metal detector

[copperhead10]

most of the logs that i get are from the urban Forrest, so my ? is about metal detectors. does anyone use a metal detector? do you check above the butt log, do you roll the log to check all sides, do you check as you are cutting the log?

[Den Socling]

I used to sell and service detectors for MDI. I'm sure you are not talking about a whole log scanner but a small, hand held device. They can work but you do need to roll and you have to avoid false trips by metal on the ground.

[Tom the Sawyer]

copperhead10,

I, too, mill a lot of urban logs and it is not at all unusual to get logs with metal.  You can see evidence of metal in some logs by looking at the butt ends of the logs.  Species that I commonly saw (oaks, walnut, ash, etc.) will usually have stains indicating the presence, and relative position of metal in a log.  If the ends are blackened from age, or they have painted the ends with something opaque, you won't be able to see.  That doesn't tell you where in the length of the log it might be, just that it is there.

In this log, the metal (fence and 2 fence staples) was only about 18" above the butt, the remainder of the log was clean. 


 
I have had 2 WoodWizard detectors and wouldn't recommend them.  I have had trouble adjusting them properly and had them miss 'known' metal.  When working they will pick up a couple of inches in hardwoods but I generally don't use them unless I am getting pretty close (by stain evidence), or to check for other metal after removing a nail. I may try a Garrett, I have heard they are more reliable.

I don't consider hitting metal to be a disaster, more of an inconvenience.  I charge $10 if a metal strike requires resharpening the blade and up to $25 if it destroys the blade (pretty rare).  From an economics standpoint (as the client) would you pass on a walnut log that had 150 board feet of lumber (maybe $400 worth), rather than risk $10 damage to a blade?  Most of my clients wouldn't.  I advise them and let them decide.

Another consideration is that the stain will be in the lumber that you mill from that portion of the log but none have been deterred by that either.

[Cedarman]

The other day a load of cedar that came in had a log that looked suspicious.  The owner said there should be no metal.  I took the detector, a regular metal detector with it in the all metal setting and in less than a minute located a single small nail about 5' up from the butt of the log.  Only took a minute to remove.  Didn't discount the log as it just took a couple minutes.  If we had not checked the log, we most likely would have hit the nail.  It is not just the blade cost, but we would have to take the log off the mill and I would have to check the slab and the rest of the log anyway. 5 minutes of down time is 5 minutes worth of sawing that didn't get done.
We check every suspicious log.  Find metal about 25% of the time.  Well worth the effort it takes to check suspicious logs IMHO.
When we find metal, I cut or chop out the metal. I do this unless there is so much metal that the log is discarded for firewood.  I mark metal free lines where it can be cut.  Sometimes barbed wired can be chopped out, sometimes it is too deep and several feet of log must be cut off.
Cedar at $1.40 per foot doesn't have the value of clear walnut, but still has value.
Visit someone who is in the metal detector sales business.  Take a small chunk of log with a nail with out.  Check out various detectors to see how they respond.  The person selling the detectors should have enough experience to show you how to find and pinpoint metal.  You should be able to find a nail at least 8" deep in a log.  It may sound like a faint whisper, but that faint whisper is not a lie.

[Den Socling]

I Googled MDI and they still have a hand held probe. http://www.metaldetectorsinc.com/products/handheld-probe-2100-metal-detectors Their claim that they can find an 8d nail buried 15" is true.

[Den Socling]

I was thinking about many years ago when I took one of MDI's probes to a sawmill to see if I could sell one. The owner had a reputation as being someone who was hard to deal with. I told him how great the probe was. He took me out back to a log pile with the probe and a chainsaw. The pile was logs with metal stains. He said "now find the metal". In log after log, the probe pinpointed the metal. He bought it on the spot and the good wood he got out of the pile probably paid for it. I wouldn't saw urban trees without one. Looking back, maybe I should have stayed with them. I was their only rep on the east coast. Their log scanners were the big money but, like vacuum kilns, could only be afforded by big companies.

[vtgreen]

In High school I worked at a local hardwood mill. My main job was scanning logs with a detector in the yard and un-stickering dried lumber. We only scanned maples due to the high instance of forgotten steel maple syrup taps. I found lots of hits but never got to see what they were. Protocol was to scan one side of all logs on landing, then roll them all and scan the other side. If we got a hit with the detector I painted a large circle on it and we cut the whole section outof the log.
I was out sick one day and one of the other yahoos was scanning. He was too lazy to roll and scan the other sides and sent a sugar maple log with a metal tap spout through the mill. Sheared all the teeth off one side of a million dollar head rig. When I came back to work there were still teeth stuck in the wall above the head rig.

[Cedarman]

Yesterday a 7" x 13' cedar log was kicked out because 2 nails were visible near the butt.  We will saw a 5x5 out of it.
I first pulled the 2 visible nails with a vise grips.  Then checked log with detector finding 3 more hits.  One was a barely visible staple.  Had to take hammer and chisel to remove a small amount of wood to get the vise grips on the staple and pull it.  Had to use the hammer and chisel to gouge out wood at the other 2 spots and pull 2 more nails.  The nail heads were within a 1/4" of the surface so very little wood had to be removed.  All of this took about 6 or 7 minutes of time from getting the tools and detector from the truck to the time I put them back.  The value of the 3' of log save is worth  $7.80 cents plus any boards that were taken from the slabs.  We need 13'   5x5, but not 10' at the moment, so I felt I salvaged enough value to more than cover the time it took to get the metal out.  Since I am basicly a floater at the mill, I can use my time as needed to fill in , so down time for the saw.
Just thought I would give an example of how using the detector saved money.

[copperhead10]

what would the cost be for probe 2100 metal detector. what do you think about the RENS 4000 metal detector?
  thanks  Dean

[CRThomas]

I used to sell and service detectors for MDI. I'm sure you are not talking about a whole log scanner but a small, hand held device. They can work but you do need to roll and you have to avoid false trips by metal on the ground.

I always check my logs with my metal detector one lesson I learned all most the hard way hit a horse the chain came off just clipped my arm If I had not slipped in the mud at that time I would have proble lost my arm and bleed to death. It don't take but a minute to look at the cut end and then run your metal detector over the log to see where the metal is even if you have meatal in the tree.

[CRThomas]

I Googled MDI and they still have a hand held probe. http://www.metaldetectorsinc.com/products/handheld-probe-2100-metal-detectors Their claim that they can find an 8d nail buried 15" is true.

I see you get a $1.40 a board foot we lucky to get $0.40 cents a board foot I am talking about prim logs Log buyers get mad because we cut good logs in to firewood I bought a semi load of logs 18 to 29 inchs 16 feet long because that all he would have got at the mill I give him cash $240.00 because I was closer

[Cedarman]

Cedar lumber is about $1.40 per board foot.  Logs are about $.50 on the cedar scale.