Starting a top bar hive with a brushed swarm

The hardest part of starting my top bar hives has been getting some bees into the first hive when I didn't have a top bar hive I could take combs from. This is how I did it, using a brushed swarm from a framed (Langstroth) nucleus hive. 
I've written more on my top bar hive design in this post about how I've been making my top bar hives. 

Splitting a hive

When you want to start a top bar hive, it's quite easy to make the hive. But then you need to get some bees into it. When I first tried to start a top bar hive (described in my blog post here), I thought I’d do it with the method known as “splitting” or “dividing”. This is where you take some of the brood, bees and honey from one strong hive, to make another. If you don’t provide a new queen, the workers in the queenless hive will usually make one for themselves from eggs in the comb. 

We have several framed hives which we split from time to time. However the challenge was that I couldn’t do a split into my top bar hive in the normal way from the Langstroth hives, because Langstroth frames won’t fit into a top bar hive. Some people cut up frames to fit them in a top bar box, but I wanted to avoid this (I'm inhibited by my deeply imbedded frugality - if you don't suffer from this you could save a lot of trouble with a little frame chopping - see https://vimeo.com/5614348). 

My plan was to put a top bar super on top of a framed hive and get the bees to build comb on the top bars. When there was brood in the top bar combs, I could simply move the bars and combs from the top bar super into a top bar hive, the bees would make a new queen, and I would have my first top bar hive. I tried this with 2 different hives. It didn’t work, because although the bees did build comb on the top bars, I couldn’t get brood laid in the top bar combs. 

Here's a little comb being started on a top bar - beautiful

When the bees made new combs in the top bar boxes, the combs hung down from the bars which make the hive roof. This meant there was a significant air gap between the top bar combs and the brood comb below, which I think made it unattractive for the queen to go up and lay eggs. Without brood in the new hive, you can’t do a split. My plan didn't work and I needed to try something different. 

A brushed swarm

Although plan A hadn’t worked as planned, the bees had built some combs on a few top bars. Having some combs on top bars was good preparation for doing what is called a “brushed swarm”, or a “shaken swarm”. 

In a brushed swarm, you take the combs from a brood box and gently brush all the bees - including the queen - into a new hive that has some comb but no bees. If the combs are strong enough you can shake most of the bees off before brushing. Langstroth frames are strong enough to shake pretty vigorously. Top bar combs are often strong enough to shake - see expert top bar shaker Sam Comfort at work here. The new hive is then set into its new place and the bees left to organise themselves. Many of the worker bees brushed into the new hive are young nurse bees, who haven't yet been outside the hive. These nurses will stay in the new hive. The queen, who also doesn’t travel and won’t go back to her old home, will start laying in the empty comb. The nurse workers will look after this new brood, and make more comb if they have some honey to eat. 

The older flying workers will leave the new hive to do their foraging work, and then return to their old hive. The new hive will appear very quiet once the flying workers have left, but will gradually build a flying worker population as the nurses mature. In 3 weeks the first of the new brood will start to emerge from their cells, and the new hive should start to get stronger. 

Back at the old mother hive, we have a population of foraging-age workers, who have flown back to the old hive. When these workers find that they are queenless, they will attempt to make a new queen from a day-old egg - usually this works out fine. 4 weeks or so after brushing the swarm, you can check for eggs in the brood comb to see if they have made a new queen. If there are no eggs, they were unsuccessful, but you can give them a second chance by introducing a comb from another hive, with day-old eggs in it, for them to make another queen from. 

Growing some top bar combs

Having some combs in the new hive is quite important to doing a shaken swarm. It means there is comb for the queen to lay in immediately, and it saves the small crew of nurse bees from having to make so much fresh comb from honey at a difficult time. Also, in a top bar hive, existing combs are important to give you control of where new comb is built. 

I tried 2 methods of starting the top bar hives, and both did produce some combs which were very useful to the brushed swarm. The first method was described in my blog post a year ago, and I suspect it’s the better way to go. I made a small top bar super that fit onto a 10 frame hive. 

Here's my brown top bar super on a white, standard, 10-frame hive. This is a reasonable way to get some combs started on some top bars, in preparation for starting a top bar hive. Once it's done its job, the top bar super could then be converted into a top bar nucleus hive - very useful. 

I attached some pieces of free comb I cut off a hive lid onto 3 or 4 bars, to give the bees some guidance where to start - if I’d just given them bare bars, I could have ended up with comb going anywhere and any direction. The bees built these combs bigger as little honey flows occurred. 

