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slabber versus wide manual band mill

Started by Norwiscutter, January 16, 2007, 12:36:41 PM

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Norwiscutter

Been thinking of a project for Febuary and March and have been looking at the merits of building a wide chainsaw slabber versus a wide manual band mill.  The mill would be dedicated to cutting slabs up to 50-55 inches wide and for breaking down logs that won't fit on the WM.  Has anyone here built a chainsaw slabber using a similar design to the Lucas or Peterson slabbers?  I worry about blade deflection with an ultra wide bandmill but have always wanted to build one so am considering that as well.  I just wonder how wide is too wide for narrow kerf band blades. Hudson makes a 52 inch bandmill so it is obviously possible, but the simplicity of a chainsaw slabber also seams attractive.  Any inital comments are welcome.
Si vis pacem, para bellum.

Murf

I'm in the process of putting together the design for a dedicated slabber for a friend who builds furniture, both fine & rustic style.

My logic with going the chainsaw route was simple, it's simpler to build and maintain. But mine will be powered by a vertical shaft 4 stroke engine, not a 'real' chainsaw engine.

The big drawback I could find to a chainsaw mill is kerf size, but if you're not making lots of cuts, and only want a few slabs out of each log anyways, kerf is sort of irrelevant.  ::)
If you're going to break a law..... make sure it's Murphy's Law.

Norwiscutter

That is kind of my first impression.

Without having conducted to much though on the topic, the simplicity of the slaber versus the bandmill was my initial perception as well. With the 4 stroke engine, do you plan on using the 12 spoke harvester drive sprocket and if so, how difficult is it to set up a compatible bar/chain combination. Was thinking of using an electric motor to run the thing....maybe 10-15 horse 3 phase.
Si vis pacem, para bellum.

Norwiscutter

After further thought, I think sticking with chainsaw heads would be best for my application because I want to keep the thing portable. So for the longer bar I was thinking of using (66") what is the concenus concerning two saw heads versus one? I like the idea of being able to easily take the saw heads off the bar when setting up the rig on site.
Si vis pacem, para bellum.

Murf

I'm thinking I'll go the other way around, to run a 4 stroke to avoid the issues of noise, smoke, fumes, fuel mixing & consumption with the chainsaw head.

If I use a belt drive to a jack shaft to step the speed up the harvestor sprocket will then be on the jackshaft not the crankshaft. That allows me to run a centrifugal clutch on the engine so the chain stops when the engine idles down. The belt should also take a lot shock load out of the driveline. By using a threaded rod and slider mechanism to tension the drive belt the engine can be removed by just slacking the belt and lifting it off the track it runs on.

::)
If you're going to break a law..... make sure it's Murphy's Law.

Dan_Shade

that's the same setup that I've envisioned, Murf.  I can't see why it wouldn't work.
Woodmizer LT40HDG25 / Stihl 066 alaskan
lots of dull bands and chains

There's a fine line between turning firewood into beautiful things and beautiful things into firewood.

Murf

What gave me the idea was my drill press.  ::)

If I used more than one pulley on the jack shaft and slide them up or down out of the way, I could use a slower engine speed and change the speed increase to accomodate soft woods, or run the engine flat out, and not as much step up for cutting very hard woods.

That way I could have a range of options.  ::)
If you're going to break a law..... make sure it's Murphy's Law.

stumpy

Hi Norwiscutter,  I'm interested in your slabber project, so I decided to resurect this thread up to the front again in hopes of getting more discussion going.
Woodmizer LT30, NHL785 skidsteer, IH 444 tractor

Norwiscutter

After a lot more thought on how I am going to go about doing this, I am still decieding between  a normal alaskan type set up with one or two powerheads or something similar to a portable manual bandmill except set up as a slabber. There are a lot of used snowmobile engines around here that I am sure would make a great power head for a large portable slaber Like I am thinking of. The real problem however is the obvious logistical limitations of dealing with big logs.
Si vis pacem, para bellum.

Rail-O-Matic

Quote from: Norwiscutter on January 21, 2007, 01:43:54 PM
After a lot more thought on how I am going to go about doing this, I am still decieding between  a normal alaskan type set up with one or two powerheads or something similar to a portable manual bandmill except set up as a slabber. There are a lot of used snowmobile engines around here that I am sure would make a great power head for a large portable slaber Like I am thinking of. The real problem however is the obvious logistical limitations of dealing with big logs.

If you use two power heads, make sure that they are both running at the same speed, I used an electronic digital tacho on each machine to do this, or the slower engine will be dragging down the faster runner of the pair.

If you use a 17 tooth harvester sprocket the periferal speed will be greater than a standard smaller chainsaw sprocket, two GXV Honda 13hp motors can be bought as a pair at about the same price as one Stihl MS880, fit harvester sprocket straight to the motor shaft with spacers to line up with the bar.

Coupling a single Honda to a bar is easy with a conversion plate, mounting the Honda to the plate is done by drilling four holes in the right place so it fits where the ready drilled holes are in the engine foot, where a generator or water pump would fit.

To mount the bar use two car hub studs, the kind that knock out of the hub with splines on the end, drill the plate to take the studs and pack out to fit the bar.

