agg221

I suggest having a play with this before getting too far down the line - cleaving tends to veer off line unless there is a fairly equal, or very weighty, bit on each side. It also tends to work very well radially from the centre to edge, ie right across the growth rings, but not so well at other angles. Alec

As has been mentioned, the starter is definitely from an 070 (earlier type). It would be useful to have photos of: The clutch side with the cover off. The top of the orange top cover. The top with the orange top cover taken off (it is held on with three screws, two visible and one at the back, under the air filter cover). From that it should be possible to confirm 070 vs. 090 and whether the visible parts go together. Assuming it is an 070, it is 106cc with a lot of torque. It will chug away all day on up to around a 4ft bar. Alec

I know you got a double-ended bar, but how exactly are you planning to get all four mounted simultaneously Alec

Yew longbows use the heartwood on the inside for compression and the sapwood on the outside for tension. The ideal is straight and clean without knots but I have seen some surprisingly twisted bits used successfully. You are looking for a piece around 6" to 8" diameter - much smaller and the interface between heartwood and sapwood is too curved in the section, bigger and the sapwood can get rather thin. It doesn't matter if there are knots up one side - you only need a wedge shaped section. The best option is to split it rather than saw it - that way you know how the grain runs. If you split it end to end with wedges, then split that in half again so you have a quarter then that is about the best size to dry. If you are good at cleaving then on the larger end you could probably get away with eighths. Alec

Several issues. Firstly it would be an awkward shape to cast - very big and thin walled so the tooling would be extremely expensive and failure rates would be high. Secondly it would be virtually impossible to repair if it cracked. Cast iron is typically brittle compared with steel. You could use cast plates and bolt them together over a ring frame. Correctly designed and sealed this would weigh a bit more but not too much and should be very durable. The best option Andy (the other one of the two 'men in suits') came up with was to use a low chromium ferritic stainless steel. I have subsequently found a few suppliers for these and they are not too expensive (it's basically the same stuff that exhausts on diesel vehicles are made from). They are also formable so it would look and act like a standard Exeter but would be a lot more durable. Alec

I copied this - [ame] [/ame] It's a good shape for getting the branches in and packing down evenly. Alec

I think you could get away with grinding the top plates off? The remainder would be too low and narrow to interfere with the cut. Ref. breaking/making chains - the links are pennies even if you don't have them with the reel. It is possible to do it without the chain breaker and rivet spinner - carefully grind the rivet back flush with the link and then knock it out with a drift over a hole drilled in a steel plate resting on a vice. Rivetting up can be done by hand with a light ball pein hammer. Chain breakers and rivet spinners do achieve a much quicker, neater result though. It is worth considering anyway as your chains will stretch as they wear in, particularly on that length, which means working near the end of the tensioning range (causing bar wear where the chain runs in from the drive sprocket) and potentially even exceeding it. I end up shortening a 46" chain twice, by a link each time. Alec

This is the one bit I really don't know how to handle in the calculations. I think I could do a reasonable job of retort vs. traditional as the paper I referenced earlier gave some good data on the mix of emissions. However, what I can't find is data for pit burning. This is less efficient on yield, but it does flare the offgas well as the flame front is always at the interface with the air. In the end, I decided the best option was to assume that, since they are both flared, emissions would be a similar in composition between a pit and a retort but allow for it through dropping presumed efficiency. Alec

