Go lo Pro?

[Wonky]

On 26/02/2021 at 11:25, Alasdairs dog said:

That's kinda the point. What's my error. Never snapped a bar or blown noses in twenty odd years. Bit suspicious me thinks. 

Do mean snapped a chain and not bar, 

 

blowing your nose so to speak or snapping a chain, there are many reason why .

 

1st what rim sprocket are you using, and has it been modified? There are reasons for this question and to all the other questions.

Ie, we could be answering one question when it could be another reason as to why your having problems.

 

2nd filing, how often are you filing you chain, and what angles also file size used or are you using a grinder.

 

3rd depth gauges what do you use to check them and how low are they, or do you just swipe a file over them

 

4th how tight and how often do retention the chain and do you slacken it off and when do you do this.

 

5th what’s the sawdust like, flour or musli.

 

6th how hard are you pushing the mill or are you holding it back.

 

Roughy hewn knows why I,m asking these questions.   And I,m sure we will have similar answers. 👍😉

 

 

 

[Rough Hewn]

Lots of photos of the damaged kit would help diagnose the issue as well[emoji106]

[Alasdairs dog]

17 minutes ago, Wonky said:

Do mean snapped a chain and not bar, 

 

blowing your nose so to speak or snapping a chain, there are many reason why .

 

1st what rim sprocket are you using, and has it been modified? There are reasons for this question and to all the other questions.

Ie, we could be answering one question when it could be another reason as to why your having problems.

 

2nd filing, how often are you filing you chain, and what angles also file size used or are you using a grinder.

 

3rd depth gauges what do you use to check them and how low are they, or do you just swipe a file over them

 

4th how tight and how often do retention the chain and do you slacken it off and when do you do this.

 

5th what’s the sawdust like, flour or musli.

 

6th how hard are you pushing the mill or are you holding it back.

 

Roughy hewn knows why I,m asking these questions.   And I,m sure we will have similar answers. 👍😉

 

 

 

Good questions. 

 

1. I was using the low pro rim sprocket supplied with the chain. 

2. It was a ripping chsin sharpened to 10 degrees was using a 4.8mm file and giving it a couple of strokes every two or three boards. The snapped chsin (not bar) only had one or two sharpens before it went. 

 

3. Didn't touch the depth gauges. When milling with my 36 inch est up I tried taking them down a good bit but didn't see a huge advantage. Normally use the stihl guide every so often. 

 

4. Run saw up for a few seconds then check tension and re tension. Check tension after every cut. Slacken off if taking a break or finishing for the day. I am really carful not to over tension a hot chain and let to cool and contract onto the bar. 

 

5. Saw dust was relatively fine as you would expect with 10 degrees on the Teath. Not flour though. 

 

6.was being super carful not to beast the saw through the cuts. Using the winch but keeping refs nice and consistent and chsin speed quite low. 

 

Your diagnosis based on this would be..? 

 

[Alasdairs dog]

12 minutes ago, Rough Hewn said:

Lots of photos of the damaged kit would help diagnose the issue as well

 

[Alasdairs dog]

Not the best pic but shows nose sprocket sticking out of the side of the bar. And two buggered bosses. 

[Alasdairs dog]

Ist nose sprocket disappearing trick

[Rough Hewn]

Any close ups of the chain and rim sprocket?
[emoji106]

[Wonky]

Just what I was going to ask 😉

 

4.8 mm file ?  
 

my guess so far is wrong file size, thus wrong angle on tooth, and or because you seemed to have filed into the gullet more making a weak spot, although it’s difficult to see from the poor quality pic of chain, although I’ve zoomed in as best as I can.

as for using the winch you could be putting a lot more pressure than you realise, thus duller chain due to wrong file size and with the power of the 880 it put to much pressure on the nose sprocket,

(people blow nose sprockets when bore cutting with a dull chain and pushing hard)

the sprocket is the other thing, that’s been a problem in the past, ie wrong, std 3/8 is wrong  the size of the drive link is different  between std  & lopro 

 

i,m not saying this is a definite answer, it’s a possibility of why.

 

 We need better pics of chain and your sprocket 😉

and don’t worry we’re here to help so others learn as well.👍

 

[Alasdairs dog]

6 hours ago, Wonky said:

Just what I was going to ask 😉

 

4.8 mm file ?  
 

my guess so far is wrong file size, thus wrong angle on tooth, and or because you seemed to have filed into the gullet more making a weak spot, although it’s difficult to see from the poor quality pic of chain, although I’ve zoomed in as best as I can.

as for using the winch you could be putting a lot more pressure than you realise, thus duller chain due to wrong file size and with the power of the 880 it put to much pressure on the nose sprocket,

(people blow nose sprockets when bore cutting with a dull chain and pushing hard)

the sprocket is the other thing, that’s been a problem in the past, ie wrong, std 3/8 is wrong  the size of the drive link is different  between std  & lopro 

 

i,m not saying this is a definite answer, it’s a possibility of why.

 

 We need better pics of chain and your sprocket 😉

and don’t worry we’re here to help so others learn as well.👍

 

Sounds like an option I can see how using the wrong file size would weekend the chain. But... It was a new chain and barely did a days work so I don't think even that would account for it snapping. I've run 3/8th on the 661 down to nothing and never had an issue. I still believe that the lo Pro stuff just isn't suitable for bigger saws. The rim sprocket was sport on. Can't send any more pics as the whole lot was returned to chain saw bars for a much appreciated refund. 

[Rough Hewn]

Sounds like an option I can see how using the wrong file size would weekend the chain. But... It was a new chain and barely did a days work so I don't think even that would account for it snapping. I've run 3/8th on the 661 down to nothing and never had an issue. I still believe that the lo Pro stuff just isn't suitable for bigger saws. The rim sprocket was sport on. Can't send any more pics as the whole lot was returned to chain saw bars for a much appreciated refund. 

I think I know what’s been happening.
You’ve been using a 660/661 with standard 3/8 chain for years.
That’s a medium torque power head with a strong chain.
You’ve upgraded to a high torque (881) power head, and downgraded the strength of your chain (3/8LP)
Gone from 36” to 48”,
Used the wrong file size
And you’re using a winch which massively reduces feedback.
Then you mill like you have done for years...
And it goes horribly wrong...
Sprockets pop and chain snaps.
And you’re 100% certain it’s the kit?