Sweep again

[kelLOGg]

I want to see if this old dog has learned a new trick. There have been a lot of posts on sweep (MM comes to mind) and now I have a log to put what I think I have learned to use.


 

The log is 16' and 18" big end and 13 small end and has ~4 to 5" of sweep. I have marked with a black MagicMarker approximately where to cut the slabs which should be discarded because boards from them will crook. Correct? Then I will cut the "horns" off and then the "hump" followed by cutting the remaining cant into 1x 6s or 8s. These boards will bow but not crook. Correct?

Actually, I will probably cut the log into two 8 footers to avoid so much loss.
Bob

[John357]

Hi Kellogg,

I'm really interested in how this turns out.  I have several logs with off center pith to mill too, but mine are much more off than yours. 

From  your description, what sections are the horns and what is the hump? 

You gonna cut today in the rain?

John

[beenthere]

Actually, I will probably cut the log into two 8 footers to avoid so much loss.

A very good plan, IMO.   ;D

[LeeB]

You pretty well hit it on the nose. I might be tempted to take a little less off the sides to try and get some wider boards.

[StimW]

You will have a lot less waste by cutting it in half and making 8'ers.

[Chuck White]

Hi Kellogg,

I'm really interested in how this turns out.  I have several logs with off center pith to mill too, but mine are much more off than yours. 

From  your description, what sections are the horns and what is the hump? 

You gonna cut today in the rain?

John

With the log laying like it is in Kelloggs pic, the horns are on the left of the pic and the hump is on the right.

The horns are the high points near the ends of the log and the hump is the high point on the opposite side of the log, near the middle.

[John357]

Thanks for the clarification Chuck.

[John357]

HI Kellogg,

After you cut off the hump and mill the boards (assuming vertical 1 or 2 x 8 as posted), you expect those boards to bow.  Will the curve assume the bend that they have now, in the curved trunk?  Or will they curve the other way? 

John

[drobertson]

sawing it as it is, or making two logs depends on what's needed correct?  There will be waste on the sweep and swope sides of the log for certain, but if it's the only one and the length is needed, then get what you can I say.  There will be short boards if left long, and the crook can be minimized by trimming the stress of the barked edges.  Again, it really boils down to what's needed and how many logs you have to work with. 

[kelLOGg]

HI Kellogg,

After you cut off the hump and mill the boards (assuming vertical 1 or 2 x 8 as posted), you expect those boards to bow.  Will the curve assume the bend that they have now, in the curved trunk?  Or will they curve the other way? 

John

John, That's a good question and I will eventually find the answer. My guess is that they will bow the way the tree grew but someone more knowledgeble my answer sooner than I can.
Bob

[jwilly3879]

If I was bucking that log on the landing it would definitely be 2 8's.

[Peter Drouin]

 

The log is 16' and 18" big end and 13 small end and has ~4 to 5" of sweep. I have marked with a black MagicMarker approximately where to cut the slabs which should be discarded because boards from them will crook. Correct? Then I will cut the "horns" off and then the "hump" followed by cutting the remaining cant into 1x 6s or 8s. These boards will bow but not crook. Correct?

You got it

[kelLOGg]

I bucked the log in half after putting it on the mill (easier for me that way) and sawed 1.125 x 9s and 10s out of it. The lower 8' cut was heartpine so it paid off to cut it as 8s.

Top 8'


 

Lower 8'


  

Typical of the lower 8' boards.


 

[5quarter]

That's some nice looking lumber Bob. 

[Magicman]

I was at the Cabin and missed the show.  Congrats on a log sawed well.   

[kelLOGg]

I was at the Cabin and missed the show.  Congrats on a log sawed well.   

Thanks, guys. I have had good teachers.
Bob

[Alligator]

I know you don't want to hear about an Ester Sash Gang, but that log, we saw the black marks, drop it to the gang and bend it thru. Yes the boards are bowed. When they wind up in the middle of 150 layers of well stickered stacks and slow air dried, they are straight when they get to the planer. And you get 11 instead of 9. A sash gang is like having a money printing machine.

[ozarkgem]

I know you don't want to hear about an Ester Sash Gang, but that log, we saw the black marks, drop it to the gang and bend it thru. Yes the boards are bowed. When they wind up in the middle of 150 layers of well stickered stacks and slow air dried, they are straight when they get to the planer. And you get 11 instead of 9. A sash gang is like having a money printing machine.

you got any pics of a sash gang?

[beenthere]

Here is a video of a sash gang. The Ehster may be one that takes a log and follows the sweep or the curve.

https://www.youtube.com/watch?v=Kq20TErRLuU

[Magicman]

That is almost cheating.

[backwoods sawyer]

That is one slow edger
We ran a Sherman curve sawing edger, when running logs that size the feed rolls on that machine come out of granny gear and shift into high gear, it  saws to the curve of the log and realy spits out the wood ;D

[John357]

Kellogg,

Thanks for the tutorial, I was able to saw up my logs with off center pith.  I cut just as you described, top and bottom, then horns and hump.  I stopped at the pith, but now realize I could have gone through.  I guess we'll have to wait a drying season to see if they're ok. 

Thanks again for the thread.


About to cut the top:


 

now the bottom:


 

my first cut was higher than this:


 

As I stopped at the pith, I condemned the little beyond the pith.  Turned it sideways to cut in half to make it easier to throw on the slab pile.  It released about a 1/4 inch of tension at both ends. 


 

... but there shouldn't have been alot of tension in this piece. 


I am trying to get an idea of whether the tree builds more tree on the inside or outside of the arching trunk.  So if I'm on the inside of the trunk, will it expand or contract to relieve the stress?   I've seen a few examples and it's still not clear to me.

John

[beenthere]

As I understand it and as the tree grows, and lays on additional "years" or "layer" of wood, each layer has more tension (maybe the trees reaction to maintaining strength as it gets larger ?? ) and referred to as growth stresses.

When sawing, that tension is relieved and can be seen by the kerf opening up. Some species and trees within species will build up more tension than others. Sweep in a log (as is off-center pith) is a sign that the growth stresses are going to show up.

IIRC

[Lawg Dawg]

Logs can be like people, sometimes finicky, hard to work with, and wishey washey!

[Privacyleech]

Noob question alert. . . Do you saw the logs into boards like the picture and leave them on the mill or are you re stacking them after you cut them to take a pretty picture?

Thanks!

I bucked the log in half after putting it on the mill (easier for me that way) and sawed 1.125 x 9s and 10s out of it. The lower 8' cut was heartpine so it paid off to cut it as 8s.

Top 8'


 

Lower 8'


  

Typical of the lower 8' boards.