I have a customer that has a 6m by 600mm tapering to 400mm talow wood log.He wants 2 8x2s and 6x2 from the rest.My thort was to cut paralel with the hart untill there is 8" on small end then get maby the 2 8''s from there then droping 6'' and cut 2'' leaving a taperd bottem section.
Or should i cut paralel with the sap untill there is 8;'' get my 8s then cut taperd section from the hart.
Ye there is also a large khot 2m form small end.
Any advice would be apreciated
And i mite add i am useing 8'' lucas.

Because of the 6m length it will be quite difficult to achieve those sizes and you will have to plan everything around the small end. I might look at marking out the cutting pattern on the end unless you are particularly good at visualising the cuts and sequence

Hopefully your log is straight. Probably not, which makes the task more difficult again.

I have never cut tallow so I can't comment on growth spring, but 400mm is sounding a little small to me particularly over that length. Perhaps others can help there. On a mill with a bed I would jack up the narrow end until I could cut parallel to the sap. With your Lucas I would be tempted to set up some timber bearers to act as a primitive bed. Then you could cut the 8x2s fom top and bottom by rotating 180 deg. Cut 6x2s from anything that's left on the cheeks and maybe one each above the 8x2s.

You would probably still jack up the log end as neccessary or angle the mill rails whichever is easier. Bear in mind I have seen Lucas mills in action but never used one myself.

Full 6m length you may get 6/ 6x2 and 2/ 8x2 if you are lucky (Actually you will lose at least 2 full length 6x2s because of the knot you mentioned)

Regards
Paul

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The log is Quit strate thats a +.
Angeling the rails is easy but fliping the log 180 is not,so could i cut in the same order without rotating log or do you sugest rotating to reduce tenchin.

Tanks Eli

I'd consider rotating the log to be an essential for such a job, and even with a 6m log doing so shouldn't be too difficult to do manually using a cant hook and crowbar. You need to be cutting parallel to the sapwood to achieve the sizes you want from such a small diameter log.

The cutting pattern Bushmiller suggests is IMO the best approach. But I suspect that it's overly optimistic to expect more than just a very few good boards from such a small log. I think you'd be fortunate to get more than 2 @ 8x2 and 2 @ 6x2 from the log unless your boards end up containing heartwood and/or sapwood. Maybe a couple more shorter lengths of 6x2 (because of the taper).

At only 200mm radius it's impossible to get quartersawn boards of the size you want from that log, so they'll have to be backsawn.


As Paul intimates above, you basically need to consider that the 'small end' is the size of your log, and work around that.

If you absolutely insist on cutting without turning the log then you'd need to jack up the small end and cut parallel to the sapwood until you reach the centre of the log, then jack up the large end (or drop the small end) so that you are cutting parallel to the sapwood again for the lower half of the log. That's fiddly, and it'd make it hard to judge for the latter portion of the job.


What I suspect you're neglecting to consider is this:

To get a decent 8x2 backsawn board which contains no sapwood or heart (pith) the sawn surface of your face cut will need to be up to 10" wide!

If you absolutely insist on cutting without turning the log then you'd need to jack up the small end and cut parallel to the sapwood until you reach the centre of the log, then jack up the large end (or drop the small end) so that you are cutting parallel to the sapwood again for the lower half of the log. That's fiddly, and it'd make it hard to judge for the latter portion of the job.


Tanks Cat for your well explained answer.Corect me if i am rong pleas, but with the lucas mill cant i cut paralel to the sap till a point then lowere one end (large end)and cut palalel to the sap again.
Thanks Eli

I'm far from being any sort of 'authority' on what can or can't be done with a Lucas Mill, Eli. I've only had a smallish play with a friend's unit. But over the years I've churned out enough timber over a sawbench to build a small city from.

What you describe there is basically the same as what I said above. To cut the log without turning it you need to raise the small end so that you're cutting parallel with the sapwood for the top half, then drop it again (or raise the other end) so that you're parallel with the sapwood again for the lower half of the log.

I'm just saying that I WOULDN'T do it that way, coz it's easier to judge your sizes when you're working from the outside in, and coz it's so easy to turn such a small diameter log!

