ucoulddoit

A few thoughts from a retired structural engineer with a fair bit of experience working on timber projects. 
 

Firstly, I’d say most visual grading is mostly done on large section timbers, not small stuff for studs, etc. Also, every milled piece of timber needs grading, it’s not possible to grade the timber in a log prior to milling. The grading process is relatively straightforward, looking at specific aspects of each milled piece of timber, such as timber species, knot sizes and positions, grain slope, growth ring spacing, etc. Soon becomes a matter of common sense really, to identify what’s good or bad. Can be self learnt using readily available publications, but not sure what is current as it’s 10 years or so since I did this.

A trained / qualified grader will stamp each piece of timber. But if it’s for your own use, you have the option of deciding whether the stamps are necessary. I’ve no experience of self grading timbers for a project needing building standards approval, but have heard of it being done. I guess it needs prior discussion with the council engineers to convince them you know enough about visual grading to be ‘trusted’ to do it. There is also the issue of what happens when a property is sold on, if a surveyor for instance queries the origin or spec of the materials used. Might make it harder to sell or reduce the value?

Re timber studs, your engineer’s spec almost certainly requires treated timber. Using a timber species with inherent natural rot resistance such as larch (heartwood) would be my starting point if looking into this. But maybe it’s possible to adequately treat other species on site? And no reason why the studs couldn’t be visually graded. Would be worthwhile checking with the design engineer if the sizes specified are based on strength, deflection, or the detailing necessary to incorporate insulation, air spaces, etc., i.e. the studs might be way ‘over engineered’ just to suit the detailing, in which case the strength grading would be less critical. But again, I’d research all theses issues and discuss all your detailed proposals with the council engineer before starting, so they are comfortable you can be ‘trusted’, rather than asking them how and what to do.

Andrew

Off topic and no experience of deliveries to the islands, but a few years ago I found a bulk delivery from Inverness to our place on the Scotland west coast (mainland) was more expensive than having the delivery sent to London!

Andrew

9 hours ago, doobin said:

It’s 550mmx3100mmx70mm Will be supplied to the customer as 8no rough cut oversized 250mmx750mm stair treads, ends sealed. He’s going to bolt them on the steelwork and bring them back once a bit drier after finishing the refurb to run through the thicknesser before final trimming and cutting. Total cost £300.  

Very nice looking slab! Those sizes equate to about 4 cu feet, so at £250, that's about £60/cu feet which I'd say is a pretty good price for green timber, even for that quality. Including the work re-sawing to size and sealing the ends I'd say at £300 it's a fair price?

Just hope the buyer can dry it without too much damage. I'd be thinking about putting 1/2 inch stickers between the treads with a similar sized sheet of ply top and bottom, with a couple of ratchet straps to hold the bundle together. Otherwise the surfaces will dry quickly causing surface checking which oak is very prone to do. Checking can occur very quickly, in warm sunny weather working outside it can be pretty much immediate. But, I guess it depends on what the buyer wants to achieve and there is certainly a current fashion for a rustic look.

Andrew

3 minutes ago, lux said:

Maybe there is a fair regional difference in pricing on boards. Last one I bought was 16ft long about 800 wide I think and 65mm thick.  that cost me about 375 inc vat at Wests if I remember correctly.  

Was just thinking it would be good to know the dimensions of that board and guessed it might be 4 or 5 cubic feet at most? So £250 for green timber doesn’t seem cheap to me. Maybe the board is bigger than it looks?

Andrew

On 18/02/2024 at 17:56, Drifter2406 said:

Oregon files are good, just make sure what you buy is for the chain you use.

Good advice. Just a shame Steve doesn’t seem to keep an eye on Arbtalk anymore. Enjoyed re-reading all the other advice on this thread from 9 years ago ……..

Andrew

I started with a 145 x 45 joist from a builders merchant but struggled to achieve a 90 degree cut as the joist was slightly cupped. After running it through the thicknesser it’s worked well, and since then I’ve stored it in the workshop, clamped to the underside of the roof trusses to keep it straight and dry.

Andrew

On 29/12/2023 at 18:02, scbk said:

 Any recommendations for manufacturers that do "off the shelf" kits in what would to them be quite a small size?

