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What, how and where is your first cut with a bandsaw mill

Started by rasorbackQ, July 09, 2013, 01:19:41 PM

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rasorbackQ

  Going to be a lot of different answers to this one.  I put a log on the mill lets say 12" on the small end  and 18" on the butt end.  I normally drop the blade 1" below the bark for the first cut . Sometimes it cuts straight along leaving a nice edge to roll over onto.  Other times the butt end is 6" thick of waste. tampering from start to finish. If the tree is not straight then still have bark on the sides in places. I guess my problem is I don't mind working with a 2x stock that is not square in order to get  more wood from a tree.
I would think what I should be doing is cut to get a cant  the right size and go from there to get the dimension lumber.   Seems I have a lot more waste that route and most times the cants are too small .

Another way others may do it is cut a cant of correct size  from a big tree then reload the thicker slab waste and make small boards.
I hope you understand where I was going.

Thanks for reading, Steven

Herb Brooks

I don't have an answer, but I'm watching with interest.

Delawhere Jack

Depends on how the taper occurs. Is it mostly butt-swell from mostly just above the root crown? Or does the log taper consistently along the entire length?

If it's butt-swell, and the taper is mostly confined to just a couple feet on one end, then just ignore that portion and try to saw parallel to the bark for the "normal" taper portion of the log.

If the taper is consistent for the length of the log, raise the log to cut parallel to the bark for the entire length.

The highest quality boards usually come off of the outer portions of butt logs. Once you start encountering knots from juvenal growth you can square up the remaining cant and either get a post or continue milling boards from it.

Often times I will start milling a butt log by milling off the butt swell. Turning the log 1/8 turn at a time and "Bibbying" it (search this forum for bibbying). Taking off the swell in 18"-24" long slabs just to get the taper more uniform along the entire length.

With all that said, a lot depends on the quality and size of the log. Larger, better quality logs -- more effort to saw parallel to the bark. Smaller logs with knots-limbs, just flat saw it.

Magicman

First, if the log has sweep, I turn the horn side toward the loader and the hump side toward the side supports.  I would then raise the small end of your described log 3" with the toe board. This will insure that the center of each end of the log is an equal distance from the saw bed.

Now it depends upon the size of the cant that you want from the log.  That cant will be centered on the small end, so measure from the bed to determine the height of the top of the cant.  Now how many boards are above the top of the cant?  Make your opening face to obtain these boards and also to reach the top of the desired cant.  After taking the side lumber from the sides, the cant can be utilized or sawed depending upon your cut list.
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

beenthere

Each log is different, and visualizing the cuts ahead of time comes with experience.
There are different ways to procede, one to saw parallel to the bark so the first boards or dimension are straight with the surface of the log. That means setting some toe boards to account for the taper in the log. Usually the quality lumber is near the surface, not in the log center. At some point, the taper needs to be removed which may be further into the log when squaring up the cant.

The other extreme is to not set up any toe board, and just cut wood out that is parallel to the face of the logs on the bunks. Boards and dimension from half the log will have the taper come out as slope of grain. That is the other extreme. There are all sorts of combinations in between the two. ;)
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Jim_Rogers

razorbackQ:
Are you talking about sawing hardwoods or softwoods?

Two different methods .....at times.......

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

rasorbackQ

Any log in general Jim.  I kind of do like Beenthere said . Visiulize the cuts to get where you want to be .  But what if a person was to cut off say 5 " below the bark that would be a very nice wide start of a cant . What happened today was I was cutting 2x8s from logs with 10 small ends.  Very hard to get a cant 2x8 size if the tree is not straight.  Is there a formula to say 8"x8" cant needs to be a tree 12" wide on the small end?
Thanks for reading, Steven

drobertson

razor, what kind of set works are you running, in fact what mill are you running,  On swelled butt ends I go about it several ways myself,  depending on what I am after,  and  a 12" small end should give you a 8x8, but if you are making 2x's the drop side should be a lil over 8-5/8"   just a thought,  david
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

Magicman

I addressed several of your questions in Reply #3.  You have to read each log to determine the proper face opening height.  Yes it takes a 11"-12" log to make a 8" cant, but even then not every one will make it.
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

drobertson

Sorry for a bad number on my last post, I was locked in on 1x's, add three kerfs to the cant size for 2x's on an 8x8  it varies of course on the actual dimension is going to be, there are many options and choices folks like for rough cut 2x's   david
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

beenthere

QuoteIs there a formula to say 8"x8" cant needs to be a tree 12" wide on the small end?

The diagonal corner to corner of a square is c2 = a2 + b2
So the square root of 128 is the diagonal for an 8" x 8" which is 11.3"
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

drobertson

forum tool box has the handy calculator as well, good stuff, david
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

WoodenHead

A quick method I use to determine what sized cant I can get from a log is to divide the diameter by 1.5.  So a 12" log might yield an 8" x 8" cant.  This could yield, in theory, four 2 x 8's.

