Thread: Any Advice?
02-13-2001, 10:42 AM #1JAMESBENNETTFirehouse.com Guest
I have had two sets of cutter blade's break in the last year. The first happened when I was cutting the hinge of a door on a late 90's model Chevy sedan. The cutter was 17 years old and other than sharpening the blade's were unchanged. I wrote this off to the age of the blade. Now this weekend, on a second cutter that is just a couple of years old, I snapped a blade at the base of the mount. I was cutting a piece of a fender of an older foreign car. This was a class That we were putting on for a local department, and the car had been wrecked and was rusty. The first blade that I broke I could see were the tool could have been in a bind, but this one stumped me! If you have any incite or have had similar problems I would appreciate any info!
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02-13-2001, 04:47 PM #2MetalMedicFirehouse.com Guest
Murphy's Law comes to mind. What brand of tool was it and what was the configuration ("O" Cutter, fixed blade, combination?). Without knowing the history of the tool, my best guess is that on a previous evolution the blade sustained damage that was undetected. This could have weakened the blade to the point that it fractured on what should have been an easy cut for it.
Orrville (OH) Fire Dept.
[This message has been edited by MetalMedic (edited 02-13-2001).]
02-14-2001, 12:04 PM #3JAMESBENNETTFirehouse.com Guest
The cutter is a Hurst S-150 II("O" style cutter). I inspected the blade after it happened and couldn't find any sign of a previous fracture(discoloration of the steel inside). That actually was my first thought that it might have been dropped and caused a hairline crack, but I didn't see and evidence of one, but then again I am not expert on steel either.
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02-14-2001, 03:25 PM #4pwc606Firehouse.com Guest
I know of at least one blade that has broken in the last year. The local rep and some other very experienced instructors were teaching the class. They were cutting an "A" post on a Volvo and the blade snapped at the base.
I have been told that one of the ways to check blades is to x-ray them. I think that that may be a little expensive to do in some cases. I also saw no signs of previous metal damage to the blade. The blades where not that old but did have quit a bit of use on them. The only thing that we could figure was that they were already damaged.
02-14-2001, 11:45 PM #5MetalMedicFirehouse.com Guest
Well James, I guess I don't have a good answer for you. Murphy's Law still sounds as good as any . It is a good example of how ANY tool can fail on you with no warning or reason. Perhaps it was just a manufacturing fluke. I have heard of x-ray testing, but I believe a process called hydra-flux is what is recommended to test for metal fatigue. I am sure someone from Hurst can give you some advise in this area should you feel the need to go that route.
If you do find out a cause for the failure, please post it here. I am sure many will be interested to hear about it.
Orrville (OH) Fire Dept.
02-15-2001, 10:03 AM #6Kevin RomerFirehouse.com Guest
I am a Hurst dealer. You didn't provide a lot of information on the cut process itself, meaning where in the blade did you attempt this cut?
If it was near the tips of the blade or in the center of the blade, the cutter may have twisted slightly and "spread" the blades causing breakage. Why did they twist? When was the last time the tool was serviced? Is the main pivot bolt torque at the required amount? The later should be performed under the service.
The main reason for any blade to break is the lack of maintenance on that pivot bolt. The 150 is required to have 250 ft/lbs on the nut... otherwise twisting is certain and breakage will follow.
By cutting hinges with the tips of tool, the blades will spread, due to the length of the blade...
With a 150...cut hinges in the notch or risk damage to the tool.
email me if I can help further:
02-16-2001, 03:56 PM #7mike mFirehouse.com Guest
while i was teaching extrication for many years the companys that were being trained some of them had the same problem that you had.we contacted our technical services div,and they looked into it. they found that over time and use the torque on the blades reduces and the alignment on the blades shift a little and the twisting og the blades when in use cause the blades to offset thus causing th e blades to break.my suggestion have the blades serviced and the torque and blades set. keep up the good work when cutting hinges remember the types of hinges the rolled steel kind which are found on the older american cars when you cut these cut the top hinge first this prevents the door from popping up,when cutting the hinge itself make two cuts one one bottom of hinge one on top of hinge. when cutting the whole hinge at once the cutter blades will twist and the blades will seperate thus causing the to break
[This message has been edited by mike m (edited 02-16-2001).]
03-08-2001, 01:32 AM #8dlyFirehouse.com Guest
To test metal, the process is called Maga-Flux. This finds faults from the making of the steel (seams, slivers, blisters,etc.) I use to test the rollers in bearings with this method. Now when I'm not at the Vol. Fire Dept. I work in a Steel Mill.
Old School...Learning New Tricks
03-09-2001, 09:25 AM #9res7cueFirehouse.com Guest
Jim, I can relate to your experience. We had similar incident, it happened when wI was cutting thru a floor support and about 2" of the blade tip broke off and was imbedded in a building wall.
I have also seen/ heard of similar events and they all seem to result when the cutting was performed using the tip areas of the cutters and not down at the notch. This is the recoomended area to sue when cutting, but it's not always possible.
My dept has started to Magna-flux all blades and arms after the tool is five years old or was involved in any questionable incident. I'm not sure of the cost, we are fortunate to have a member that owns a shop and performs the process free of charge.
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