Starting a top bar bee hive

December 2018 update: The post below describes my first attempt at starting a top bar hive. My cunning plan didn't work out as I hoped, so I ended up trying a different approach - which did work. I describe my successful use of a "brushed swarm" in my later post here. However the process described below was useful for getting me some comb on top bars, which made the brushed swarm much easier. My evolving hive design is described in my post here. 

Today I started my first top bar bee hive. This has been coming for some time, and taken a lot of thinking, planning and building. Now to see if it works!

The brown top bar hive is on top of (and part of) the white 10-frame hive. The queen excluder is below the top white (brood) box.

Why top bar?

There’s been a long lead up to this: Erika and I kept bees for years (I started by catching a swarm in Abney Park Cemetery, Stoke Newington, London with my mate Gomez in 1985), until family life overwhelmed and we gave our hives away. A couple of years ago I got sucked back into beekeeping when Erika’s mother and brother started hives in Stanthorpe. They bought 10 frame, full depth boxes, so I ended being the only person who knew how to do bees, wasn’t scared of stings, and was tall enough and strong enough to lift the boxes.
10 frame full depth boxes (supers) are very heavy things, when full of honey. They need to be lifted high: onto a hive of up to 4 boxes (sometimes more), which is already on a stand to keep the hives above the grass and away from toads, termites, ants, etc.. Most times you go to do anything with the bees, it starts with climbing up and lifting a 40kg+ box full of sting-ready bees down off the top. I’m finding this is at the limit of my strength, which I don’t think is a good idea. I’m also squashing a lot of bees, especially when replacing heavy boxes onto crowded hives. This feels bad and gets the bees cranky.
There is no way my late-70s mother in law with arthritic fingers is going to be doing anything much at all with these he-man hives, which is a real pity. My strong but short brother-in-law is also not able to do much work on his hives when the honey is flowing. Both of them miss the pleasure of learning about the bees, the hives get neglected between my visits, and I end up responsible.
So I’m feeling pretty strongly motivated to find a way of keeping bees that doesn’t involve frequent heavy lifting from ladders.
Top bar hives fix this. They use a single box - one level. They don’t use supers (unless you get clever), so nothing heavier than a single comb (equivalent to a single frame) needs to be lifted (unless perhaps the hive has a heavy lid). They are managed by frequent, low-intensity visits, instead of periodic major exercises. I’m hoping they are suited to a determined old lady who has a fascination with nature.

Home made

I also like the whole top-bar style. Especially that I can make every part of the hive myself, from wood we have grown and milled, with my existing tools. The top bars can be sawn from off-cuts which would otherwise be firewood.
The hive I started today has been made in my workshop at Mt Glorious, and brought out to Stanthorpe this week. I’ve made 2 nucleus hives (small hives to start a new colony in). One has an open bottom and is designed to fit on top of a standard 10-frame box - that’s how I’m planning to start the hive with a colony of bees.

This brown top bar hive has no bottom, so it's open to the 10-frame brood box below it. The lid has a layer of pine boards on top of the top bars for insulation, then a corrugated iron roof.

The other box has a bottom and is planned to be self-contained, housing the new colony when it is separated from the 10-frame hive.

This is the top bar nucleus hive with a bottom, intended to house the independent colony when it's separated from the mother hive. 

The boxes are made from un-treated slash pine boards I cut years ago with a chainsaw mill, but which have been slightly attacked by borers (because I didn’t treat the wood with borax after milling), so the wood can’t be used for furniture. If it works for a few years as bee hives, I’ll be pleased - and in the dry Stanthorpe climate I expect them to last fine. The boxes have one coat of water-based paint (from the tip).

What design?

I’d like to benefit from other people's expert experience, but it took some time to decide on a design - I even started and then abandoned some bars and a box after deciding they weren’t the way to go (bars too short and box too deep).
My main concern with hive design is to avoid combs breaking off on hot days, due to being too deep and narrow. I’ve used the top bar design of Les Crowder, whose excellent youtube video is very helpful, and whose book I bought. Les uses bars 20” long, which I metricised to 505mm. I was a bit torn between Les’s size and the “Standard top bar” size of 19 1/2” (495mm), but if I ever want to I can easily cut mine down to standard length. I’ve made the box sides from 250mm wide boards, tilted at 60* to horizontal. This all results in internal dimensions of 464mm max width (at top) and 200mm depth.
To make the top bars, I’ve dressed my timber to 35 x 25mm section, 505mm long. I have then rebated both sides and ends of the bars, to leave a bar 18mm thick, plus a square ridge along the bottom for the bees to start their comb on. I ran melted beeswax down the ridge, which is advised to help the bees start their combs where you want them to.

