machining tree trunk into thin boards

[LittleOaks]

:?: Ihave looked but cannot see any thread so does anyone know how best to take a 350mm diameter tree trunk around 1200mm long and split this into usable slices for making decorative boxes?

I have a band saw big enough but I am worried about holding the round log and jamming or snapping the blade.

 

[galleywood]

Check out YouTube for designs of jigs to safely hold the log.
You need to be sure that the log is dry enough for planking.
You will probably be better off to plank it to the normal recommended thickness and then resawing at a later date when it is at the right moisture content - it will still move though.

 

[MikeG.]

It isn't the size of the bandsaw which is going to be the issue, but it's power and it's rigidity. I'm pretty sure my 14" bandsaw could fit 350mm under it with the guides raised to their highest, but there is no way on this planet that the motor would pull the blade through that resistance, nor the frame provide the stiffness required to tension the blade high enough to maintain a straight cut.

If this is a newly felled tree then you are obviously going to have to stack the boards to dry for quite some time. If it isn't (ie the wood is already seasoned), then your chances of success are very low indeed. Either way, I hope you haven't promised your mother in law a box for next month!!

 

[sunnybob]

I can cut the maximum distance on my bandsaw (200 mm) it just needs to be allowed to go at its own pace rather than pushing the plank through.
A 1200 mm long log would take something like 10 minutes per slice though.

 

[LittleOaks]

thanks for info so far
the trunk is an old apple tree that is about 150 years old when felled twelve month ago and has been stored in the garden for a year. very heavy and hopefully good grain, bandsaw is axminster with 400 depth cut and 2hp motor but stability of wood during cut is more my concern?

 

[AJB Temple]

I have done this with oak and it is not easy. In my case I cut 2" thick boards at first.

Your biggest problem is handling. You will need an infeed and outfeed arrangement and you must be able to feed the log dead straight and slowly. Sharp blade, low tooth count, high tension.

 

[marcros]

I think that I would use a set of wedges and split it in half first, and deal with the 2 halves then. For decorative boxes, 100mm is my standard width timber on a 300x200mm box.

You could also use a chainsaw for that first cut, but my preference is the low tech approach for this task.

 

[Orraloon]

A 2hp saw will cut the full depth but the real problem is handleing the weight. It could break the table mounts. Better to break it down into quarters with a chainsaw and have manageable pieces. You do not want the heart of the log anyway as that is where splits start. You will get narrower boards but on the plus side more quarter sawn stock.
Regards
John

 

[adidat]

I did something similar with a fruit wood log, I made and mdf L shape frame about 200mm wide and high and about the same length as the log, and just fired in a few short screws through the mdf and this made a good bandsaw jig then, ran it against the fence cutting 30mm planks, after a while when there was a good flat width exposed I took it off the jig and ran the log face against the fence and sawed the whole log up.

I planked it with some weight on top, but after a few days it had warped and twisted, I possibly could have left it and planned it down but would have ended up with tiny bits of wood that was really quite boring and bland for all the effort involved, so they kept me warm for an hour or two instead.... :lol: :lol:


Adidat

 

[adidat]

Hopefully this explains what i'm rambling on about

Adidat

 

[Lazurus]

Chainsaw mill to boards then stick till dry..
https://arbtalk.co.uk/forums/topic/9821 ... nt-1466130

 

[Woody2Shoes]

Chainsaw mill to boards then stick till dry..
https://arbtalk.co.uk/forums/topic/9821 ... nt-1466130

The trouble with using a chainsaw is that it has quite a fat kerf and thus quite a lot of precious material is lost on each cut.

One option might be to split (if the grain is straight), or saw (by hand or chainsaw) the log in half. Once halved, you have a relatively flat cut surface on each half - which can be further flattened if necessary - which you can then use as the "base" for repeatedly sliding the halved log along the band saw table against a fence - to cut each half into a set of boards, say 15-`19mm thick, with each cut at right angles to the original 'base' (or alternating after each cut).

Another key success factor is choice of blade. Cheers, W2S

Cheers, W2S

 

[LittleOaks]

thanks to all involved some great and clear advice.
I am nervy about trying the jig with scews as i have done this before and broken an expensive blade due to rotation on the log as it traverses, the turning force of the downward blade is quite strong and did take some holding on a 5 inch log so I have no chance on a 15 inch log !
i wondered about planing on a jointer or hand plane to get rough flat? log is still fairly green, would this cause power plane problem? will the bark need stripping first? - no one had this problem 200 years ago !

 

[bourbon]

get yourself a froe and a big mallet. Go old school and split it down the grain. Then leave it to dry.

 

[Deadeye]

Hmmm. I have a similar log currently dead standing.
I was planning to do this:
1. Take the bark off with a billhook
2. Sit it on a ply v sled on both slots and run it down the table saw slowly at max cut to creat a slot to start
3. Wedge split it
4. Repeat to quarters. Then handsaw to slabs and stick to dry
5. Bandsaw to boards

But I'm just a newbie making it up as I go along!

 

[custard]

Don't be greedy.

If you try and cut boards that are too thin they will warp and you'll end up with nothing.

Most boxes that I make are made from 10-12mm thick boards. I start with 22-25mm thick boards and then run it through the planer/thicknesser to get down to finished thickness. 50% or more of the board ends up in the dust extractor. Horrible isn't it, but that's just par for the course. Talk to any experienced woodworker and they'll confirm that's simply how it is. Looked at this way the thicker kerf from a chain saw suddenly doesn't seem too terrible.

I'd recommend converting your log into 25mm thick boards and just take the wastage on the chin.

 

[sunnybob]

Just one of many ways to safely cut a large log on a bandsaw
https://www.youtube.com/watch?v=05eyXBWLsKY

 

[custard]

One other thing, get rid of the pith as soon as you can. It's called "boxing the pith", where you cut your boards to lose the very centre of the log.

Boards that contain the pith generally end up as banana boards with horrific shakes,

 

[Steliz]

I've recently done this with a load of Walnut and a some Plum and after some time I figured the best way was to make a flat side on the log using an electric plane and a straight edge and then run it through the bandsaw with the fence, flat side down.
I started with a new blade (3/4", 3 tpi), which worked very well for the first 50 or so cuts but the bark took the edge off it eventually. Also, with green wood, the blade will get choked up with fibres which will cause it to wander and it will need cleaning afterwards.

 

[custard]

Really good point.

Tuff Saws do an excellent green wood bandsaw blade with whopping great gullets that won't choke.

https://www.tuffsaws.co.uk/index.php?ro ... &path=4_86

You need everything possible on your side to achieve a successful outcome, investing in the right tooling is a smart move.