Capital Steel Buildings sell kits for DIY small buildings (and large buildings) made from cold formed steel sections. No experience of dealing with them, but a colleague worked on the development of their automated design and costing software plus automated calculations for Building Standards approvals, and I recall they seemed a fairly progressive company, really pushing to create a quality product. Capital Steel Buildings | Leading Designer and Supplier of Cold Formed Steel Buildings  Based in Scotland as well.

But! Their buildings are designed for metal cladding and not sure how the thin cold formed steel sections would stand up to knocks and abuse in an ‘industrial’ environment? Not sure what you’re proposing to use it for? The sections might be as thin as 1 to 2mm and severe dents could significantly reduce the overall strength and stability. Whereas I guess timber wall studs might well stand up better to occasional impacts.

Andrew

Here's a photo of the milling and drying books I've collected over the years including the two I mentioned before and the Malloff book Mark suggested. A lot of repetition, but each book has something unique, so they are all worthwhile having and I've learnt a lot from them over the years. With the exception of Malloff's book, all written for timber to be used by furniture makers, joinery work and wood working generally. But little or nothing really about timber for fencing, structural timber or grading timbers, nor for green oak framing timbers. They are very focused on producing high quality, defect free timber which I guess translates into high value?

There are several publications on the ASHS website as well.

Andrew

About 20 years ago I tried sourcing small to medium sized round timber for milling by advertising, phone calls, etc. but didn’t have much success at first. The small quantities meant I was probably regarded as a ‘time waster’ by busy people! But then I found a couple of businesses who cut and sold firewood and they had lots of timber waiting to be cut. One of them had literally hundreds of tons of round logs piled up and I was able to take my pick and they were able to lift what I bought into the tipper truck I hired, so it was easy to offload back at home or at a sawmill. Bought 2 to 3 tons the first visit for £100 and never looked back after that.

Andrew

4 minutes ago, ucoulddoit said:

I’ve a book of articles from the Fine Woodworking magazine which again are a bit dated, but still some good stuff about how to select trees for milling, how to mill different species to get the best results, etc. Can’t remember the title, but I’ll look it up.

 

Andrew

 

 

‘Fine Woodworking on Wood and How to Dry It’ 41 articles, under £6 on Amazon.

Andrew

‘The Conversion and Seasoning of Wood’ was published about 30 years ago but only has one chapter about milling. I’d still recommend it though. Lots of info about other topics though, such as drying characteristics of different timbers, different methods of seasoning, etc. I’ve a book of articles from the Fine Woodworking magazine which again are a bit dated, but still some good stuff about how to select trees for milling, how to mill different species to get the best results, etc. Can’t remember the title, but I’ll look it up.

Andrew

14 minutes ago, Dan Maynard said:

Can you sell the Victorian insert?

That's my thinking also. When I said to the stove installer I'd like to remove it before they start as I want it to be intact, he looked at me and laughed and reassured me they'd been doing it for 'decades' and if anyone could remove it in one piece, they could! So for once, I'll probably just take a back seat and leave this project to the experts. My wife likes to tease me that all my questions about 'details, etc.' probably just adds 10% to the cost! But it does help to get a good job done, instead of cutting a few corners.

Andrew

Thanks for the further advice. Was looking into this as one of two options. Minimal expense using what’s there with a Hobbit stove, suitable for an existing Victorian cast iron insert with tiles (fitted 20 years ago). Or, remove the insert, open up the ingle and have a larger stove with a new flue liner. I’ve had someone out to look at it and despite the cost of option 2, that’s probably the way I’ll go. Should ‘see me out’ and hopefully I’ll not be changing this again within the next 20 years.

Andrew

Thanks for all the encouraging comments.

Andrew

More or less finished this dining table so here are a few photos. It’s a fairly simple trestle type table design. It’s just over 1.7m long, and comfortably suitable for 6 people for day to day use, two each side and one at each end. But it can accommodate an extra person at each side if needed, making 8 in total. 

Here is the finished table. Not the best picture as the lighting doesn’t really bring out the glow of the burr oak. But you’ll get the idea.

