iDRY Vacuum Kilns

Sponsors:

How do you guys deal with "chain shot"?

Started by Oregon Engineer, June 14, 2005, 01:10:18 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Oregon Engineer

I'm curious what you do to deal with "chain shot" and if you've ever experienced it.

Tom

Welcome to the forum, Oregon Engineer.

I've never experienced Chain Shot.  It was a projectile used in Naval Warfare a bit before my time.  A link of chain attached to two cannon balls was devastating to infantry, marines aboard ship and rigging. 

How would I deal with it?   I'd run to beat Hades. :D

Oregon Engineer

Oh, I'm sorry, the "chain shot" I'm referring to is when a mechanized tree harvester breaks a chain and a small portion shoots out at super sonic speeds.

Buzz-sawyer

TOM
Took the words out of my mouth :D :D :D
Welcome to the group!
    HEAR THAT BLADE SING!

Tom

That was fun, Buzz.  Couldn't resist.

:D I was just having a good time Oregon  Engineer.  :)

I didn't really know what you were talking about, but I did know it wasn't about cannon rounds.  :D   I have heard some of the guys on the forum talking about you're kind of "chain shot" and there is at least one thread somewhere concerning the subject.  a search might get something until one of the "knowledgeable"  ones comes along.

;D  That was fun.  :D :D

Here are two links I found.

https://forestryforum.com/board/index.php?topic=9659.msg131764#msg131764

https://forestryforum.com/board/index.php?topic=11029.msg151664#msg151664

Bro. Noble

Welcome OE,

I hope you'll excuse Tom for acting so silly :D :D

If I were around one of those things when it came apart,  I'd run to beat  Hades.

I wonder if that's one of the reasons they have a caution sign that says to stay back a couple of hunnard feet?  The guy in the cab should be shielded by the machinery. 

I'd also wear a hardhat.

Someone will probably come along that knows what the heck they are talking about ;)
milking and logging and sawing and milking

Jeff

Welcome Oregon Engineer. Sumpthin tells me you might know a little about this already? :)
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

Oregon Engineer

Yah, yah that's a right good welcome I got from the welcoming commitee. Pouncing on a new comer with a new thread. Kinda like the new hire on the job site with a new lunch bucket and clothes. The crew's out to get him dirty and flatten the lunch bucket. I feel right at home now, thanks!

Yes Jeff, I do know a little bit about chain shot and was hoping to get a feel for the general knowledge base of the forum members.  Based upon the first couple of replies, I figured I had a real job a head of me.

Texas Ranger

Yep, welcome aboard, bout time we had somebody here that really knows about harvesting, and stuff. ::)
The Ranger, home of Texas Forestry

beenthere

Okay OE

You're on deck, now 'splain more about what yer question was, and maybe some here might get 'dirty' with you.  ;D ;D
We sometimes poke holes in 'unidentified flying objects' launched here.  :D :D but we are most times harmless.

I'm bettin' you can feel right at home here. Most do.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Jeff

We have a few mechanized loggers out there but it may take more then a day or so to flush em outta da bush.
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

Oregon Engineer

While we're waiting for the operators to get out of their cabs and onto the computer you can get a quick look at chain shot via a slide show at this web site:

http://www.healthandsafetycentre.org/enews/050516/fse2.htm

Take a look, afterwards you'll duck for cover every time you're in plane with a bar and chain while its in the cut.

Tom

That was a good show.  :)

Sounded a bit  like Paul H. :D

crtreedude

Welcome Oregon Engineer,

I think you are just getting the semi-retired, retired, and on injured reserved people in the middle of the day - eventually you will get the people who still work.

Good group of guys, even though some of them do eat grits - be for warned.

I thought the video was pretty good - the most important thing is to increase the protection. Something bad is going to happen someday - so about the only way to be sure is to make it impossible for it to hurt the operator.

Sure hope no one else is in the field though.

Did you by chance find this while looking for information?

LINK 1
and
LINK 2
and
LINK 3
So, how did I end up here anyway?

Kevin

That's definitely preventable.
I would compare it to standing in front of a chain saw bar nose while someone is operating the saw.
A qualified person meaning experienced and knowledgeable should be well aware of the danger.

crtreedude

One other comment - if something is potentially as dangerous as a rifle - DON'T point it at me, and I sure wouldn't use it in a way that it points at me myself.

