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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.
Electric Chainsaw Mill.
(This page)


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Workshop Fitting Out & Project Pages.


An Electric Chainsaw Mill.

Why consider using an Electric Chainsaw for milling?
As a wood-turner and small-project woodworker, I obtain a variety of hardwoods and some softwoods such as Yew and Pine from tree surgeons, arborists, farmers, park & estate managers who, when felling or pruning, kindly look out for unusual timbers with attractive or unusual features or figuring. Normally most of the wood from these sources would be destined for shredding or for re-sale as firewood. For the past 9 years I have been able to successfully convert such timber using a 1.8 Kw Bosch mains powered electric chainsaw with a 16" (40 cm) guide bar. Once cut to a manageable size, conversion is completed using a medium sized bandsaw (capable of ripping to a maximum depth of 190 mm (7½"), to cut boards and circular turning blanks up to about 16" (405 mm) diameter.

However, with some of the more attractive and rare timbers offered, instead of butchering the wood by free cutting, I would like to utilise as much as possible by using the chainsaw with a small "Alaskan Mill". The overall diameter of these boles and boughs is generally limited to about 14" (355 mm) diameter, with a maximum length of about 91.5 cm (3 feet) which (depending on the 'greeness' of the timber), is the maximum in weight and size that can be man-handled by one person for transport in the back of a car. The other major constraint in converting this timber is working in a residential area where the noise and pollution generated by a petrol powered chainsaw is really not an option. Ideally I want to continue using an electric chainsaw which occasionally can be adapted for use with a small "Alaskan Mill".

Why Milling is the toughest job for a saw.
Milling a wooden log usually involves the chainsaw cutting along the grain (or more simply put, cutting in a direction parallel to the log sides) which requires much more motive power compared to cutting across the grain (cutting across the fibres of the wood). Cutting across a log is also a smaller job as less wood has to be cut and the saw is quickly through the maximum width (log diameter) of cut. Compare that to cutting along the log which requires near maximum power and involves the saw cutting near the maximum width of the guide bar for the length of the log being milled. Milling is therefore the toughest job for a saw and will push it to the extremes of it's capabilities.

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 can electric chainsaws be considered for occasional small-scale milling? The chain and the drive sprocket specifications for these saws, as discussed below, are designed to deliver maximum performance.

How Electric Chainsaws are configured to deliver maximum performance.

Chain size
Chains are manufactured in five sizes from small chains (designed to maximise the available power from small saws), to large (designed for the largest most powerful saws). The pitch ranges from:

For electric chainsaws it seems that ⅜" Lo Profile (0.375") has become the standard chain size used either with a gauge (width) of 0.043" (1.1mm), (e.g. Bosch electric Chainsaws), or 0.050" (1.3mm), (the gauge that most other mains powered electric chainsaws seem to utilise).

Torque
In electric chainsaws, torque is maximised by using smaller diameter drive sprockets (the teeth of these engage with the chain, driving it round the guide bar), using between 6 and 7 teeth. The overall effect is to drive the chain at a slower speed (than on larger chainsaws), but with a corresponding increase of force.

The Practical Investigation of Using an Electric Chainsaw with an "Alaskan Mill"

Although in theory electric chainsaws are underpowered for milling, I decided that it would still be worth experimenting with my two electric chainsaws to see what could be achieved for my small-scale occasional requirements.

Choice of Mill
I purchased a Royston 24 inch capacity "Alaskan" Portable Chainsaw Mill. These so called "Alaskan 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.

A Royston "Alaskan Mill"

Royston Alaskan Mill. Royston Portable Chainsaw Mill ("Alaskan Mill").

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

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Chainsaw Specifications.
The next option to consider is which (if any), of the two electric chainsaws at my disposal, could be adapted for milling?

Option 1: The Bosch AKE 40-19 S which has the following specifications:

Photograph of a Bosch AKE 40-19 S chainsaw. Photograph of a Bosch AKE 40-19 S chainsaw.

(Click on image for larger view)

Model No: AKE 40-19 S
Guide Bar (effective) Length: 40 cm 16" (Note that the effective cutting length is actually 38 cm (15")). It is 2⅛" (54mm) wide and is an Oregon Micro-lite® (narrow kerf cutting system), part number 164MLEA041. The guide bar is reversible (can be flipped), when the chain tensioner catch is unscrewed and attached on the other side of the bar. The bar mount is A041.
Power Output (kw): 1.9 kw
Power Voltage Supply (UK mains): 240 V
Total Product Weight: 4.5 kg (9.9 lb)
Oregon chain: Chain gauge 0.043" (1.1mm). Chain pitch ⅜" Lo Pro, 57 links. Chain was originally designated as 90SG by Oregon, now replaced by 90PX. Chain part No. 90PX057E.

