Process for Milling Rough Lumber

[Michael Zerance]

I feel that my process for milling rough lumber is inefficient. Specifically, I find that I am edge jointing (and sometimes face jointing) lumber a second time after it comes off the table saw because the wood sometimes bows from the released tension after it's cut. Some species are worse than others but I am noticing it a lot with my current project, using African mahogany.

My process is:

Cross cut rough boards a few inches oversize on the miter saw.
Face joint one surface.
Edge joint one edge.
Rip to 1/4" oversize on table saw.
Check to see if the board bowed or twisted along it's face and face joint again if necessary.
Edge joint one edge to remove curve or bow after releasing tensions from rough rip cut.
Rip to finished width.
Plane to desired thickness.
Cut to length.

I am curious how others are doing it.

[glenn bradley]

Your experience is not uncommon. I'm sure we've all read or watched videos where the person doing the build comments that they are milling their lumber/blanks to "over-size" and setting them aside to "rest". Certainly there is a valid form of woodworking that relies on quick breakdown, a little force and brad-nailers/staplers to keep things put. Folks doing other types of woodworking use more traditional joinery techniques so things go much smoother when parts are stable and well fitted.

It took me awhile and more than a few failed attempts to achieve what I was trying to do before I began to follow the parts-making process we so often see/hear. If I have some lively material (and I think we've all had some) I cut my blanks even more over-sized than normal. Generally my process is no different than most. I face joint and then plane to over-thickness before moving to edges. This allows me to choose grain direction when edge jointing but, to each their own.

Overall I would say the milling to oversize, acclimating and then final milling close to assembly time is the pattern I try to follow. Exceptions to this process are almost a requirement on larger pieces in my little one-man shop. I will build out web frames many days in advance of installing them for instance. I do try to do large panel assemblies as close to finishing and assembly as I can. Sometimes I's wins and sometimes I's don't but, milling to over-size, acclimating and then milling to size yields me a success more often than not.

[Doug Herzberg]

I face plane, thickness plane, joint one edge, rip, wait a day with the wood stored at ambient temperature and repeat. Something I learned watching TV (Tommy Mac). Not 100%, but better.

If I crosscut first, I leave a little more to allow for planer snipe.

[John TenEyck]

How long has the wood been in your shop before you start using it? If the answer is less than a couple of weeks you need to change your buying habits. And that's for 4/4 stock. For 8/4 stock you might have to let it sit for a month or more on stickers for it to acclimate with your shop, depending upon how different the MC was when you brought it in and the EMC of your shop. I think well over half of all surprises that occur when milling stock is because the MC isn't in harmony with the shop. But if your wood has been in your shop for many months and it's doing this then you still need to change your buying habits. You need to find a new wood supplier. Wood that is properly dried and in harmony with the RH of your shop should not move. Of course reaction wood will move no matter what, but if that's the final explanation then I'd still be looking for a new supplier.

John

[Michael Zerance]

How long has the wood been in your shop before you start using it?

This batch has been in the shop for about 6 weeks but usually it is much shorter than that (a week or two). I don't think moisture content is the issue. It appears to be tension in the wood which makes it either bind or spread behind the cut. Is that related to the moisture content or is it the grain/tension in the wood?

I don't have any issues worth mentioning with the wood moving after it has been fully milled, processed, and cut to size.

[John TenEyck]

Six weeks stickered or dense stacked? MC won't change much if it was dense stacked except for the outside surface of the boards on top.

You can prove to yourself if the problem is moisture related or reaction wood, dead simple if you have a moisture meter, but still possible if you don't. Next time you rip a piece and it bends, stop, cut off a piece from the unripped section, weigh it, put it in the oven at 220F until the weight is constant and record that final weight. On the same board cut off another equal size piece then cut 1/4" off both faces and an inch off both edges. Weigh, dry till the weight is constant and record the final weight. Calc. the MC of both pieces. (W initial - W final) / W final x 100 = %MC. If the MC of both pieces is within 1 - 2% then the problem was due to reaction wood. But if the MC is much more than 2% different then it was due to non uniform MC. If you rip another board and it doesn't move, repeat the same experiment and see what values you get.

John

[David Eisenhauer]

I found that African Mahogany moved on me more than any other species that I have used In over 30 years of woodworking. Beautiful wood, but it will move, especially in the 2+" wide rail/stile configuration. I typically don't have any problems using the same basic process you first described, with a delay of a few days to a week or two between the slightly oversized initial face-edge jointing/planning/ripping. I do tend to buy wood in somewhat of a "bulk" amount if I find a good deal or see something that looks good and I have a few extra $ available, so sometimes the second time I use a particular batch it has been sitting in the rafters of my shop for a year or more.

[Robert Engel]

Your process is ok, IMO.

You are also correct re: tension.
When wood comes off the saw bowed I do not try to remill it immediately.
Let is sit for a while in stickers (up to a week).

General rule: don't rush the process. Depends on how much fresh material is being exposed.
If I'm ripping an 8" wide board in 1/2 I expect it to bow because the middle (moister) part of the board is being exposed.
Same thing with resawing, except much more dramatic.

[Frank Drew]

I've never used African mahogany so don't know how it behaves, but in general I'll leave a board a few inches over final length and a maybe a half inch or a bit more over final width, then I face plane followed by thickness planing (approaching the final thickness in stages over a few days or more); I won't cut to exact width or length until I'm about to begin the joinery for whatever part of the job I'm about to work on.

[Bill Orbine]

Mahogany is one of the worse lumber with so much internal tension. I've ripped a straight boards in half and get two bananas. Best to bring wood to 1/4" or little more over size width and thickness and an inch or two longer before joint face and edge and then plane/rip/cross cut to final dimensions. Sometimes you are gonna get a bad banana to toss out.

[John TenEyck]

Your process is ok, IMO.

You are also correct re: tension.
When wood comes off the saw bowed I do not try to remill it immediately.
Let is sit for a while in stickers (up to a week).

General rule: don't rush the process. Depends on how much fresh material is being exposed.
If I'm ripping an 8" wide board in 1/2 I expect it to bow because the middle (moister) part of the board is being exposed.
Same thing with resawing, except much more dramatic.

That's the problem. Non uniform MC will always result in problems. But if the wood is at EMC with your shop the moisture will be the same everywhere in that board and it will not crook when you rip it unless it has reaction wood. Milling oversize, stickering for a few days, blah, blah, blah, is unnecessary if the wood is in equilibrium with your shop.

John

[Michael Zerance]

Thanks for the replies, fellas!

My take away is this:

Ideally, lumber should be stickered and left to acclimate for as long as possible prior to processing.
When possible, processing rough lumber should be done in stages, over a few days, to allow the wood to stabilize.
African mahogany is going to move, regardless.

[Clay Fails]

I tend to follow the method described by Glenn, but even then some lumber will not always be cooperative. I've had lumber that's been in my shop, stickered, for a couple years get springy after resawing or milling. Sometimes the lumber is in control, not the woodworker.