I think a lot of times accidents happen because someone starts "getting away" with things. Do it enough, and the law of averages will get you.

So, how did I end up here anyway?

Gary_C

I have heard of "chain shot" but never seen it. Without a high speed connection I gave up on the slide show.

Most of the time when a chain comes off, it is either caught in the tree or the head. There is a pin under the drive sprocket and a cage on the back side of the head. Never seen one come off with any velocity. I have had times when I could not find the chain, but that was usually in deep snow and unless you can see a mark in undisturbed snow it is very hard to find. That only happens just after you put on a new chain.  :'(   If you find the chain, you can just put it back on unless it has hit metal. I seldom break a chain, but then I sharpen my own and usually find any cracks or bent links and fix them.

A larger hazard is from those disc saws or "hot saws" as they are called. The disc is a very thick and about four foot diameter steel disc that turns at such high speed that operators say you can shut down the power and still cut down two trees and it will be still spinning. You actually just drive through or push the head thru the tree. The large teeth on those discs will throw many large chunks of wood for hundreds of feet.  :o  :o

The windows on those machines are supposed to be tough enough to stop a bullet. I have accidentially banged logs against the windows and never broken or cracked one yet.
Never take life seriously. Nobody gets out alive anyway.

Frank_Pender

Welcome OE.  It is always nice to have another Oregonian  (and I do not mean the fishwrapper out of Portland) onto the Forum. 8) 8)  Whereabout in Portland area are you located?
Frank Pender

Jeff

Gary_C, I gotta say that that slideshow is an ineffective way to reach everyone that should see it. Frankly, because I think you should have saw it and you couldn't.

Below is a screen shot of where the chain link blasted through the poly carbonate window (bullet proof)  before it struck the operator in the abdomen.

Here is a document that should load that describes a brief discription ofthis accident.
http://publications.healthandsafetycentre.org/html/ib_processor.htm



Another shot that they show is this diagram of what happened.


Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

redpowerd

NO FARMERS -- NO FOOD
northern adirondak yankee farmer

Oregon Engineer

Crtreedude - The guy that got injured was doing many things wrong and put himself in harm's way. The slide show details a few of the things. The articles on your links by Skogforsk are excellent. Ulf Hallenborg has done a lot of work on chain shot in coordination with a Swedish test lab that has a "chain shot" machine capable of generating chain shots on demand. 

The following site shows an artical on chain shot:
http://www.feric.ca/en/ed/May-2002-English.pdf

Gary C - Keep a close watch on broken loops to see if any links are missing. Some articles suggest a chain shot occurs about one in every 50 chain breaks.

Frank_Pender - I live in West Linn and work in Milwaukie, OR.

Gary_C

Jeff  Thanks for the info. I actually dozed of waiting for that slideshow to load and when I woke up, it was still not finished.  :)

From what I see, it looks like that machine is a Timbco tracked harvester. It probably has twice as much horsepower available as my Valmet rubber tired machine. When they have that much power available to drive those tracks, they usually put on huge hydraulic pumps and can out muscle any size tree. The older John Deere tracked machines that were basically an excavator had a reputation for even bending the booms. My point is those high HP machines can easily over power and over speed the saw chains. Most of the harvester heads on those machines use 3/4 pitch chains and those cutters are huge. I can see where chain shot could easily happen and I would not want to be anywhere nearby.

I can not remember any time a chain has broken under power. I have bent a few chains and have broken a very few, but it was in trying to pull the chain (and bar) free.  I do try to straighten bent links, usually the drive links but almost always have to replace parts as they crack either in the drive link or the holes in the cutters. If they are well used, I leave them hanging by the sharpener and only fix them if I get desperate which means short of good chains.

I use a .404 harvester chain loop that costs about $15 each and the bar is $45-60 each. For comparison, the 3/4 pitch chains are $35 each and the bars are $310 each.

I must either be lucky or don't have enough power to have experienced "chain shot" yet, but there are certainly no guarantees. I also have cut right outside the side windows at times and I will make sure that rifle is not pointed at me the next time.
Never take life seriously. Nobody gets out alive anyway.

caryr

I have only experience chain shot once and it was on a many 100 HP chainsaw using ¾ chain (yes that is many hundreds). Sorry the exact HP is classified, but it is statistically the fastest saw on the planet!  I'm not sure what type of information you are after, but here are some observations and comments.