The second method was a bit clumsy, but was necessary in the circumstances. I made a 4-frame nucleus hive (“nuke”) by splitting, that I took home to Mt Glorious when it appeared strong. It was easily transported on the roof rack of our hatchback, in cool weather. At home, I cut a large hole in the bottom of a full length (1200mm) top bar box, and strapped the nuke (with lid removed) to the bottom of the top bar box, giving the bees easy access from the nuke to the top bar box. 

Here's the top bar hive upside down, being painted, showing the hole in the bottom

Here's the nucleus hive strapped to the bottom of the top bar hive. The strap went over a separator board

Looking down into the top bar hive after it was joined to the nuke, showing frames of the nucleus thru the hole in the bottom  

The bees seemed to prefer to build free comb onto the top of their nuke frames, inside the top bar box, but I kept cutting the combs off and attaching them to the top bars. Eventually I had a few combs hanging on the top bars. 

Realising that my splitting idea wasn’t going to work for a long time if at all, I separated the nuke from the top bar box, and made my brushed swarm. I took out the nuke frames one by one, and brushed all the bees into the top bar box, making sure the queen wasn’t hiding in the frames after brushing. Once all the frames were clear of bees, I put them back into the nuke and replaced the lid. Foraging bees quickly re-populated the nuke hive. 

Here are the framed nucleus hive (background) and the newly separated top bar hive, with all their bees adapting to the new arrangement

I fed the top bar hive with honey cappings I had kept from our framed hives, spooning cappings onto a piece of wire mesh in the hive bottom and letting the bees lick them clean. I expect this was a help to their work in making new comb, which takes a lot of honey. Top bar hives make this sort of feeding easy, as there is open space under the top bars in the part of the hive where the comb hasn’t yet been built - framed hives have no open spaces. 

Over the next few weeks, the top bar hive settled down and gradually grew in strength. The framed nuke didn't manage to make a new queen the first time, but I gave it a top bar of comb from the top bar hive (replacing a frame), and they were successful at the second attempt. 

Catching a swarm

After I got the top bar hive going well, I made a couple of top bar nukes: 10 bar hives, only 410mm long, according to Les Crowder’s description in his book. I made these in preparation for splitting off new hives. This was also good preparation for swarms: a couple of days after finishing the top bar nukes, I found a swarm in a tree nearby (from a wild hive). A nuke was very convenient to take out to catch the swarm: small and easy to take out to the bush to catch the swarm, has a fixed bottom (unlike a framed super) so it can be put on the ground, and unlike a cardboard box, doesn’t require tipping the bees out into a hive when you get home. Before putting the swarm in, I put some combs on top bars into the top bar nuke, from the established top bar hive. 

Here's the 10 bar nucleus hive, swarm installed, with temporary roof

Having already-built combs on top bars was very helpful for installing the swarm: it made the bees feel at home (I think), it gave the queen comb so she could start laying immediately, and it gave me control of how the swarm bees built their comb: using existing combs to get them to build along the bars. The swarm hive established very quickly, and soon overtook my first hive (from the shaken swarm) in strength. 

Splitting

Making new hives is essential to frugal beekeeping, even if you want to keep a steady number of hives. I don’t buy new queens: they cost a lot of money, and travelling to pick them up is time consuming and expensive. I prefer to split hives when they’re strong, and unite them when hives seem weak or are found to be queenless - which happens to me reasonably often. This means that you need to either have more than one hive, or some friendly neighbours with compatible hives, who can help you with brood combs or a healthy nucleus hive when you find you have no queen. 

Now that I have plenty of top bar combs, it is easy for me or my friends to start new hives, by splitting or by shaken swarms from framed hives. 
I split hives from a strong hive, when they seem to be vigorous and there is a reasonable honey flow. 
I put 2 or 3 brood combs (on top bars), with plenty of fresh eggs (look for the tiny rod-like eggs standing up in the bottoms of the cells), into a top bar nucleus hive. I usually shake extra nurse bees, off some more of the mother hive's brood combs, into the nuke to provide more working population, and replace the combs into the mother hive. 
I also put 3 or 4 honey combs (on top bars) into the nuke, to provide food for the new hive until it is strong enough to harvest its own. 
The bars taken from the mother hive are replaced with bare bars, usually in the same places. 
I close the doorway to the hive down to a small entrance, maybe 20mm wide, to make it easier for the weak new hive to defend itself. 
I try to minimise disturbance of the new hive for about 4 weeks, so I don't mess up their making new queens. After 4 weeks, the new queen will have hatched, killed off her competing sisters, mated and started laying. If I find fresh eggs at this time, the split has worked. 
If there is no sign of eggs, there is no queen, and the colony is doomed if left alone. The nuke can either be joined to another hive or given new brood combs to try again to make a new queen. 

