Blades for Sawing Old Timbers with Embedded Nails

There are no easy answers if you need a blade that will saw wood and also cut through nails. April 18, 2009

Question
I have run an older Woodmizer LT40 Super for almost ten years. In the last few months I have started sawing a lot of old, hand hewn barn timbers. The timbers are typically 8x8 or larger, 8 to 16 ft long, and northern hardwood in species (white oak, white and red elm, ash, basswood, etc). Many of the timbers can be over 100 years old, and can have some twists or bows in them. The main problem is that the timbers almost always have anywhere from a few to more like 30 or 40 nails in them. The nails are frequently iron spikes somewhere between 8d up to 16d in size. Steel nails are also common. What we want to do is the cut off the 2 hand hewn faces from the timber. I want to saw through the nails with having to pull them and scar the wood.

In general I think the Woodmizer is a great machine but for this situation it is a pain. I have tried a variety of different band manufacturers and both carbon and bimetal bands. None of the bands holds up to that many nails. We wind up spending days pulling nails - frequently badly scarring the surface we are trying to sell. Frequently the iron nails will break off making them impossible to pull out. Of course when you hit the nail it can destroy the band and more importantly screw up the cut. In a day’s cutting I can destroy 10 or 15 normal carbon bands.

I am looking for a better solution. I don't mind if the sawing is slow. I am open to just about anything to help to the productivity and improve the quality of the product. Would the carbide tips of a swing blade do better than the bands on my Woodmizer? Is there some other blade insert that would work better than carbide? The kerf of the cut doesn't mean anything to me for this situation. Is there some other sawing technology that could handle the nails?

Forum Responses
(Sawing and Drying Forum)
From contributor D:
Carbide on the swingblade is not the answer. It is hard but brittle. The first nail will break your teeth off and possibly wreck the seats in the blade as well.


From contributor S:
How about using a saw blade made for a metal cutting bandsaw. Try using the 12 tpi blade and just use a slow feed speed.

From contributor U:

I wonder if you could break them off and drive them deeper with a slightly bigger punch just beyond where the sawblade will run. It would be a cheap solution if it worked.

From contributor C:
I like the idea of pushing them deeper/through. For this you could use a pneumatic chisel with a long thin punch.

From contributor G:
There are machines sold to industry that do nothing but saw up pallets, called if I remember pallet destructors. This allows them to reduce the bulk of the pallet for disposal. I also saw somewhere on the web a company that sells bandsaw blades for those machines with some clever name that was like "Nail Eaters" or "Destructors" or some such. The point being that they were designed to go through nails and hard oak etcetera without any great problem. Try hunting on the web a few minutes for such.

From contributor B:
Not really sure but perhaps if you got a saw doctor to tip the swing blade with a softer carbide it would survive the task. In researching carbide chainsaw chain for milling I came across the fact that rescue workers sometime outfit a chainsaw with the softest carbides to cut open crashed vehicles.

From contributor A:
Swing mill will cut the nails but the cost will just be as bad or worst then the band mill. Most pallet saws are a metal cutting blade that will saw the nail off where they are put together but does saw through dry oak some.

My best cutting in dry timbers is with 4 degree 0.055 blades from WM. Pulling nails is the best and one of the reasons reclaimed timber lumber cost so much. Dirt in the checks is another cause of blade wear and not much you can do about it.


From contributor M:
Have you tried carbide tipped band saw blades? I have a twin blade circular mill and cut with carbide teeth. I once cut half my mild steel log dog off before I got the saw into reverse. The issue with circle mills and metal in the log would be hitting something like a spike and having a shoulder break of the saw. The next tooth can pick up the metal fragment and turn it into a projectile. Not much guarding around the swing saws so safety would be a concern.

From contributor J:
Having a swing mill and milling city trees, we have gone thru our share of nails. I use the standard tipped blades from Baileys (carbide), and when i know there is metal in the tree, I go nice and slow. Hit the nail, inspect blade and it’s a minor issue. Even a small lag bolt if you’re going slow is ok.

From contributor J:
Thank you for all of the great ideas everyone. I have spoken with a couple of the manufacturer reps and the general consensus is that no band can handle both very well because it requires the band to be both hard and soft simultaneously. They say that the bimetal bands are my best bet.

I did try the pneumatic punch idea. I need to grind down my punch to a small diameter but for most of the nails it works pretty well as long as they are driven in close to straight. The depth of the surface I am cutting is 1 1/4" ->1 1/2" so I drive them in approx 1 3/4". It’s pretty easy to do and the best part is the scar is hardly noticeable.

The other thing I experimented with was the speed of the cut. I reduced my speed down to a crawl - approximately two plus minutes per cut compared to my normal 30 or 45 seconds. This makes a huge difference especially on iron nails. Instead of the nail breaking off a few teeth, the band grinds the nail more evenly across all of the teeth. The slow speed also prevents the band from dipping after you hit a nail.

As an experiment I tried stacking two old pine 4x6 beams on the sawmill to be cut at the same time. Both were loaded with iron nails - approx 8d in size. I crawled through the timbers with a regular carbon band. I cut 38 nails in the first beam and 14 in the second beam all in one pass. I couldn't believe it - the band survived! The band was dinged up but still cutting straight and relatively smooth. The cut took about three minutes. I consider that light speed when you compared it to pulling 50 plus nails by hand and scarring the surface to boot.

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