Had our evening meal using it today with children plus grand children and it was good to be able to just enjoy it with good company. Making a dining table was the prime reason I bought the burr oak butt about 11 years ago. And the day dream of making a burr oak dining table pre-dates that by a few years, after seeing a gorgeous, much larger, single plank burry oak table at an exhibition. So it’s taken about 15 years to get here!

When I bought the oak butt I was aware the slabs for the top would only just be long enough for this type of trestle design. Another 3 to 6 inches would have been preferable and I’d been hoping to find a burr oak log suitable for milling long, wide, table sized slabs. After several years of casual searching, when I saw this burr oak butt for sale close to home, which promised pretty stunning timber, I decided to compromise on the length and it’s turned out fine. I guess I could have bought a large wide slab from a sawmill, possibly dry and ready for use. But I was keen to start with a whole log, get it milled, dry the wood, then take my pick of the best slabs for projects needing large flawless areas of burry timber. I wanted to use it as a learning process with a longer term view of one day making use of these skills for a business. It’s worked out much more economical working that way, as I’ll be using all the milled timber (eventually!). But I did have quite a bit of previous experience of this whole process so that reduced the risk of ending up with a pile of (very expensive) firewood.

The last post discussed the design of the table top, so here are a few notes about the trestle supports. The following picture is a similar table made from two book matched planks of burry elm about 8 years ago which was used as the starting point for the design of this burr oak table. It had an ‘inside out theme’ of natural edges along the centre of the table top, trestles and rail, with formed, smooth edges on the outsides.

It’s been well admired over the years, but ever since finishing it, I’ve felt the design of the trestle supports could be improved. They are good and strong, simple to make and the table is very stable. But I’ve always been uneasy about the aesthetics, although my wife thinks they look fine. Picture below shows one of the trestles. My main issues are that I dislike the way the top rail spans the full width, so the end grain is visible at the top of the curved sides. Also, there is a noticeable colour variation between the four pieces of wood.

So I spent a while thinking about how to improve the design of the trestles for the burr oak table and started with a few sketches, see below. Followed by a photo of the final result which bears a close resemblance to the elm trestles! So it turned into a case of incremental improvement instead of starting from scratch. I’m much happier with the revised design. The colours of the four pieces of wood match nicely, the curved uprights are book matched (as was done on the elm table). And the top rail is fitted between the curved uprights and set back a bit. I feel setting it back a bit really helps the visual impression of the curved pieces going all the way up to the underside of the table top. I suppose no one will see that unless they crawl underneath the table. But at least I know that effort has gone into improving the design, still using a similar amount of material and no more difficult to make.

Instead of small wood ‘buttons’ to attach the top, it is fixed to the trestle with four, 5mm thick stainless steel plates. These are screwed into the end grain of the uprights with slotted holes for the fixings into the top which may expand and contract over time.

The trestles are made from two slabs of the burr oak which were a book matched pair, but not as good as the other five pairs as there are shakes and splits. See photos below. I felt they weren’t suitable for use as large slabs of timber and cutting them into smaller pieces was the best way to use them. But I guess they could have been used in a design with plenty of coloured resin to fill the defects? Never made anything like that though. I’m intending to use parts of these two slabs including the natural edges for a future project, so I cut off these curved sections first. Then used templates for the trestle parts to mark them out avoiding the worst of the splits and shakes.

The following photos show one of the mdf templates being made. A thin flexible strip of wood was used to create a pleasing curve to draw round with a pencil. Then the waste wood was removed on the bandsaw, sawing to within about 3mm of the pencil line. Then a Fisch Flexi Curve ( available from Axminster tools, quite pricey, but well used over the years ) was attached to the mdf with screws so that it exactly followed the curve. Then the remaining waste mdf was removed using a bearing guided router cutter following the Flexi Curve which was then unscrewed leaving the completed template immediately ready for use. A bit of a faff, but for repeated identical shaping, it’s good to use the router and a template which creates a more or less finished and accurate shape and surface very quickly.

For the rail between the trestles I’d put an offcut to one side for this. But was subsequently concerned that although it was the right size, it was too plain and not a good match to the timbers in the trestles. As it was the last component for the table, I decided to choose another piece from the pile of burr oak. This time considering the colour, burr, grain, etc. instead of just finding a bit of wood the right size and minimising waste. It seemed a shame to cut a good looking medium sized slab into smaller pieces. But I’d decided it wasn’t worth compromising at this stage and glad I made that decision. 