Top bar, with waxed ridge planed into the bottom face (upside down in picture)

Getting bees into the top bar hive

Today’s great event is simply the placement of the open-bottomed top bar box onto one of the family's 10-frame hives. This took some thinking, right up to this morning, and I hope it works.
Bee keeping context is that it is mid-summer, with a good flow of honey from local Orange gums (first Orange gum flowering in about 10 years). I’ve chosen a strong 10-frame "mother hive” which is working hard on honey production.
My first step was to take off a full box of honey from the top of the "mother hive". I can extract this tomorrow with some other boxes.
Then I inverted the order of boxes on the mother hive: I took off the 2 (half filled) honey supers from the brood box, and removed the queen excluder from the brood box. I took the brood box off the base board and put it aside. The 2 honey supers were then placed onto the base board, and the queen excluder placed on top of the honey supers. The brood box was then placed on top of the queen excluder, making a 3-box hive with brood box on top. The open-bottomed top bar box was then put on top of the open-topped brood box, with top bars and a lid on top of the top bar box. There are no openings in the top bar box.

Hopefully the bees are building combs exactly along the bottoms of the top bars

Now the bees have access to the top bar box, to hang combs from the top bars. The queen has access to lay eggs in the new comb. My plan is that brood and honey combs will be built into the top bar box, and when it’s all looking sweet, I can transfer the combs (on the top bars) into the other top bar box, where the bees will find themselves queenless and rear a strong (but fair) queen and we will have an independent top bar hive to work from.
Once a colony is established with a queen in the nucleus top bar hive, I can build a longer hive (I'm planning on 1200mm) and shift the colony into that, for proper production next year (if I'm lucky).
The main risk (I can see) is that the bees ignore my instructions and build their comb all over the place. I’m hoping weekly visits will be able to push things into line. In hope of encouraging compliance, I have made 3 top bars with central grooves instead of ridges, and attached some strips of foundation wax into the grooves with hot wax. At the last minute I realised that I’ve put in the foundation in the wrong orientation: normal comb has vertical lines in the hexagons, I’ve put the foundation in with horizontal lines. I don’t know if bees will work with wrongly-oriented foundation, let’s call this an experiment…
The other risk is that the queen rearing is unsuccessful, and the top bar hive dwindles on separation. If that happens, I can re-unite it with the 10-frame hive and try again when the season is good.

Update 24 August 2018

Progress has been slow with the top bar hive. About the time I installed the top bar super, the Orange gum honey flow stopped. As there are only very few honey-producing tree species locally, and it's been very dry, honey production has been stopped since. 

The consequence of this for the top bar project has been that without a honey flow, there has been no comb building, and the top bar box has been pretty much empty. A few months ago a little burr comb was built on the tops of the brood box frames, so I tied some of that onto a top bar to help get things started. The bees did anchor the comb to the top bar, but really nothing happened more than that. 

Today, however, I had a look and found grand progress! A few bushes and trees, mostly not native locals, are flowering, and giving the bees a light honey flow, so they're building some comb. Here are some pictures: 

This bar had some wild comb tied on, and is the end frame of the top bar super. Honey and comb!

The second top bar, with beautiful brand new comb

Just getting started on this bar

To my surprise, the comb is being built exactly where I asked them to. Consequently it was easy to lift out the bars to inspect the comb. To try to build on this alignment, I shuffled the 2 first bars apart and added in a bare top bar between them, hoping this will guide the construction of a new comb on the bare bar. 

Makita electric chainsaw review

Makita UC4041A: a good electric chainsaw for recutting firewood in the shed

Why I bought a new saw

I use electric chainsaws quite a lot, mostly inside the shed, cutting pole wood into firewood blocks. My old Stihl E140 was working fine, but I like to have a backup for the tools I depend on, so I went looking for a new electric chainsaw (see my blog post on electric chainsaws here).