When the fragment of chain (our guess was 3-6") went out of view it was about 300' out, at least 75' up and it appeared to still be heading for apogee. I have some pictures of the fragments that stayed with the saw if you are interested.

To me the major contributor to chain shot is as you try to go faster you use more HP, but this extra HP can ripe a chain to pieces if it binds in any way. If you want to minimize the damage reduce the HP driving the chain and slow it down. I guess that's basically what Gary said above. Reducing the HP should minimize the chance of fragmenting the chain and slowing it down reduces the kinetic energy. I'm also curious how you get the chain supersonic? I understand how you get some acceleration as the unconstrained chain whips past the sprocket, but there is usually not enough room around the sprocket to get things going that fast. If there is a lot of room a shroud around the back of the sprocket should help limit the exit chain speed.

Like I said earlier. I'm not sure what you are after, but I hope this helps.

Regards,

Cary

Ianab

QuoteI'm also curious how you get the chain supersonic?

I'd guess thats it's the same as getting a stock whip to CRACK (the tip of the whip goes supersonic at that point) When the chain breaks there must be a situation where the loose end is whiplashed to extremely high speed, and the end link or 2 break off (again) and make like a bullet  :o

I've seen the web write-up about it happening with that V8 hotsaw, the loose fragment went thru a pickup tyre and punched a hole in the engine sump, anyone in the way could have been killed.

Cheers

Ian
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

crtreedude

Something that I have observed down here is that you probably wouldn't have machines that could do that - honest. There is an interesting attitude down here that many foreignors hit that really perplexes them. No one is going to engage in a dangerous job for very long or deal with bad employers - they just leave and do something else.

The reason? You can't starve or freeze to death down here. There is always stuff on the trees to eat and a whole kilo of cheese can be bought for a couple of dollars. Never gets cold and for most of the country, doesn't get hot either. No one is going to put their life on the line just to make a few more bucks.

Since it takes nearly a signed letter from God to get a loan, very few people have debt either. Also, family is very strong, so if you need something, family will help.

When I lived in the USA I was always seeing people push production to the point of danger, just to make some more money, and often not for the person working, but for the shareholders, etc. Honestly, when people are talking about sweatshops - they should look at the USA. Just my not so humble opinion. I own a tree plantation down here and I can not imagine being willing to have a machine that could kill someone like that.  No amount of profit is worth me having the guilt of someone dying on the job because of a dangerous piece of equipment.

Down here just about EVERY wage has a minimum wage - want a raise? Get better educated - no kidding. For example, if you know English, then you get paid better BY LAW, even if your job is a housekeeper. Because of this all the night classes are full of people learning English and other skills - it really is amazing.

I guess what I am wondering about is, if higher rate of speed and power causes such a dangerous event, perhaps the real answer is slow down...  If I drive a car at 100, and get a blowout, I am probably dead - but at 30, nothing much normally happens. Is it really necessary to cut the tree down that much faster?  Just wondering out loud.

Sometimes the question is wrong, not what to do about it - but should we be doing it...

Just my dos colones,

Fred


So, how did I end up here anyway?

hosslog

Howdy Fred, From your description of folks attitudes it sounds like I would fit right in.Can I bring my horses?
Seriously, after I saw the pics my reaction was, is all that power necesary.

crtreedude

They would love your horses!  We have a herd - or so it seems at times. 4 mares, one gelding that was a stallion. And one of the mares is pregnant. We are about to buy two more horses for the second finca (farm) 

My horse, Toro, was used to haul logs when we bought him - he isn't very big, but boy is he strong! If a 4x4 gets stuck in a ditch, they hook it up to him and he pulls it right out, and we are talking some steep ditches.

We just had some visitors and she owns a Morgan, she rode Flor, Amy's chestnut mare and wanted to take Flor home.  It is pretty rare down here to use a bit - almost all the horse are neck reined and respond very well to just about command.

The only issue for me when I first got here is dealing with horses that love to run! You will spend you entire time holding the horse back if you like to walk.  :D

I have a friend down here that uses a Water Buffalo for dragging logs - usually they use two oxen, but only one Water Buffalo is necessary.

Fred
So, how did I end up here anyway?