In theory, yes. I do have access to some life cycle analysis (LCA) software (GaBi) which does this if you have the right input data. However in practice the input data is probably not good enough to achieve anything more than a crude estimate. With that in mind, I get the following. Working purely on an emissions basis (ie this is not an economic or energy-source based calculation), some quick figures I can find from a Google search suggest: Steel production: 1.37 tons CO2/tonne ( G.P.Hammond and C.I.Jones (2006) Embodied energy and carbon footprint database, Department of Mechanical Engineering, University of Bath, United Kingdom) Kiln manufacturing: 33 tons CO2/tonne (assuming forging, cutting and machining energy values from N. Duque Ciceri et. al, 'A Tool to Estimate Materials and Manufacturing Energy for a Product' - http://web.mit.edu/ebm/www/Publications/9_Paper.pdf and converting MJ to tonnes CO2 using the Carbon Trust calculator - http://www.knowlton.org.uk/wp-content/files/Energy%20carbon%20conversions.pdf) Shipping (assuming an Exeter retort from their site to Hadleigh, towed behind a diesel vehicle averaging 35mpg unladen, 25mpg laden): 0.25tonnes CO2 (Diesel emissions figure from Calculation of CO2 emissions) Weight of Exeter retort: 1.25tonnes (The Exeter Charcoal Retort - The cleaner and more efficient method of producing barbeque charcoal and biochar.) Operational outputs For a retort kiln: 1.95±0.21 tons CO2/ton of charcoal For a standard kiln: 2.38±0.97 tons CO2/ton of charcoal (Sparrevik, M. et. al. 'Emissions of gases and particles from charcoal/biochar production in rural areas using medium-sized traditional and improved “retort” kilns', Biomass and Bioenergy, Volume 72, January 2015, Pages 65–73) Based on the above (very) crude assumptions, working with mid-point values throughout. If TVI has an Exeter kiln, the embodied CO2 at point of use is 43 tonnes. TVI's kiln will produce 0.43 tonnes CO2 less per ton of production than my pit. The embodied CO2 will therefore be offset after 100 tonnes of production. This would be longer if the retort has to have work done on it. The biggest error in this calculation is that I have only included CO2. Other emissions from the burn have greater greenhouse gas (GHG) potential and the levels will be higher from the pit burn, so in practice the offset will be significantly faster. Not a great calculation, but shows the general principle. Alec

This is basically what I am doing - pit burning, adding layer by layer when the surface just starts to ash and quenching at the end. I am burning dry brash, up to 3" diameter, plus some bigger leylandii. Hard to say on yield as you just keep throwing it in, but it seems OK. I am riddling out at 1" and above as charcoal (mine is looking nice and black and shiny rather than ashy), below 3/8" as biochar. In between gets thrown in a barrel of water to separate out stones and wet it down, then thrown through the shredder. Surprisingly little dust and a good even material as the output. Roughly, 1.5hrs to burn, then quench, stamp down well and take out the unburnt ends. Digging out and riddling takes a long time as my riddles are too small, but if I make them wheelbarrow-sized I reckon I could process a burn in about half an hour, total yield ~250l of char. So far I have found I need a supply of short logs to fill in the ends. Getting the timing right on adding more is fairly easy to judge but I haven't found a good way to finish a burn - the last layer tends to end up ashing on the outside before the middle is charred. The best option I have found so far is to cover the pit over with a metal sheet once the last layer starts to ash, then wait 15mins before quenching. Very low impact, zero investment (beyond a pick and shovel) and whilst I am using a fixed location, it would be very easy to dig pits where you want them and fill them in again afterwards. The only thing you need is some water - I am finding about 20l from a watering can is enough if I take out the unburned ends and stamp it down well, then riddle quickly afterwards (the lumps going in the barrel deals with anything still 'live' and the fines don't seem to keep burning, and get mixed with grass cuttings soon after anyway). Alec

Chainsawbars can supply by the reel. Not sure what can be obtained in the way of ripping chains - some patterns can only be had from the US and Oregon won't supply to the UK, but standard ripping would be easy enough. Alec

Yep, it was discussed with several people but for some reason all the carvers seem to be in the northwest, which is really inconvenient when you live in the east Alec

A sort of postscript. Following on from Goodpig (Rick)'s post, we wanted someone to carve a green man on the end of the exposed oak beam in the porch of the extension. Rick and I discussed it but concluded we are too far apart, so this was carved by Peter Boyd. For those who know Weird & Wonderful Wood, Peter is the carver who works in the barn. He carved this on Monday on the way home. I thought Goodpig (and others) might like to see it. Alec

What are you looking for - someone to mill it for you or someone who wants to buy it as a lump? Alec

