Safety Chain Catch

[clearance]

The damage might be from the sprocket, but just because Object A is harder than Object B doesn't mean that Object A can't be hurt by Object B.

When an aircraft crashes into the sea, is there any doubt that the water was softer than the plane?

I was right, Skwerl figured it out. Water can cut steel under the right circumstances, your point is well taken, in this case aluminum cannot cut steel.

 

[geofore]

Drive links

You get to Post#17, till we get the right answer. Drive tangs are beaten up by the sprocket. It knocks the tangs up bad. Questions you need to ask. Is the sprocket worn out. Does the sprocket on the saw match the sprocket on the tip of the bar? Are you trying to run 3/8" chain on .325 sprockets? Are you running .050 chain in a bar guide wide enough to handle .058, .060 or .063 chain? It's very easy to mismatch chains and bars if you don't look to see what you have. Then there is the possibility that you're flicking your wrist, the bar tip heading downward, at full throttle and this will throw the chain.

You'd be suprised to find out the chain companies test their chains cutting aluminium plate. So the chain, bar tip sprocket and the sprocket on the saw all have to match and be in good working order before you look for other problems such as the flip of the wrist at the wrong moment. It is normal that the sprocket damages the tangs when you throw a chain at high speed. It takes the tips off and the tangs look flatened out having been ground off by the sprocket hitting them at high speed. So, if you throw a chain at 12,000 RPM the tang gets hit/ ground at a rate of what? 200 RPM per second, times 7 tooth =1,400 times per second. END of tangs as we knew them. So the sprocket is slapping the tangs on the drivers at WOT(wide open throttle) somewhere around 1,400 times per second. Steel toooth on steel tang, grind,grind,GONE.

 

[clearance]

Sorry

I am sorry Hydro, I thought you were talking about the edge and thought wtf, this has happened to me before and I could not just "run" it back in. I take the chain of the saw, get my raker file and file the burrs off the side of the drivers, it can be a frustrating process but it works. Time for a new sprocket maybe, I have done this on brand new bars and chains though.

 

[hydro2]

I am sorry Hydro, I thought you were talking about the edge and thought wtf, this has happened to me before and I could not just "run" it back in. I take the chain of the saw, get my raker file and file the burrs off the side of the drivers, it can be a frustrating process but it works. Time for a new sprocket maybe, I have done this on brand new bars and chains though.

No problem! I thought about filing the sides of them down, but the hook in the drive link is gone and I was not sure it it would lead to pre-mature sprocket wear. Bar, chain and sproket are matched, I think the brush, gravines etc blew it off. I never happens in the midst of a cut on a log, just when hogging through the brush and it had only happened twice in about 18 cords of wood.
Thanks again,
Mark

 

[KarlP]

The damage to the drive links is caused by the drive sprocket, not the aluminum chain catcher.

I have threw the chain on my 353 once the drivers got chewed up by the sprocket.

I would think this could be prevented by switching the 353 spur drive to a 346 rim drive. Does anyone know what other parts need to be replaced along with the rim/drum? Is it just a 346xp oil pump?

 

[AZLOGGER]

I have threw the chain on my 353 once the drivers got chewed up by the sprocket.

I would think this could be prevented by switching the 353 spur drive to a 346 rim drive. Does anyone know what other parts need to be replaced along with the rim/drum? Is it just a 346xp oil pump?

Looks like KarlP nailed the problem perfectly, a rim system will not damage the drivers (drive links) as bad as a spur system will when you throw the chain. Also the same rim system fits 340,345,346.346XP,350,351,353, & 357.
Good Luck-Remember keep your chain tight & sharp and never ever remove or disable any safety equipment, you are just an accident waiting to happen!

 

[Oregon Engineer]

1) Drive tangs are beaten up by the sprocket. It knocks the tangs up bad.....

2) Then there is the possibility that you're flicking your wrist, the bar tip heading downward, at full throttle and this will throw the chain.

3) You'd be suprised to find out the chain companies test their chains cutting aluminium plate. .

geofore

Regarding 1: perfect advice
Regarding 2: It works on any chain, any bar, any chain tension, every time. What were you doing when you FIRST figured it out?
Regarding 3: Were you ever a lab techician at a chain manufacturer?

 

[geofore]

advice/chains

I was cutting firewood back in the early 70's when I noticed it only took a flip of the wrist to throw the chain. I learned about the aluminium plate testing talking to George at Oregon chain. I sent him a few pics of things I've cut out of trees.

 

[SawTroll]

... I would think this could be prevented by switching the 353 spur drive to a 346 rim drive. Does anyone know what other parts need to be replaced along with the rim/drum? Is it just a 346xp oil pump?

:jawdrop: I have never seen or heard of a 353 with a spur sprocket before.
They don't come that wat over here, at least.....

 

[jp hallman]

Chain catchers on all my 372's and 575's aren't aluminum, they're plastic. On the handle the factory put a piece of reinforced rubber. Thought that was a good idea so I put a piece of 5/8" heater hose over the factory chain catcher. Seems I'm not alone in this line of thought. I've noticed a few pro's doing the same thing. Tossed chains don't require a bar wrench to put em' back on. "Flex" the bar and roll that puppy back on! Works with the longer bars(32"). Might not work too well on the shorter bar.

 

[SawTroll]

Unknown Quantity and Proud of it!

I just discovered that your signature need to be updated (not my fault).