SwampDonkey

Oregon, I think I seen a thread you had started on this earlier on a forum at Forests.com . Glad to see you over here as a new member, as it doesn't seem like their forum is very active. Sorry I can't help with your question though. If we had some experienced operators on here that were trained and certified by the NBCC we may have some type of answer for you. I'm sure there are other folks experienced with the problem somewhere on the forum, they just haven't discovered your question. Just be patient. I'm on dialup , like Gary is and I can't even come close to loading those internet videos within a limited time frame. ;)

cheers
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

Sawyerfortyish

Oregon I don't have a feller buncher but I think it is safer to have one guy sit in a heated or air conditioned cab of a machine then to have two or three guys doing the same job with chainsaws.  Your chances of getting hurt in that cab are minimal. Yes mishaps happen but the danger of getting hurt doing the same thing manualy are many times more. Of course if you guys are leary of running these dangerous machines you can send them to me and I'll experiment with them for while to see if there is really a problem ::) ;D

crtreedude

I suspect the best approach is inbetween. I think if I were to ride a horse between here and the finca, besides taking a long time, it would increase my chances of an accident. However, using a race car would probably shorten my life expectancy.

There is probably a safe rate of power and speed - and then there is something else.

Just my dos colones

So, how did I end up here anyway?

Oregon Engineer

Gary C - Don't be fooled by the "big" Timbco with 3/4 pitch chain as the only machine capable of chain shot. Any machine set to over speed and over power any chain (3/4 pitch or .404 pitch) will produce a chain shot. Most of the chain shot work done is on .404 pitch chains.
Most used chains that have been bent have micro cracks on the surface. Please do not try to straighten them as there is a crack just waiting to get bigger! Besides the danger of breaking, bent drive links also will gouge out your bar rails and over heat adjoining chain links.

Happy to hear you have tuned your system so the chains are not breaking. Chain manufacturers will supply you with recomended maximum speed and power for safe operation of the chains you are running. Check the chain box for factory phone number and give them a call. You can verify your chain speed with a tachometer, the power is done using the gallons / minute and the line pressure. Send me a private message with your address and I will send you a handbook that gives advice on proper chain speeds and how to calculate power.

Here is an article from a Canadian magazine with some good tips.
http://www.findarticles.com/p/articles/mi_qa3764/is_200408/ai_n9449962

Thanks for the input on your operating methods!!

Caryr - Motor power, chain speed, bar sweep speed, bar feed force, lubrication, and chain maintenance are the major factors in generating a chain shot. Direction of the plane of the bar, thickness of the cab windows, location of bystanders, and presence of a chain catcher are the major factors that determine if the chain shot is going to hurt someone.

Super sonic speeds can be obtained when a bull whip is cracked with your bare arm. Imagine what 20 to 100 HP will do!!!!!!! The pieces can be accelerated to 894 miles/hour and turning 400,000 rpm, those are some of the numbers published from test labs in Europe for .404 pitch chains. The dynamics of the chain motion impart all the energy in the chain to the last two or three links durng the "snap".

Many manufacturers have come out with "chain catchers". These are not designed to catch a chain shot. They are designed to prevent the chain from "snapping" so a chain shot is never generated. They are usually located close to the drive sprocket so the chain is "caught" before the end of the chain goes into the dynamic "snap". But, there is nothing stopping a chain shot if it comes off the nose of the bar!!!

Thanks for your input, and be careful that machine is within the power and speed limits of the chain.

Crtreedude -  Higher power and chain speed mean higher production. There is a balance between production and operator safety. I'm hoping this thread will alert operators to methods to increase their safety, they already know how to increase production.

Sawyerfortyish -  The machines are fffffffffffffffaaaaaaaaaaaaaaarrrrrrrrrr safer than a man in the woods with a chain saw in his hands!!!!!! But when you can cut a 20 inch tree in 2 - 3 seconds there is alot of power that needs to be respected and handled carefully!!