Air-drying for around six months per inch of thickness is a good start. You want to keep it out of the sun, particularly if you mill at this time of year. If you stack it in the shade, somewhere the air can get through it (with sticks around 3/4" thick if the boards are full width) then it should be fine. On that size, with no particular plan for it, I would be inclined to slab it through and through (say a mix of 4" first off, then 3", finally a 2") to the centreline, then take the other half and use a mini-mill (vertical) to cut the remaining half so that you have two quarters of the original tree. By taking a board off each face in turn you will get quartersawn timber which will be much more stable. Well stacked with stickers every 18" or so you should have few problems with splitting or warping. Alec

TVI does still come on here (except when he is busy chasing the wizards out of his wood) and he does indeed have an Exeter retort. They are a very expensive way to make biochar. What scale do you really want to work on? I have been experimenting with pit burning biochar, with some very satisfactory results. I reckon I am making about 250litres in a 1.5hr burn. It's the post-processing which takes the time, but if I got this automated I could probably sort it in about half an hour. Alec

A lot depends on what you would want to do with it. Options: 1. Offer it on here as a lump - if you give clean length, diameter, approximate location and ideally a picture you might find someone who wants it. This is the minimum effort on your part and the most certain return. 2. Get in someone with a mill (Alaskan or Lucas). This will mean up-front payment but will draw on their experience. Up to about 15' long at that diameter would be a sensible day's milling, less if you need either thin boards or squared sections. 3. Buy an Alaskan and mill it yourself. This size is a bit of a baptism of fire, but perfectly do-able if you want to and take your time over it. I reckon it would take you a couple of days, with a helper (the timber will be very heavy) and you will probably wreck a board or two through errors but you can write this down to experience. This will establish whether you are either addicted to milling or never want to see it again. Apart from the mill, it may well also not take that many more man-days than ringing it up and extracting would. 2 and 3 will give you a big pile of wood. What are you going to do with it? If you have a use for it, mill it to those sizes and save a huge amount over buying in. If you are the sort of person who uses wood generally for DIY etc then it will come in useful if you mill the sort of sizes you generally buy. If you are thinking of selling it, be warned it will be either hard work in marketing, go quickly if you sell very cheap (but you won't make a decent return on your effort as milling in-situ is relatively slow and carries a high cost per cubic foot compared with a production mill or even a portable bandsaw), or it will go very, very slowly. On the plus side, oak is durable outside so that also means it keeps well once sawn with minimal effort. Alec

I've got some photos - now just need to remember where I have put the camera! Alec

Sawlogs will vary widely on price depending on quality, size, location and demand. Standing price will also be lower as there is more risk of hidden decay. Assume they are felled and cleaned up but left long as first and second lengths, the oak if around 2 to 3' mid girth and minimum 3m first length may reach £6/Hoppus but go down from there depending on the above factors. If the beech has been left lying it may now be worthless but even at best £4/Hoppus would be unlikely. If you can make up a full load then it may pay you to have the lot viewed by a local sawmill and get an offer cut to their spec on length. You could then extract to roadside and let them pick up, knowing how much you will get back. Alec

Failed to do so as the job I was getting it out for got pushed back when other things took a lot longer than planned. Should be tomorrow evening now. Alec

If you want to check whether the main stem is dead, a slight nick in the bark with a sharp knife will soon tell you. Green and it's alive, brown and stick-like and it's dead. If you find a dead bit, try another nick a bit lower, then keep going down. If it is dead all the way down then it looks like you need to go back to the suckers which, since this is grown from seed rather than grafted, will be the same as the parent. If you want to grow it on a clean stem, I would choose the nicest of the suckers and take the rest out. What has the weather been like where you are? Particularly cold/wet/dry at the time of onset? Alternatively, any sign of damage to the tree near the base? Alec

Yes, should be able to take a couple of pictures tomorrow. Alec

If you can live with 12.5" then the DeWalt DW733 is a very good machine. Mine was bought secondhand, has taken a lot of punishment (I have worn out three sets of blades after sharpening down to the limit) and it is still going strong. If you occasionally need to go a bit wider then you can put a plate over the internal guides and go through twice on a setting, biasing it first to one side and then the other - I think the widest I have done is around 13.5". Alec

Enjoying the Austrian entry much more - it's a happy little song and she has a really good voice. Alec

Well I wasn't too impressed with the Russian song - the staging was good but the song itself was pretty ordinary I thought. Alec