What causes this surface, grain or blade ?

[Tom the Sawyer]

Milled a small log yesterday and found this pattern on the cant.  Had a similar occurance once about a year ago.  Both times I was sawing ash.  Milled 11 other logs yesterday without any hint of a similar pattern, both before and after this log.  Last time I was using a TK Ultra Max 10° blade, this time a WM 7° blade.  The only thing that sounded any different was a slight change in the 'hiss' of the blade.  Is this an unusual grain pattern or is it symptomatic of something with the mill?


 


 

Thanks for the help,

[ladylake]

 I've seen that also mostly in basswood, has to be the grain.  Steve

[hackberry jake]

I think its a harmonic blade vibration effect.

[Magicman]

I occasionally see it when sawing harder species such as Oak, but I have never seen it extend to the length that you show.   For me, it will often show up within the first 18" upon entering the butt of a log, so the log's hardness is a factor.   

Now if you could intentionally do it to kinda replicate circle saw marks, you would have a winner.   

[barbender]

Whenever I've had marks like that my feed speed is too slow, FWIW.

[Dave Shepard]

Whenever I've had marks like that my feed speed is too slow, FWIW.

Same here. I think that is why it usually shows up in the first foot or so for me. I haven't seen an entire log look like that. Also more prevalent in wider cuts.

[ladylake]

As mentioned I see the often in basswood, no slow feed rate .  Looking at the saw marks on that cant looks like Tom is moving right along for ash.   Steve

[Macgyver]

I had a whole reply all typed up and ready to send, got distracted and 5 more came in in the mean time.  My post is summed up by pretty much saying ditto to these others.  I've noticed the pattern when my blade tension isn't high enough.  And, I've found that the pattern changes with my feed rate...another hint that it's due to the band.

[Chuck White]

Once in a while I'll get a similar pattern, but it's usually within the first 3-4 inches of entering the log/cant.

There have been a few posts posted, discussing this issue in the past!

[tyb525]

In the 2nd picture looks like there could be a little burning from the band, also caused by a slow feed rate. Slower feed rates tend to let the band vibrate more.

[Tom the Sawyer]

Just as additional information, I tried slowing down and speeding up to the point of bogging the engine down.  This log appeared to be limb stock, started out at 9" diameter by 5'7" long, the pattern was on all sides, the cant was 8" wide.  I've seen the patterns if I enter the cut at the wrong speed, this is different.   :-\

Just to clarify, the blade tooth pattern is directly perpendicular to the cant, the pattern I am curious about are the diagonal markings which are at the same angle (about 45°)on all sides of this cant but none of the other ash logs I sawed that day.   There was no noticeable head vibration, using the normal amount of lube, and the tension was consistent.  It wasn't my log so I don't have any to play with (like running it through a planer).   :-\

Client thought it was an interesting look but if it something within my control I'd like to know how to prevent it.  I only milled another 75 bf on this blade before i finished so I'll set up here at home and see if I can recreate it although I don't have any ash to mill.   

[Kansas]

Its curl. It should bring premium price. It is not the blade, and that stuff can be a bear to cut.

[ladylake]

 Now we're on the right track .  The pattern also shows up after planing which really elimates anything to do with the blade or feed speed.  Steve

[mad murdock]

Curly grained wood does bring a premium price, especially with Luthiers, if it is the right species for their instruments.  wood workers like it as well, it is real nice looking grain when finished! Lots of character.

[Peter Drouin]

Was it a old log or new green one, and did you make 1" boards and did they have the same thing

[Tom the Sawyer]

I think the trees came down in January of this year.  The boards in this cant were sawn at slightly over an inch.  All of the boards from this cant had the same pattern.  These trees were taken down as part of a construction project. 

They were landscape plantings around a library, not native or forest trees. They were healthy and not that large, the biggest ash butt log was about 16" diameter.  The rest of this particular tree may still be in the pile.  There are about 25 logs left to saw in this project, a mix of pin oak, sycamore, and ash.

[Ga Mtn Man]

Tom,

Interesting.  Did the pattern vary at all with your feed rate?  I have seen a similar pattern left in the sawdust on a cant, although at a much sharper angle:



 

[WDH]

Hopefully you will find some more logs like that one in the pile.

[beenthere]

This log appeared to be limb stock,

And may thus be part or most of the explanation. In one pic, the ring pattern was pretty abrupt steep (2nd pic, left side).

[WDH]

BT,

Looks like where a live limb branched off, maybe.

[tyb525]

If that is curl, it looks really uniform (evenly spaced). I have heard of curly ash, I know every species can have curl. Will be a bear to plane! Drum sanding would be better.

[Brucer]

It has the sort of pattern you'd see with harmonic vibration of the blade. However, I've never seen the vibration marks anywhere close to 45 degrees. I've also never seen it run the whole length of a cant. It usually appears in short lengths, with clean cuts between them.

[beenthere]

Maybe a bad bearing? Thinking it could resonate the band for the harmonics at certain speeds, ?? 

[Okrafarmer]

I milled some leyland cypress recently and it mostly did that, too. I didn't take any pictures though. My phone camera bit the dust and it's a lot less convenient now for me to take pics and post them.

[giant splinter]

It has a nice effect, The only time I have seen anything even close was when I milled some cottonwood, rift cut for a trailer deck.