The options

I didn’t see very many options for a good quality electric chainsaw. The Stihl MSE 170 looks like it would be good, but it’s expensive at $380 and I suspect parts are costly too. Stihl has dropped most corded electric chainsaws from its Australian catalogue (they want to sell cordless) and the 170 is the last one standing. In Germany Stihl list 9 corded chainsaws, including a 2.5kw model which runs 3/8” chain on a 16” bar, that costs around $1000. Husqvarna sells a 2kW corded chainsaw in Europe, but not in Australia. Clearly Australia has a weak market for corded electric chainsaws.
There are a few low cost, low quality corded saws available, which I took no interest in. The time spent and the materials wasted on poor quality, un-repairable machines are not worth it. Saws in particular have to work well to work at all.
The Makita was priced at around $200, was available from many retailers, and importantly, had easy and low cost availability of spare parts. Tradetools priced a replacement armature (commonly burnt out) at $62.

The Makita

I like the new Makita chainsaw. It’s sturdy and well made, has good power (for an electric saw), and is comfortable to use.

Makita with Stihl E140: same format really

This is the Makita chain sprocket, which will need replacing every 2 or 3 chains

Bar and chain

In Australia the Makita is only sold with a 16” bar, but in other countries the same body and motor is sold with 12” and 14” bars – much better suited to the motor’s power. In Australia, our timbers are generally harder and tougher than other countries, so a shorter bar makes more sense here, to reduce the load on the motor and provide more power per tooth. I'm not sure why Makita thinks Australians need the long bar, something with Aussie blokes?...

Makita box image appealing to buyers with bar inadequacy issues

A long bar is easily swapped for a short bar, so that wasn’t a deal breaker.
The Makita uses Oregon 3/8” Low Profile chain, which is normal on small chainsaws. The chain and bar supplied were narrow 1.1mm gauge, which cut a narrow kerf (the slot cut into the wood), reducing the load on the motor. The teeth are shorter than standard 3/8LP chain, promising a shorter chain life - they will file away sooner.

Standard Stihl 3/8LP chain above, Makita (actually Oregon) low kickback chain below - note the short teeth and the kickback-reducing ramps in front of the depth gauges

Makita uses the same chain bar base pattern as Husqvarna, so there are plenty of non-genuine 3/8”LP replacement bars available.

The Makita bar above, Husqvarna bar below - same pattern

I was able to buy a couple different 12” bars cheaply online, one of them was described as for 3/8” chain when it was for 3/8” LP. I also buy chain loops from Huztl.net which work very well. Interestingly, different bars sold as 12” were different lengths, needed different numbers of chain links and definitely weren’t 12” long in cutting length.

Cheap bars and chains: some feedback

One of the short bars I bought for the Makita was sold with a “Mondis” branding on ebay, with a chain, for $28 - very cheap. It fit straight on and worked, but needed some attention and understanding to work fully.
Like many cheap Chinese bar and chain sets, the bar groove was significantly too wide for the chain supplied, and the bar rails (the edge where the chain slides along) were not level. I found it worthwhile to hammer and dress the bar before its first use, closing the rails together to fit the chain without sideways slop, and grinding the rail surface square and smooth (see my video on hammering and dressing chain bars here).
The Mondis chain also has some problems of geometry. The cutter top plates are too narrow to cover the full width of the kerf, leaving about 1mm between left and right teeth which isn’t directly cut. This is fine for crosscutting, but means the chain won’t rip because it leaves a wafer of wood uncut down the middle of the teeth. For most firewood cutting, this is no problem, but it does mean this chain can’t be used for ripping.
For someone who just wants a machine that works and pays a shop to do repairs, cheap bars and chains are often a dud: they need some work to be useable, or at least will need some after a short cutting life. However if you are willing to do some saw doctoring, they will do a lot of work and save you some money.

Chain kerf

Trying different chains, I noticed significantly different kerf widths. The Oregon narrow chain supplied with the Makita cuts a kerf of 5.5mm, where the 3/8”LP chain on the Mondis cuts a kerf of 6.8mm: 25% wider than the Makita. Standard Stihl 3/8LP 1.3mm gauge chain (after a few sharpenings - which makes them narrower) cuts a kerf of 6.0mm (10% wider). I’m not sure how much more power the wider kerf takes to cut, presumably more, but I don’t believe it would be 25% more, it certainly doesn’t feel like it is working harder. The main load in normal crosscutting is in cutting the end grain of the fibres, which is the same whatever the kerf width.