True It would be easier to judge sizes from the top.Ye maby i mite nee to man up a bit and just flip it.
Thank you both

Backsawn boards out of a small young log usualy means trouble.

I've done a few tallowwood and found it to be a very stable timber, Particualrly when compared to something like Gympie messmate. Mine were a bit bigger than yours and as I recall it was difficult to pick the sapwood boundary.

Also had problems with gum pockets and some remaining bark. If you have taken the bark off then you will have a fair idea if you have many gum pockets.

Good luck

And quartersawn boards of that size from such a log is an absolute impossibility, so....

You should be able to get a couple of decent backsawn 8x2 from such a small, young log OK. Centreline of them need to be in line with the centreline of the log though, or they'll spring. Bow will be pretty much inevitable, but that shouldn't be a problem unless the boards are intended for use as beams spanning any amount of distance. (If the boards are intended for such use the log is unsuitable!) The biggest potential problem would be 'cupping' as the material dries.


Seems to me that there's just a touch of a naivety involved here, with perhaps an assumption creeping in that every square inch of cross section can be converted to usable full-length timber. Doesn't work that way, though, especially with young, small logs.

Ye i have stacked,graded,cut lots of tallowwood in large mills and its not to bad hay.
Dont think the tention will be a problem as the timber is only to hold up a roof over a shiping container.
Eli

eli szoko

Just as an exercise to see whether your materials list was possible out of a log with only a 400mm diameter I drew up a couple of cutting lists as outlined below.

Do take note of Catweazle's "naivety" comment as he is quite correct. My diagram makes no allowance for the bark, no allowance for the sapwood and no allowance for other defects such as the knot you described, which would almost certainly prohibit a full length boards on that face of the log.

Another point is that I have allowed 100mm for the heart. That may well be insufficient!

To maximise recovery you would have to turn the log frequently, but that should not be too difficult with a long cant hook or crowbar and chain if no cant hook is available. A mate to help (with another cant hook) would be excellent and it does become easier as the log sheds weight. Turning a small diameter log will improve the chances of good timber too.

My apologies for numbering the cutting order of boards. If you have sawmill experience, I am probably telling you how to suck eggs. I am trying to emphasise how difficult good recovery will be without turning.

One last comment: A 200 x 50 board will not support it's own weight over a 6m length without deflecting. I am hoping your customer is not planing to use the beams to support the rest of the roof.

Regards
Paul

Attached Images

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Thanks paul for your time and exprtise.
Yes i too hope he is useing the timber crectly.
I have decided to cut like your first paten.
Dont worry Ive been told how to suck eggs befor.
Mite get the job done if this dam rain went away.
Thans Eli

there is no need to ever rotate a log in a lucas mill (unless cuting 10x10 or bigger)

what grade do you need to achieve?

a lucas cuts the oposite way to a bench and needs a completely different cutting pattern to a bench sawing.

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Oh bunkum and balderdash! Even though I've spent a negligible amount of time operating a Lucas Mill myself, I'll still call BS to that.

The amount and position of recoverable timber in a log is dictated by the size, shape and other characteristics of the log itself much, MUCH more so than by the equipment used to recover it.

In truth, the only real difference between cutting it on a Lucas and cutting it on a resaw breast bench is that, with the Lucas, you should be able to recover a wee tad higher proportion of timber than you could on a breast bench. Because you've eliminated the extra wastage incurred by the need to cut into flitches to provide a flat surface for the breast bench.

The challenge Eli has posed above is recovering 2 8x2 boards and as many 6x2 boards as possible from a small, tapered 20' log. That is going to be achieved by cutting them around what will become a tapered heart section.

In the advice given above the suggestion to turn the log isn't anywhere near as important as is the suggestion to cut in line with the sapwood by elevating the small end of the log when necessary. But simple fact is that if you turn the log a time or three during the cutting of it you're gonna provide an easy 'line of sight' check against the mill rails to ensure that you're doing just that!

And it's so damned easy to flip that log, or nudge one end of it over a couple of inches, using a cant hook and crowbar. If you're trying to recover boards from the log, rather than garden sleepers or somesuch, then I kinda think the question isn't "why would you flip it?" It's "why WOULDN'T you?"

And I suspect that there are only a couple of not very complimentary answers to that question.