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Author Topic: Steaming saw blades  (Read 8462 times)

Offline Stevem

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Steaming saw blades
« on: April 14, 2017, 11:50:33 PM »
I was sawing yew wood today with my band mill and as the blade entered the log, water running, steam was coming out with the saw dust. Yes, yew is a very hard conifer.  Didn't seem to matter how wide the cut, from entry to widest point, I was getting steam.  It seemed that the faster I cut the less steam I'd get.  Tried a different blade and then tried a new blade with little or no difference.  I did notice that there was quite a bit of packed wet sawdust being left in the cut!  Cutting maple was better but still had steam coming out.
Anybody got an explanation?
Stevem
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Offline Kirk Allen

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Re: Steaming saw blades
« Reply #1 on: April 15, 2017, 08:11:16 AM »
Blade rubbing somewhere else creating friction?  What did your tension do when you saw the steam?  I assume blade tension dropped considerably if it got that hot. 
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Offline Stevem

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Re: Steaming saw blades
« Reply #2 on: April 15, 2017, 10:50:08 AM »
Didn't look. Dah.   I'll check the tension next time I saw.
Stevem
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Offline HaroldCR - AKA Fla.-Deadheader

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Re: Steaming saw blades
« Reply #3 on: April 15, 2017, 03:52:06 PM »

 We found a swamp log one time, that looked good enough to saw. That thing gave me all sorts of fits. Best thing I found was to cut with no water running on the blade. Seems water was causing rapid swelling of the dust and binding the blade.

Offline furu

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Re: Steaming saw blades
« Reply #4 on: April 16, 2017, 01:13:51 PM »
I have seen something that I would also describe as steam several times while cutting  Douglas fir. 

At the end of the cut I shut down the blade and it is not hot and the wood is not that warm either.  I have never figured out what causes it, have decided that it is not predictable, and have almost given up wondering what it is and where it is coming from. 

I say almost because I have a half-baked plan to put a blade on with more set the next time I see it and see of it still occurs with a larger set. 
Problem is I have to remember to set a blade different than normal and then keep it separate and then decide to switch out the blade the next time it happens.
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Offline Stevem

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Re: Steaming saw blades
« Reply #5 on: April 17, 2017, 01:31:14 AM »
Per Kirk I'm going to check blade temp while running and not sawing to see if it starts hot.  No logs to saw right now.  Just went through a major alignment and might have missed something.  The blade was "steaming" just has it started cutting not 2" into the wood.  I might have had one of Harold's "swamp logs".  Blade was cutting straight and exited the log what I'd call perfect, no up or down movement, just "steam".  Looks really bad.
Maybe "steamy" logs are just a west coast thing?
Stevem
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Offline backwoods sawyer

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Re: Steaming saw blades
« Reply #6 on: April 17, 2017, 02:25:35 PM »
Steam=friction
I increase set when I sharpen to 28-31
Pacific yew, Juniper both will shed slivers of bark that will build up under the diesle wipe pushing the saw down away from the guide....

Offline Stevem

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Re: Steaming saw blades
« Reply #7 on: April 20, 2017, 01:02:19 PM »
Wow, that's a lot of set! Is that per tooth or total set?  What's your normal?

No heat buildup with just running the blade!

Talked with Timberking and they said it may not be steam but vapor (there's a difference?) and not related to blade heat but more to air temperature differences.  Very common, hmmm.   No wood to saw at present to check.

I'll be slabbing redwood tomorrow with the Lucas.  Customer made a deal to trade redwood slabs for Myrtle wood logs.  Why don't people make me offers like that?
Stevem
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Offline furu

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Re: Steaming saw blades
« Reply #8 on: April 21, 2017, 03:55:58 PM »

Talked with Timberking and they said it may not be steam but vapor (there's a difference?) and not related to blade heat but more to air temperature differences.  Very common, hmmm.   

Steve
An interesting idea on the vapor explanation. 
Think of fog, formed when the dew point, temperature spread is near zero.  Definitely not steam on a cool/cold morning.
Saturated air.  Might explain why it only happens occasionally, as the conditions have to be right. 
Will check out the spread the next time I see the "steam"/vapor when sawing.   
Thanks for the update.

Steve
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Offline 4x4American

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Re: Steaming saw blades
« Reply #9 on: April 21, 2017, 06:54:55 PM »
I have this happen too and I was told that it is because the inside of the log is a warmer temperature than the outside air is.  Kinda like when you breathe outside in the cold and you can see your breath.  Makes sense to me..
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Offline jake

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Re: Steaming saw blades
« Reply #10 on: April 24, 2017, 03:16:43 PM »
agree with the vapor explanation from TK.  sawed cherry and ash on saturday temps were in the 40s and there was a lot of "steam".  have had this happen often with colder temps, but the band is not wandering or changing tension like it would with over-heating. 

Offline mountainlake

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Re: Steaming saw blades
« Reply #11 on: April 26, 2017, 04:26:55 AM »
 
 In the right weather conditions mine looks more like steam engine.  Steve