Splitting top bar hives is so easy!

Compared to splitting framed hives, splitting top bar hives is very easy. 
It's so easy to get to the brood combs in the top bar hive: lift the lid, and every comb in the hive is accessible immediately. You know where the brood is, because you've looked after this hive already, and you can lift out a brood comb straight away and see if it looks suitable for use in the new nuke. There is hardly any disturbance to the hive, rarely many upset bees, and I can comfortably work wearing shorts and with bare hands (I do always use a veil, in case things do go wrong). 
With a framed hive, you need to lift off all the honey supers (could be up to 40kg each), then the queen excluder, before the brood frames are accessible. The whole hive is in pieces and the bees are upset - but not as upset as they'll be when you squash dozens of them while reassembling the hive. You need long pants and plenty of smoke! 
With a framed hive, you need to replace the brood frames you take away, with new frames with fresh foundation (or other suitable worker-comb frames), which you need to have prepared first. In top bar beekeeping, you simply drop new or comb-less top bars in place of the ones you've taken away, and the bees build whatever comb they think best onto the new bars - in the brood chamber this will generally be worker brood comb. 
Checking the success of a split is likewise easy in top bar hives. When I split, I'm not particularly careful where the queen ends up - it takes so long for me to find her with my ageing eyesight, and I've never found it easy. I also don't consider it to be important most of the time to find the queen: if there are plenty of fresh eggs, there's a reasonable queen. It's important to check in the mother hive and the new nucleus to see which hive has the old queen, by looking for fresh eggs in a week or so. Again, in a top bar hive it's so easy to lift out a few brood combs and check, without having to un-stack the hive, and without causing much disturbance to the hive. 

Huztl chainsaw chain review

Huztl chains are cheap and cut well, but often have hard spots that blunt your file, and you can’t predict what profile or manufacturer of chain you’ll get.

Over the last few years I’ve been using Huztl chains on nearly all my saws, doing work ranging from thinning cypress to milling. Overall they've worked very well, and have been remarkably cheap. 

I haven’t noticed a difference in how long the Huztl chains stay sharp compared to Stihl chain, but I would expect Stihl chain, which is noticeably harder to file, to stay sharp longer in clean wood. 

Varying chain types

Most chains I’ve bought from Huztl have been marked “KANGXIN” on the side plates, with semi-chisel tooth profile. I like this chain: semi-chisel is good general purpose chain, and copes better with dirty conditions  than full chisel tooth. Chisel tooth cuts very well, but when you find some sand in the bark or a termite pipe, the corner can be badly damaged and it needs a lot of sharpening to cut well again. 

Lately some chains from Huztl have been a different make. They are full chisel and unbranded. This was first with 3/8 LP, then with .325, now with 3/8 pitch chain. 

Huztl's .325" chisel-tooth chain. See it is a low-kickback chain with ramps on the drive links. This is safer, but can obstruct boring cuts. 

I wrote to Huztl to ask if they can still provide the semi-chisel chain, and they replied that they couldn’t. Because of this, I’m now trying the chain from jonoandjohno.com.au, which is a similar price to Huztl if you buy a roll. 

Hard spots

The biggest problem I’ve had with these Huztl semi-chisel chains has been frequent hard spots in the steel, in the gullets of the teeth. Small spots of steel are hard enough to damage the saw file when sharpening. I really don’t like this: it’s terrible to damage a new sharp file. 

I think the cause of these hard spots is easy to guess: when the chains are being machine sharpened with a grinder in the factory, poor quality control of the grinding wheel condition, or the feed rate, or something, is causing overheating of the teeth. 

I’ve seen hard spots in chains before, usually on chains sharpened inexpertly with electric grinders. I’ve even caused the problem myself, overheating teeth with a bench grinder while modifying chains to “Granberg” ripping chain pattern. 

What happens is that the heat created by the friction of the grinding wheel, is enough in some small part of the steel, to bring the steel to red heat - critical temperature for hardening. Then when the grinding stops, heat quickly flows from the tiny volume of hot steel into the surrounding metal, quenching and hardening the steel that was red. 

A remedy

The easiest solution to the hard spots is to carefully grind the tooth gullets of these hard-spotted chains before sharpening them the first time with a file. One grinding should remove the hard bits permanently. 

