Milling Flooring from Old Barn Boards

With carbide moulder blades, it's no big deal but check carefully for nails. May 13, 2005

I have been asked to make flooring out of used barn boards. These boards would be roof sheeting boards and barn siding and floor boards. The siding and floor boards seem to me to be next to impossible to machine. I would think that 100+ years of dirt being blown at the stuff and ground in would ruin knives in no time. The roof boards might work, but there is always a chance of hitting nails that did not get removed. Has anyone tried this? I will be using a new 6 head moulder and would hate to tear it up.

Forum Responses
(Solid Wood Machining Forum)
From contributor G:
I think I would run a metal detector over every board. Dust and dirt shouldn't be much of a problem unless it's obvious, like mud or caked on dirt. Then I would wire brush it off.

From contributor C:
I do this quite often. I use carbide knives, but the dirt doesn't seem to hurt anything. I can run several thousand linear feet before sharpening. I agree to wire brush off anything obvious, but the ground in fine particles won't trash the knives in short order. Use a metal detector... for sure. It only takes one small nail to ruin a hundred dollars or more worth of knives.

From contributor R:
We do it all the time, as we are an antique lumber dealer. We run carbide insert tooling on the tongue and groove, but HSS is sufficient for the top and bottom. Carbide would be too expensive to run, as it shatters when a nail is occasionally encountered. Considering how much material we run, we expect the to hit something now and then. Rocks can't be detected, so one can only do so much.

From contributor H:
If you have access to a wide drum/belt sander, that does a great job of removing ground in dirt and debris. I cleaned up some walnut and cedar stock from 30 years of laying in a barn with my 16-32 Jet drum sander before planing to final thickness. I don't know how much stock you have to process, but there are a wide variety of sanders to choose from. You might also rent time on a commercial sander.

From the original questioner:
We will be running this stuff by the semi load. It just seems to me that we will go through quite a few knives or at least sharpenings per load. Am I right?

From contributor C:
You're right! It will definitely take some sharpenings, and depending on the wood variety, you may need to replace the knives during each load. The side cutters (tongue and groove) will wear much slower than the top and bottom. If you are running antique longleaf, I would recommend against sanding. You'll clog up the sander in minutes with pitch. Also, antique longleaf is rough on knives. You can probably expect to have to lightly hone the planer knives every 2000 to 3000 linear feet or so, depending on the wood. Probably more often if using HSS. By that time, you'll need to shut down the machine anyway to remove the buildup of pitch and dust on the feed rollers and around the collectors on the side heads and gibbs. Spray silicone works well with a small brass wire brush for cleaning this pitch off, and then spraying the areas that the pitch tends to build on makes it easier to remove when it does accumulate. Watch the wear on the bed, too.

From the original questioner:
Thanks for the info. This will all be antique oak, so at least I will not have to worry about pitch. Do you recommend insert tooling for the side heads?

From contributor C:
Antique oak won't require as much maintenance on the machine and knives during the runs (in comparison to the longleaf pine I was using as an example). I use insert tooling on the side heads with great results, but I haven't tried anything else, so I can't say that one is any better than the other.

Also, when I mentioned clogging the sander with pitch, I was assuming it was pine you were running. That's what I run most of the time and it's probably the most common reclaim wood used. The longleaf I run will clog a sander up in no time flat. Oak shouldn't be a problem.

From Dave Rankin, forum technical advisor:
I agree with the responses that have been posted. For reclaiming oak, I suggest carbide on T&G profile and HSS or DGK on the top and bottom. If you have a grinder, then the HSS would do fine. If you have 2 tops and 2 bottoms, then I would use carbide inserts on the first top and first bottom to clean the material. It should be no major problem, but do expect to have some tool nicking or breakage.

From contributor M:
We have also done several jobs using barn wood. It was supplied by a vendor who supposedly scanned all boards for nails. Guess what? They missed by 30 plus pounds! I would be especially cautious when it comes to roof boards. They are usually full of the most nails (used to hold the sheeting and likely shake shingles) that are rusted and break when removing. Running the material with the constant fear of sending an explosion-causing spark up the dust collector from a missed metal object was too stressful. I personally would never do it again. Too time consuming and costly, not to mention the dust, old paint, oil, diesel, urine, more dust, and every stinky thing that regenerates once you run it through a planer.

From contributor D:
I agree with contributor R. Be ready to nick a few planer knives. The t&g shouldn't be a problem, but with the face planing, accept the fact that you will hit something. I deal with this on a daily basis, running mostly longleaf pine. A few months ago I ran 3500 sq ft of beautiful 1x8 longleaf pine, but was plagued with bits and pieces of nails (roofing nails, I think). After chipping trails in the knives a few times, I raised the planer head 1/16 and finished running it with the chipped knives, picked the uncovered metal from the flooring, and shot it through the planer to clean the trails off. Wouldn't want to do that every day, but it did produce a really nice product from a difficult stack of wood.