Can the Bosch AKE 40-19 S chainsaw be adapted for use with an "Alaskan Mill"?
I have used this saw since 2009 and (with proper maintenance), it has proved to be very reliable in the first stage preparation of all kinds of hardwood and softwood boles and branches for subsequent conversion of the timber into bowl and spindle blanks (for woodturning).

However, it is NOT suitable for milling, being underpowered (rated at 1.9 Kw), and would certainly require an upgraded guide bar, as illustrated below.

Bosch AKE 40-19 S guide bar mounted in an Alaskan Mill. Bosch AKE 40-19 S guide bar mounted in an "Alaskan Mill".

This photograph of the guide bar mounted in the front and rear "Alaskan Mill" clamps illustrates a general problem with all electric chainsaws. They are supplied with guide bars designed for the home/occasional chainsaw user, with a narrow width and small diameter sprocket head to minimise the risk of kickback. Consequently the "Alaskan Mill" clamps are too wide for the bar with a risk of pinching, impeding the movement of the chain around the guide bar rails. There is also a high risk of the chain contacting the metal of the clamps which would potentially be extremely dangerous. In addition, the bar is thin with rails designed to fit a narrow chain gauge of 0.043" (1.1mm) and, when gripped in the mill clamps, it feels very whippy and easily bent when supporting the 4.5 Kg weight of the saw powerhead. Conclusion: It would be dangerous to attempt to use this saw with the default bar in a mill. A stronger bar, (A041 mount), supporting a Lo Pro gauge of 0.050" (1.3mm), would be essential as the bare minimum. Possibly the Oregon 160SDEA041 bar (with matching chain of 0.050" gauge), would be an option. But then the mechanical advantage of using the slimmer 0.043 gauge would be lost, which is an important factor in maximising the performance of the 1.9 kw rating of this saw.

(Click on image for larger view)


Chainsaw Specifications.
Option 2: The Oregon CS1500 which has the following specifications:

Photograph of an Oregon CS1500 Electric Chainsaw. Photograph of an Oregon CS1500 Electric Chainsaw.

(Click on image for larger view)

Model No: CS1500
Guide Bar (effective) Length: Advertised as 45 cm (18") but actually 43 cm (17"). This is currently about the maximum effective length of guide bar available for an electric chainsaw. The 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 (currently the maximum rating for a UK mains powered chainsaw)
Power Voltage Supply (UK Mains): 240 V
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 3/8 Lo Pro .050. (part No. G729-2).


Can the Oregon CS1500 chainsaw be adapted for use with an "Alaskan Mill"?
The CS 1500 has the maximum power rating for an electric chainsaw (2.4kw), and is one of the few designed to operate with an 18" effective length guide bar. The guide bar is certainly robust enough to support the powerhead when mounted in an "Alaskan Mill", but the problem lies in the 54 mm width of the bar which, like the Bosch AKE 40-19 S chainsaw (described above), is designed for the home/occasional chainsaw user, with a narrow width and small diameter sprocket head to minimise kickback risk. Consequently the "Alaskan Mill" clamps are too wide for the bar.

The Oregon CS1500 Chainsaw Guide Bar is too narrow!

Oregon CS1500 Electric Chainsaw Guide Bar. The Oregon CS1500 Electric Chainsaw Guide Bar.

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 "Alaskan Mill" clamping system (See description below).

(Click on image for larger view)

Oregon CS1500 Electric Chainsaw Guide Bar in Alaskan Mill clamp. 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.

(Click on image for larger view)


Would a wider guide bar be the solution?
One possible solution would be 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. The WoodlandPro Arbormax Chainsaw Guide Bar.

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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. I decided that an alternative method of attaching the existing guide bar to the "Alaskan Mill" might be a better option, as discussed below.

Using the Existing Guide Bar.
I decided to try an alternative method of attaching a chainsaw guide bar to an "Alaskan Mill" by bolting it in place instead of using clamps. This is a tried and tested method as shown on this Instructables; Chainsaw Mill Build, Use & Tips N Tricks very informative and helpful website. To apply the same technique to the project described here required one modification to the chainsaw guide bar and two modifications (one on each clamp) to the "Alaskan Mill". These are described as follow.

