Subject: Building a Saw Mill

From: [email-masked] (David A. Sticha)
Date: 15 Oct 1993 00:12:37 GMT

Hello all. I am looking for plans for building a band saw type saw mill.
I remember seeing an advert for plans several years ago in one of the handy
man mags like popular mechanics, etc but have not seen them lately. Or,
alternately, has anyone built one from scratch or have any ideas along this line?
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 Dave Sticha ([email-masked])
 Motorola Cellular Infrastructure Group - Arlington Heights IL
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From: [email-masked] (John Cooper)
Date: Mon, 18 Oct 1993 23:25:55 GMT

>alternately, has anyone built one from scratch or have any ideas along this line?

I am in the process of collecting pieces+parts to do just this.  I didn't
realize published plans existed for a bandmill.  I would appreciate any
pointers to what mag these may have been in.

I'm still jostling a few ideas around for some of the details and wouldn't
mind scrounging a few from an existing design.  I've looked at the Woodmiser,
Kasco, and Timberking(?) mills but alas only from glossy brochures that try
to entice $6-15K out of my wallet.

The Woodmiser is probably the most hi-tech of the lot of 'luggable' bandmills.
It has a tubular steel bed with a single main member and cross members
square to the former.  The saw carriage rides on a set of open linear
bearings on the main member and is cantilevered over the bed.  The saw is
positioned vertically with a chain and may also ride on linear bearings.
This saw is available with gas engines from 16-24HP.  Most models have
powered carriage travel.  The high-end model also has hydraulic log handling
(flips the log onto the bed from ground level) and positioning/clamping.
A really nice set of features.

The Timberking is similar but the carriage is not cantilevered.  Rather there
are two main members to the bed and the carriage rides on wheels riding
on these two members.  Vertical saw positioning is again via chain.
I think the features/options are very similar to the Woodmiser.

The Kasco mill is the cheapest of the lot, but still is $6K minimally
configured.  The bed is a low tech set of 1/2" angle steel 4"x4" flange lying
down, web up, connected with cross members.  The carriage rides on four
grooved steel wheels riding on the webs of the angle steel powered by _you_.

I've also looked at a portable hand-held bandsaw called something like
'Ripsaw' made locally in MA.  I've even seen one in action but this thing
takes some effort to use, EATS blades due to the small wheel diameter (10")
and relatively high tension needed to keep the 3/4" blade stiff, and IMHO
is a bit overpriced at $2K with a 5HP 2-cycle chainsaw engine.

Anyway, I've been collecting parts and ideas, but I still haven't drawn-up
even rough plans.  Probably because there are several ways to accomplish
many of the tasks and I feel I need more info.  For instance, I want this
thing to be towable so the bed needs to be fairly rigid yet light enough to
haul with a vehicle.  I considered welding a bed frame together v.s. scrounging
a mini-pickup ladder frame from a junkyard.  And the list goes on.

For the saw itself you could outright buy a 18" Taiwanese clone BS and unbolt
the top and bottom castings, add a 12+" section of 1/8" square tube and
bolt the castings back together with threaded rod.  Now you can cut 20"
clear.  Put the motor, table, fence, stand, and most other assorted and sundry
parts in the spare parts bin.  Take the saw rotated 90 degrees and bolt it to
a carrier riding on threaded rod.  This positions the saw vertically in the
carriage, etc..  

I chose to just buy the wheels and tires and build the saw frame myself.
Ball bearings in pillow blocks are fairly cheap and structural steel is even
cheaper.  I thought that if I use water lubrication on the blade while cutting
that I would rather build the blade/wheel housing from scrap aluminum or SS
sheet to minimize rust problems.

Anyway I could go on (or have I already?), but you get the picture.  I'm quite
willing to discuss this and offer whatever suggestions I can.  Good luck!

-john

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From: [email-masked] (Peter F Bastien)
Date: 21 Oct 1993 04:34:11 GMT

John Cooper ([email-masked]) wrote:
: In article <[email-masked]> [email-masked] (David A. Sticha) writes:
: >Hello all. I am looking for plans for building a band saw type saw mill.
: >I remember seeing an advert for plans several years ago in one of the handy
: >man mags like popular mechanics, etc but have not seen them lately. Or,
: >alternately, has anyone built one from scratch or have any ideas along this line?

: I am in the process of collecting pieces+parts to do just this.  I didn't
: realize published plans existed for a bandmill.  I would appreciate any
: pointers to what mag these may have been in.

	[stuff deleted]

I think that about a year or so ago Mother Earth had an article about someone
who built a band saw for some small amout of money. Since I've recently
moved I don't have many back issues. You might want to check the past
two years issues in your local library.

Hope this helps,
Pete

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From: [email-masked] (Basse)
Date: Thu, 21 Oct 1993 20:48:52 GMT

> two years issues in your local library.
I saw the article too.  I believe it was in Mother Earth news.  If I remember	
correctly,  I think they actually used automobile wheels and tires for the 
bandsaw wheels and tires.  

Now that I think about it, maybe the rear axle/transmission could also be used
to drive the beast.

My opinions , not my employer's.
Hank Basse

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From: [email-masked] (JOHN FARMER)
Date: 25 Oct 1993 16:56:29 -0400

In article <[email-masked]> [email-masked] (David Lagzdin) writes:
>I recently had opportunity to briefly examine a locally built
>"affordable" ( $4k CDN) mill and noted two interesting ideas
>were incorporated 1-one wheel was grooved and the drive belt
>acts as the tire  2- a sectional garage door wound spring/cable
>assy was used to counterbalance the motor/bandsaw on the carriage.
>
>dave
>
>-> In article <[email-masked]>
>-> [email-masked] (David A. Sticha) writes:
>-> >Hello all. I am looking for plans for building a band saw type saw
>-> mill. >I remember seeing an advert for plans several years ago in one
>-> of the handy >man mags like popular mechanics, etc but have not seen
>-> them lately. Or, >alternately, has anyone built one from scratch or
>-> have any ideas along this line?
>
>.... other excellent stuff truncated ....