Bar and chain adjustment

My preference for simple, durable and repairable, instead of complex and sophisticated, makes me mistrust the tool-free chain and bar adjustment system in the Makita (and plenty of other new consumer chainsaws). My mistrust is comforted, to a large extent, by my assessment that when/if these components break in the Makita, I'll be able to make a relatively simple bush mechanic repair.
Instead of old-fashioned bar nuts, the Makita has a sort of plastic folding wing nut, designed to be undone without using a spanner.

Clutch cover with plastic folding wing nut

This seems robust enough, but if it gave trouble, it is easily replaced with a normal M8 nut, or (more likely for me) a standard Stihl bar nut which has a bigger bearing surface and can be turned with a normal chainsaw tool (and is available very cheaply from Huztl.net).

See: a Stihl standard bar nut spins straight on. That feels better. 

More potentially problematic is the chain tensioning mechanism, with a finger wheel, presumably using a pair of bevel gears to drive the chain tensioning thread. This works fine but feels flimsy. If it broke, it looks like it could be easily enough removed and bypassed by drilling through the plastic housing beside the bar, to install a traditional bar-side chain tensioning screw (oh for simple, reliable, old-style machines...).

The black metal bit below pushes the bar forward to tension the chain. I reckon it could easily be replaced with a traditional bar-side screw by drilling thru the plastic 

This vulnerable-looking chain adjustment mechanism is probably the aspect of this saw I feel most sceptical about. However I see it as easily repairable, and thus something I can easily live with.

Safety

The Makita has all the usual safety features of good electric chainsaws. It has a thumb button which must be depressed to use the main switch (I want to call it the throttle, but it isn’t). It has an effective chain brake for kickback. It has a run-down brake which stops the motor quickly when you take your finger off the main switch.
The chain supplied by Makita is low-kickback chain, which has a geometry that reduces the digging-in of teeth when they’re going around the bar nose. The disadvantage of this type of chain is that it also makes the chain poor at boring cuts, where you do want the chain to cut as it turns around the bar nose. I prefer to use standard chain and be able to do boring cuts, but for the infrequent chainsaw user, the low-kickback chain is safer.

Summary

The Makita works very well. 1800 watts of power is noticeably more than my 1400w Stihl, and makes it easy to maintain high motor rpm (this is very important to avoid overheating the motor - see my post on electric chainsaws). It seems robust and well built, and after a few hours of use I’m very happy with it. I’m careful not to do frequent starts (which heat the motor) when cutting small pieces: I take the risk of keeping the motor running between multiple cuts. I would advise avoiding cutting with the full bar length, and considering a shorter bar and chain. Overall, this seems to me like the best buy for an electric chainsaw in Australia.

Update - 18 months later

Recently I broke the chain tensioner on my Makita saw. A falling branch gave the bar and chain a bit of a pinch, which managed to break off the little stud that pushes the bar forward when tensioning. 

The bar tensioning stud is missing from the black rectangle which slides back and forth under the bar stud - it broke off

To repair, I split the case and dismantled the chain tensioner. I drilled out the remains of the stud, cut a piece of spring steel from a garage door spring, and brazed it into the hole where the original stud had been. A simple enough repair - if you have access to brazing gear. 

While the case was open, I took a couple of pictures:

This is the right hand side of the case - the gear drives the chain sprocket. On the right of the gear is the cover for the chain tensioner mechanism. The gears are steel and appear robust. I packed in some extra grease before reassembling. 

Here's the left side of the case - that includes the motor. The little gear is on the end of the motor shaft, and to its left is the oil pump. 

Getting the most from electric chainsaws

Here I explore some of the issues for electric and low-powered chainsaws, including the sensitive question of bar length

The benefits of electric chainsaws

We have a shed full of petrol chainsaws, which are a marvellous technology: powerful, fast, reliable and able to work anywhere. No other household technology can deliver such a big energy return on energy invested: delivering large amounts of wood fuel energy from a small amount of fossil fuel.

Compared to petrol saws, electric chainsaws are much less powerful and much slower for bigger cuts. They are also more fragile: their motors can be quickly wrecked by labouring them. But if you treat them right, electric chainsaws are an economical and helpful asset for the frugal household. They are cheap to buy and run, and last a long time if used carefully. They start instantly and easily – a boon to the house without bush mechanic skills. In our household electric chainsaws use free surplus solar electricity from our PV panels (we only use them when it’s sunny) to produce wood energy. They make no smoke and can be used comfortably in a shed. They are relatively quiet and don’t fill our valley with motor noise. They require much less time on maintenance – the motors go for years needing only cleaning with compressed air. When used for the right jobs, with care and understanding, they’re great.