Step 1; Adapting the Guide Bar

Large chainsaw guide bar bolted to an Alaskan Mill. 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 to the author of this excellent and informative post can't be made).
(Click on image for larger view)

Oregon CS1500 Electric Chainsaw Guide Bar. Adapting the Oregon CS1500 Electric Chainsaw Guide Bar.

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 "Alaskan 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 (not shown in this photograph), towards the tail of the bar to enable a second point of attachment by bolting.

(Click on image for larger view)

Marking the position of a rear bolting hole in a chainsaw guide bar. Marking the position of a rear bolting hole in the CS1500 chainsaw guide bar - 1.

This shows how the position of the second (rear) bolt hole was marked out. With the guide bar plus chain fitted to the saw, the rear clamp of the "Alaskan Mill" is positioned on the guide bar just in front of the spike bumper (with about 5 mm to spare). The position must take account of variations due to the progressive wear of the chain. Note that it is also possible to temporarily unscrew and remove the spike bumper when using the saw in the mill (For safety and practical considerations the spike bumper must be replaced for normal use of the chainsaw).

(Click on image for larger view)

Marking the position of a rear bolting hole in a chainsaw guide bar. Marking the position of a rear bolting hole in the CS1500 chainsaw guide bar - 2.

Measure back from the first line, half the width of the "Alaskan Mill" clamp (in this case about 12.5 mm), and draw a line parallel to the first line. Draw another line to intersect this at half the width of the guide bar (54 ÷ 2 = 27 mm). Where the two lines intersect on the guide bar is the position of the additional bolt hole.

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Drilling a rear bolting hole in a chainsaw guide bar. Drilling a rear bolting hole in the CS1500 chainsaw guide bar.

This is best done with the guide bar clamped to the table of a drill press. 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 hole was the only modification made to the guide bar.

(Click on image for larger view)


Step 2; Adapting the Royston "Alaskan Mill"
This required two new holes to be drilled in the upper parts of the guide bar clamps (one new hole in each clamp).

The positioning of new attachment points in the Alaskan Mill clamps. The positioning of new attachment points in the "Alaskan Mill" clamps

Two new attachment holes in the upper parts of the "Alaskan Mill" rear and front clamps were required to enable the CS1500 chainsaw guide bar to be bolted on instead of being clamped.

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Drilling a new attachment point in the Alaskan Mill rear clamp. Drilling a new attachment point on the upper part of the "Alaskan 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 tip of the guide bar).

(Click on image for larger view)


Step 3; Assembly of the CS1500 chainsaw to the Royston "Alaskan Mill"
With the modifications completed to the chainsaw guide bar and the clamps of the "Alaskan Mill", the next stage was to put everything together by bolting the chainsaw guide bar to the Royston "Alaskan Mill" clamps.

Components ready for assembly. Components ready for assembly

The components are shown ready for assembly. The large penny washers ensure that the narrow guide bar and chain are kept well clear of the metal of the "Alaskan Mill" clamps. Note that this method of attachment by bolting results in the lower parts of the "Alaskan Mill" clamps not being needed.

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Nose sprocket rotation test. Is the nose sprocket running freely?

With the front of the guide bar firmly bolted to the "Alaskan Mill" clamp, it is vitally important to check that the tightened nut & bolt is not pinching the bar to cause the nose sprocket to bind and not run freely. Check by rotating the sprocket by using a finger against the teeth as shown in this picure. There should be no binding or resistance of any kind.

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Components assembled. Assembled chainsaw with "Alaskan Mill"

This photograph shows the CS1500 chainsaw attached to the Royston "Alaskan 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.

Note that with the enlarged version of the photograph, hovering the mouse over the pictures changes the mouse pointer into a magnifying glass.

(Click on image for larger view)

Components assembled. Assembled chainsaw with "Alaskan Mill"

In this photograph, a vertical view of the attachment, shows how the penny washers give a safe separation between the cutting chain and the clamps of the "Alaskan Mill". This also shows the maximum cutting width of the guide bar when mounted in the mill which is 12¾" (325 mm).

Note that with the enlarged version of the photograph, hovering the mouse over the pictures changes the mouse pointer into a magnifying glass.

(Click on image for larger view)

Video of Dummy Run. Video of Dummy Run of chainsaw with "Alaskan Mill"

Having completed the assembly of the Chainsaw to the "Alaskan 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 "Alaskan Mill" is operating.

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

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.

Devising a cutting platform to support the "Alaskan Mill" and the timber being milled


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