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HOME PAGE FITTING OUT & PROJECT PAGES. PROJECT 1.
Bandsaw Installation & Configuration.
PROJECT 2.
Constructing a Workbench.
PROJECT 3.
Making a Wood-turning Sandpaper Dispenser.
PROJECT 4.
Log Cross-cutting Sled Jigs for the Bandsaw.
PROJECT 5.
Making a Chainsaw Horse.

PROJECT 6 (Part 1)
Electric Chainsaw Mill
Overview
(This page)

PROJECT 6 (Part 2).
Electric Chainsaw Mill
Design & construction
PROJECT 6 (Part 3).
Electric Chainsaw Mill
Assembly & operation

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Current Wood-Turning Project
Walnut Wood.
WT PROJECT 1
Making Belaying Pins
WT PROJECT 2
Experimental Drying
WT PROJECT 3
Walnut Platter.
WT PROJECT 4
Turning Green Cherry.

Workshop Fitting Out & Project Pages.


An Electric Chainsaw Mill (Part 1).

The cost of so-called "Alaskan" chainsaw milling attachments has come down in price. Currently (January 2018), It is possible to purchase a small (24" capacity) well-made mill for less than 80 GBP. These milling attachments are designed to be used with powerful petrol (gasolene) driven chainsaws but this article explores the possibility of occasionally using an electric chainsaw with a small mill.

SO DOES AN ELECTRIC CHAINSAW HAVE THE REQUIRED POWER TO DRIVE AN "ALASKAN MILL"?

The following table compares the required power ratings for petrol powered milling to the available power of electric chainsaws.

Minimum required power ratings for chainsaws driving an "Alaskan Mill" with the chainsaw Guide Bar lengths listed in column 1. (data adapted from the Granberg International website.)

Guide bar length

Guide bar length

Maximum Width of Milled Boards

Approximate Power Required for Petrol (Gasolene) powered chainsaws.

Approximate Power Ratings for Mains Powered * (UK) Electric Chainsaws

16" - 18" Guide Bar.
In an Alaskan Mill these will yield boards of 8" - 12" 50 cc, (about 3.2 hp or 2.4 kw) to 60 cc (about 4.0 hp or 2.9 kw) is considered to be the bare minimum for light to medium milling of soft and hardwoods. Electric chainsaws range from 1.8 kw (about 2.4 hp), to an absolute maximum of 2.4 kw (about 3.2 hp).

Most top-rated electric chainsaws have a maximum guide bar length of 16" (40 cm) with a few supplied with an 18" (45 cm) bar. Even a top-rated 2.4 kw 3.2 hp electric chainsaw will have a power rating equivalent to the bare minimum of the recommended power required to drive an Alaskan Mill.

20" - 24" Guide Bar.
In an Alaskan Mill these will yield boards of 14" - 20"

Not applicable as 18" (45 cm) is the absolute maximum length of the supplied guide bars and the required power (for bars in excess of 18"), is substantially beyond that of an electrically powered chainsaw using a domestic supply.

28" - 30" Guide Bar.
In an Alaskan Mill these will yield boards of between 22" - 26" 60 cc, (about 4.0 hp or 2.9 kw) to 64 cc (about 4.2 hp or 3.1 kw).
32" - 36" Guide Bar.
In an Alaskan Mill these will yield boards of between 26" - 32" 70 cc, (about 4.6 hp or 3.4 kw)
42" - 48" Guide Bar.
In an Alaskan Mill these will yield boards of between 36" - 44" 90 cc, (about 6.0 hp or 4.4 kw)
50" + Guide Bar.
In an Alaskan Mill these will yield boards of between 50" - 52" + 120 cc, (about 20 hp or 14.9 kw)
*Note that battery powered chainsaws are not considered here, as even the most powerful models with 18" guide bars are rated at about 1.2 kw, which is significantly below that of the majority of mains powered models.

The specifications listed above clearly show why serious electric chainsaw milling is not a viable option. But from the table above it seemed that small-scale milling with a 2.4Kw electric chainsaw driving the chain round an 18" guide-bar was possible and worth trying.

