Not long ago there was a thread discussing whether to saw parallel to the pith or parallel to the bark.
With the best grade being on the outer part of the log I'm thinking of cutting parallel to the bark but I need some clarificaton on how it's done and when it makes sense to do so.
Theoretically you could saw all four sides parallel to the bark and end up with a long pyramid in the center but that would require leveling each time when the log is turned.
In the real world what's the technique?
Actually you would only need to level the bark with the blade on the first two face openings. Then turn the bark sides to the bed and saw the two pith wedges out.
Had to think about that a minute, but I think I understand. Just trying to decide the actual sequence so that you don't end up with a lot of flitches to edge.
When I grade mill for flat sawn, I'll select the best face for the opening face, and level the log so that the bark on top is parallel to the blade. I'll mill boards until the grade starts to fall off, and then will turn to the second best face and repeat.
If the log is clear on opposing faces, I'll saw a few boards off of face one, turn the log 180 degrees and then saw a similar amount off of face 2. This provides me with boards with centered cathedral grain. Usually I end up with a wedge cant 6" or so in thickness on the small end depending upon the log.
Once I pull the grade boards off, I'll pull a wedge off of the two sawn faces so that my cant is the same thickness from end to end, and then turn 90 degrees and through saw the remainder for mixed grade.
Sometimes I won't turn it but simply keep sawing until I'm left with a wedge. It depends on what I need to yield and the particulars of the log.
With logs that have a high degree of taper, sometimes I'll pull the wedge out on each side about 1/3 of the way from the bark to the pith. This allows me to have low slope of grain in the boards coming from the center of the log. It all depends upon the log though.
You saw parallel to the bark to get good lumber at the cost of the heart. Sometimes a log only has one good board in it and to get that board you do any amount of tapering or none. The rules only work on nice logs.
Quote from: D6c on June 03, 2020, 06:48:09 PMTheoretically you could saw all four sides parallel to the bark and end up with a long pyramid in the center but that would require leveling each time when the log is turned.
That actually describes what I do when producing QS, pine flooring by making multiple cants out of a log. At some point in the process I drop the toe boards and end up with a few short boards from each cant as they are tapered, but I get tighter grain as a result, and we recover the vertical grain boards from the center cant on the edger, so the "waste" is worth it.
Quote from: moodnacreek on June 03, 2020, 09:04:07 PM
You saw parallel to the bark to get good lumber at the cost of the heart. Sometimes a log only has one good board in it and to get that board you do any amount of tapering or none. The rules only work on nice logs.
In my case the opposite: my most commonly encountered defect is pipe, and mostly the pipe is tapered at the same rate as the log taper. If you cut them heart centred you don't get a lot of end to end saw through. The joys of sawing didgeridoos
I think it would be very educational if someone posted a condensed video of beginning-to-end taper sawing. I find it hard to visualize the process in detail (and I don't want to ruin a log ;D)
On top of this stack is the center cant from a log I had to taper saw like @longtime lurker (https://forestryforum.com/board/index.php?action=profile;u=22746) commonly encounters. I got perfectly clear boards from the outside even though the middle was hollow. I just raised the toe rollers to level the bark and cut until I lost grade then turned. When I turned to a face that had been cut once already, I leveled out the top flat face as close as I could to the blade then took a 1/16-1/8" skim cut then cut as normal.
(https://forestryforum.com/gallery/albums/userpics/49164/Snapchat-1976661561.jpg?easyrotate_cache=1588601500)
(https://forestryforum.com/gallery/albums/userpics/32746/1560477122642.jpg?easyrotate_cache=1580391096)
Under the state log assessment rules that log classes as optional... So 1" more pipe than a compulsory log. The math works out at 65% of the volume of that log being outside the pipe. At compulsory 75% of the log volume is outside the pipe... There's a lot of volume in the outside 50% of a circle
(Me playing with backsawn radial taper sawing on the Forestmill. Need knuckle turners and laser guides to make it work cost effectively but the recovery numbers relative to log grade are outstanding)
Quote from: kelLOGg on June 04, 2020, 07:37:02 AM
I think it would be very educational if someone posted a condensed video of beginning-to-end taper sawing. I find it hard to visualize the process in detail (and I don't want to ruin a log ;D)
+1 I'd like to see a video too.
Me three.
You don't need a video, just saw parallel to the problem as best you can and when you see it coming or hit it turn the log and saw the same. The waste cant will come out tapered as opposed to having tapered jacket boards.
Quote from: moodnacreek on June 04, 2020, 09:17:29 PM
You don't need a video, just saw parallel to the problem as best you can and when you see it coming or hit it turn the log and saw the same. The waste cant will come out tapered as opposed to having tapered jacket boards.
That makes as much sense as anything....I'm going to give it a try next time I've got a decent log on the mill (not as often as I would like.)