SwampDonkey

Oregon,

Thanks for bringing this info forward to the forum. As you read through the forum you'll notice that some threads can take a turn, then a twist, and land back on the tracks. That's just the way things fall into play alot of times and most of us are comfortable with that format. There is less tension if there isn't someone leaning over your shoulder asking you to stay on topic. Plus we get more interesting threads. ;D Don't be surprised if a thread turns into food (grits) or the weather. When some of us get reading a thread we inadvertantly reply with the first thoughts in our heads. ;) ;D We are all (or most of us are) friendly on here and value everyone's contribution, large or small. :)

I'm aware of the Canadian Woodlands Forum and I wish there was more participation by small woodlot owners and contractors working woodlots. It seems to me purhaps those forums are geered more towards industrial contractors , maybe I'm wrong. Of course our provincial Marketing Boards are doing what they can to promote safety, as I was employeed by our local board for over 10 years. There are alot of folks still not attending field days and training courses that would greatly benefit. It's been a problem sometimes attracting interest and alot of it (I think) has to do with everyone's schedules and plans during their quality time. Some folks are putting in long days and sitting in a public forum or training course isn't what they have in mind at the end of the day or weekend. It's everyone's responsibily however, to be educated/informed.

cheers
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

Oregon Engineer

Swamp Donkey - A bit of variety does make it a lot more interesting.

I'm curious if anyone has found any damage on their machines from a chain shot.

The picture shows part of a "chain shot machine" that is operating in a Swedish test lab. The orange line shows the shape of the chain.  The number 1 shows where a knife breaks the chain (first break). The number 2 shows the shape of the chain when the broken end gets back to the drive sprocket. The number 3 shows the shape and location of the chain when the chain end whips or snaps and a chain shot occurs.



DanManofStihl

Yeah I saw that post on arborist site.com earleir this week. It looks pretty dangerous I feel sorry for the guy it happened to one of those freak accidents kinda like being struck by lightening I guess. I liked the discription and the slide show never heard of the chain snaping and going through the protective cage though. First time for everything I guess.
Two Things in life to be proud of a good wife and a good saw.

sawguy21

All this is why I am uncomfortable with being on the "dummy" end of a two man saw.  I only tried it once and the chain headed toward my kisser was unnerving.
old age and treachery will always overcome youth and enthusiasm

Oregon Engineer

Hello DanManofStihl - The accidents are not all that freak. There have been several reported ones and likely many unreported minor injuries and near misses. Here is one from New Zealand.





Oregon Engineer

Here is an example of a "near miss", most likely a little too NEAR to the guy in the cab.





You can read the entire article at the link below as it is from
a Canadian magazine with some good tips.
Link

Barkman

Quote from: Oregon Engineer on June 14, 2005, 01:10:18 PM
I'm curious what you do to deal with "chain shot" and if you've ever experienced it.

My first thought would have been flack jacket and kevlar helmet, but I like the thicker polycarbonate as well.  It seems to me a basic design flaw that such an expensive piece of modern equipment doesn't include "bullet proof" protection for the operator.  I can't imagine an extra half inch of polycarbonate could be so expensive that it would be worth losing a man over.

Oregon Engineer

Polycarbonate is a "softer" plastic and tends to scratch easily. I've heard that operators have to change out windows every two years because the windows get too scratched up to see through.

I don't think it was a cheap operation trying to cut costs as much as just not knowing about the danger. A lot of operators and manufacturers are just getting educated on chain shot and are still unclear as to how thick of a window is needed. It's a sharp learning curve for the market.

Check out the piece of chain that tore up the operator. It entered the operators front and had to be surgically removed from his back.



slowzuki

I find this pretty interesting...  I know guys may find it offensive to try and make a tool that is already so much safer than a chainsaw even safer but I'm sure old fellas protested chain brakes on chainsaws.

Reusing bent links would be a big no-no in my book.  I don't know for sure the metalurgy of those chains but would guess they are strain hardened already so a lower grade of steel can be used.  This means it doesn't take much bending to get them to fail.

Limiting the chainspeed would seem to be an obvious answer, I suppose guys would swap out motors and valves etc to try and speed them up.

Oregon Engineer

slowsuki,

You're absolutely correct! Reusing bent links is a very bad idea for two reasons. 1) The bent link will not have enough room in the bar groove and will greatly increase the friction generated heat. This wears out the bar grooves faster and burns up the chain links close to the bent link. 2) If you look at used harvester links with a 10X or better magnification you will see very small cracks called "heat checks". The "heat checks" are on most chain surfaces in contact with the bar because of the heat generated during cutting with the power of the harvester. When the link gets bent the cracks on one side grow deeper into the metal and weaken the link. The link does work harden from the bend and its toughness decreases.