Sketch below shows the overall sizes of the oak table and the starting point was the size of the available slabs for the top. After making the elm table previously, with hindsight I realised the space between the trestles needs to accommodate two chairs pushed under the table. I hadn’t thought about that, and was lucky there was just enough space. But I’ve seen a finished table where this wasn’t allowed for and the chairs wouldn’t fit under the top when not being used. So that’s a pitfall with this design to be wary of. Some chairs are wider than others, so the dimensions on the sketch won’t necessarily work. I chose chairs for this table before finalising the trestle design.The table top cantilevers 330mm beyond the trestles at each end which I reckon is the minimum needed to sit at the end and also to be able to push a chair most of the way in when not in use.

My plan now is to start using the table and do a bit more finishing / oiling on the top after it’s acclimatised for a few months. It’s in a room with lots of windows which gets pretty warm on occasions, so I envisage a wee bit of movement in the burry wood, despite being dried down to 10% moisture content and stored in a low humidity environment for several years before starting. 

How do I feel it’s turned out after taking 15 years to get here? Well, if I’d pursued my daydream all those years ago of setting up as a furniture designer / maker, I’d be happy now to replicate this design, having reached the end of a trial and error process to find a solution that I’m comfortable with. That doesn’t mean the design would appeal to everyone, and it could be further refined. I guess some folk would be more enthused by a unique / arty design. But that type of work is just way beyond me and I suspect many others also? So instead of trying (and failing) to copy ‘arty’ designs created by others. Over the years I’ve progressively focused more and more on bringing together my inherent interests of geometry, engineering details, precision and proportion, then applied incremental improvement on successive projects. I’ve found that works for me and I’ve had enough positive comments over the years to confirm the designs also appeal to a fair proportion of other people. So perhaps I could have made a go of setting up in business? But retired now and very unlikely that I’ll pursue the day dream of setting up in business. Happy to carry on as a hobby woodworker making stuff for the family and so I thought I’d share all these thoughts as maybe there are others who can make use of them.

I’ve used about half the planks from this burr oak butt over the past 18 months making the three projects discussed so far on this thread. Planning to make a dresser for my daughter next, with the design developed from two past projects in elm which are shown in the following two photos. Lots of natural edges! First one is shelves made about 20 years ago for my son from a single small log bought from a firewood merchant, which he used for his TV and Hi-Fi when a teenager. Second picture is a cupboard / shelves, made for myself, which fits into a wall alcove in our bedroom. Both pieces are favourites of mine, and my daughter, so looking forwards to the challenge of re-working the designs to bring them together into a single piece.

The dresser is a project for next year though, as I’m taking a break from woodworking to work on a small building project. So the lack of posts over the coming months on this thread doesn’t mean I’ve given up! 

Andrew

12 hours ago, Dan Maynard said:

Yes, flue sizes are minimum so will be fine. Otherwise nobody could ever connect to an unlined chimney.

Thanks Dan

We've an open fireplace with a 7 inch twin wall stainless steel flexible liner which was installed about 20 years ago. Now looking at changing this to a wood burning stove and the spec is a 6 in twin wall liner. Just wondered if that's a minimum size and would the existing 7 inch liner be OK with a suitable transition piece at the bottom?

Andrew

2 hours ago, Scuttlefish said:

I technique I sometimes use to try to reduce cupping is to mill a series of grooves along the length of the board a couple of inches apart, on the underside , stopping short of the ends, about half the depth of the plank.It takes some of the inherent tension out of the board as it drys.  It works well for work tops but it might be considered sacrilege on a really good board used for a table, especially it you have a change of heart and want to reuse the boards for another project - if the your requirements change at a later date.

I’ve heard about this technique, but never tried it. Have you any before and after photos? Also wondered if the sawcuts need to be filled, or maybe thin strips of wood glued in?

Just re-read your post after posting the above and realise you’re cutting the grooves in the green timber? Not heard of that before, only ‘kerfing’ in dried timber. Some pics would be good.