However, you may also want to watch out for where your centre is.  In a perfect 12" log if you want 2" thick lumber you will be sawing right through the centre (which is usually not desirable).  Instead you may have to cut 1" off the top of your cant, next 2", probably flip, 2", 1", leaving you with a 2" piece with the heart dead centre. 

Unfortunately in many cases we don't see these perfect logs.  It takes a lot of practice to learn how saw.  I've now sawn for almost two years and I'm beginning to learn.   ;)

Magicman

The pith can easily wander between several of the center boards.
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

rasorbackQ

Quote from: beenthere on July 09, 2013, 05:03:14 PM
QuoteIs there a formula to say 8"x8" cant needs to be a tree 12" wide on the small end?

The diagonal corner to corner of a square is c2 = a2 + b2
So the square root of 128 is the diagonal for an 8" x 8" which is 11.3"
Who thought you needed a math degree to run a sawmill. LOL
Thanks for reading, Steven

rasorbackQ

Quote from: drobertson on July 09, 2013, 04:48:33 PM
but if you are making 2x's the drop side should be a lil over 8-5/8"   just a thought,  david
What is a the DROP SIDE?
Home made band saw mill.
Thanks for reading, Steven

rasorbackQ

Quote from: Magicman on July 09, 2013, 01:46:11 PM
First, if the log has sweep, I turn the horn side toward the loader and the hump side toward the side supports.  I would then raise the small end of your described log 3" with the toe board. This will insure that the center of each end of the log is an equal distance from the saw bed.

Now it depends upon the size of the cant that you want from the log.  That cant will be centered on the small end, so measure from the bed to determine the height of the top of the cant.  Now how many boards are above the top of the cant?  Make your opening face to obtain these boards and also to reach the top of the desired cant.  After taking the side lumber from the sides, the cant can be utilized or sawed depending upon your cut list.
That was an other question altogether ..... log taper .  I neighbor tried to explain to me last year about toe board and log taper.

To me if no toe board is used there should be the same amount a waste  if there is a toe board.  The angle of the butt  will be cut off in one cut rather then 2 cuts one on each side Or top and bottom. The only dif I can see is the grain will be cut on an angle rather then straighter with a toe board.

Thanks for reading, Steven

beenthere

QuoteThe only dif I can see is the grain will be cut on an angle rather then straighter with a toe board.


Which when at an angle, can lead to more warp when dry. 

If your log were just one homogeneous material (and not of different grain and defects such as knots) then your "only diff" might have merit. But logs are not that way, as the tree had limbs, sweepy logs, pith centers off center, taper, etc, etc. ;)

But best would be to start cutting up logs and see what you discover. If it works for you, then that is a good thing. And it may just work fine for you.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

drobertson

In any case, whether toe boards are used or not, a swelled but will yield premium short boards,  length of the logs is another factor as well,  trying to describe cutting techniques online is a challenge to say the least,  if it were me, I would take 1" boards to the desired cant size, reducing the stress in the log, (keeping the pith centered) then proceed in making your 2x's, watch for the reaction as cutting through the log while making 1", if the boards raise, this is your drop side, if they curl left or right this is your dimension,(6",8" or whatever) unless you desire a crowned 2x,  just my opinion,  david, hope this helps, I saw parallel to the sweep(curve) of the log for the 2" drops, only to reduce the crowning of 2x's, well 1x's as well, straight boards are the objective for me,
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

rasorbackQ

Quote from: drobertson on July 09, 2013, 06:05:18 PM
In any case, whether toe boards are used or not, a swelled but will yield premium short boards,  length of the logs is another factor as well,  trying to describe cutting techniques online is a challenge to say the least,  if it were me, I would take 1" boards to the desired cant size, reducing the stress in the log, (keeping the pith centered) then proceed in making your 2x's, watch for the reaction as cutting through the log while making 1", if the boards raise, this is your drop side, if they curl left or right this is your dimension,(6",8" or whatever) unless you desire a crowned 2x,  just my opinion,  david, hope this helps, I saw parallel to the sweep(curve) of the log for the 2" drops, only to reduce the crowning of 2x's, well 1x's as well, straight boards are the objective for me,
So is what you are saying is as I cut 1" boards off to get the cant size watch to see if the 1" board cups or raises.  If it raises this side goes down for the cant cutting?
Thanks for reading, Steven

bandmiller2

If we were dealing with perfect cylinders it would be easier but were not so each log is its own entity. If your cutting timbers its desirable to center the pith. Logs 8' and under you gain little using toe,longer logs it can be usefull.Myself I don't diddle with less than 6" boards,I plan my cut so the second cut gives me a 6" board then generally turn the log and repeat.I end up with a cant the dimention I'am looking for and side wood that needs edging. Frank C.
A man armed with common sense is packing a big piece