Cordless electric chainsaws

A Stihl cordless electric chainsaw: I wouldn't have one

Battery-powered chainsaws are becoming prominent in the shops, but they look like a poor deal to me unless you’re doing a lot of something that really uses their cordless characteristics (perhaps like pruning trees in an old people’s home). Lithium batteries are remarkable energy carriers, but they are very expensive, use a lot of energy and valuable materials to produce, and they only last a few years. I love lithium batteries for electric bikes, where their power is a good match for the job, and they help to take a whole car off the road. But I think cordless chainsaws are pushing the battery thing past its effective zone: only just enough power for a very small chainsaw, a short charge life, requiring frequent recharging or multiple batteries, expensive saws and expensive batteries, and expensive replacement in a few years. 
I service a family cordless chainsaw (a Stihl), and I'm very unimpressed: the chains are extra narrow to reduce cutting load, but have tiny teeth with a very short life. The bars are also small, light, weak and short-lived. Over time, the cost (money and resources) of the saw, plus batteries, plus chains, bars and sprockets, promises to be far more than a larger saw. Really, the only plus is that they're quiet and don't need an extension cord. 

If your goal is frugality and energy efficiency and your product is household firewood, I'd leave cordless chainsaws alone. I expect far less cost and fossil fuel will be invested in using a petrol saw to cut wood into lengths in the forest, then recut back at the shed with a corded electric saw, than the embodied manufacturing energy in a cordless saw and batteries.

My experience with electric chainsaws

I’ve had good and bad experience with electric chainsaws, over 20+ years. My first was a Stihl E20, a marvellous 2kW machine made for professional use, comfortably pulling 3/8” chain on a 16” bar. It did a lot of work before its armature was cooked while a friend was using it. I was unable to get a replacement armature at the time, so it went into a sack in the shed. I was recently quoted $355 for an armature: this seems excessive to me so I don’t plan to repair it currently. Stihl no longer sells the bigger electric saws in Australia.

I then bought a Stihl E140 (1400W), which has worked well for over 10 years and cut many tons of wood. It’s mostly used in the shed for firewood: re-cutting short poles of smaller diameter wood to stove length. It cuts clean wood, up on a saw horse, so chains stay sharp for surprisingly long and have long lives.

Here's my Stihl E140, on the saw horse where it's cut many tons of wood

I’m very careful to maintain a high motor speed while using this saw, being conscious of the many power tools I’ve seen that have had their motors burnt by being worked too hard and run too slow.

My E140 was supplied with a 14” bar running 3/8 low profile (LP) x 1.3mm gauge chain. This has always been obviously too much bar for the saw: the motor can’t pull that many teeth through wood without being overloaded.

I now have a Makita 1800w electric chainsaw, reviewed in the next post. It's good, cheap and repairable at reasonable cost - I think Stihl has lost me as an electric saw customer. 

Makita and Stihl E140 side-by-side: basically the same layout

Who’s got the biggest bar?

To get the most from small saws, especially electric, we do need to talk about bar length.

Marketing of domestic chainsaws seems to focus on exploiting blokes’ macho anxieties, and I reckon most small chainsaws are sold with bars that are simply too long for them. It’s as if people are being told they’re getting more saw if the bar is long – but they’re not.

Box photo designed to plug in to bar-length anxiety disorder

With all chainsaws, you get the best out of them with the shortest bar that will do the job, and this is much more so with low powered saws like electric ones. Short bars are safer: their noses are less likely to contact another piece of wood behind the cut and cause kickback, if they do kickback they have less leverage over the operator’s arms, and they are simply safer by being more compact. Short bars make a saw lighter to carry, quicker to sharpen, and lubricate bar and chain better with a given amount of oil.

On top of all this, a short bar makes your saw more powerful (in effect). There’s less chain dragging through less bar groove and wasting power on friction. Most importantly, a short bar sets a maximum number of teeth that can cut wood at the same time, which has real advantages.

