Machining Knotty Alder

Rustic alder mouldings are in demand because of energetic marketing. But the material is extremely rough on knives, machines badly, and has a high waste factor. July 3, 2006

We've been moulding 4/4, 6/4 and 8/4 premium frame alder into casing patterns to achieve a rustic look (knotty, but intact). However, the knots that look tight going into the moulder often open up or blow out on the way out, making the profile unusable. It seems like it's almost more expensive to make good rustic profiles than clear ones out of upper grade material. What is the best way to manufacture a good, useable, rustic moulding?

Forum Responses
(Architectural Woodworking Forum)
From contributor R:
What grade of lumber? #1 or #2 common? In my opinion, the #1 common would be a better choice. Take a small rubber mallet and see if the knots will dislodge before sending them through the moulder. That way you save downtime and injury to yourself and damage to the machine.

From contributor D:
I've used rustic alder for a number of years due to demand in the resort areas of Colorado. It used to be knotty butternut until the prices went up. The knots and resultant knot-holes are what my clients desired. (I am long over the arguments there. This is much akin to having a customer want you to take chains and nails to a beautiful set of cabinets to distress them. I was the one getting distressed. The cabinets just looked beat to pieces.) Due to manufacturing difficulties and the wear on equipment, I charged more for the rustic impressions. I rarely had a problem with the higher pricing once I explained the additional craftsmanship necessary and the huge waste factors present to produce what they wanted. Maybe you should try this approach. After all, we do this work because we love it, but the bottom line is to make money.

From contributor A:
One thing that will help is running a 10-12 degree cutting hook. This will help keep the knives from catching and chunking out the knots. It will still happen some, though. Another thing is to run an upgraded HSS from regular M2. I would run a minimum of M3+, T1, or OPTI and if possible run V3N or M42. Especially the last two premium steels will retain a sharp edge longer while dealing with the mineral deposits absorbed in the knots of the wood. Sharper edges means less chunking, too.

From contributor J:
It seems like premium frame alder works well for cabinet parts but is a nightmare for millwork and doors. We end up mixing in a lot of superior grade for moldings and door parts. And the sawyer needs a keen eye and understanding of the end product to make his cuts. We have also used the character mark grade and it is worse than premium frame for millwork. The grades even from the same mills are not consistent. We have had both superior and premium frame that had perfect small red knots and other times the superior was just too clear and the premium frame had big black knots. For us it is also more costly to do a good rustic grade than clear. On doors we end up using black epoxy to fill open knots (labor intensive). A lot of millwork companies just run the premium frame and donít worry about it. To me, the sharp open knots could be dangerous to the homeowner placed in the wrong spot.

From contributor C:
The real problem is the material. A bit of history, albeit from a cynical view. Alder was considered a weed species that would crowd out more desirable pine, hemlock and fir regrowth after clear cuts. The alder that sprouted up was destroyed to make way for the "better" trees. When the chemicals used to kill off the alder were restricted/banned, it was allowed to grow in.

A large timber/paper concern, one of the largest in N. America, remembered their history on knotty pine, and turned the alder/lemons into lumber/lemonade. They hired shops to produce kitchens, upholstery frames, millwork, and hired designers to put it all together, then photographed the results and promoted the wood - created the market. No coincidence that it was once the cheapest thing that could be called wood, and is now quite a bit higher than it was 15 years ago.

The result is this little boom of "gotta have alder" resounding around the country, and the unlucky woodworkers trying to deal with the stuff. Yes, rustic costs more to produce - by far. And the results are fair to marginal. Exterior doors made of the stuff have more callbacks than a Yugo, and the long term survivability of alder in exterior is doubtful.

Would that we could be strong enough to substitute a species more appropriate, easier to work with and more performance specific. Knotty pine (sugar pine) is one example, at a better price, far more workable, and with tighter knots. However, it is a hard sell with the design professionals all atwitter on the alder.

From the original questioner:
Thank you for all the helpful responses. I think the upshot is that it is expensive to make good rustic mouldings, even though the layperson thinks cheap lumber = cheap mouldings.

From contributor A:
Familiar or not with alder, the rubber mallet idea is good. I ran a moulder for 10 years and the first time I got hit with a knot that kicked out, I thought I was gonna die. It knocked my breath out and left a 4" welt on my belly. Don't worry - I had plenty of belly left to spare. Through the years, most knots won't fly out, but some will. Some fly hard enough to break knives and/or seriously hurt you. I wouldn't use a mallet, but I would hold the piece like a karate staff and smack one end on the floor if the integrity looked suspicious. I'd also make the Karate Hi-Yaw sound, but I don't think that helped the woodworking any. Point is, you can run great production for years, but all it takes is one accident to rearrange the map.

From contributor M:
I feel your pain with the rustic alder troubles, as our plant cuts a huge quantity of it, mostly premium grade. We have gone to carbide on our s4s, using a back pack type knife, and on our mouldings that contain any type of flat, we lower the profiled portion to allow for overhead sanding. We have experimented with every hook angle and type of steel, both softer and harder, to prevent rapid nicking of the knives, all to no avail. Stick with good old M2 and a 12-15 degree hook and that's as good as it gets. We don't see a lot of projectile knots from the premium grade, and I would stay away from standard and the lesser cutting grades.

On a side note, and to comment on the alder story, we are now seeing a large influx of not only finished products, but cut stock and component parts being brought in from China. The upsetting part is it is being brought in and distributed by the very lumber companies that are selling us the raw material that we use for, as you can guess, finish goods and component parts. It's tough to compete with the very people that control the raw material.

From contributor R:
Just a note about rapid nicking of the knives. Most alder is abrasive planed and between the knots, mineral, and the fall off from the abrasive planer, this is where all your nicks are coming from. It's the nature of the product. But again, I will agree with you on the carbide and on the better grades of high speed steel.

From contributor M:
You are absolutely correct about Alder being abrasive planed, and it was not mentioned before. We surface all our material down prior to moulding to remove abrasive. I learned that lesson early on running a superior and just could not understand why my knives were only good for a couple hundred feet, till the little light went on.