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Horizontal vs. Vertical

Started by handcrafted, November 07, 2013, 09:37:41 PM

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handcrafted

Howdy all, I'm new here but I am a lifetime woodworker with my own cabinet shop business and on my own acreage here in the northwest. I for sometime now have been gathering the components to build me own sawmill on a 24' sled bed. Trailer base. And am finally beginning construction with the optimistic hope of taking the first cut in two to three weeks. Well while in my shop and fabricating the rise and lower mechanism of my design (based on the radial arm saw rise and fall) I wonder why are all the saw mills I've seen horizontal and not vertical, similarly to the way a shop band saw operates. Seems to me that the entire head could slide thru a log just as well vertically as it could horizontally. I spent sometime reviewing my design and cannot see why I couldn't just as easily mike my band saw mill vertical. And while we're kicking the can around does anyone have a ratio so to speak of the wheel diameter to blade length. My thoughts are the smaller the diameter wheel driving the blade the faster the blade rotation, with that said is there a good match of blade size to wheel to pulley from engine. Well thanks for having me and I really look forward to your input. Photos to follow over the next several days

POSTON WIDEHEAD

Welcome to the Forum.
I am not an engineer but I think your vertical mill would work.
My first thoughts would be is about the sawdust.

A vertical head wood either throw the sawdust straight up or straight down depending which way the blade is sawing.
A horizontal mill throws the dust out the side away from the mill.

Like I said, I'm no engineer but do I make sense?   say_what

Maybe you could put a conveyor under your mill to take the sawdust out.
The older I get I wish my body could Re-Gen.

handcrafted

Thank you, It would be downward cutting and as quickly as I posted that I do believe the bed the log rests to is the reason for most saws to be horizontal, but sometimes it takes me to write something to rational the question in my brain  8)

POSTON WIDEHEAD

Your OK HandCrafted. Thats the best way I have found to learn......just throw your thoughts to the forum.  :D
And again....I'm glad you joined!  smiley_thumbsup
The older I get I wish my body could Re-Gen.

Magicman

Welcome to the Forestry Forum, handcrafted.   :)
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Delawhere Jack

There have been some vertical band mills made, one by Woodland Mills (but I don't think it's the same Woodland Mills that advertises here). They tend to be stationary mills, since the log clamping and feeding system is like that of a circular mill.

The size of material you intend to mill would effect the choice. A mill that could cut small logs vertically would be pretty straight forward. But when you get into 2-3k lbs + logs, it tends to be easier to move the saw head in a horizontal orientation than it would be to move the log.

A horizontal mill also leaves the cut board resting on the cant, which makes it easier for one man to operate.


thecfarm

handcrafted,welcome to the forum. Seem like Sanborn,a sawmill builder here in Maine, made some like that.I think they mostly built commercial ones. I saw them at a fair. Those mills were built!!!
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

5quarter

Welcome Handcrafted. Anxious to see your progress on the mill. bandsaw heads have been configured both horizontal, vertical and at angles in between. Different layouts have different advantages/drawbacks. Most of the vertical bandsaws I have seen were stationary and are laid out like a circle mill. If you'll be cutting lumber in a few weeks, you must have the design largely worked out. once you put up some pictures, myself and others can provide more specific comments that might be of more help.
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Delawhere Jack

To your other question, 1 1/4" and 1 1/2" bands perform best at around 4,500 ft per minute band speed ( regulars please chime in if I'm off on that, I'm going from memory).


handcrafted

Thanks for the warm Welcome All  8) after careful consideration over the course of the past hour it seems relevant to me that my mill just morphed into a vertical to horizontal unit. Yep glad I got's parts laying around to pull this off. Just seems to make sense to have the power head go from 90 to 180 if I want to make me an 12x14 beam. Yeah and why's it taken me two plus years to build this  :P Hmmmm
P.S. 5quarter thanks in advance for the mention of "and angle increments" this whole project just got that much better :)

drobertson

There are vertical bands saws, most are stationary, and use a carriage for the log, this dust is then isolated to one location, they work much like a circle mill, just a bit slower on average with the smaller bands, mill layout would most likely determine the appropriate mill design.    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,

Tom the Sawyer

handcrafted,

Your thought about wheel diameter is going in the wrong direction - larger diameter wheels will work better than smaller diameter.  Smaller diameter will have to turn much faster to get optimum blade speed.  Most mills are engineered to get the proper blade speed (fpm) with a wheel diameter that will allow the power source (engine or motor) to operate in its best torque range. 

Smaller diameter will limit how tall a cant you can mill.  Smaller diameter means that the blade will make more rotations around the wheels and the smaller arc means more flexing of the band, both of which will decrease band life.

Good luck with your project,
Tom
07 TK B-20, Custom log arch, 20' trailer w/log loading arch, F350 flatbed dually dump.  Piggy-back forklift.  LS tractor w/FEL, Bobcat S250 w/grapple, Stihl 025C 16", Husky 372XP 24/30" bars, Grizzly 20" planer, Nyle L200M DH kiln.
If you call and my wife says, "He's sawin logs", I ain't snoring.

Ianab

There is no physical reason you can't run the band vertical (like a shop bandsaw does).

The issue I can see though is supporting the log. On a conventional small band mill gravity is a great help in holding the log in place on the bed. Then a simple back stop and clamp just has to stop it moving. Easy enough to engineer. The saw head can also run on the same bed that supports the log., which only needs to be a couple of feet longer then the log. But if you have a vertical band you will need a much more serious dogging system to hold the log, remembering it needs to be cantilevered out from the clamps so the band can pass by. (Or move the log on a carriage past a stationary band). Look at the carriage and clamps on a circle sawmill and you will see what I mean, that's the sort of set up you will need.

