Frozen Wood

[JimFX]

Just wondering if frozen wood can be milled with out adverse effects to wood or blade?
I was talking to someone who said the didn't mill in the winter because the wood was frozen .....

[SwampDonkey]

Ah they're just whiners. Commercial bandmills run around the clock year round sawing softwood.

Shouldn't matter too much in Ill. this time of year, the grass is growing. ;D

Fellow up the road sawed ash and maple on small orders all winter with a Woodmizer..

[thecfarm]

I have sawed hemlock and white pine here in Maine in the winter and had no problems at all. I know the wood was froze at that time of year.

[Ron Wenrich]

Its not a problem if all the wood is frozen.  What is a problem is when part of the log is frozen and part of it is not.  I would always have problems with logs that were laying on the ground and the rest of the pile was thawed out.  But, I run a circle mill.

The bigger problem is what's frozen on the bark.  You can saw through ice, but the stuff frozen in the ice is the problem.

[Jeff]

Back in the "olden days"  they use to saw more in the summer and log in the winter, but it had very little to do with the milling and everything to do with the logging. Winter snow and high spring water levels where instrumental in the movement and delivery of logs to the mills. Maybe that is somehow where this person came up with that idea.

[bandmiller2]

Prehaps I'am not observant enough but I've never noticed any difference,more of a cop out than anything. Frank C.

[WoodenHead]

Maybe it depends on the mill and what you are milling (and the operator ;)).  I cut a bit through the winter, but found that it was almost not worth my while.  I was using up to 3 blades per log trying to saw through frozen red oak.  The white pine would go a little better, but was slower than in the warmer season.  Partially frozen red oak made lots of wavy cuts.  So, I didn't have much fun sawing frozen logs.  The lube and/or sawdust would freeze to the boards.
 

[JimFX]

Well I was thinking that would be the answer, i could not figure out how it would have made a difference.
I mean folks used to cut lake water in the winter for ice ..... probably with some kind of saw.
Thanks for the feedback!

[sparky]

My father had problems in early winter when the exterior of a log was frozen and the heartwood was not. The reverse was true in the spring when the heartwood remained frozen and the outer wood had thawed. When sawing in mid-winter on a circular mill we used ice teeth that cleared the chips better than standard teeth.

Sparky

[John Bartley]

I haven't sawed a lot of frozen wood, but enough to know that I don't have to be worried about it. I have found that the wood saws a bit harder thru' the knots, and a little bit of extra "set" goes a long way. I also found that the ice in the logs dulls the bands a lot faster, so where I might get 300-400 easy bdft in a summer time White Pine log, I only get 1/2 to 2/3 of that when that same log is frozen.

So, other than the cutting being a bit slower and the bands dulling a bit quicker, cutting frozen logs is no problem.

John

[Brucer]

I don't do it much.

After a lengthy freeze I found some of the softer species would freeze on the outside (sapwood) but not in the heartwood. The blade would cut fine in either type of wood, but if it hit the interface between them it would try to follow the interface. That could lead to some pretty extreme diving.

When a dirty log got covered with snow and ice, the blade could no longer blow the dirt out on the exit side. The ice would hold it there and sparks would fly -- literally.

Wood-Mizer recommends 4° blades for frozen wood. They also recommend 1-1/4" blades instead of the wider ones. That should eliminate a lot of waves, at least in clean wood.

[Jeff]

Yea, partially frozen wood it a whole other issue. Its basically case hardened. It will give you fits. Fully frozen or fully thawed. We never ran winter teeth, just super shanks in the circle mill and we ran those all year. The standall bits they recommend for winter wood were simply not to my likings.

[Peter Drouin]

I use the WM 1 1/4 7 x55 on every thing, and the 7s cut well, the hard thing I have is when the dirt is frozen to the log and the debarker rides over it then the 7 cut the dirt in half :D :D :D and the 7 cuts the dirt well too :D :D ;D

[GeneWengert-WoodDoc]

Here is a bit of theory so that you might be able to figure out what is happening and what to do.