With all types of saw, a key issue is power per tooth. When a saw is cutting, the motor power must be divided amongst the teeth that are actually cutting wood. The closer together the teeth are, the more teeth bite at once in a given cut, and the less power each tooth can have.
Up to a point, the more power each tooth gets, the more efficient the whole sawing process is: the tooth can cut deeper, lift chips instead of dust, and the tooth will stay sharp longer because it isn’t "rubbing" (rubbing is when a saw tooth rubs dust off the surface instead of biting under and lifting chips or a shaving. It happens to any type of wood saw if it's too blunt or underpowered).
A tooth that is biting deeply and cutting good chips will produce a high volume of chips, that are more likely to fill the space between the saw teeth, potentially overloading the cut with sawdust. Wider tooth spaces and shorter cuts can remedy this.

Lots of low-powered saws are sold with 16” bars (including the Makita reviewed in my next post). This is (I find in practice) too long for them. These saws don’t have enough power to pull 16” of teeth cutting at full depth, and if you try, their motors will overload and bog down, risking motor damage. To avoid overload, the operator can hold the saw back and make the teeth rub, which is slow and inefficient and also blunts the saw. He (or she) may rock the saw so that fewer teeth are cutting at any one time – clumsy and ineffective. If the operator pulls the saw back and uses the outer half of the bar, it will reduce the number of teeth cutting. However this seriously risks kickback, as the spikes are not engaged in the wood and the tip of the bar is pushed into the back of the cut, with a lot of leverage over the operator’s arms. These issues of power and safety are easily addressed by using shorter bars.

If you really need a long bar on a low-powered saw because you can’t do your cut any other way, you can increase the power per tooth by reducing the number of teeth along the chain. One way to do this is using “skip tooth” chain, which has 2 (or sometimes 3) blank links between teeth, instead of the usual 1. This is often done in chainsaw milling, where long bars are often used cutting in a difficult orientation (teeth ripping across end grain). Another option, also used in chainsaw milling, is to take a normal chain and grind away most of the top plates of a proportion of the teeth, following the style of Granberg ripping chain (have a google) - this doesn't have to be just for milling. 

Photo of modified chain

If you’re using a long bar so you can cut wood on the ground while standing up, there are often better ways. Squatting and kneeling are both good for your body! And you will reduce your cutting into the ground – the reliable way to blunt your saw and wear your bar.

Getting a shorter bar

My advice (if it isn’t already obvious) is to use a short bar on an electric chainsaw: 12” is a good size for most. You may be able to ask for a short bar on purchase, but most saws come in a box without options, so you may need to change bar and chain yourself.

If you want to buy a bar for a saw, you need to first know the chain pitch: this is a measure of how big the teeth and links are. Most consumer electric saws have a pitch of 3/8” Low Profile (also called 3/8LP or 3/8P). 3/8” means that the average length of a link in the chain is 3/8 of an inch (measure the distance between one rivet and the second one on, and halve it). A saw with a pitch of 3/8” LP will have a drive sprocket (on the motor) of 3/8” LP, and the bar will also have a nose sprocket of 3/8” LP.

3/8” Low Profile is different from and not compatible with standard 3/8” saw chain. It is specially made for small saws. Stihl calls it “picco” chain. 3/8LP has largely superceded the old ¼” chain for small saws, because it has 1/3 fewer teeth. In line with the principle explained above: on a lower powered saw, you want fewer teeth so that they each have more power. I’ve noticed that 3/8” LP bars are often sold as 3/8” (without mention of low profile), which is not helpful. This can make buying online a bit risky, but I’ve never heard of a 12” 3/8” not-low-profile bar, so that helps.

The chainsaw bar and chain have another critical measure: the pitch. This is a measure of the thickness of the chain drive links: the hook-triangle shaped bits that run in the groove. If the sprocket on the chainsaw is 3/8” LP it can drive any gauge of 3/8” LP chain. However the bar and chain need to be the same gauge, or the chain will be too tight or too loose side-to-side. If you are getting a new bar for your chainsaw, you don’t need to use the same gauge as your old bar, but you need to ensure you get chains of the same gauge as the new bar.

Chain of a particular pitch and gauge can be bought either in ready-made loops, measured by the number of drive links, or you can buy a roll (usually 25 or 100 feet long) and make your own chains. Riveting chain into loops is relatively easy, and doesn’t need any bought tools if you have a little metalworking ability.