Andrew

1 hour ago, ucoulddoit said:

Another approach, which I often use for hardwoods for furniture making, is to have a 3 or 4 inch board with the pith in the centre of the depth. Then split this board lengthwise along the pith. Or sometimes cut out a 2 or 3 inch strip along the pith to remove all the juvenile wood most likely to be defective or from which splits can extend further into the planks when drying. The two halves will be quarter sawn, and for furniture making, I find it’s useful to have some thicker stuff.

 

Andrew

Just to add to my earlier post, a couple of photos taken in the woodstore this morning.

First one is a smallish 'boatskin' larch, chainsaw milled in the wood behind our house a few years ago for furniture making. The 4 inch plank through the centre is split into two along the pith.

Second picture is a slab of burr oak, showing the splits and defects around the pith and juvenile wood that was largely removed, to minimise the risk of these extending into the slab during drying which would spoil an otherwise superb lump of wood.

Andrew

8 hours ago, skc101fc said:

Shouldn't split the pith ever in a board.  Workout your cuts to keep it in the centre of a board's depth to balance tensions as it dries

Another approach, which I often use for hardwoods for furniture making, is to have a 3 or 4 inch board with the pith in the centre of the depth. Then split this board lengthwise along the pith. Or sometimes cut out a 2 or 3 inch strip along the pith to remove all the juvenile wood most likely to be defective or from which splits can extend further into the planks when drying. The two halves will be quarter sawn, and for furniture making, I find it’s useful to have some thicker stuff.

Andrew

I’m sure I’m not the only person who has noticed the succession of posts over recent months that defy belief and they are all first posts and never heard from again ………….

I guess the value of ‘logs’ is often over estimated by folk who are more used to seeing the price of dried planks. As an example of the difference in values, the picture below is one of three apple logs I bought from a tree surgeon a few years ago for £20 each. They were 22 inches diameter by 4 feet long. Biggest apple trees I’d ever seen. About 10 cubic feet per log which equates to £2 per cu ft for green round timber. What would 30ish cubic feet of this size and quality of milled apple slabs be worth now that it’s dry? Well into 4 figures I’d guess, if you could find a buyer. But this is for my own use.

Interestingly, the tree surgeon / firewood merchant was clearing an entire orchard of several hundred trees, and he was paying the orchard owner to do this………! Is apple firewood valuable? He was selling off the last of the butts to woodworkers as he’d already got the quantity of firewood needed to make it a profitable contract.

Andrew

I suspect ‘deals’ like that don’t happen very often, but I’ve done it and no regrets. The householder had trimmed all the branches from two cherry trees using a handsaw and cleared it all away. Must have taken them quite a while to do it. But they couldn’t tackle the two trunks which were about 16 inches diameter by 4 1/2 feet long, so a reasonable size for a hobby woodworker. Took me maybe 20 minutes to cut them at ground level with a small chainsaw and load them into the back of an estate car to get them home.

My avatar is a hall table made using one of these trees.

Andrew

Pretty sure the timing of felling a sycamore tree affects the likelihood of staining and mould after milling. Mid winter when the sap is at its lowest is best, as it’s the sap which leads to the defects. Not sure if it’s also best to mill it soon after, also in the winter? Anyone know?
 

Andrew

8 hours ago, waterbuoy said:

- if I manage to mill it.  I only have a Stihl 066 with a 36" bar (and ripping chain) but will see how I get on. 

I’m planning to mill a shortish length of oak in a neighbours garden in a few weeks, max 40 inches diameter but my longest bar is 28 inches and my Alaskan will only go to just over 20 inches. So I’ve a similar problem. And it’s halfway up a hillside next to a ravine, so not viable to extract it in one piece. Will probably halve it by freehand sawing and splitting with wedges, then mill each half with the Alaskan into thick slabs which can be re-sawn on a bandsaw after drying to get pairs of book matched planks for table tops if that’s what I decide to use it for. 

Will be interested to see how you get on with this. I’ve had a couple of sycamore trees milled on a bandsaw and found the planks were very stable and stayed flat. But on one of them, the planks were left stacked overnight without stickers as we finished milling late in the afternoon, and in the morning they were already looking mouldy and pretty rubbish! Managed to salvage them by coating them with borax and end rearing for a few weeks to dry the faces before being stacked with stickers.

Andrew