Milling advice

[Tony]

  I bought my mill so I could cut a few ties from family land. Well, by word of mouth, I now get a few calls to mill logs for others. : :
  I need info and advice on how to get the most out of the logs. Example: customer wanted 1"x6" bds out of a 15" x16" cant. I got it to a 12"x16", split the heart a started slicing. I don't feel this was the proper way to mill the log. What would you advise and where can I go to get other info?   Thanks  :P :P

                                    Tony 8)

[Fla._Deadheader]

Within 24 hours, you will have more info, right here, than you can ever use. Just don't get impatient.  ;) ;D ;D

[Tom]

That is the difficult part of custom sawing. When a customer asks for only one size stick from a log, he is negating that there is any difference in the configuration of one board over the other. What you did may not be the best way to saw a log, but it is a valid way.  You will find that sawing is made up of "better" ways of breaking down a log, not necessarily pure rights and wrongs.  It's your job as a sawyer to know and be able to relate these things to the customer.   They still might not care.

Sawing a log like you have described on a bandmill, I would approach it like this for the "best" boards.

(What you are attempting to do is keep the heart/pith centered}

Place the log on the mill with the heart check vertical.  The heart check is that crack in the middle of the log that intersects the pith.

Remove 1 inch boards from the top, keeping in mind a target size from the middle of the log.  Stop sawing when you are 3 or so inches from the pith.

Turn the log over onto its flat.

Remove 1 inch boards until you are about 3 inches of the pith.

Turn the cant (which should be about 6⁺ inches) 90 degrees and cut it through and through. This will give you 1 x 6's that have centered grain. (the heartcheck will be horizontal)

Trim the boards that you took off of the side of the cant by taking the 1x6 from their center's  You will get one  1 x 6 from each flitch (board with bark edges)  You may get some 1 x 2 or 1 x 4 in the trimmings.

Now this is the way to get the most 1 x 6's with centered grain.

More efficiency can be accomplished by turning the side boards into boards larger than 1 x 6, but that is the customer's choice.

What you did is valid and produced as many or more 1x6's.  But, the grain isn't centered and the boards will twist and crook (bend to the side)   That doesn't make it wrong, only less desirable.  Custom sawing requires that you do what your customer wants and/or give him enough information to make an educated decision.

When sawing for sizes, keep in mind the fact that your cant will move according to the growing stresses in the log.  You are working with a living thing, not a piece of plastic and you should allow yourself room to make trimming cuts that will keep your sizes within specification.

If you make the first cuts in the log to within 3 inches of the pith, turn the log and cut down untill you reach 6 inches, you might be left with a cant that is only 5 inches wide.  The stresses in the cant will lift the cant off of the bed of the mill and your target will be missed.   Never saw a log as if you are doing something to it, saw as if it is "allowing" you to do something to it.  Always leave yourself room to make a leveling or sizing trim-cut from  one side or the other.

What I have described is a short version of what you should learn about "centering", "leveling", "grade sawing", sawing for construction, Log tension, knots, cracks(splits or shake), heartwood, sapwood and a myriad of other things that can enter into the decision to make a cut on one log different from the same cut on another. 

You don't have to be a rocket scientist.  You have to be smarter than that because you are dealing as much with an art as you are a science.  Just because a log is supposed to react a certain way doesn't mean that it will. :D

[EZ]

Tony,
Tom has said it all and he really knows his stuff. The only thing I can say is tell your customers that they will have a few 1x2,1x4 and things like that.
EZ

[Dan_Shade]

like this?



the circle is 20" scaled, 8x1 boards (kerf pretty much ignored)

[FeltzE]

Understanding the costmers needs like Tom said is important. Squaring up at 12inches and ripping the cant in half to pull 2 1x6 in each pass of the cants is very acceptable for pine boards used for general construction put up green.

Grade sawing hard woods lends itself more to centered grain clear cuts. Rotating your log to open on your best face with the knots angled to come out the "corners" of the cant if possible. This will allow for the largest clear areas for grade lumber with the knots in the edge of the boards. Much more cant rotation during the sawing process may be required.

Making structural grade lumber 2x 6-8-10-12's will require greater attention to knott placement to ensure avoidance of spike knots. And generally with 2x stock you will be cutting longer length logs where attention to the log stress is very important. As you cut one or two boards from one side you may need to flip the cant 180 and cut the next one or two boards to keep your cant from bowing too much.

Attention to the growth rings is very important if you have logs with a crook often pulled from leaning trees. Orient your log for the opening cut with the bow all the way up .... or down that will be the orientation of the flat (wide) side of your lumber. The lumber will attempt to bow opposite the lean of the tree and it's much easier to nail out a board that is bowing along its flat side than on edge... (did i say that right?)

::)Eric