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When you hit a nail

Started by Pabene, January 09, 2018, 07:54:58 PM

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Pabene

What happens when your log band saw blade, hit a nail in the log?
Sometimes it can be good to think about the proportion of the things as are going on. Here are some data I calculated many years ago.
At normal blade speed one tooth on the blade, is running 5-6 complete "laps" within one second.
At a feed of 30'/minute, 25 teeth will pass the distance to cross cut a 4" nail. If your feed is slower more teeth will be tuched.
If you have a "bimetal" blade, it is HSS steel in the blade tips and the nail is a normal "soft" steel nail, you will see blue small chips from the nail sitting on the tips on at least 20 teeth.
I have, in most cases, been able to clean the teeth from chips and then sharpen the blade. In some case I have been forced to check the set and perform an other sharpening. Then the blade has cut as normal.
There are nails made of harder steel. Such nails will destroy the blades, in my opinion.
No one can listen, hear the sound when the blade starts to cut the nail, stop the saw and save the blade that way. To cross cut a nail like this takes about 0.1 second.

Percy

Quote from: Pabene on January 09, 2018, 07:54:58 PM
What happens when your log band saw blade, hit a nail in the log?


I pretty much always say a bunch of bad words.
GOLDEN RULE : The guy with the gold, makes the rules.

Lawg Dawg

Quote from: Pabene on January 09, 2018, 07:54:58 PM
What happens when your log band saw blade, hit a nail in the log?
Sometimes it can be good to think about the proportion of the things as are going on. Here are some data I calculated many years ago.
At normal blade speed one tooth on the blade, is running 5-6 complete "laps" within one second.
At a feed of 30'/minute, 25 teeth will pass the distance to cross cut a 4" nail. If your feed is slower more teeth will be tuched.
If you have a "bimetal" blade, it is HSS steel in the blade tips and the nail is a normal "soft" steel nail, you will see blue small chips from the nail sitting on the tips on at least 20 teeth.
I have, in most cases, been able to clean the teeth from chips and then sharpen the blade. In some case I have been forced to check the set and perform an other sharpening. Then the blade has cut as normal.
There are nails made of harder steel. Such nails will destroy the blades, in my opinion.
No one can listen, hear the sound when the blade starts to cut the nail, stop the saw and save the blade that way. To cross cut a nail like this takes about 0.1 second.

Yep, what he said..
2018  LT 40 Wide 999cc, 2019 t595 Bobcat track loader,
John Deere 4000, 2016 F150, Husky 268, 394xp, Shindiawa 591, 2 Railroad jacks, and a comealong. Woodmaster Planer, and a Skilsaw, bunch of Phillips head screwdrivers, and a pair of pliers!

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bandmiller2

A lot depends on the angle you hit the nail. At right angle usually minor damage, check set and remove small curl of nail on the tooth tip. If you hit a nail at a low angle it will usually mess up the set on one side, band can usually be reset and sharpened. Drywall screws are pure poison to a band along with lag bolts and ceramic insulators. Frank C.
A man armed with common sense is packing a big piece

JB Griffin

Frank, your on to something right there.
2000 LT40hyd remote 33hp Kubota with 6gpm hyd unit, 150 Prentice, WM bms250, Suffolk dual tooth setter

Over 3.5million bdft sawn with a Baker Dominator.

Southside

Quote from: bandmiller2 on January 09, 2018, 08:21:04 PM
Drywall screws are pure poison to a band along with lag bolts and ceramic insulators. Frank C.

Not to mention the dreaded ring shank nail and those dang backstops!!
Franklin buncher and skidder
JD Processor
Woodmizer LT Super 70 and LT35 sawmill, KD250 kiln, BMS 250 sharpener and setter
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Woodmaster 725 and 4000 planner and moulder
Enough cows to ensure there is no spare time.
White Oak Meadows

Cedarman

The only decision to be made when hitting a ceramic insulator is whether to take the blade to the junk blade pile now or later.
I am in the pink when sawing cedar.

slider

Cedarman is 100% correct on that one.
al glenn

ladylake

 

  2 of the worst I've hit , a ceramic insulator, sawed all the way through it , the blade was almost as smooth on the front as the back.  Later a pole bar nail a angle , every tooth was bent around in a U shape. I'd have thought they would have broke off before bending like that.  Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

Sixacresand

The biggest concern is getting through the cut after hitting metal. 
"Sometimes you can make more hay with less equipment if you just use your head."  Tom, Forestry Forum.  Tenth year with a LT40 Woodmizer,

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