This is the tooth before grinding. The hard spots seem to be on or around that little peak in the bottom of the gullet. 

Here's a tooth after grinding. See the little peak is gone and the gullet is a bit deeper. 

I’ve been using a cheap chainsaw-sharpening grinder I inherited from a neighbour. It’s a terrible machine really: terribly inaccurate and totally unsuitable for sharpening - I nearly took it to the tip more than once. The greatest benefit of an electric chainsaw sharpener is to accurately equalise the teeth of a poorly sharpened chain. However this machine is no good for that because the plastic parts give it so much flex. However for gulleting these chains to remove the hard spots, this cheap machine is good: the flex allows the grinding wheel to be swept back and forth in the gullet. 

This is the cheap chainsaw chain grinder. Mostly plastic construction makes it very flexible and inaccurate. An old angle grinder cutting disc is mounted on the plastic spindle, held on with a plastic nut. It works very well for this job but not for sharpening.

Because the original sharpening wheel was broken, I mounted an old 2.5mm thick angle grinder cutting disc in it. This would be too coarse for sharpening, but is good for this gulleting task. The plastic spindle needed to be trimmed a little (spinning it against a chisel) to fit the disc.  

Hard depth gauges

I’ve also noticed some depth gauges are hard to sharpen, in the Huztl chains but also in genuine Stihl chains. It only seems to be a problem the first time the dept gauge is filed, perhaps due to the chrome plating instead of steel hardness. This is also annoying, leaving visible lines of damage to the file teeth. If I’m in the workshop when I find these hard depth gauges, I’ll use the grinder to take the tip off the depth gauge, so my files will last longer. 

Conclusions

Huztl chains are alright, but you need to be flexible about what tooth profile you get. 

It’s not worth buying a cheap electric chainsaw sharpener, but they can be useful to remove hard spots. 

If you use an electric chainsaw sharpener, grind very gently, to avoid overheating and hardening. 

Some of this cheap Chinese chainsaw gear is good enough, if you have the time and bush engineering skills to make it work properly. Spending less money means less time earning money, more time in the workshop at home. That works for me. 

[but some of this cheap Chinese gear isn’t good enough: see my review of the Huztl/Holzfforma chainsaw bars]

Here's another chain bought from Huztl, this time branded "ZHUANG". It looks like the riveting machine missed a side plate, and no one was checking. Easily enough repaired - but remember to do your own quality control.

Holzfforma/Huztl Alaskan Chainsaw Mill Review (with Huztl MS660)

A light, effective and very cheap chainsaw mill can be made from the Holzfforma Alaskan chainsaw mill and the Huztl MS660 chainsaw, but it does need some bush engineering to work well. The mill needed some adjusting to work properly, the Holzfforma bar didn’t last long and needed replacing, and there's a few things to look out for in the MS660, but overall it is a low-cost mill that can do the job. 

The Huztl MS660, the Holzfforma Alaskan mill, and a stack of beautiful silky oak boards

I’ve done a lot of chainsaw milling since I started in the mid-1980s. I’ve used a genuine Granberg Alaskan mill, 48”, with .404 chain. I drove this with a Sachs Dolmar 120cc chainsaw for many years, now I use a Stihl 090 as the mill motor. I’ve milled many tons of wood with this setup. It’s been very reliable, but it’s big: it is very heavy to carry and use and was relatively expensive to set up. 

Recently I set up a new, low cost, lightweight mill for myself, entirely made of Chinese Huztl components. I bought a Huztl MS660 kit and assembled the saw (a friend and I made an MS660 each in one day), adding a 25” Holzfforma bar from Huztl, and a Huztl chain. I bought the Holzfforma 24” Alaskan chainsaw mill, also from Huztl, and made a range of modifications to it, some to correct manufacturing faults, but mostly to make it easier to use. 

The motor: Huztl MS660 kit

Here's my freshly assembled Huztl MS660

This was astonishingly cheap (just over AU$300 on sale), was easy and fun to assemble, and works really well.  

There is a lot of information on youtube about making these MS660 clone saws, and their various issues. One of the best sources is afleetcommand’s videos . My experiences with building Huztl/Farmertec chainsaws, including the MS660s, is mostly documented in my post on building a Huztl/Farmertec MS360. 

