Another "Bar Type Question"

[HUSKYMAN]

It's funny John, that is exactly the way I imagined tundraotto to look like

 

[chainsawworld]

Originally posted by Gypo Logger
Hi there, this isnt a universal statement or an attempt to hurt the feelings of my Southern brothers/ or sisters, but any U.S. bars I have used were not as tough as Canadian bars, ie, Oregon, or Winsor. The bar groove seemed to wear at an alarming rate, however I havent used a U.S. bar for some time now.
Tip explosion is usually a user related problem steming from bar groove wear and using the tip too much which compounds the problem by the kickback that results.
John

if tip exlposion is user related, how come the rest or the bar compinies have no problem here? stihl,GB,homelite,partner,echo,jonsered,etc. the same guys that run the huskys run the rest.
maybe husky saw bars can not handle the open face,bore cutting tecnique that their man(soren erikson) came up with.
protect yourselves; marty

 

[dozerdan]

Hi Marty
I have one customer that bores almost everything.The mans good at what he does and they give him the nicest timber to cut.If he runs the Husky/Oregon the tips last him a total 2 month.I talked him into trying one of the GB bars with the sprocket tip.He never made it past 3 weeks with one,some were less then a week.GB was really good about it and would send me replacement tips,but it was still a pain.Down time is money lost.
Later

 

[Walt Galer]

Howdy,

The wearing out of guidebar grooves is usually related to the width of the groove gauge on the guidebar as new. If the groove is sloppy on the chain after the paint is worn out, the life will be short. This is true with a vengence on longer bars, where the laying over of the chain causes the bar to hang in the cut when trying to fall a tree.

The wear rate is always faster in a loose fit. If you couple this with filing of the chain that causes it to persistantly lead one way, the bar life for a professional faller with a 30 inch bar can be as little as two weeks! (I documented this at Franklin River camp on Vancouver Island with 36 fallers).

As far as alloy differences are conscerned, it is fairly standard for professional bars to be made on an alloy of 5150 or 5160. Laminated bars are usually made for the consumer market on high carbon alloys, usually 1075. There is such a thing as professional laminated bars, such as by Sandvick in Sweden, and they are on a slightly improved alloy with Vanadium and Silicon added. These are a special design to resist cold weather useage. Even they have never proven successful in lengths over 18 inches, due to the fact that any laminated bar tends to open up that groove width due to stretch and fatigue of the spotwelds or projection welds, and this then gets into the groove width problem previously described.

Nose starwheel breakage is usually a function of the starwheel design. The big secret is the coined tooth tip. If the tip of the tooth is relieved to the side (like a bicycle sprocket) the chain can derail with minimum twisting of the sprocket, and hence greatly reduced forces on the starwheel. It may not break at the time of the derailment, but will be seriously weakened and fail later. Field tests have demonstrated that a simple martempered starwheel with this relief, will out-last even an Austempered and shotpeened starwheel without! Ok, the secret is out.

The problem with all this is the "Quality costs money" problem. It is expensive to do it right and it requires knowledge of what is required. Different markets do have somewhat different requirements, as I have alluded to above.

Regards,
Walt Galer

 

[Gary N Carter]

Hey Fellas, Do you guys know something I don't! So far I have not had a problem with any of my Husky bars! I have a couple GB bars on my small saws, also with no problem. I mostly have higher rpm XP saws and now I am curious! I do grease the sprocket bearing with regularity. Someone tell me more about the complaint with Husky nose sprockets/bearings.

 

[Walt Galer]

Howdy,

Lubrication is the likely cause of bearing failure. Most folks do not grease these days, and then use as sticky of goop as they can find for chain oil. The "sticky" keeps it from getting down into the bearings and most of the oil present is carried away with the chips.

Highspeed, together with this lubrication problem accounts for guarantee'd trouble. Either you have to use a good lubricating oil of reasonable viscosity, or you have to grease. This is especially true if you do a lot of cutting with the nose, which greatly increases the load on the bearings. They will stand it nicely if proper lubrication is provided.

Another cause of "nose trouble" is an operating techigue that habitually sets trees on the nose, such as reaching through the hinge of a falling tree, or other nose pinching scenario. I've seen many cases where the broken nose pieces are burned with blue streaks, and the operator asking "What happened"? "I was just cutting, and bang! She blew up". (Frictionally formed transformations make micro cracks, that later propogate into major cracks and then failure, which why it blows up later in some innocent cut).

Regards,
Walt Galer

 

[Gypo Logger]

Hi there, tip failure can also be compounded by not flipping the bar regularly. I bet if you looked at most of the failed tip you would see a wire edge on one side of the tip, indicatating that the operator didnt flip or dress and used the tip too much.
Since 3/8 tips are made to accomadate up to 1.6mm chains, using a 1.3 mm chain will cause the tip to spread earlier since side deflection in that area adds stress. Couple all these factors with a worn bar, sprocket and dull chain and inadequate lubrication and its not hard to see how problems can result.
Your best assurance for happy, effortless and productive cutting is to religiously maintain bar, chain and sprocket. Forcing a cut with dull chain is absolutely sacreligious and seperates the men from the boys.
My favourite tool for bar dressing is a palm sander that evenly removes any real or imagined burr or wire edge. Not doing this just causes premature wear and bar rail chipping.
Taking the time to be fussy about these things is not a waste of time and you will outcut most bushworkers if you do.
John

 

[Walt Galer]

Howdy John,
You bring up a point about which the manufacturers of guidebars have complete disagreement, namely the groove gauge of the sprocketnose bar nose assembly itself. Have you noticed:

Oregon has individual gauged nose assemblies for Power Match. The nose sideplates are longest. They claim "to take the punishment and accidents and be replaced".

Stihl puts a little plate on each side of the nose inner race and bearings (supposed to hold lube in and dirt out, they claim). On some of their pro bars, they tried relieving the inside of the sideplate to recieve a longer bearing and labryth seal the race from dirt (and oil).

Windsor has always had all nose assemblies .063 gauge and claimed this to be an advantge. Lubricaton gets in easier, more resistant to pinching damage, dirt can get OUT. The area of the assembly that actually functions as rail under the chain is as short as possible to minimize the wide gauge situation. The transition zone under the rail hardness is carefully designed to allow the rail hardness to have a shock absorber under it and therebye help prevent rail chipping. (Too little of the transition zone, and the rail is too solid. Kind of like hammering on glass. Too much and the rail is prone to cracking up due to too much movement).

Many manufacturers have tried through hardening the sideplates, but this has always ended in a rail chipping disaster. (It seems like every engineer who comes down the road, suggests this one!)

Myself, I have always found the Windsor design to be the most successfull.

Regards,
Walt Galer