Reverse Roll Quarter Sawing

[Brad_bb]

I just need some clarification. Back on page 9 somewhere, Yellowhammer advised not blindly cutting through the center of the log to halve it.  He said to go up a border or two from the center so you're not making a blind cut. I don't really understand what he means by blind cut. For example on the log I am working on now which is very straight, I've made an octagon leveling the pith in all directions. The pith is completely level relative to each opposing face. I've drawn some lines which you might be able to see here in red on medullary rays.  The rays are pretty darn level going through the center of the log.  So I wouldn't think that would be a blind cut, other than I can see no fleck on the face, but you would never be able to see the face on your first cut before you cut it.  Is he trying to say that from the center I should go up A Board Thickness so that I can cut out two boards from the center straightaway Before I start dealing with the log halves? If I go up to board thicknesses I think the grain will no longer be sufficiently perpendicular to the cut.

 

[doc henderson]

@YellowHammer can explain it best.  I know in Ga, they took off about the top 1/3 of the log.  I think there is a video.  but the theory belongs to him.  I would then think saw down about 3 slabs centering the pith in the middle one.  then start rolling up the side on the backstops.  so almost like doing thirds.

[Stephen1]

I'm with BB. I have been working through my RO log pile. I have beem collectiong them for 5-6 years. I only saw them when someone pays me. 
I have decided that I'm going to sw them for flooring in my new house. I am working on RRQS method after reading through all this.
Then of course, I start digging out these RO logs that have been hiding behind everything. I do have quite the collection of mostly Urban Salvage RO logs. At one time when I 1st starting sawing, I thought big logs were worth money...lol We ll RO only if you can find the 1 in a million. I guess I'm going to be that person. 
Most of the logs are not 8' so I do not get to use the roller toe boards. Most of the logs are not 20" like I had thought  they were. I did manage to learn the technique, I have lots of firewood now, which is okay also. I also have a bundle 280 bd ft of QS RO from 5' to 8' long. Some as wide as 7" and down to 3". I have about 500bd ft of flat sawn RO and anouther 250bd ft of RO oavals and cookies.
pictures to follow in the next post.

[Stephen1]

 

 





 

 

 

 This is my nepheh that showed up this summer with nothing to do. He is 15! He worked for me all August and wants to comeback next summer. I think he is dreaming sawdust. ;D




 Some of the logs were not worth QS so we sawed some ovals, very nice end table size.

 



 I only have 2-3 QS logs left. most of my logs will have knots in them. They willGive me some nice character flooring for sure. My aim is 6" and 8" wide boards. Here I marked my through cut. It worked nicely on the smaller logs with the off centered pith. I was able to get a few boards out of the large half. I can see where the toe boards really can help to get rays to show.

 

[WDH]

Imagine that you are splitting the pith exactly with a cut, then move the head up one full cut.  That is 2.5" if you are sawing 9/4.  That will yield a board that is 2 3/8" thick and 1/8" kerf (2 3/8 + 1/8 = 2 4/8 = 2.5").  This yields one thick board above and one below with the bottom face of the upper board and the upper face of the bottom one perfectly quartersawn with all rings perfectly perpendicular or 90° to the flat face.  By positioning the head this way, you are not sawing "blind", but you have positioned the blade just right to get that perfect 90°. 

This also removes almost all of the juvenile core in the first thick boards so the resulting quartersawn boards from the top and bottom "thirds" that are sawn out with the reverse roll do not side-bend.  And, one face of each of those two boards is perfectly quartersawn.  In oak or sycamore, go ahead and edge the juvenile core out of each of these first two cuts which gives you 4 boards that are the widest and finest 4 quartersawn boards in the log. 

If you are sawing 4/4, then start at the pith and move up two 4/4 boards for the first cut.  If you are targeting 1 1/8" thick boards, you move the blade up 2.5" also.  Then make 4 cuts.  Two above the pith and two below the pith.  So up 2.5" and the cut sequence looks like this +2.5" - 1/8 kerf - 1 1/8" board - 1/8" kerf - 1 1/8" board = 2.5".  Then make two more cuts below the pith.