It all just gets a lot more complicated, heavier, expensive etc.

Ian
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

bandmiller2

Ian nailed it, its just plumb easier horizontal. Bandwheel size should match the size of the mill.A large heavy duty mill with small wheel would be a waste.For a medium sized mill the readily available 19" single groove pulley will work well with a tight "V" belt.Larger pulleys are of course preferable but the cost ramps up considerably.  Frank C.
A man armed with common sense is packing a big piece

Ron Wenrich

I have run circular mills only.  Woodland mills ran vertical and were higher in production rates than the horizontal mills, from what I've seen.  The vertical does get rid of the problem of handling sawdust and makes handling lumber easier.  But, it requires a little more engineering for material handling.  As for log size, I worked on hand carriages where we put large logs on a carriage.  To advance it, they use a mechanical setworks.  Moving the log is not that difficult, since you only have 3 or 4 contact points to overcome the friction and rolling resistance.  Since you're moving the log in a horizontal direction, you're not lifting the log.  You're sliding it.  Big difference.  But you need upright supports to put your dogs on and to provide a vertical bed to pull the log and prevent rolling during the advance.  Its the way a typical carriage and rail system has worked for a long time.

At the end of the cut, the piece will fall down.  A set of rolls will help with the removal of the piece.  It could also be moved in either direction.  It gives more leeway in how you set up your production.  The rolls only need to be dead rolls.  It also gives you the leeway of making a double cut mill.  Sawdust is directed downwards and can be handled by a trough with a paddle and chain removal system.  No shoveling. 

Another option is to put the head at an angle other than 90°.  This is how some of the bigger resaws handle cants.  I believe the Sanborn Min-Max handles material the same way.  The angle is somewhere around 20-25°.  Material slides off the side instead of falling straight down.  The Sanborn mill has material fall onto a table and it is brought back to the operator.  But, that mill is run with a wide band.  No reason a small band can't run that way. You're now lifting the log somewhat, but still only have a few contact points.  Your log is sitting in more of a V and not as apt to roll.  Vertical and angled head mills would have a track on the outside of the log area, and would be wider.  It would lessen the portability aspect.

The only drawback I see on the vertical operation is the end of the cut where a slab drops.  I don't know if the slower feed rates of the think kerf bands would cause a slab or heavy flitch to drop and break before you finish the cut.  That may cause blade damage  as well as other problems.

What are your plans for the mill?  Are you going to custom saw, or are you sawing for your shop?  What sort of material are you planning to saw?
Never under estimate the power of stupid people in large groups.

Satamax

French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb dead as of 06/2020. Replaced by a Brimont TL80 CSA.

Chuck White

Welcome to the Forestry Forum, Handcrafted! 

That's quite a sawmill in the video Satamax, but I couldn't imagine what a mill like that would cost!  Nice though!  ;)
~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!

Hilltop366

Welcome Handcrafted

A You tube link to a much smaller angled mill.

If you watch this and a few others of this mill it should get your brain running.

http://www.youtube.com/watch?v=O_LVKX9dPH8

Nomad

     Isn't there an Amish built angled bandmill called the "Lumber Tiger?"  I seem to recall one like that.
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shenandoahsawmill

Horizontal vs vertical vs slant bed. and wheel dia. Quite a few topics here. Horizontal vs. vertical vs. slant bed is all about what happens to the board/slab after it is cut free from the cant or log. On a horizontal bandmill, the board needs to be pushed off of the top of the log/cant by one/two off-bearers making $10.00/hr or the log/cant needs to be tilted to dump the board to get it off to the side or the board needs to be dragged back when the carriage returns with a dragback feature built into the mill. In a vertical or slant bed bandmill gravity does the work and the board that is just cut loose is released onto a conveyor belt and pulled away to a secondary operation. Gravity is pretty darn reliable for getting a board away from the cant/log. One of the fastest mills on the planet, other than a sash gang mill for throughput (of same board thicknesses) is a slant bed double cut bandmill. I would prefer a slant bed over a horizontal or vertical because gravity does the work to get rid of the board but if the bandmill is vertical there are tremendous stresses in the last few inches of board as it is cut off of the cant or log resulting in grain tear out. Not so much on a slant head. The board is somewhat supported until it is cut away from the cant but gravity still does the work to remove it. I have a horizontal doublecut bandmill and saw in both directions and very wide but can keep up with the saw as far as material handling so I am thinking about tilting the whole mill to get the boards off the cant/log with gravity.  As far as bandsaw wheel dia. it is all about metal fatigue. The smaller the wheel dia. the bandsaw blade has to go around a small dia wheel which stretches the outside face of the blade and compresses the inside face of the blade. After thousands and thousands of cycles this takes a toll on a blade. The larger dia. the wheel the less a blade has to bend or flex so it lasts longer. The thicker the blade the more tension you can put on so it cuts straighter. This is called beam strength. But thicker blades require larger dia wheels to reduce metal fatigue.  Catch 22 situation.                                     Gary

backwoods sawyer

On a stationary vertical bandmill wheather it is a single, double, or quad bandmill set up, running a single cut or double cut saw the last few inches of wood is suporting the whole length of the piece being cut off so speeding up the carrige the last few inches to creat a controled rip-out is common. A shear plate to kick the bottom of the cant away from the saw and saw guide is needed, as well as a live roll or live slat bed to move the cut piece out of the throat of the saw so it does not fall into the saw.

Making the opening cut means you have odd shaped edgings dropping down into the guides as well. 

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