I’ve remained genuinely non-genuine: I haven’t added any real Stihl parts to my MS660s or MS360. Many kit builders replace some components with genuine Stihl parts:  

• Afleetcommand points out a problem with some Huztl MS660s, including mine, with the half throttle setting not working properly. When I need half throttle (mostly in cold starts after turning off the choke) I simply use the traditional solution of putting my boot in the rear handle and pushing the throttle up with the top of my boot - a good trick for a flooded saw too.
• Quite a few kit builders report piston and cylinder damage from piston pin clips. My Huztl MS360 post outlines my response, modifying the Huztl clips. 2022 update: I recently helped a friend build a Farmertec 066 kit, whose piston pin clips had no tails at all, so it appears Farmertec is fixing that problem.
  
• Decompression valves routinely lose their plastic heads (all mine have). You can buy a genuine valve, or make a simple fix (also in my MS360 post).
• I've had one bad Huztl carby, but this was willing replaced by the supplier. 
• I've had some trouble with Huztl oil pumps, but each time it's been repairable - see below. 

The MS660 has a 92cc engine which is powerful enough for the 24” Alaskan mill, especially for smaller logs. It would be worth having a bigger saw if you were consistently milling over about 450mm diameter, but that would be balanced against the much greater expense of the motor and the increased kerf of .404 chain used by bigger saws. For most people’s needs the MS660 makes a fine mill. 

MS660 oiler

In the first few hours of milling, I was a bit concerned about the low use of bar oil by the MS660. I’m particularly sensitive to my bar oiling, as I use used cooking oil for bar lube (see my post here on using vegetable oil for bar lube)  and I want to make sure I use plenty, to compensate for possible quality problems with the oil (not that I’m convinced it’s any worse than other oils). Milling hardwoods is particularly hard on chainsaw bars. 

After joining the facebook "Huztl Farmertec Chainsaw Builders" group, I found some illuminating discussion of MS660 oil pumps, and dismantled mine to see if I could improve it. 

What I found was that the pump piston stroke was inhibited by the end pin of the piston control bolt. To increase the oil flow, I tried grinding the end pin right off the control bolt. This enabled singificantly greater oil flow, but disabled the ability to turn down the oil flow. 
I could have achieved the same result with a less dramatic modification, by simply grinding a flat on the end pin in the right place. 

Here's the MS660 oil pump piston (top) and control bolt below. If you look carefully, you can see a gap between the ramp on the piston (to the right of the gear) and the control bolt, caused by the pin on the end of the control bolt.  

Here's the control bolt

And here's the control bolt with the end ground off. 

I later dismantled my earlier Farmertec MS660 saw, and found its pump didn't have this problem, so I left it unmodified. 

The bar

I bought a Holzfforma 25” bar from Huztl (3/8” x 1.6mm, 84 drive links). Outside the Alaskan mill, this has a maximum cut of 610mm (24”) with the saw spikes removed. With the spikes on the saw it will cut about 570mm (about 22.5”) (this labelling of saws with lengths they can’t actually cut is common to various brands including Stihl, not just Holzfforma). In an Alaskan mill, a 25” bar will cut up to about 465mm (18”) wide boards - this is plenty for many trees. 

If you want to use the full capacity of the 24” Alaskan mill, I recommend a 28” or longer bar. Depending on the spot welds in the roller nose, you may be able to drill the bar as I describe below. 

My friend and I both bought 25” Holzfforma bars with our MS660 kits, and both failed very early. Bad steel quality has caused failure of the rails, mostly near the nose. 

See the chip broken off the 25" bar nose? It's where the chain hits the bar rails after coming off the sprocket. The heat mark in the middle is where the Alaskan mill bar clamp squeezed it a bit when I was trying different positions. 

I give a more comprehensive review of Holzfforma bars in my blog post here .

I’ve bought a 28” Tsumura bar from chainsawspares.com.au, which has worked without any problems at all. 

The mill

Here's the shipping box for the Holzfforma Alaskan mill. The serving suggestion shows an 070 motor, which is 105cc and uses .404" chain. 

The maximum width of cut in the 24” Holzfforma Alaskan mill is 540mm (just over 21”), which covers most logs. This requires a 28” or longer bar. A longer mill is good when you have a big log, but it is a nuisance to carry around the longer frame when you’re milling smaller logs. I’m finding it very convenient to have this smaller mill. 

The quality of the Holzfforma Alaskan mill is okay, but (like many things from Huztl) it needs some work before it is ready to use. 

Squaring the cast aluminium bridges

The mill has 2 cast aluminium bridges that join the 2 fence rails to the bar posts. These (in my mill at least) were out of square, so they sprang a bend in the chainsaw bar when I first assembled the mill, and made adjustment of slab thickness difficult. 

