Thread: lucas mills cant rival traditional sawmills!?

Charlsie, I reckon the log will have the same amount of tension, but it appears 'less' as the log is 'larger' as the tension is spread over bigger area - if that makes sense.

It's only a personal thought, not based on any study or actual experiments.

yes if you have to have quater sawn boards you most likely have to resaw it.

but thats wha ti was saying before.

anyone can cut up a log but you have to know how to cut it to relive teh tention and still get streight boards.

when i cut straight boards for feedstock they want it with less that 5mm of spring and not much bow.

if you work the centers you get zero spring on those boards. teh rest of the log can go for other purposes. depending on species and age.

tension in a log varies a lot and depends on a lot of things. growing location, growth speed, species, size, branches and pipe all have an affect on the amount of tension in a log.

when sawing on benches you are constantly resawing and cut all teh tension out as you go.

allan,yes i do know what you mean and carl for feed stock are you supplying mainly backsawn timber? or are you quarter sawing from the bottom half of the log which will have less tension in it?

i am suplying nearly all backsawn.

ill show you my cutting pattern to produce good quality board at decent recovery.

sounds good

here is how i cut out my boards.

this would be cutting 100 x 25 out of a 600mm diamiter log.

green boards will have zero spring and only slight bow.
yellow will have slight spring and slight bow.
red boards can have a fair about of spring and slight bow.

cutting like this i can keep all the boards even thickness not the thick centered boards that mobile saws are known for.

every thing else will go for garden stakes and survey pegs.

the red boards out of a 600mm diamater log would be quarter sawn hence a great amount of spring, so if you cut them wider you could resaw them straight (possibly increasing your recovery) if that's what they will accept. ps carl your'e getting as good as bobl with the diagrams LOL

yer almost quarter sawn.

i normaly cut these over and run them threw a bench.

Carl why don't you cut two vertical layers? Ie. Two of those middle layers.
The less winding the gauges the better

by cutting 2 verticle layers you get a #### load of spring. and lose twice the boards to heart inclusions.

Umm clear as mud

Just to be clear because I am new to all this. Commercial mills slab big logs into cants, ie bark to bark slab x desired board width deep, and then cut these cants into the desired thickness of board. For small logs the logs are squared to produce one cant and then this is milled into boards.

Producing the cants removes the tension from the log so that when boards are cut they do not have spring and or bow (or at least not much?).

If my understanding is correct then one of the touted advantages of swing mills could actually be a disadvantage namely that you don't have to turn the log. The turning of the log that is often involved in many small mills (procut, bandsaw mills, logosol) and is said to waste time by swing mill manufacturers might not actually waste as much time as it would first appear and may add to a greater recovery of quailty timber since wood with spring would not need to be resawn to eliminate the defect.

Do I have this right? Is my understanding flawed?

you are mostly correct.

traditional mills cut from the inside out and mobiles cut from the outside in. this is what allows standing mills to cut straight boards more easily.

bansaw mills still cut from teh outside in but they can cut teh other way if the operator is smart enough.

I was wondering if the whole tension issue with swing blade mills could be reduced by having the log suspended from a pivot screwed into each end .So rotate and lock it and work around the log from the outside in .Has anyone made something similar ,good to see some pics and feedback
--- thanks -- mat --