The Forestry Forum

General Forestry => Sawmills and Milling => Topic started by: Mt406 on March 19, 2014, 01:39:58 AM

Title: Swing Blade Qustion
Post by: Mt406 on March 19, 2014, 01:39:58 AM
I am cutting a big DF 775 bf in a 16.5 log with big knots some are 6" or more.
I have a D&L 10-20 37hp.
When I saw though a knot at 90 degrees no problem.
When I cut though a knot parallel the blade will some times  deflect and return after passing though leaving a high spot.
My question is ... Is this a common occurrence???
This log is very dry.

Thanks   
 

 (http://www.forestryforum.com/gallery/albums/userpics/33427/IMAG0783.jpg)
Title: Re: Swing Blade Qustion
Post by: dgdrls on March 19, 2014, 05:59:03 AM

I haven't sawn any knots that large,  I'm certain they are hard as concrete,
have you slowed your cut at those?

Any pictures you can post?

DGDrls
Title: Re: Swing Blade Qustion
Post by: longtime lurker on March 19, 2014, 06:30:41 AM
I have that issue occasionally in my nice dense Australian hardwoods that go over a 10 on the Janka scale (when green ;D)... but no way is D.F. that hard no matter how long it's been down... a 3 at best.

Still it does happen, and the only solution is to slow your feed rate down and let it nibble it's way through.
Title: Re: Swing Blade Qustion
Post by: Seaman on March 19, 2014, 06:40:02 AM
I have not had that happen in a knot, but I haven't sawn any knots that big. I have had it happen in a crotch section where the wood is very dense. So I would say it's the wood, not the blade,
Frank
Title: Re: Swing Blade Qustion
Post by: bandmiller2 on March 19, 2014, 06:55:32 AM
I would say its normal for old dry hard knots even a sharp band would do the same thing. As suggested slow to a crawl going through. Frank C.
Title: Re: Swing Blade Qustion
Post by: sigidi on March 19, 2014, 06:56:31 AM
Knots/cranky grain will do it to you all the time.

Things like crotches are good education, you get the nice even grain leading up to it and you get to push the saw at its limit, but then you come up to that cranky grain and it'll bring you down every time  ;D don't ask me how I know  8)


Best thing is like most have mentioned already, feed a bit slower at knots, also keep your blade sharp, plus take smaller bites on horizontal cuts that come across the 'the face' of knots/cranky grain.
Title: Re: Swing Blade Qustion
Post by: ET on March 19, 2014, 09:26:13 AM
Mt406, Ive been sawing with my swing now for about 2 years. When I hit big knots, especially white oak, i know I hit something. Ive never got any measureable deflection that Im aware of, but boy its hard pushing through it. I agree, just slow goes it and keep blade sharp.

By the way, those bunks your using look interesting. Did they come with your mill. How about some details on them. Thanks, Ernie
Title: Re: Swing Blade Qustion
Post by: Mt406 on March 19, 2014, 09:39:12 AM
Thanks
Have a dentist appointment this morning will try to take some photos this afternoon.
still have a 1/3 of that log to saw.
Title: Re: Swing Blade Qustion
Post by: Mt406 on March 19, 2014, 11:50:33 PM
Didn't get to saw today, on the way home from the dentist. one of the tree guys flaged me down and gave me 3 loads of cotton wood.
Nice wood 16-26in tips 9-10 ft long hauled 16 home today should have another 8 or so tomorrow.
I did take some photos. Its kinda hard to see the level is sitting  on to knots with a gap in the middle.
I will take some pic of the bunks - dog system it came with the mill needs to be built heavier I have a bow in 2 of them.
 

 (http://www.forestryforum.com/gallery/albums/userpics/33427/IMAG0793_1_1.jpg) 

 (http://www.forestryforum.com/gallery/albums/userpics/33427/IMAG0795.jpg)