The heat from cutting is often enough to instantly thaw the water on the surface of sawdust chips.  This heat rapidly leaves and the sawdust wants to refreeze onto the lumber.  This refreezing means that the saw is forced over and the cut gets wavy.  The Standal bit was an attempt with circle saws to keep the chips rotating so they could not freeze and stick.  So, gullet shape is important to preventing refreezing.  Likewise, a fast tooth speed is helpful as it will carry the chips out more quickly.

A dull saw runs hotter, so maybe the heat will keep the sawdust from refreezing...anyone notice this affect?

Also, a small chip is more likely to thaw and refreeze, so an aggressive cut will be better as that gives bigger chips.

[Ron Wenrich]

I was told by an old timer that to saw frozen wood, you need to take some lead off the saw.  The sawdust of frozen wood is different than that of thawed wood.  It's finer.  You also should have narrower teeth.  Short teeth saw better than new teeth.  The worst problems are from new teeth.

My theory was that the frozen wood freezes to the thawed wood.  It doesn't have anything to do with the heat of the saw.  If saw heat was a problem, then you wouldn't be able to saw any frozen wood, as it would thaw out.  The problems only occur when its partially thawed.  The sawdust cakes to the side, and pushes on the saw.  That's where the heat comes from - the saw rubbing on the log. 

[Peter Drouin]

Some times when I cut, I do 4 or 5 boards then try to take them off the mill and their all frozen to the cant :D :D :D

[John Bartley]

This is probably also why the extra bit of "set" that I mentioned helps. Creating a bit of extra space for the dust to clear the wood keeps it from freezing to the board or the cant. In the winter I also use 50/50 WW a/f mixed with my regular soap/oil lube.

John

Here is a bit of theory so that you might be able to figure out what is happening and what to do.

The heat from cutting is often enough to instantly thaw the water on the surface of sawdust chips.  This heat rapidly leaves and the sawdust wants to refreeze onto the lumber.  This refreezing means that the saw is forced over and the cut gets wavy.  The Standal bit was an attempt with circle saws to keep the chips rotating so they could not freeze and stick.  So, gullet shape is important to preventing refreezing.  Likewise, a fast tooth speed is helpful as it will carry the chips out more quickly.

A dull saw runs hotter, so maybe the heat will keep the sawdust from refreezing...anyone notice this affect?

Also, a small chip is more likely to thaw and refreeze, so an aggressive cut will be better as that gives bigger chips.

[Jeff]

My theory was that the frozen wood freezes to the thawed wood.  It doesn't have anything to do with the heat of the saw.  If saw heat was a problem, then you wouldn't be able to saw any frozen wood, as it would thaw out.  The problems only occur when its partially thawed.  The sawdust cakes to the side, and pushes on the saw.  That's where the heat comes from - the saw rubbing on the log.

Exactly!

[GeneWengert-WoodDoc]

The heat I am suggesting is right at the tip of the tooth.  You can see this heat with an IR camera.  I do agree that Once the sawdust is deposited, then we have rubbing and more general heating.  Sorry for the possible confusion..., although it is more a theory based on my observations sawing frozen red oak.  If it is just the tip, then sharpening, length, etc. of the tooth will affect this freezing, which Ron's post seems to confirm.

The sap in the tree has some antifreeze in it...when talking about frozen, how cold does it have to get before you see this problem.  Again, my experience is that we had issues when we were 20 F or lower during the day.

[5quarter]

Gene and Ron ... That's good thinking. A small advantage can often make a big difference.

[Brucer]

When I had problems with softwood, the temperatures were in the range -15° C to -10° C. That translates to 5° F to 14° F. Warmer or colder than that and there wasn't a problem. Well ... colder than that and the sawyer had a real problem with body heat :(.

[Ianab]

Makes sense. If it was colder than that the wood chips stay frozen, and the frozen chips are cleared normally.
Warmer than that, the ice melts and doesn't refreeze fast enough to bind up.