Looking along the bar now, it is straight, but this was bent before filing the bridges. 

You can see the mill post (vertical steel piece which clamps onto the bar at bottom) is not parallel to the square

Here's one of the mill fence bridges in the vice, ready to filed square with the dreadnought file. These files are specially designed for aluminium and work very well

The remedy is simple: file the landings where the fence rails meet the bridge, so they’re square to the post. A dreadnought file is the best tool for filing aluminium (should be in every bush engineer’s toolbox) because it doesn’t clog, but if you don’t have one, you can get away with your coarsest file and frequent cleaning of the teeth. 

Filing the landing on the fence bridge

A freshly filed landing

This is how I checked the landings for square while I was filing them. A piece of pipe is clamped where the mill post goes, and a square is clamped onto the landing where the fence rail goes. You can see they're not parallel yet. 

Adding a bridging rail

Alaskan mills usually have 1 or 2 bridging rails, that go between the long fence rails, and are flush with the fence’s bottom surface. These are very helpful when starting and finishing cuts, making it easier to start a cut parallel to the previous cut, and reducing the tendency for the leading fence rail to fall off the end of the log and curve the cut downwards at the end of the cut. The 24” mill only has 1 bridging rail, so I made another one from wood and attached it to the cast aluminium bridge at the engine end of the mill. 

The extra bridging rail is painted green, and helps start and finish cuts

Frame bolt failures

Here's the junction between the mill bridge and the mill rail, with failed bolts and nuts on top. See how shallow the nyloc nut is, and see the stripped section halfway along the thread of the coach bolt in the middle. 

I had an early failure of the bolts that were provided with the mill to hold the bridges onto the rails. These are metric 8mm (M8) coach bolts: they have a domed head with a square base, instead of a hex head. 

The bolts on the outer bridge (furthest from the motor) stripped after a few hours use. This appears to be because the nyloc nuts provided have a very short metal thread, and my need to loosen and tighten these bolts, in order to use different length bars, quickly stressed and stripped the bolt threads. 

These bolts have their heads in the slot of the mill rails, so need to be keyed into the slot - using the square base of the coach bolt - to stop the bolt from spinning when the nut is tightened (you can't put a spanner on the bolt head). Although I didn’t have any M8 coach bolts in stock, I was able to easily replace the bolts with hex head bolts with filed rebates under the head, which key into the mill rail slot. 

Here's the M8 bolt replacing the failed coach bolts. See the rebates filed on each side of the hex head, to key into the rail slot and stop the bolt from spinning when you tighten the nut. I used standard nuts to replace the poor-quality nyloc nuts.

Drilling and direct bolting the chainsaw bar

I’ve done hundreds of hours of chainsaw milling before getting this setup, and I’ve learnt to keep checking and tightening all the bolts in the mill: they tend to vibrate loose. When the bolts that clamp the chainsaw bar to the mill posts come loose, your bar slips and the saw cuts into the clamping bolts. I’ve done this, it feels bad. 

The solution I’ve come up with, and which I’ve been happy with for years, is to drill holes in the chainsaw bar, drill and thread the landings at the bottoms of the 2 mill bar posts, and bolt the bar directly on to the mill. This gives a more positive connection of the bar to the mill posts. Now that you are not depending on friction to hold the bar, less will go wrong if the bolt comes loose. This method also makes attaching and detaching the saw from the mill - for sharpening or other servicing - quicker and easier. 

This is a bar that has been drilled and bolted onto the mill posts. You can see a centre bolt in the left side clamp, and a bolt going thru the roller nose on the right

Here is the bottom clamp piece from the engine-end of the bar, with a 10mm hole drilled thru the centre and a bolt ready to go thru the hole in the chainsaw bar. See the M8 bolt at top, which keeps the bottom clamp in alignment. 

An M10 threaded hole has been made in the middle of the landing at the bottom of the mill post

Here is the bar bolted on with the M10 bolt at the motor end. Both skids are kept in place to run along the side of the log. The M8 bolt on the top end of the clamp is there to stop the bottom skid from turning, but is only bolted to the bottom clamp/skid. 

At the bar nose, only the M10 bolt is needed to hold the bar on

Sometimes it’s hard to find a place to drill some bars around the sprocket nose, so you need to use the clamp. One engine-end bolt still makes for a quick and positive connection, which won’t slide if it loosens. 

I use M10 bolts for this job, and an M10 tap for the mill posts. 