CHOICE OF PORTABLE MILL
I purchased a Royston 24 inch capacity "Alaskan" Portable Chainsaw Mill. These so called "Portable Chainsaw Mills" are much cheaper (Chinese made) copies of the genuine Alaskan Mills first developed in the 1960's by Elof Granberg and currently manufactured by the company that bears his name Granberg International. I'm not sure how the copies compare in quality to the "genuine" Alaskan Mills, but they are considerably cheaper (For example a Royston copy 24" mill is 77.98 GBP as against about 300.00 GBP for an equivalent genuine Granberg Alaskan Mill, December 2017 prices). The Royston (Chinese) copies seem reasonably well constructed and to be a good option for an occasional use mill.

Royston Alaskan Mill.

(Click on image for larger view)

Royston Portable Chainsaw Mill ("Alaskan Mill").
Photograph of an assembled 24 inch Royston Portable Chainsaw Mill.


Choice of Chainsaw.
Of the two electric chainsaws at my disposal the Oregon CS1500 was the only viable option. The Bosch AKE 40-19 S chainsaw is underpowered (rated at 1.9 Kw), has a 40cm (16") guide bar with a gauge (thickness) of 0.043" (1.1mm). This gauge is too thin to support the weight of the chainsaw powerhead of about 4 kg (9 lb), which is what it would have to do when mounted in "Alaskan Mill" mode. It would be dangerous to attempt to use this saw with the default bar in a mill.


Photograph of an Oregon CS1500 Electric Chainsaw.

(Click on image for larger view)

The Oregon CS1500 Electric Chainsaw.

The Oregon CS1500 has the following specifications:

Photograph of an Oregon CS1500 Electric Chainsaw.

(Click on image for larger view)

Photograph of an Oregon CS1500 Electric Chainsaw.
Model No: CS1500
Guide Bar (effective) Length: Advertised as 45 cm (18"), this is currently (2018) about the maximum effective length of guide bar available for an electric chainsaw. The guide bar mount is A041 and the supplied bar is an Oregon Double Guard 91, part number 180SDEA041, designed for Lo Pro ⅜" pitch chain of 0.050" gauge with 62 drive links. It is described as a lightweight, laminated reversible bar for the occasional and hobby user. Small radius nose reduces kickback. It has a maximum width of 2⅛" (54mm) and can be reversed (can be flipped), by unscrewing the chain tensioner and re-attaching on the other side.
Power Output (kw): 2.4 kw (3.2 hp, currently [evaluated in 2018], the maximum rating for a UK mains powered chainsaw)
Power Voltage Supply (UK Mains): 240 Volts ac
Total Product Weight: 5.7 kg (12.6lb)
Oregon chain: The guide bar will accept any chain that's Lo Pro ⅜" with a gauge of 0.050" (1.1mm), with 62 links. However, the CS1500 chainsaw comes with the Oregon PowerSharp® Chain and is unique in having an automatic chain sharpener built into the powerhead. Oregon part number 571037 (includes replacement chain & stone which must be replaced together), and Part Number PS62 (chain only). Note that if chain other than the PowerSharp® is fitted, the on-board powerhead sharpening stone must be temporarily removed (unscrewed), as it is only compatible with the PowerSharp® chain and serious damage can result if used with a different chain type.

Other compatible (non PowerSharp®) chains include Oregon low kickback chain (Part No. 91P062E), Oregon Lo Pro Ripping Chain (Part No. 91R062E), Stihl PMX Ripping Chain (Part No. 3614), Granberg Ripping Chain ⅜" Lo Pro .050. (part No. G729-2).


Fitting the Oregon CS1500 to the Royston 24 inch Portable Chainsaw Mill

The CS 1500 has one of the maximum power ratings for an electric chainsaw (2.4kw), and is one of the few designed to operate with an 18" effective length (0.050" gauge) guide bar which is certainly robust enough to support the powerhead when mounted in an "Alaskan Mill". The problem lies in the 54 mm width of the bar. The narrow bar width is not wide enough to extend outside the width of the "Alaskan Mill" clamps. This is shown in the photograph below.

The Oregon CS1500 Chainsaw Guide Bar is too narrow!

Oregon CS1500 Electric Chainsaw Guide Bar.

(Click on image for larger view)

The Oregon Double Guard guide bar as supplied with the CS1500 Chainsaw. Note the two holes of 6 mm & 7 mm diameter drilled through the bar near the nose. These holes (an original feature of the bar), facilitate the attachment of a PowerSharp® sharpening jig to the guide bar to enable chain sharpening when the saw is running. The 7 mm diameter hole was subsequently used (in part) for attaching the guide bar to the Royston Chainsaw Mill clamping system (See description below).