This might be overkill but what about doing the whole system using 
hydraulics?  This is prob. due my recent visit to Northern Hydraulics
newest store in Knoxville TN, but if one was trying to build a serious
sawmill, this would seem to be one way.  Pick the Hyd. motor needed to
drive the bandsaw blade, another one to move the carriage,  cylinders
to position the log and lock it down...  One gas engine to drive the 
pump, controls could be all at one location. 

Related to all of this, is there any rule of thumb or real rules
that would relate the size of the wheels used to the size of the blade,
size of the max cutting depth, etc.?  I know that flexing of the blade
around small diameter wheels at high tension tends to cause failure,
so if one wanted to saw logs roughly 18" to 24" in dia. (i.e. cut
a 2' wide by N feet long by x" thick board from a log) where would
you start in the design?

John T.

-- 
John T. Farmer, Jr.					[email-masked]
Full-time Daddy, Part-time Grad Student,
Full-time wage slave, Wood butcher when I can.
My son's hero's are Capt. Jean Luc Picard, Norm Abrams, and Mr. Rogers!

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From: [email-masked] (David Lagzdin)
Date: Mon, 25 Oct 93 08:46:00 -0400

dave

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From: [email-masked] (John Cooper)
Date: Mon, 25 Oct 1993 22:35:59 GMT

In article <[email-masked]> [email-masked] (JOHN FARMER) writes:
>drive the bandsaw blade

Using a hydraulic motor to drive the blade would not be terribly efficient.
I seem to recall about 65% efficiency for a hydraulic motor vs. driving
directly with a gas engine.  Note these portable mills get between 8-24HP
delivered to the blade.  Also it is much more convenient to move the
engine with the saw.  Cradling a set of 20+ foot hydraulic hoses during
carriage movement is probably going to be a bit awkward.

>another one to move the carriage,  cylinders

This is the way full-featured mills operate with respect to log handling.
I've seen 12V winch-style carriage drives though.  Normally the larger mills
(which have larger engines) have an on-board 12V system which provides for
carriage feed.  The hydraulics are powered via 12V hydraulic pump (snowplow
style).  This actually works out well since you are not sawing while you are
moving the log around so you don't lose any cutting power.

>a 2' wide by N feet long by x" thick board from a log) where would

I've chosen 18" wheels which I am told are 'small' but are on par with the
sizes used by other mill manufacturers.  A 'small' wheel will compromise ~30%
blade life compared with a 30-36" (fullsize?) wheel.  It really isn't as bad
as it sounds since a 14" bandsaw will consume another 20-30% of blade life
and you can gauge this against actual experience with this size of machine.
I don't expect to be replacing blades very often.  I also didn't plan on
building a gyroscope.

There is a quantum step in blade life going from 1" to 1.25" width in terms of
beam stiffness, reduced working tension, and heat dissipation.  The rule of
thumb for blade working tension is 'the minimum that produces an acceptable
cut'.  The idle tension should be minimal in order to minimize
blade/bearing/tire fatigue.

I get most of this 'blade' info from the owner of Suffolk Machinery himself.
If there is anyone who ever earned the title of Mr. Bandsaw Blade it is he.
Additionally, you can get all of this info from their pamphlet which contains
pricing, sizes, types, etc..

If you want to cut up to 24" logs I would think a 20" clear span would be
sufficient unless for some reason you wanted to rip the raw log in half.
You will take a few cuts off the log to build-up a reasonably flat surface
and then rotate the cant 90 degrees and repeat.  Starting with a 24" raw
log you will remove a surprising amount of bark/waste before you have a clean
cant to begin slabbing.  The motivation to keep the blade (beam) clearspan
minimal is of course to minimize blade working tension.  For a given tension 
blade stiffness decreases with the cube of the blade's clearspan.  If a blade
with 20" clearspan deflects X a 24" clearspan will deflect 1.73X assuming
the same lateral cutting load and blade working tension.

Anyway, that's my 2 cents.  Please understand also that I'm in the early
stages of building this myself.  I do enjoy seeing this thread continue on...

-john

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From: [email-masked] (Bill Brown)
Date: 26 Oct 1993 15:36:48 GMT

re: wheel sizes

I worked for a few years in a sawmill.  Perhaps these dimensions will give
a starting point.

	Size logs - 	30" max, 6" min, butt diameter.
			    In reality, the max size was more like
			    24", due to debarker and log-handling
			    considerations.

	Band Mill	72" wheels - don't remember center-center
			    distance, but I think it was about 12'
			    The tension applied to the blade was
			    aboout 10,000  lbs!

	Saws		12" wide, ~3/32 thick.  Designed to cut a
			    1/8" kerf, but the Saw Filer ended up
			    with a tooth width that gave ~0.140" kerf,
			    based on "black magic.

	Feed rate	~250 ft/min, max for 6" logs, slower depending
			    on log size.

Each band saw was driven by a 150 HP induction motor; the carriage was
driven by a 350 HP servo motor which ran a winch.  The carriage was
pulled by a steel cable.

Clearly, one does not build a mill like this to cut up a few trees
after work, but it may give some useful information to the "home sawmill
builder."

Disclaimer:  These opinions are my own and have	    |
    nothing to do with the official policy or the   |  -bill
    management of L.B.L, who probably couldn't      |   [email-masked]
    care less about employees who play with trains. |