New bar - Chains too tight?

[Marleywood]

I just bought a replacement bar for my Stihl MS311. I had two bars to start off with which I have been rotating, so this is the first "new" bar into the mix for 5+ years. My chains now fit so tightly I'd be afraid to try to run the saw if I forced it into the bar. I've double checked that the bar is correct to spec, it's OEM, and it's .050 gauge anyway, so it's not like the bar was mis-packaged & it's too small. Has this ever happened to any of you? My old bars are spayed out.

 

[Bob Hedgecutter]

Old chains in new bars are never a good mix- new chains in new bars are a good idea and a NEW drive spur or sprocket.
My guess is the drive links on the old chains are quite damaged/burred and binding in the tighter groove of the unsplayed new bar.
Damaged drive links will in turn damage new bar nose sprockets and new clutch spurs or derive spurs- just like running new chains in well used, well worn drive spur/sprockets will ruin a new chain.
My suggestion would be- new bar, new chains and new drive spur/sprocket will last a long time (or at least longer than one component new and the rest well worn).
Keep the old bars/chains/spur sprocket for rough work, dirty wood and stumping. Dress the old bars, or take them to a shop to be dressed.

 

[Marleywood]

I hear what your saying, but these chains aren't exactly what I would call "old" plus they just came back from being professionally sharpened (as they frequently are) at a local shop that is owned by a retired logger.

 

[Bob Hedgecutter]

Fair enough- pictures pain a thousand words.
Can you put up a good clear photo of the drive links of the chain and the device the drives them off the clutch?
And clarify if we are talking tight drivers in the new bar groove- or too tight over all once the chain is fitted to the newly acquired bar?

 

[Marleywood]

I'll try to take some pictures, IDK how illuminating they will be. I probably have 4 chains for this unit currently in the "OK to use" category, I will also try all of them, I think I tried two already.

They are tight all along the bar on both sides of the bar fitting it onto the bar. I haven't even tried mounting the bar & chain with machine, it's so tight on the bar as it is.

Thanks for helping with this, it seems kind of stupid, but there it is...

 

[Bob Hedgecutter]

Nothing stupid about it at all. I bet many have suffered similar before.
You noted earlier the old bars rails are splayed, so there is play available for the drivers and I would put money on the fact they have just a wee bit of burring on them that is causing them to bind in the tight new bar.

 

[Old-Feller]

Measure the drive link with a caliper, You may have an 058 chain in an 050 bar

 

[Marleywood]

Measure the drive link with a caliper, You may have an 058 chain in an 050 bar

I considered that and cannot find my caliper. If so, it would mean I have been running.058 chains in .050 bars for some time. The chains I have for that saw were made up for me by the aforementioned sharpener, I guess they could have made them in the wrong gauge. They had a Stihl chain for reference when they made it (but they have MUCH more aggressive teeth). That would mean I was running the wrong one(s) for at least a year ...

 

[Bob Hedgecutter]

I considered that and cannot find my caliper. If so, it would mean I have been running.058 chains in .050 bars for some time. The chains I have for that saw were made up for me by the aforementioned sharpener, I guess they could have made them in the wrong gauge. They had a Stihl chain for reference when they made it (but they have MUCH more aggressive teeth). That would mean I was running the wrong one(s) for at least a year ...

Post#1 references old bars being splayed out.
Post #3 mentions local shop owned by a retired logger.

A well known hack by old time saw users looking to get maximum life out of a bar is to start with an 0.050 bar and chain, then as the bar groove wears, increase the gauge of the chain to suit the wear, step up to 0.058 chain and then if the bar is not completely trashed you can step up again to 0.063, all in the original 0.050 bar!
If you have taken the saw to the shop, it could be they fitted the chain to the bar, rather than supply a chain to suit the stampings on the bar specs and either not informed you- or you missed picking it up.
You could always pop in and ask them to confirm gauge of your old chains- and buy some new 0.050 chain loops while you are in there.

 

[Marleywood]

Well, one update to report, I went through my chains and came up with one I'm sure is a Stihl chain, and it fits...