Oregon CS1500 Electric Chainsaw Guide Bar in Alaskan Mill clamp.

(Click on image for larger view)

The problem of clamping the CS1500 Guide Bar in an "Alaskan Mill" clamp.
The guide bar is too narrow for the clamp jaws which would pinch the rails. The running chain could also impact with the jaws of the clamp, especially if there was any slippage of the guide bar in the clamp jaws when the "Alaskan Mill" was in operation.


Would a wider guide bar be the solution?
One possible solution considered was to replace the existing bar and use something like a WoodlandPro 18" ArborMAX® Chainsaw Bar (Part number WPA 18 UM50). The specification is:

Effective Length 18" (45 cm), Pitch Low Profile (⅜" Picco), Gauge 0.050" (1.3 mm), Drive Link Count 62, Nose Sprocket 9 Teeth, Weight 1.40 lbs (0.64 kg).
The description states:
"The wide contour body and large radius nose makes this bar much stronger and longer lasting than standard consumer bars. These bars are made of three silicon manganese alloy steel plates that are electrically welded together. The center plate has been hollowed out to reduce weight. Rails are induction hardened for a long life. Sprocket nose tip contains high quality Swiss bearings held in place with 4 sturdy rivets."

The WoodlandPro Arbormax Chainsaw Guide Bar.

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The WoodlandPro Arbormax Chainsaw Guide Bar.

The broader form of this bar and sturdier construction would make it much more compatible with the clamping system of an "Alaskan Mill". Unfortunately these bars are currently unavailable in the UK. Also the downside of using a broader bar, is that it would diminish the performance of the electric saw, requiring more power to drive the chain effectively.


THE OPTION OF BOLTING THE EXISTING CHAINSAW GUIDE BAR TO THE PORTABLE CHAINSAW MILL

The author of Chainsaw Mill Build, Use & Tips N Tricks argues strongly against using clamps for the following reasons:

Large chainsaw guide bar bolted to an Alaskan Mill.

Photographer: "Bongo Drummer" (Click on image for larger view)

LARGE CHAINSAW GUIDE BAR BOLTED TO AN "ALASKAN MILL"
This is a modified photograph from the Instructables website of a Stihl MS440 petrol driven chainsaw with the guide bar attached using two bolts (one at each end of the bar), into the aluminium frame of a custom built "Alaskan Mill". The M8 bolts are made of high tensile steel and tapped into the frame of the "mill" to a depth of 50 mm. The actual length of the Stihl Rollomatic ES(uper) guide bar is not given but the top and bottom aluminium rails of the "mill" (in the photograph), are given as 900 mm (35½") long, so a guesstimate of the effective length of the bar might be 28" (710 mm).

Photographers pseudonym: "Bongo Drummer" (real name unknown so a proper acknowledgement can't be made)



STEP 1: DRILLING THE CHAINSAW GUIDE BAR

The unmodified Oregon Double Guard chainsaw guide bar (Oregon Part No.180SDEA041).

Oregon CS1500 Electric Chainsaw Guide Bar.

(Click on image for larger view)

The Oregon Double Guard guide bar as supplied with the CS1500 Chainsaw. Either of the two (PowerSharp® sharpener mounting) holes of 6 mm & 7 mm diameter passing through the bar near the nose, could be used for bolting to the Portable Chainsaw Mill, but the 7 mm diameter hole, nearest the nose of the bar was used, thereby maximising the potential cutting width in the milling process.

A new hole was drilled (See photograph below), towards the tail of the bar to enable a second point of attachment by bolting.


Marking the position of a rear bolting hole in the chainsaw guide bar - 1.

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MARKING THE POSITION OF A REAR BOLTING HOLE IN THE CHAINSAW GUIDE BAR - 1
This shows how the position of the second (rear) 6mm diameter bolt hole was marked out. With the chainsaw guide bar plus chain fitted to the saw, the rear clamp (25 mm wide), of the Portable Chainsaw Mill is positioned on the guide bar just in front of the spike bumper (with about 5 mm to spare), and a pencil line drawn across the front edge.


Marking the position of a rear bolting hole in a chainsaw guide bar.