After these first cuts above and below the pith on the octogoned log, you then reverse roll the top and bottom "thirds" (they are not actually thirds but are the thick pieces above the first cuts above the pith and the first cuts below the pith). 

[Brad_bb]

@WDH ,
Well you confirmed what I thought, however I'm cutting so I end up with 1-7/16" thick boards  so later they will finish at 1" after drying and planing.

Problem is, if I go up from the center(pith) two boards, the upper board will not be perpendicular to the grain.  It will be off.  Do you just accept that because you're trying to get rid of the juvenile wood?

[WDH]

Yes.  You need to get the juvenile core out.  Another way to do that is to draw the juvenile core on the octogoned log with a sharpie of lumber crayon.  Draw the juvenile core circle then color it in solid.  Split the pith with the first cut so you then have two halves.  Reverse roll these two halves.  Then examine each board, and any that shows any part of the colored juvenile core, edge that board to remove the colored part.  Just a good bit more work this way. 

[Brad_bb]

So how do you identify the juvenile core?  Do you just take a certain dia measurement, or is there a clear demarcation?

[YellowHammer]

As WDH says, getting out the juvenile core is quick and easy if you take a couple boards out in the first halving cuts.  These should be pretty good to excellent ray fleck, but the "sawing blind" part references exactly the question you are asking, how far up can you go and still get good fleck on those first few center cuts?  They are aligned with the pith after gun barreling, and should be gimmee boards, but not all logs are created equal and all don't have good fleck the same distance from the pith.  Since you have to start sawing on the highest of the center cut boards, you are essentially guessing whether you should try for 5 boards, 4 boards, 3 boards, or only 2 from the center.  If you guess and set up too high, you may not have good fleck on some of the widest boards in the log.  For example, you may try to get 4 center cut boards, 2 above the pith and 2 below, and make your first blind cut 2 boards up, and find out that the fleck wasn't good because it was too far from the pith. So that's a reduced quality board.  Then the second board is closer to the pith and it's dead on. The third board is one board below the pith, and looks good, but the fourth board is a little too low, and a bust.  So then the next log you think you have it figured out and only take 3 boards from the pith and find out you could have done 4.

Furthermore, since you've taken 4 boards from the middle, that means the halves are now reduced in size by 2 boards, and now all the RRQS boards will be at least 2 inches narrower.  So the first few center cut boards are a gamble that effects every board thereafter.  

I have confidence that any RRQS board will have at least as good ray fleck as a center cut board, so sometimes I only take 3 from the center, even though I could "probably" get more, but I want wide log halves instead of thirds, so I can also get lots of wide RRQS boards.  Every center cut board will reduce the width of every log half board, so a non excellent ray fleck center cut board is a double penalty.  

You can generally easily see the juvenile wood in the end grain.  However, it's more important to get good ray fleck than to cut out the very last bit of juvenile wood.  The ultimate goal is to get fleck on every single board, and it's better to have to edge out a curved board than have a miss.  For example, some months ago I RRQS a single white oak log that I paid a $800 for.  One log.  It made some of the most beautiful, zero miss wide ray fleck I have ever seen, and within 2 weeks of putting the wood on the sales rack, sold every board off it for a net of over $1,500 on one log.  On logs of that quality and expense, misses are not allowed.  

[doc henderson]

Dr. Wengert has said the juvenile wood is about the first 15 rings.  sometimes it is a different color, or may have ring shake.  if you cut down the pith, you can sometimes see the outline of the original small tree within the log. sometime the end check is different and you see a pattern.  @GeneWengert-WoodDoc 

[Brad_bb]

Thanks you guys.  I pulled that log off the mill until I got this clear.  I'll go for it tomorrow.

[WDH]

There is no sure fire way to determine the exact juvenile core. So as long as you remove most of it, you are doing OK.  It can vary from tree to tree within the same species due to a variety of factors such as genetics, site, etc.  One thing that you know for sure is that it is the circle of wood centered around the pith.  I figure about a 4" circle as a rough rule of thumb.  At least this will get a great deal of it.  I agree with YH that the goal is to maximize the fleck, and if a few boards have to be edged after drying due to crook, the loss of wood is minor compared to the value of the ray fleck on the board. 