On the bar clamp, drill it to line up with the studs and oil holes would be on a chainsaw, fit the bar as close as you can to the harvester sprocket/s.

One 13hp engine is sufficient to drive a 60 inch bar, two motors for 80 inch bar, two Honda motors are easier to balance than two chainsaw motors because they have a fixed throttles.

Oiling of the bar is done via a vaccum pump that is attatched either to the exhaust or crankcase.

The cutting unit can be fitted to a rolling chassis via holes drilled through the bar, make one end adjustable so you can take out any flex in the bar, keep things simple.

I'm very sorry but I cannot send pictures of mine, because I cannot work out how to do it on the forum, if you would like a drawing e-mail me at dds.uilleann@talktalk.net.








Logg-saw bandmill, Stihl 088, Stihl MS880, Stihl MS660, Stihl 017, 018,  Husky 385XP, Husky 395, Husky 350, Echo WES 350ES, Echo CS 27T, Jonsered 2150 Turbo, Jonsered 111S, good old saw still going after more than 20 years hard service.

fencerowphil (Phil L.)

In the world of big logs, I decided that the prime issue was to be
able to move to the log, rather than move the log to a position
for milling.  I started with the Granberg Alaskan solution and ended
up with a swingblade.  I have not added a dedicated slabber...yet.

My medium Alaskan rig is one Stihl 090 bought new from Canada
a few years back with a 41" bar on a 36" Alaskan.  The max. cut
is 32".   My bigger rig is a 56" bar with two 090s with a 52" Alaskan.
The medium rig weighs about 65? lbs - manageable by one person.
The larger one is a two person job, even if you rig up a control for both
engines to be operated from one side.  The size is so cumbersome, as
well as heavy, that it is no longer a one-man proposition.

Even with the big rig, however, the techniques are simply Will Malloff
all over again:   Some sort of straight guide system to make the first
cut, followed by cuts which use the previous cut as the guiding plane.

My point is this.  Weight and size are a considerable issue.   If you go
with a large four-stroke engine, you will be into a major project with
tracks and set-up (similar to Lucas or Peterson) to be able to operate.
You would then proceed to set up the track systems around the log.
On the other hand, if you go with single or dual chainsaw engines, you
can still use basic chainsaw lumber making techniques.   Of course, if you
have all the support equipment to move and manipulate four to six tons
much of what I am saying may be beside the point.  You could build a
set-up and move the logs to it.

PHil L.
Bi-VacAtional:  Piano tuner and sawyer.  (Use one to take a vacation from the other.) Have two Stihl 090s, one Stihl 075, Echo CS8000, Echo 346,  two Homely-ite 27AVs, Peterson 10" Swingblade Winch Production Frame, 36" and 54"Alaskan mills, and a sore back.

Fla._Deadheader


QuoteThere are a lot of used snowmobile engines around here that I am sure would make a great power head for a large portable slaber Like I am thinking of.

Would there possibly be a used Variable Speed Drive laying around, for cheap, from a snowmobile???  Possibly able to withstand 20 HP or so ???
All truth passes through three stages:
   First, it is ridiculed;
   Second, it is violently opposed; and
   Third, it is accepted as self-evident.

-- Arthur Schopenhauer (1788-1860)

Ianab

QuoteThe real problem however is the obvious logistical limitations of dealing with big logs.

Thats why Peterson and Lucas make their slabbers pretty portable. Often those big logs will be in awkward spots, backyards, swamps etc. Sometimes the cost of getting heavy machinery in to move them is prohibitive or impractical.

My old mill is pretty basic, you just lay down the 2 aluminium tracks either side of the log and they are held in place by 2 more steel cross pieces. A few stray blocks of wood to level things up and support the centre of the rails and you can wheel the whole carriage frame into place. Lower the carriage onto the rails, and remove the handling wheels. The wheels attach to the saw mechanism, not the frame, so you can wind the sawhead down after you bolt on the wheels. Wind it up again to lower the track runners onto the track.
The track setup on the swingmills look pretty flimsy compared to most bandmills, but the tracks only carry the sawhead, never the log. That can be sitting on seperate bunks, or just on the ground if it's too big to move.

Which is easier to move, a 4 ton log to a 400lb sawmill  ;)

Cheers

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

Norwiscutter

Great responses here.
Rail O Matic- I had to reread your post a number of times to grasp all the information you posted, very impressive and most appreciated.
I have had a difficult time finding good information on whether or not it is necessary to have both saw heads running at the same RPM or not. Thank you again for your clarification.
I would have a hard time spending allot of money on a large sawhead that would otherwise serve only as a boat anchor when not being used for this intended purpose. However for the sake of portability, that might be a necessary evil. All the stuff that I would be cutting here at the wider (40-50 inch) widths would almost exclusively be white pine so perhaps I could get away with a single large chainsaw power head rather than two heads.  Having three phase in my shop, I have been up late at night dreaming of a 15-20 horse electric slabber ripping through giant white pine.  However the logistical difficulties seem easily addressed simple by employing what has worked many times before for others. 
Si vis pacem, para bellum.