(Click on image for larger view)

MARKING THE POSITION OF A REAR BOLTING HOLE IN THE CHAINSAW GUIDE BAR - 2
Measure back from the first line, half the width of the Portable Chainsaw Mill clamp (25 mm ÷ 2 = 12.5 mm), and draw a line parallel to the first line. Draw another line to intersect this at half the width of the chainsaw guide bar (54 ÷ 2 = 27 mm). Where the two lines intersect on the guide bar is the position of the additional bolt hole.


Drilling a rear bolting hole in the chainsaw guide bar.

(Click on image for larger view)

DRILLING A REAR BOLTING HOLE IN THE CHAINSAW GUIDE BAR
This is best done with the guide bar clamped to the table of a drill press. Use Cobalt twist drill bits. A centre-punch was used to mark the position of the hole at the intersection of the two pencil lines (to ensure the drill bit registered in the exact position). The drill press was set to its lowest speed and a 2 mm pilot hole drilled. The hole was then widened in increments of a millimetre to the final diameter of 6 mm. Oil was added whilst drilling to lubricate the drill bits. Drilling this single hole was the only modification made to the guide bar.


Distance between the bolting holes in the chainsaw guide bar.

(Click on image for larger view)

DISTANCE BETWEEN THE TWO BOLTING HOLES IN THE CHAINSAW GUIDE BAR
For the benefit of anyone replicating this adaption (using this Oregon 18" 180SDEA041 guide bar), the distance between the existing (nose) 7mm hole and new (rear) 6mm bolt hole is 355mm (14"). In the Royston Chainsaw Mill, this gives an effective maximum cutting width of 320mm (12⅝").


STEP 2: ADAPTING THE ROYSTON 24 INCH PORTABLE CHAINSAW MILL

The positioning of new attachment points in the mill clamps.

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THE POSITIONING OF NEW ATTACHMENT POINTS IN THE PORTABLE MILL CLAMPS
Two new attachment holes in the upper parts of the mill rear and front clamps were drilled to enable the CS1500 chainsaw guide bar to be bolted on instead of being clamped.


Drilling a new attachment point in the mill rear clamp.

(Click on image for larger view)

DRILLING A NEW ATTACHMENT POINT ON THE UPPER PART OF THE MILL REAR CLAMP
The position was marked with a centre-punch (to make a registration point for the drill bit). It was impossible to mount on the drill press, so was clamped using a Workmate portable bench vice instead, and drilled freehand. A 2 mm diameter drill bit was used to make a pilot hole (low drill speed), and was widened in increments of a millimetre to the final diameter of 6 mm. Oil was added whilst drilling to lubricate the drill bits. The procedure was repeated for the front clamp but drilled out to a diameter of 7mm (to match the pre-existing 7 mm diameter hole in the toe of the guide bar). Set the drill speed to slow and use Cobalt twist drill bits which are designed for drilling through metal.


STEP 3: ASSEMBLY OF THE CHAINSAW GUIDEBAR TO THE ROYSTON 24 INCH PORTABLE CHAINSAW MILL

Components for assembly.

(Click on image for larger view)

COMPONENTS FOR ASSEMBLY
All the components are shown here. The large penny washers ensure that the narrow guide bar and chain are kept well clear of the metal of the mill clamps.

Animation of the attachment of the front chainsaw mill clamp to the chainsaw guidebar bar.

(Click picture for larger animation)

Animated overview

This animated sketch shows how the front fastening bolt was secured with the M7 nut & bolt inside the square tubing of the mill clamp.

(Click thumbnail image for larger animatiom)

Sketch of assembled components.

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Sketch of assembled components

This sketch shows in detail how the front fastening M7 nut & bolt secured the front of the chainsaw guidebar to the square tubing of the mill clamp. The same technique was used for the M6 nut & bolt fastenings securing the rear of the guidebar to the mill clamp.

(Click thumbnail image for larger picture)


PUTTING IT ALL TOGETHER

The most difficult part of this operation was locating and tightening the M6 & M7 nuts in the square tubing of the mill clamps. Details are outlined below.

Components ready for assembly.

