bar sprocket tip woes

[bluthum]

Today the sprocket tip on a Husky 440 started dragging enough to almost stall the clutch. Taken apart the sprocket isn't seized but will only turn with being tapped on, small hammer and punch. I dug out some wood fibers which may have been sufficient to stall it but it's still stiff. If there's any more junk in there I can't spy it and it's been tapped around a couple good spins each way] and lubed. It wasn't pinched prior to the seizure but I do recall a little attempted kick back just before the fail. Odd though, the fibers being jammed in there like that?

The bar hasn't been used a lot, maybe 3-4 chains but it is the cheesy homeowner bar. Nonreplaceable tip of course. Seems awfully premature failure even for a low end bar.

[sawguy21]

There is likely debris in the bearing that can't be removed without disassembling the tip which isn't advisable. The best alternative is an Oregon pro with the replaceable tip.

[doc henderson]

when I sharpen a chain, the bar gets cleaned in the grove, and the tip gets a bit of oil and freed up by spinning by hand.  a little air at the proper angle and it sounds like a turbo revving up.  if not, it will drag on the power of the saw.

[lxskllr]

Maybe you lost a bearing? I blew out a virtually brand new bar once when I had a light kickback, and the bearings fell out.

[barbender]

You knocked the bearing out with the kickback, I'd put money on it. I've done it a few times.

[thecfarm]

I've screwed up a good bar with the kickback a few times. I just go get the spare one and put it on and start cutting again.

[Al_Smith]

There has always been a debate of weather to lubricate the bar sprocket bearing or not to .Some claim the grease or oil would collect fine dust only making matters worse .On that I don't and what others do is none of my business not my bar .  However on that about two weeks ago I unpluged the bar on my neighbors Makita (Dolmar )because it was really binding things up and blued the bar .Fouled with fines on the nose and entire bar .Nice guy but can't file a chain . 

[lxskllr]

I don't grease tips, and I have no bar problems. A friend of mine greases religiously, and he doesn't have problems either  :shrugs:

[B.C.C. Lapp]

Yup, just knock the rivets out and take that tip off, take a file to the bar and get the rail's all cleaned and even and put a new tip on.  Run the new tip and bar over a sander lightly and your good to go.   But I don't know about the other guys but I only retip a bar once.   Seems the second time I try it they never last long.  Nope, one new tip and thats it.

[Al_Smith]

I've only changed one tip I think on a Windsor bar that was given to me.It must have been a west coaster because it was 50 thou slot with a .404 sprocket and I replaced that tip with 3/8" .It was a 36" bar but I can't remember if it was  a Stihl mount or McCulloch .

[Al_Smith]

Some years back TSC sold what they called a "cord cutter " package .It had two chains,a file and a banana bar .That bar design was not very good because they could not be reversed and failed in not too much time .It was not one of Oregons better ideas . 

[bluthum]

I took another look at the tip today, rotated the spurs with a punch and hammer a couple times both ways as before. Only thing excavated was 2 slivers of steel about the diameter of coarse still wool but 1/2" long and shiny like maybe stainless. I dunno what they represent but it seems ominous, like maybe time to play taps. I hate throwing stuff away but the metal shards do support the blown bearing theory, perhaps. 

Meantime I dug out a low miles 16" bar and a new chain from my stash and installed. All good except I'm more used to an 18" bar on this little saw. Time to test out the shorter one and see if I like it, it's certainly not my go to saw so maybe the shorter bar will suit me. I remember when 16" bars were normal fitment for a 60 cc saw but that ship has sailed.

As for the grease/no grease argument it seems I'm seeing no grease tips more often than past years. If the big boys can't agree on grease or no it's unreasonable to expect the consumer to figure out which way is best. For me I'll continue to grease if there's a port and otherwise not worry. Most of the bars I've shelled out over time was due to the rails being worn too short or groove too wide, umm, well maybe a bent one or two also. The earlier nonreplaceable sprocket tips seemed short lived but I've had great luck with ones made the last few decades. I can see me buying a nice oregon pro with replaceable tip and having an accident bend it the first week, the wailing would be heard for miles. None the less I'll do some new bar shopping, sitting down of course.

As usual I've learned a lot from all the comments and I thank everyone that posted!

[doc henderson]

If I get a gummy tip, that is when I might hit it with a bit of WD or light oil to get things moving again.  then get it to spin with air.  otherwise, new bar.

[bluthum]

If I get a gummy tip, that is when I might hit it with a bit of WD or light oil to get things moving again.  then get it to spin with air.  otherwise, new bar.

I've tried to spin the tip assisted with solvents and and tap with a hammer and punch just this side of extensively and it's still far too stiff to turn without tapping. I do suspect it could just be debris resistance but if so it's sure persistent resistant. Of course the debris could be destroyed bearing giblets but there have been both big wood fiber chunks and tiny metal frags exposed so far. Given your recommends I may try it again, it appeals to my never waste anything side which sometimes overpowers good sense. Of course good sense also involves the 3-4 new chains I have to fit the sticky bar. Good sense... hmmm.. trying to locate mine once more...

One thing I would disagree on [from a perspective of not much knowledge] is spinning a bearing with air. Proly not an issue in this case but it is, I think, in some cases ill advised with over revving potential on ball bearings if dried out. If I got it to spin with finger pressure I'd just high five the chainsaw gods, grease it and call victory.

If I ever give up on the fix I may just punch out those rivets for a looksee just for forensic satisfaction, I don't even know what that nonreplaceable tip bearing even looks like on a good day. 

[doc henderson]

if you are getting metal shreds out, then this one is done, but I like the idea of an autopsy.

[bluthum]

Out of respect for doc Henderson's interest in the bar tip autopsy I'll report. I ground off the rivets and pulled out the pieces, nothing was obvious but I lost some of the disc shaped bearings in the scuffle so I'm not certain about them. My best guess is though, the  kick back bent the rivets holding the inner disc in place enough to keep it from spinning. Just a guess, maybe I could have measured the height of the tip's teeth on either side of the bar before disassembly, dunno. 

It was interesting to see how the tip worked, I'd always envisioned some tiny ball bearings in there rather than some discs. Decided it wasn't worth trying to find all the discs dropped in my messy work area to see if they are spaced out or jammed together while in normal use. After I bought a new bar of the preferred length, I noticed I had a good used one of course, meantime I'm experimenting with the shorter used bar I also had on hand just for grins.

[doc henderson]

nice.  I guess if you really want to know how they work, you can cut the new one apart!    8) 8) 8)      

[bluthum]

Wow, that oughta do it, I hadn't considered it. Thanks for the idea!

[doc henderson]

 :D :D :D