Bob_T

I happened to be talking to Linn Lumber last week and at a customer's request, they have a 50 inch or so wide cutting slabber bandmill in the works.  It might be worth talking to them (541-367-6900).   I like the idea, especially if it would be possible to have a long wheel distance adjustment, to allow you to change blade sizes, a long one for slabbing and a shorter one for smaller stuff.  For wide slabbing it seems like it might be necessary to add some sort of blade flutter damper on the upper non-cutting part of the blade.  I wonder if their extra wide throat bandmill will also require a wider track?

Bob
1959 FWD Model 286 Dump Truck
1955 Allis Chalmers HD-6G Crawler Loader
1941 GMC CCKW 6X6
Wood-Mizer LT30 G18

tlooney

You know what is really sad is I live about three miles from Linnlumber and until now never knew it existed. ::)
Lucasmill 827
Kubota tractor with forks
current project: finished solar kiln now trying to sell lumber

TexasTimbers

Murf are you still on track for this project ? Furby and myself also are two other converts to 4 stroke slabbers. Just wondered if you had to put it on hold or if you're making headway.
The oil is all in Texas, but the dipsticks are in D.C.

Murf

Kevjay, I'm still in the scrounging....errr, umm, 'inventory assembly' part of the process, that and I keep getting design changes (Read: "Hey Murf, do ya figger we can make it......") from my buddy I'm making it for.   ::)

So far I've got a handle on the drive speed increase setup. I'm going to run a double or triple pulley set so I can vary the speed of the chain, or keep it the same and reduce the engine RPM's. This also allows me to run a flywheel, vertical shaft engines need an external flywheel since they are designed to drive something like a mower, where the blade acts as a flywheel. The flywheel should also help with keeping the speed more constant, knots and such shouldn't bog it as much.

I found a 15.5 hp Briggs off a riding mower that might be the power supply, it's almost new so it won't have "tired iron syndrome" for a while.  :D
If you're going to break a law..... make sure it's Murphy's Law.

aom

For some time thinking about these matters, I like the slabber attatchments on peterson/lucas etc. But have not bought one for my peterson, due to the limited depth of cut. With a slabber I would want to use it not only to slab but also split and quarter large logs, so instead of a max cut of between 8-10" you could split a 48"Diam log in half. So has anybody out there bought a secand hand swing mill and cut it up, rebuilt it so that it can slab a deeper slab?
With regard wide cutting narrow bandsaws, any body out there using one or knows of one being used. It seems that various companies advertise them but havent seen one working. If your wondering why I want to split large diam logs rather than mill with a swing blade, basically with large oak if possible we tend to quarter and saw on a bandsaw to get wide figured boards
aom

Rail-O-Matic

Quote from: Norwiscutter on January 16, 2007, 06:59:26 PM
After further thought, I think sticking with chainsaw heads would be best for my application because I want to keep the thing portable. So for the longer bar I was thinking of using (66") what is the concenus concerning two saw heads versus one? I like the idea of being able to easily take the saw heads off the bar when setting up the rig on site.

I have written many a thread on a double header, but here is what  Procut is saying, I second this after trying the same route.

http://www.procutportablesawmills.com/doublesawbars.htm
Logg-saw bandmill, Stihl 088, Stihl MS880, Stihl MS660, Stihl 017, 018,  Husky 385XP, Husky 395, Husky 350, Echo WES 350ES, Echo CS 27T, Jonsered 2150 Turbo, Jonsered 111S, good old saw still going after more than 20 years hard service.

Murf

Preamble: This is purely achedemic speculation based on raw calculations, and not based on any actual tests on a log.

I agree the 2 saw engine idea is deeply flawed, for several reasons, as set out in Procut's article.

This is the very reason for my "bigger hammer" theory of running a larger 4 stroke engine instead.

I don't understand why a slabber would be limited, other than physical space within the saw's frame, to depth of cut, the only limiting factors should be, aside from horsepower, length of wood contacting the saw, moisture level of the wood being cut, hardness of the wood and of course the opening the saw has through which the log has to pass.

When cutting thicker slabs it might be necessary to use wedges or something to support the weight, but I don't see that that would even be a big deal.
If you're going to break a law..... make sure it's Murphy's Law.

aom

Funny really, will malloof said the same thing years ago, better to go down the 1 engine route, so for more power 4stroke engine better[easier maintenance]. Thought it better to go down the double headed bar route. Why?, been using one and using 56"canon bar, my guess is that a double end bar with helper handle[hence larger bearing etc] in the long term would last longer, as compared to a normal guidebare with its much smaller nose bearing etc.
regards aom

Ianab

Murf

I agree with your post there.

Some ideas for you. This page shows a big Dolmar made chainsaw mill that will splt big logs or cut slabs.
http://www.talaricohardwoods.com/logyard.htm

These pictures are the big brother Lucas slabber, 9 ft bar with a nice reliable 4 stroke engine.







A normal Lucas slabber for comparison, although this one has had the frame modified to increase the depth of cut.



Wedges inserted in the cut is standard operating procedure. The BIG slabber also needed a crane to offload the slabs  :D

Cheers

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

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