Cheap Chinese bars are okay, if you are willing to give them some attention before using them. The ones I’ve been trying on my electric saws seem to mostly be made for pole saws: 12” bars, taking 3/8” LP 1.3mm gauge chains. A number of these I’ve tried seem to have too wide a gauge of bar groove for the chains supplied with them (like some Baumr chainsaws – see my review here). This will probably work fine when new, but will become a problem after a while. Hammering a new bar to fit the chain gauge is a reasonable solution, which I’ve used sometimes. Cheap bars sometimes also need dressing: filing, grinding or linishing the bar rails (the surface the chain runs on around the edge) to make them square. Here's a video on how to hammer and dress an old bar:

Electric motors

A key thing about electric chainsaws is that they have electric motors (!), and that these are very different from petrol motors. What kills petrol chainsaw motors is (roughly speaking) going too fast or too dry (too little oil or too lean a fuel mixture). What kills electric motors is going too slow.

The faster an electric motor goes, the less power it draws. The slower it goes, the more current it draws and the more heat it generates in the motor.

When you first switch on an electric motor, it draws a huge current for a short time until it spins up. Next (before it gets a job to do) it uses minimum current when spinning at top speed with no load. Then, as the motor is loaded up and slows down, it draws more current and becomes more powerful. However if the motor is further loaded and slowed even more, the current increases but the output power decreases. When it’s bogged down, a high proportion of the electric energy stays in the motor as heat (instead of leaving as shaft power), and the copper windings heat up. If the copper windings get hot enough, their insulation will start to fail, and electricity can then find short circuit paths through the motor, making even more heat and “burning the motor out”. 

Brush motors, as used in mains powered chainsaws, drills, circular saws etc., often show this sort of winding failure as arcing around the brushes. This is usually a symptom of winding failure in the armature: the spinning rotor in the centre of the motor. Burnt armatures can’t generally be repaired, but they can often be replaced if reasonably priced. I recommend checking the price of a replacement armature when considering a new electric chainsaw (or other large brush-motor power tool).

Some electric chainsaws, including my Stihl E140, are made with a thermal cutout switch, to help protect the motor. This switch doesn’t sense the temperature of the motor windings, instead it is designed to heat internally in a similar way to the motor, and to switch off when the current has been high enough for long enough.

Electric chainsaw consumables

If you’re using an electric chainsaw to produce firewood, or some other repeating task (not just pruning the garden twice a year), it’s worth being conscious of what parts you can expect to consume over time.

Chains and sprockets are the main consumables of any chainsaw. These parts wear and are replaced together, like the chain and sprockets of a bicycle.

It’s most economical to rotate 2 or 3 chains together with one sprocket, then replace chains and sprocket when the chains are sharpened away. As most chainsaws are sold with a single chain and a new sprocket, it’s good to decide on what bar you intend to use soon after you get your saw, and get 2 or 3 chains to suit. This could be from the seller, or from another supplier, especially if you are chainging bars. I change chains and turn over my bar (to wear both edges evenly) every few sharpenings, swapping to the chain with the longest teeth.

I usually use chains until teeth start breaking off, because the teeth have been sharpened so far back. By the time they are this worn, they cut a narrower kerf and are more difficult to use.

The sprocket will take a long time to wear – you’ll have to wear out 2 or 3 chains first. However I like to have these things in stock well ahead of time: living out of town it saves a lot of cost and trouble to be well stocked.

The bar will last for a few sprockets – which is years of cutting. Unless they get bent by a big log falling on them, well maintained bars wear out by the groove becoming too shallow for the chain – so the drive links reach the bottom.

Electric chainsaws, used with care, will eventually wear out their motor brushes: the carbon blocks that conduct electricity into the spinning armature. Some brushes are made so that they stop working before they wear down to their springs and damage the commutator on the armature (the ring of copper bars on the rotor). Sometimes a power tool suddenly stops working, appears to be dead, but simply needs a pair of new brushes worth a few dollars.

Summary

Electric chainsaws can be a useful and economical part of a firewood cutting system. If you want a long and productive life from your electric chainsaw, keep them spinning fast and running cool and avoid frequent starts. As a key to working your saw within its capabilities, I recommend looking sceptically at the supplied bar length and considering how you can give the fragile electric motor an easy life with a short bar. Running 2 or 3 chains in rotation will reduce maintenance costs.