The saw and mill ready to cut

Saw chains

Special chains are available for ripping (cutting along the grain), which is what you are doing when milling. For example, skip tooth chains have fewer teeth, achieved by having 2 blank links between the teeth instead of the usual 1. Having fewer teeth in the cut gives more horsepower per tooth, which allows teeth to dig deeper and cut chips instead of dust, making the cutting action more efficient and the teeth stay sharp longer. 

Chains can also be bought that have been sharpened specially for ripping: filed at 10 degrees from square, instead of 30 or 35 degrees which is normal for cross cutting.  

For milling I usually make my chains from standard crosscutting chain: this means I only have to buy one type of chain for crosscutting and ripping (I use semi-chisel chain, as the teeth cope better with dirty conditions). However I modify the chains as I sharpen them to make them better for ripping: gradually changing the sharpening angle to 10 degrees from square. 
I also often do a more dramatic modification, following the Granberg ripping chain model: grinding the top plates off 1/2 of the teeth in a regular pattern. 

(It's hard to photograph chain teeth) Here are 2 teeth with their tops ground back. The tooth is still full height, but the top plate has been ground back so the tooth is very narrow at the top. 

And here are the next 2 teeth, normal size. As this chain is sharpened, I will make the teeth more square. 

This achieves a similar effect to skip tooth chain, reducing the cutting load of some teeth so that there is more horsepower per full tooth. 

For this mill, I bought 3/8” chains from Huztl to match the 25” bar. The Huztl chains seem quite good (I have written a review of Huztl chains here). I’m sure they’re not as good as Stihl (they’re certainly softer to file), but they keep their edge surprisingly well. I have found a few chains where there are hard spots in the base of the gullet that blunt the file - hard spots are usually caused by sharpening teeth with a grinder, and grinding too hard so a spot of steel briefly becomes red hot and quenches hard. A few sharpenings with a little grinding sharpener should get past the hard spots. 

The mill guide ladder

The mill guide ladder spiked onto the log, with the saw ready to start and cut. Note how the weight of the engine tends to tilt the mill

Alaskan mills need something to guide the saw in a flat plane for the first cut. This is usually based on a ladder or something that looks like a ladder, fixed to the top of the log. 

The saw ready to make the first cut in this log. The ladder has been offset so that the force of the teeth cutting is borne by the mill skids against the log, and the ladder doesn't have to bear the force. The fence has been adjusted high enough so there's no risk of cutting into the spikes (I've done that too...)

For years I’ve used a 4-rung “ladder” I made for the job. It has steel rungs or bridges that span between 2 pieces of very straight timber, dressed from 75mm x 50mm hardwood. The rungs are about 315mm long, made of 25mm solid square section steel, with flat bar pieces welded onto the ends for bolting onto the rails. 8mm vertical holes are drilled thru the rungs at 25mm centres to take spikes that fix the ladder to the log. The spikes are locked into the vertical holes with M8 bolts, which thread into horizontal holes in the rungs. 

Here is one of my steel rungs: the spikes can be put into the vertical holes and knocked into the log with the back of an axe. Then the horizontal bolts are tightened to grip the spikes. The ladder must be checked for twist and adjusted flat.

The rungs are about 450mm from each end of the ladder, leaving the ladder overhanging the ends of the log enough to hold the mill up before the cut starts. 
After the half-round flitch is sawn off the top of the log, I use a barking bar (a small, specialised crowbar for removing bark from logs) to lever the spikes out of the log while they're still clamped into the ladder, by levering up on the steel bridges. The ladder is then removed and the half-round flitch is slid off the log and out of the way. Now you have a log with a flat top. 
To mill slabs and boards, the mill fence is now adjusted closer to the bar, to mill whatever thickness you want. 
Sometimes I put the ladder back on top of the log when it has a flat top, if I've made some bad cuts and I want the ladder to help straighten the cuts. 

What you need

If you are considering setting up an Alaskan mill similar to mine, this is the minimum you’d need:

• Huztl MS660 chainsaw (smaller saws, maybe down to 70cc, would work in small, softwood logs, but the bigger saw will work better, and probably last longer)
• Holzfforma 24” Alaskan chainsaw mill (if you go bigger than 24”, you probably need a bigger-engined saw)
• A good quality chainsaw bar up to about 28” (don’t try Holzfforma, I’ve done that for you)
• Chainsaw chains (it’s good to get 3 at a time, wear them out together, then replace the sprocket and 3 chains together)
• Milling ladder with spikes or screws to attach it (people improvise all sorts of ladders, but you want it to be strong and steady so the first cut is straight)
• Some thin wedges (to put in the kerf behind the saw, when you get close to the end of the cut)
• A cant hook to roll the logs (a crow bar might substitute, but it’s far inferior). Here's my post on how to make a cant hook. 
• A crow bar (useful for lifting and sliding logs and slabs)

Here's a centre board from a silky oak log. See the very centre of the log (called the heart or pith) is within the board (look at the rings on the end grain). This heart needs to be cut thru, or even "boxed out" (cut out in a section of timber and discarded) to avoid drying stresses from damaging the timber around it.

