Hardness of old pine knot

[Sixacresand]

I ran into this situation today.  I took perfect cuts on two sides of a 16 ft pine log.  The tree had been dead for a while,no bark, no shake, dry and solid.  On the first cut on the third side, after a couple of inches the began to wonder and wave, so I eased out of the cut and looked for a nail.  What I found was small knot about 3/4 inch diameter:  no metal even after digging around looking.  I installed a fresh blade.  As soon as the blade hit this same knot the blade began wondering again,  I think this knot is as hard a steel giving me a fit.

I changed blades again, chainsawed off the end containing the knot and did not have any more problems.

[Kbeitz]

I jack up the blade pressure when that happens.

[Ga Mtn Man]

I don't know that I've ever had that happen to me.  Were you getting blade marks as if you had hit metal?  Wondering if it was hard enough to mess up the set. 

[Sixacresand]

I don't know that I've ever had that happen to me.  Were you getting blade marks as if you had hit metal?  Wondering if it was hard enough to mess up the set.

It did leave marks after the knot, so was probably disrupted the set.

[WDH]

Some logs get back at you.

[Ga Mtn Man]

It's a hard-knot life...

[Magicman]

4° Blades should not wave on Pine knots.  I had good results Saturday with 7° Turbos.

[bandmiller2]

John, when I see a large knot or area that causes deflection I slow the feed to a crawl which is fine if you see it. As mentioned less hook is good. If a knot is hit at too high a feed rate there is a likelihood the set will be affected and that trips the dive alarm. Frank C.

[pineywoods]

I ran into the same situation. Didn't make any sense until close examination of the knot revealed a marble sized rock embedded right in the middle. Band blades don't like rocks  :

[TKehl]

If you want to send me a piece I can test it to see how it compares to steel.  I have access to a micro indenter.   :D :D :D

[moodnacreek]

Frozen hemlock knots  can break mill saw teeth. I*'ve seen petrified e. red cedar suckers throw sparks.  Theses things happen.

[Sixacresand]

Well, It happened again yesterday in the second log of the same dead, dry pine.  With a brand new WM 4 degree blade, after the knot the rest of the cut was like a sine wave.  It will be a blessing when these logs with petrified knots are gone.  These logs are presently the only one's long enough to get 14 foot boards.