Right in that "Goldilocks" zone, and things mess up.

Luckily it doesn't get that cold here, so I haven't encountered the problem  ;)

Ian

[Jeff]

Right in that "Goldilocks" zone, and things mess up.

If there was ever a quotable quote, here it is.  :D

[SwampDonkey]

*Wood* hate to mess her hair up. :D

[Ron Wenrich]

The biggest issues we had is when you get the beginning of a long cold spell.  It isn't so much how cold it is during the day, but how cold it gets at night.  Those low nighttime temps will freeze the wood rather quickly.  If the daytime temps stay in the 20s or even the low 30s, there won't be any thawing.  After they're completely frozen, there isn't a problem.  Warm sunshine on the logs can cause a little bit of a problem. 

We also get the problem of uneven thawing in the spring.  A good rain will pull the frost out of the logs, just like it does out of the ground.  But, the logs on the bottom of the pile that are laying on the ground can be a problem for weeks after the air has warmed up. 

My experience with short teeth is that it also works on hickory, no matter what the time of year.  I always thought it was more of the way the wood chipped off when frozen vs when it is thawed in the other species.  ie, frozen wood is similar to hickory.

The only problem I have with the tip heating the wood, at what point is it that the tip no longer thaws out the wood?  If it thawed out the wood, you would have that problem anytime you have frozen wood.  The problem goes away when the entire log is frozen and returns when it is partially frozen.  I'm not saying that there isn't heat, just that it isn't sufficient to be a problem.

[bandmiller2]

I don't go out to play in the "goldilocks"zone which probably explains why I've never had problems with frozen logs.I know we have super hardy northern type sawyers here but when the temp.gets too low its brutal on the mill machinery.Some have no choice,if you can do outher work when its below zero by much, your mill will thank you. Frank C.

[Andries]

I'm with band miller - when Goldilocks has gone home to hug the wood stove, I'll be in the woodshop with her. That's the perfect time to change milled lumber into finished products.
I've milled when its really cold (spit freezes before it lands on the ground) and its not worth it. Anything that's temp sensitive it going to make things ugly or break engine and mill parts.
However, on a warmer winter day that doesn't have too much wind, burr oak mills well with a 4 degree band and -40 degree rated windshield washer fluid. Red pine will also mill well with the 7 degree bands and the ww. fluid still gets rid of the band pitch that thaws during cutting.
We've still got snow on the ground here, so milling when its cold and wood is frozen is part of the game !

[JimFX]

I was told by an old timer that to saw frozen wood, you need to take some lead off the saw.  The sawdust of frozen wood is different than that of thawed wood.  It's finer.  You also should have narrower teeth.  Short teeth saw better than new teeth.  The worst problems are from new teeth.

My theory was that the frozen wood freezes to the thawed wood.  It doesn't have anything to do with the heat of the saw.  If saw heat was a problem, then you wouldn't be able to saw any frozen wood, as it would thaw out.  The problems only occur when its partially thawed.  The sawdust cakes to the side, and pushes on the saw.  That's where the heat comes from - the saw rubbing on the log.

Take some lead off the saw?  Short teeth?  You are kinda loosing me with those two.
Could you splain those please ....
Thanks
JimFX

[beenthere]

Jim

Take some lead off the saw?  Short teeth?  You are kinda loosing me with those two

Talking about circular saw, that has some "lead".

I think you are interested in a band mill....  right?

[JimFX]

So is the lead the means to secure the teeth to the steel blade?
and yes, a band mill is what I am looking at.

[beenthere]

Lead pronounced as in "leed", not as in "led"

A circular sawing word.
It is one of the adjustments in the alignment of the track with the carriage and the husk with the circular saw blade.

The lead can be fine tuned with the help of the guide pins near the leading edge of the circular blade just behind the inserted teeth. More to it than that, but it is maybe the general idea of lead.

;)  Some words in the English language, like read (reed) and read (red)