See the short split at the near end of the board, caused by growth stresses in the log. With fast-grown Eucalyptus wood (this isn't), there is much more growth stress, the centre board can split itself in 2 while you mill it. I'll often rip down the centre of a Eucalyptus log with a circular saw cutting the centre slab in 2 before I mill it off the log.

The board has been re-sawn with a hand-held circular saw (1200w Makita) with 8 teeth (a 20 tooth blade with most of the teeth cut off to increase horsepower per tooth - very effective). The board has been sawn down the pith to reduce immediate splits from growth stress, and long term splitting and distortions from drying stresses. The sapwood has been sawn off as it would be eaten by lyctus borers (unless the sapwood was soaked in borax solution).  

Thoughts on Alaskan chainsaw milling

In many ways, Alaskan mills are a terrible way to cut wood: they’re slow, noisy, vibratey, smokey, take lots of time to maintain, waste a lot of wood as sawdust, etc.. However, we use them because they can do what no other technology can do: for a few hundred dollars, and some time setting up, we can mill almost any log, any place. With these mills you don’t need a bulldozer or tractor to snig your logs to a mobile mill, or a truck to haul them to a stationary mill. All you need is the chainsaw and mill, a cant hook, and probably a hand-held circular saw for resawing (it’s very helpful to have a second chainsaw to hand as well, for crosscutting.) They make it worthwhile milling small amounts of timber that wouldn’t justify bringing in a mobile mill. 

For me, although I have a big bandsaw mill, and access to friends’ Lucas mills - both far more efficient and fast ways to mill logs - my chainsaw mills are extremely useful.

Years ago, I had a tiny, 800cc Suzuki four wheel drive with roof racks. I could take my chainsaw mill anywhere this little car could get to, and mill almost any log. 
Chainsaw milling does use a lot of petrol per cubic metre of wood sawn, as the chainsaw engine and the chainsaw cutting process are not particularly efficient. However overall I think this is an energy-efficient method of milling wood in the circumstances it's used in. The massive energy cost of tractor snigging and loading, truck transport, etc., are avoided just at the start of the process. Then if you use the wood at home (as most chainsaw millers do), you avoid another whole set of energy costs in processing, retailing and delivering. 

You still need to know about wood

The setup I’m describing in this post is so cheap, it puts milling within the reach of many people. However whatever saw you use to cut up logs, you still need to understand wood, cut it to deal with its growth and drying stresses, know how to protect it from insects, have space to store it straight and dry; so that you end up with wood you can use, and not a pile of expensive firewood (I’ve done that, it doesn’t feel good). I’ll write more on that later. 

Freehand milling

There is another way to mill wood which is cheap and accessible. A chainsaw can be used "freehand", cutting along a chalk line, to make beams and posts. I've milled many beams this way for houses and sheds. 

Here is the basic kit needed to cut beams freehand. The cant hook and crow bar are used to position the log on vee cradles (short pieces of log with vee notches cut in). The spirit level and builder's square are used to mark the ends of the log with the sections to be cut. The chalk line is used to mark along the length of the log. The small chainsaw is used to make a marking cut along the chalk line, and the big chainsaw is used to rip the log. The axe and adze are sometimes used to cut the sapwood off the beam.

The log has been cut twice to leave a centre slab and 2 flitches (on right), then has been turned and is now being ripped thru the heart into 2 beams. This fast-grown flooded gum has a lot of growth tension that is released in this cut and is bending the beams. Often this bend is pulled straight in the building structure, by placing beams with opposing bends, and using threaded rod to pull them both straight. 

I usually work backwards when freehand milling, but some tropical village chainsaw timber millers use a very different technique to great effect, working forwards along the log. Here's an example of freehand milling with an old Stihl 070:
https://www.youtube.com/watch?v=44i9AMphxrE&t=118s
Here's a Russian with a small chainsaw using a similar technique on soft pine wood:
https://www.youtube.com/watch?v=8qz64ELkxdA
I'll write more on freehand milling beams later.