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Components laid out on a workbench, ready for Assembly

Tools needed include a double-headed long reach spanner with a ring at one end to fit a 10 mm headed (M6 bolt), and an 11 mm ring at the other end to fit over the head of an M7 bolt. It was essential that both ends of the spanner would fit inside the clamp box sections (20 mm width). A shorter normal sized double-headed spanner (also 10 mm & 11 mm capacities) and 2 wooden wedges helped to guide and keep the long reach spanner (and cradled nuts) in position within the box section. These were used when inserting the bolts through the chainsaw guide bar, penny washers and through the top of the box section to engage the nuts within the box section. The way that this was carried out is shown in the following two video clips.

(Click thumbnail image for larger view)

Bolting the chainsaw guidebar to the mill - part 1.

(Click picture to view video)

Bolting the chainsaw guidebar to the mill - part 1

Video demonstrating how the front end of the chainsaw guidebar was bolted to the chainsaw mill.

(Click thumbnail image to view video)

Bolting the chainsaw guidbar to the chainsaw mill - part 2.

(Click picture to view video)

Bolting the chainsaw guidebar to the mill - part 2

Video demonstrating how the rear end of the chainsaw guidebar was bolted to the chainsaw mill.

(Click thumbnail image to view video)

Note that this method of attachment by bolting results in the lower parts of the mill clamps not being needed.


COMPONENTS ASSEMBLED

Components assembled, bottom view.

(Click on image for larger view)

Bottom view of assembled chainsaw with the Royston 24 inch Portable Chainsaw Mill
This photograph shows the CS1500 chainsaw attached to the Royston Mill by means of two (M6 & M7) bolts through the guide bar to the clamps of the mill. It's crucially important to ensure that when the nuts & bolts are tightened, there is no pinching of the rails or impairment to the rotation of the nose sprocket or anything else to cause impediment to the free circulation of the chain round the guide bar.

(Click thumbnail image for larger view)

Components assembled, side view.

(Click on image for larger view)

Side view of assembled chainsaw with the Royston 24 inch Portable Chainsaw Mill
In this photograph, a side view of the attachment shows how the penny washers give a safe separation between the cutting chain and the clamps of the mill. This also shows the maximum cutting width of the guide bar when mounted in the mill which is 320 mm (12⅝"). (Click thumbnail image for larger view)

VIDEO OF A DUMMY RUN OF THE CHAINSAW WITH THE ROYSTON 24" PORTABLE CHAINSAW MILL.

Having completed the assembly of the Chainsaw to the Royston Mill, the next step was to run the saw to ensure that the chain ran freely within the framework of the mill. Note that the shield guarding the tip of the guide bar is fitted for this test. For reasons of safety, it is very important to ensure that this is fitted whenever the "Mill" is operated.

Video of Dummy Run.

(Click on image to view video)


What type of chain to use?
Having completed and tested the assembly of the chainsaw to the Royston Mill, before using the mill it was necessary to decide which sort of cutting chain to use. A number of available choices include:

Note that although the Oregon CS 1500 chainsaw can be used with any of the chains listed above, the on-board chain sharpening system can ONLY be used with the Powersharp® chain and under no circumstances should it be used with any of the other chains listed.

Ripping Chain Description
This refers to a special purpose semi-chisel saw chain with shallow angle cutters that is only used in chainsaw mills to make planks. The cutter angles (are usually at 10o, whereas with conventional chain the cutter angles are 25-35o), enable the chainsaw to cut smooth planks with a good quality finish to the cut timber. The rip cut is along the grain; essentially, "ripping" the wood apart, like splitting it with an axe, except the cut is straighter as some of the wood fibres are sliced. The rip cut has a tendency to bind the cutters of the chain as the wood fibres relax. Ripping chain is ALWAYS semi-chisel.

As the milled wood will be used mainly for producing turning blanks, speed of cut has a higher priority over quality of finish. The crucial question is whether ripping chain eases the load on the chainsaw when milling? I cannot find a definitive answer to that question but one quote stated "If speed of cut rather than quality of finish is the aim, then full chisel normal chain will do the job fine, and cut faster". On the basis of that quote I therefore decided to begin milling using the default Oregon Powersharp® chain, possibly experimenting with ripping chain at a later date.

The other big advantage of using Powersharp® chain is the on-board sharpening system which makes sharpening the work of a few seconds!


DEVISING A JIG TO SUPPORT THE PORTABLE CHAINSAW MILL AND THE TIMBER BEING MILLED


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