When to replace bar tip?

[Muddy42]

Please see below a picture of my bar tip- stihl rollomatic ES in .063 / .404

 

Annoyingly I accidentally clamped my mill too close to the tip and the sprocket must have been pinched and it overheated for a few seconds (before I noticed and stopped cutting).

 

I was surprised by how expensive replacement tips are.

 

The sprocket still turns freely and I have to treat it carefully: lots of grease and cleaning out the groove.

 

Is it OK to continue using a bar tip in this condition?

 

 

[peatff]

Is there any play in it with the chain removed ? If it still spins and is guiding the chain I would use it, it's only scorched the paint.

[adw]

That is not going to last 5 minutes, all the rollers will be blue and probably square, if it goes it may well damage the chain to boot.

[Muddy42]

No play at all. The sprocket spins and behaves as it should. I do force grease into it when the chain is off.

[Khriss]

Same- tip sprocket blows out, damage to drive sprocket bearing and a damaged/ stretched chain. Long annoyed walk back to shed, K

[Wonky]

I’d buy a new tip, and chalk it up as a lesson learnt. 
 

if it goes pop while milling, you will be cussing.  

btw there were a few lopro tips popping and chains  braking…

it’s not what you really want to have to deal with while milling.

I had a std 3/8 chain snap while milling in the cut due to nails.🙄

 

I prefer everything to go smoothly now as it could snapped while just getting in the cut where I’d have been very close to the chain.🤔

 

 

 

 

 

[bmp01]

Think I'm with adw on this, the metal bits that are made hard in manufacture by heat treatment have most likely been re-heat treated - meaning they will now be softer than they should be and not last.

 

The scortched paint tells where it got hot. The thing to note; its not just hot where it was pinched .... I'd say the (nose) sprocket itself got hot and subsequenly transferred the heat to the near by bar, hence the circular pattern of scorched paint. For the little sprocket to put that amount of heat into the relatively bIg bar I'd say it got very hot. And if the sprocket got hot so did the needle rollers, these are (were ?) both hardened material parts.

If you take the chain off and clean / degrease the nose spocket can you see if it has gone blue ?

 

Edit: heat pattern is inboard of the nose sprocket, looks like it matches with where the rolling bearing is....

Edited May 6, 2022 by bmp01

[Mike Hill]

1 hour ago, Khriss said:

Same- tip sprocket blows out, damage to drive sprocket bearing and a damaged/ stretched chain. Long annoyed walk back to shed, K

You do talk some shite .

 

Will it break the crank too?

[Khriss]

3 hours ago, Mike Hill said:

You do talk some shite .

 

Will it break the crank too?

Still trying to catch up  with your efforts, frankly. K

[Muddy42]

More pics, top and bottom, after a clean up