You're right on the chain speed issues. Slower chain speeds do a great deal to reduce chain shot. The test lab reported it can not generate a chain shot when the chain is broken while moving below 5900 ft/min but at or above 9800 ft/min they get 100% chain shots with every chain break.  The lab recommends running chain around 8000 ft/min to give the needed cutting speed without overly increasing the risk of a chain shot.

I've talked with operators who drilled out the hydraulic fuild flow restrictor to increase the speed of the chain, they thought they were clever in out smarting the manufacturer. An accident waiting to happen!

Here is some information on how to reduce chain shot.




To reduce the risk of chain shot and injury:
•   Operators and bystanders must never be in the plane of the bar when the chain is moving about the bar.
•   Appropriate windshield material must be installed.
•   Chain speed should be 40 m/s (8000 ft/min) or less for .404 pitch OREGON® chain and 35 m/s (7000 ft/min) or less for ¾ pitch OREGON® chain.
•   A chain shot guard should be installed near the drive sprocket.
•   Chains should be inspected frequently and damaged or cracked chains removed from service.
•   Always use new  parts when repairing chains.
•   Industry groups recommend that chains should be discarded after the second break.
•   Remove dull chains from service.
•   Always sharpen chains to factory specifications.
•   Maintain proper bar and chain lubrication.
•   Maintain proper chain tension.
•   Replace the drive sprocket when it has visible signs of wear.



Dom

I believe our Logmax heads all come equipped with a safety device to help prevent chain shot. I was talking to my boss about it, and he mentioned that one fellow in Sweden nearly got killed, as the chain hit him a few millimeters from a artery. Apparently we already had a few machines come in the shop with chains dangling from the cab area.  The windows are bullet proof, but a chain at high speed can still do alot of damage!

Oregon Engineer

Hello Dom,

I've seen chain shot guards on the Log Max machines at some recent logging shows. I took a picture of one. The chain shot guard is the bright metal semi-circular piece directly behind the chain that is rapped around the drive sprocket.




Hey, if there are chains parts hanging from the cab, someone is playing Russian Roulette!! Let them know the parts fly as supersonic speeds and they should not be in line with the bar and chain. Treat the bar and chain like a loaded gun, don't aim it at anything important!



Do you know who made the window and what model it is? I'm curious as I'm also in contact with a New Zealand logging company that is installing bullet proof laminated windows as a safety measure.


Dom

Yes, that would be the chain catcher. We always have plenty in stock for our customers.

I know what you mean about Russian Roulette!

As for the windows, I'll have to check. We sell all of our machines (Rottne's and MHT's) with lexan windows.

Oregon Engineer

Just to make sure I've been clear. The LogMax machine in the picture has both a chain shot guard and a chain catcher. I've labeled them both.



Dom

Yup, I understood. I went for a short walk in the partsroom today, and found both parts. We use Marguard windows for our machines, if that's any help.

Also,  Oregon chains are great, that's all we sell.  ;D

Buzz-sawyer

I would like to use some of these windows to build a shield to use on my headrig...I have nothing now I would like to rig it t o swing into positionwhile sawing........basically a simple bulletproof window...........???? Sound like a winner? How much would a 4'x4' piece run?
    HEAR THAT BLADE SING!

SwampDonkey

Buzz, don't forget the A/C in that booth.  smiley_sun smiley_sweat_drop smiley_sweat_drop smiley_sweat_drop smiley_sweat_drop smiley_sweat_drop
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

Oregon Engineer

Buzz-sawyer

Marguard and Lexan are two brand names of polycarbonate that are used in cab windows. The European test labs have found that .404 pitch chains can penatrate a 12mm thick window. There have been no tests done with 3/4 pitch chain so I don't have any info to pass on there. Some tests were done to determine how thick of a window was needed to stop cutter teeth from the large hot saws (circular saws with a 2 foot or larger diameter mounted in a harvester head). The material thickness was 1 1/4". 

I'm in contact with a New Zealand logging company that has installed "bullet resistant" series 300 windows from Ace Security (www.acesecuritylaminates.com  1-888-607-0000 or email info@usace.com). The web site has some very interesting videos and check out the news reports. The bullet resistant windows are a lamination of glass and plastic. The glass is easy to clean and does not get scratched up like an all plastic window.