GAB

rasorbackQ:
For a perfectly round and straight log the largest square cant available is the diameter inside the bark times .70711 (square root of 2 divided by 2).  For a quick reference multiply the diameter x .7.  So a 15" log will yield a 10.61" cant for a max. number, the quick calculation is 10.5".
I try to position the log so that the center line of the log is parallel to the bed of the mill.  This hopefully will yield the fewest boards with pith in them.  If the log has a lot of butt flare then you need to ignore the flare end when positioning it on the mill. If the log is 16' or more I try and get some 8, 10 or 12 footers off of the sides.  Hope some of this helps.  Gerald
W-M LT40HDD34, SLR, JD 420, JD 950w/loader and Woods backhoe, V3507 Fransguard winch, Cordwood Saw, 18' flat bed trailer, and other toys.

drobertson

Quote from: rasorbackQ on July 09, 2013, 08:12:59 PM
Quote from: drobertson on July 09, 2013, 06:05:18 PM
In any case, whether toe boards are used or not, a swelled but will yield premium short boards,  length of the logs is another factor as well,  trying to describe cutting techniques online is a challenge to say the least,  if it were me, I would take 1" boards to the desired cant size, reducing the stress in the log, (keeping the pith centered) then proceed in making your 2x's, watch for the reaction as cutting through the log while making 1", if the boards raise, this is your drop side, if they curl left or right this is your dimension,(6",8" or whatever) unless you desire a crowned 2x,  just my opinion,  david, hope this helps, I saw parallel to the sweep(curve) of the log for the 2" drops, only to reduce the crowning of 2x's, well 1x's as well, straight boards are the objective for me,
So is what you are saying is as I cut 1" boards off to get the cant size watch to see if the 1" board cups or raises.  If it raises this side goes down for the cant cutting?
this is how I do it. I have found it easier to line up a board and keep it straight for walls and joists, a crown is another matter all together.  Lots more force required to get them straight. It boils down (for me) more straight boards of useable length, and less short boards due to excessive crowning.  Time and experience will teach more than any other explanation in my opinion.  Some logs are just a pain, regardless of cutting technique.  david
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

dboyt

This advice is for hardwoods.  For taper, I level the log with a jack so that the pith is nearly level to the mill.  When possible, try to keep the boards centered on the pith to avoid warping as it dries.  This means a lot of edging, though.  Hopefully most of your boards will come off straight and stress-free, but drobertson gives a good strategy for those that don't.  This is a typical sawing pattern for me.  The 1x6 and 2x8 lumber comes off first to make a cant as wide as the lumber width, then just slice it up.



 
Norwood MX34 Pro portable sawmill, 8N Ford, Lewis Winch

Brucer

I saw nearly all softwoods, and mostly timbers at that.

I generally set the log up the way MagicMan does. If it's a sweepy log, ears point to the loader side. I always put the log on the mill with the small end facing me.

When I'm boxing the heart I will use the saw head to measure the diameter of the log at the furthest bed rail -- just run the head down to that point and then lower it until the band just touches. The scale tells me what the diameter is and dividing by 2 tells me where the center will be. Then I move the head back to the front and raise the small end so it is centered at the same distance above the rails. The height where I made my first measurement won't change as I raise the small end of the log.

When I'm sawing FOHC or cutting the log into boards, I measure the height of the pith at the far end, then raise the small end to the same height. If the log is hanging way over the last supporting rail, I guestimate how much the far end will drop as I raise the small end and adjust accordingly.

I always picture the timber or cant centered on the log's centerline and saw down to that final dimension. Usually I'm taking 1" boards off the sides unless I have a specific order for 6/4 or 2" material.

If I'm trying to dodge a defect in the center, I will use the saw head to measure the diameter over the furthest bed rail, then raise the small end to the same height. This way I'm sawing parallel to the top surface.

You can use fancy math to figure out the perfect diameter for your intended cant but logs often have surface defects or minor sweep that messes up your calculations. If you want a wane-free cant, best to use the "half again" rule (thanks for that, Arky). For a square timber, add half the width to the original width to get your ideal top diameter (8x8 --> 8" + 8"/2 = 12").

If you want to saw a rectangular cant, average the two dimensions and apply the "half again" rule to the average. This works as long as the ratio of width to thickness is less than 2. Usually I'll add an extra half inch at the end when I'm doing rectangular calculations. For example ....
8x10 --> average = (8+10)/2 = 9"  average dimension
9" + 9"/2 = 13.5"    half-again rule
13.5" + 0.5" = 14"    for safety

For a log with a little sweep, I usually add 1" to the top diameter.
Bruce    LT40HDG28 bandsaw
"Complex problems have simple, easy to understand wrong answers."

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