[customsawyer]

Another thing to keep in mind. When I am RRQS a log, I'm not doing it with a log less than 25" SED. I normally keep them in the 30" SED or bigger. This is why we can get a one or two more boards out of the center of the log. If you are trying to do this on a 20" dia. log you might get less lumber out of the center but you will still want to try to remove the juvenile core. 

[trimguy]

Thanks for bringing this thread back to the top! RRQS has been mentioned in several threads since I've been a member, I wasn't quite sure exactly what it was. I just read the whole thing, now I know thanks a bunch. I have a sycamore log to try this to , at some point.

[Brad_bb]

Whittling away on my WO log.  Milling 1-7/16" green.


 

Now at this point in the roll, it gets a little precarious on the LT15.  The backstops helped me when gunbarreling the log, but now they cannot support anything because straight up, they are too tall and I'd cut them.  Halfway down and they will not support the pie section.  Although I have it up at the correct orientation, I don't have enough support to cut it.  


 

 
I think I need to rig something up.  I could probably get by with a 2x8 or 2x6 up against the backstops partially up, but they would need to be clamped.  But I need the clamps for the oak....  I'll have to see what I can rig up for tomorrow....  I've got an idea for a support for pie sections-


 
The base is secured to a cross bar by set screws.  "A" translates back and forth via a threaded rod which changes the angle of the hinged plate.  This plate gives support to the pie section as it gets smaller.  The total height must be fairly low, like maybe 6-7 inches high.  There are two of these devices, one on a cross bar on each end of the log section.  The regular log clamps push against the pie log section which in turn is supported by the devices.  Anyone tried something like this?  Would it work?  Not having adjustable height backstops, nor a claw turner drive me to think of this.

[YellowHammer]

I think that should work.  

As a different strategy, I could RRQS on my LT40 even though it had rotating backstops because I could hydraulically rotate them into position and hold them stable.  

It occurs to me that I was able to do the same thing on my LT15 when I used a lever and bar to link and stabilize all the rotating backstops to a single pull handle at the head of the mill. I loved the mod as I could raise and lower all the backstops at one time, but it would also probably work just fine for this.  

[doc henderson]

I think that will work, but a lot of work if you do not plan to saw a lot of QS.  can you make a backstop out of wood for a one off, that you can saw through?  not sure what your long term plans are for QSing.  If you want a long term reusable accessory, go for it.  

[doc henderson]

you can also turn end for end, to get a flat against the back, but more physical work.

[Brad_bb]

Well I solved it with just lumber scraps for now.  I stabilized it by installing two 4x6 scraps against the uprights and then leaned the cant section against the 6" high corner.  Then I used an 8' 2x4 to push against the other side and it also gave a flat face for my clamps to press against.  Now the cant section was stabilized so that the cutting force pushed the section against the 4x6 corner.


 

 

 

Once I cut down to the 6", I then turned the 4x6 down so that the remaining cant section would push up against the 4" high corner.  Once I cut that, I took the remaining small section and flipped it upside down so that the nice q-sawn face was down on the bed.  I went up 2 board widths and one sticker thickness.  I took the top thin section for stickers, then did the final cut to get two Q-sawn boards to finish this half of the log.


 

As I was wetting the wood with timbor, I took a couple pics.  All boards had good fleck.  This was my 2nd RRQS.  The other was cutting Q-sawn 2x6 rafters(for stability).  


 

 

 

 

[YellowHammer]

Nice sawing with full fleck across the faces.  It looks like you got the hang of it pretty quick.  

[WV Sawmiller]

Doc,

   I often turn a cant end to end when cutting live edge siding and the technique I use is to raise the cant near the center of the cant with the movable hydraulic clamp. I can lift the cant an inch or two and using the clamp as a pivot I can spin even a very heavy cant end to end reversing it. This should work with RRQS if you need to reverse ends.

[doc henderson]

great work.  

[Greyhound]

This is a project a customer of mine did with some red oak that @PA_Walnut sawed for me.

 

[terrifictimbersllc]

Wow nice, maybe PA Walnut needs a new name.  :D :D :D

[Stephen1]

Nice QS Brad. I see that get a few knots in your wood also.