checking is a concern and as the 20 footers being made are near the log length limit I can't cut much off so some checking could be in the joinery of a scarf or a rafter tail. How much end checking do you find acceptable and which of those pictured might one reasonably reject?

Well as you can see I am definitely over my head here so any further advice appreciated.



 

http://www.youtube.com/watch?v=kOlrHsJV3Mw

[Jay C. White Cloud]

Hi Canopy,

I'll try to be brief. I didn't think they would modify there operation to much.  Thai are very traditional in many respects about a lot of things they do.  They are also visual learners in large, so if you couldn't show them a concept that they can see and touch, they normally won't do it.  Written or verbal descriptions fall on deaf ears, (ties back to that "not asking question, just watching comment I made.)

By the way the band saw blades are diamond and I've also attached a 20 sec clip below of a better look at them.

This is definitely a re-saw blade.  Was this the type of blade they used in the vertical band saw from the first video?  Diamond must be a brand name, because I also carve and cut stone and diamond blades look more like cable than a saw blade.  Did you get to see the teeth close up, do they have a carbide chip brazed on them?  There are blades like that, though this one did not look carbide to me.

The end checking is a concern and as the 20 footers being made are near the log length limit I can't cut much off so some checking could be in the joinery of a scarf or a rafter tail. How much end checking do you find acceptable and which of those pictured might one reasonably reject?

The logs I'm seeing have a lot of stress inside them, and without seeing the forest the logs are coming from it is difficult to make a real assessment of the logs applicability to timber craft.  Timber framing has similarities to furniture, but that's it...similarities.  I try to see the forest as well as the logs my frames come from. 

Can you use checked logs, yes, but you are taking some real risks, and you shouldn't have checks or any reaction wood in your joints.  The more experience you have in the craft and/or with a species of wood, the more you can flaunt the rules of timber framing you should follow, but you risk failure in doing so.  Teak does not respond well to most structural adhesives either, so gluing those checks would probably be futile, and the epoxy expensive.  Are you buying the wood you need from them, or are these your trees? If just buy wood, take the best you can find or wait for better to come into the yard.  Try and select the log your timbers come from.

Regards,  jay