Oregon Engineer

Here are some pictures of chain shot guards on other machines. The pictures were taken at the 2005 Oregon Logging Conference in Eugene, OR.
The chain shot guard is the semi circular band of metal following the edge of the of the drive sprocket and chain path.

The spindle coming off the center of the drive sprocket is the chain catcher.


Denharco chain shot guard





A Valment chain shot guard, the grease flung off the drive sprocket at piled up on the chain shot guard, (no chain on this head).





A Waratah/John Deere chain shot guard






tiny3

hi guys 
on our harvesters we have a 20mm (margard)front window on the out side of the cab guard and 2 20mm margard windows bolted together in the front window of the cab,as well a chain guard.there are a few simple rules we use as well like never use it when another machine or person is in line with it in case it broke.i know of a bloke who was struck in the neck by a flying link(hes ok now)and a chain broke an went through the front window and out the back,hows that for CLOSE.hope this helps
artest formely known as tiny

Oregon Engineer

Hey Tiny,
How long ago was the operator injured in the neck? What was the loggin company name?

beenthere

OR Engineer
I'm curious. What is your interest in the chain guards?  :)
User?  State? Federal? Law Firm? Insurance Co.? Just interested? Chain Guard Co.? OSHA?
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

tiny3

the guy was cut in the neck about 4 months ago i guess.im not sure on the name of the company,
artest formely known as tiny

Oregon Engineer

Beenthere,
I'm interested in the phenomenon of "chain shot" as it relates to mechanical timber harvesting and ways to reduce the risk of chain shot. The chain shot guards and chain catchers are ways to reduce the risk.

The dynamic phenomenon involved in chain shot has intrigued me ever since I was a kid. As a kid, my buddies and I played "crack the whip" on a frozen pond with ice skates. When it was my turn I still remember getting blasted into a snow bank from the sudden acceleration. Then when I got a bull whip and started snapping every thing insight, including my ears, I was amazed at  how the power was concentrated into just the tip of the string.  Now I work for a saw chain manufacturer and the forums are a good way to help educate machine operators and increase our understanding of work practices and other issues the operators are dealing with.

Tiny3,
What country was the accident in?

beenthere

Thanks OE.

I resemble that 'crack the whip' on ice thing. I wasn't the best skater, so I was 'volunteered' to be at the end of the 'whip', only we ice skated on the river in Iowa. Now getting 'whipped' off the end of the line and skating toward open river water was part of the thrill everyone got. I was 'out of control' but never did get wet.
It was the same river we swam in during the summer. Would climb on the railroad trestle, and dive off. Had to dive accurately, because the old bridge pilings were still in the river, right beside where we dove, just cut off a bit below the water line. Remember well getting too close and feeling the splintery, slimy wood sliding along my skin. Doubt I'd let my kids do such a thing, or my grandkids to even think about doing it.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

sawguy21

 :D :D :D I hear ya. I told my buddy's son that if I ever caught him trying any of the stunts his dad and I pulled, I would beat him like a rented mule.
old age and treachery will always overcome youth and enthusiasm

leweee

Back on topic here.....When the chain is SHOT....we  FIXEM. :D :D :D :)
just another beaver with a chainsaw &  it's never so bad that it couldn't get worse.

tiny3

oregon engineer
the country is tasmania austraila
artest formely known as tiny

Oregon Engineer

Many thanks Tiny3,  I've been contacted by people involved in that or a similar situation there. It looks like many many harvesters have been idled until they are fitted with thicker cab windows. That's a very good move!

SYOUNG

Greetings,

I am involved with forestry equipment design and engineering with a major forestry equipment manufacturer.  All of our harvesters and feller bunchers fitted with a high rotation disc saw are equipped with an 1 1/4" thick front Lexan window.  The Timbco in the safety video only appears to have a 3/4" thick from window as do many carriers that are converted to harvesters.  If you are operating such a machine, please be aware that thicker front windows are available.

Regards,
Steve

Jeff

Welcome to the Forestry Forum Steve. Who is it you work for?
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

SYOUNG

Thanks for the welcome Jeff!  I work for Tigercat and do some part time logging and milling as well.  I enjoy this forum and look forward to all of the interesting posts and knowledge that is available.

Oregon Engineer

Steve,
    Will you be at the Lake States logging congress in Marquette, MI during early September?

Thank You Sponsors!