.404 on Husky 385

[jsikkema1]

let me explain...

The tie straps have nothing to do with it... The rivet and the drive link are what wear and cause the stretch. The side straps are 'rigidly' connected to the rivet so no motion or movement occurs at this junction. The rivet and the drive link are free to rotate and in a sense the bearing load of the chain is transmitted through the drive link to the rivet. Now on .050 and .058 chain the drive link thickness is .058 at the rivet (note that .050 chain still is .058 at the rivet). Well if you have a drive link thickness of .063 instead of .058 there is 63/58 or 8.6% greater bearing load surface so the chain will effectively stretch less due to this. Additionally, the drive sprocket life should also be greater due to the larger contact surface area of the drive link.

Just some thoughts...

 

[Qatanlison]

Isn't 0.050, 0.058 and 0.063 only the width of the drive link?
How do you figure the .050 and .058 are .058" at the rivets?
Are we using the same vocabulary? The rivets for me is the caps you pound or press on to the preset tie-straps. Where does the measure .058" on the rivets fit in?

/Ola - In pondering...

 

[Stumper]

You are correct Qantanlison. However the outer portion that serves for riveting the parts together is the same piece of metal tha constitutes the bearing for the drivelink holes to pivot on. I see Jeff's point about a wider bearing surface slowing wear at the pivot "post", but I have thought that much chain stretching is actually tiestrap elongation. I still believe that to be the case. The amount of pivot point wear I see on used chain doesn't seem to account for the lengths they are stretched.

 

[bwalker]

I cant comment on saw chain, but in industrial applications chain "stretch" as its called is almost always caused by the pin to plate interface wearing. I imagine this would be the same for saw chain also.

 

[Crofter]

The pivot point is the hub of the rivet and the body of the drive links. The point where the tie straps fasten to the rivet is immobile connection and no elongation or movement occurs at this point.

Frank

 

[jsikkema1]

details on the .050 and .058 question

See picture- all .050 chain is flattened to .050 from .058 stock and the drive link as shown in pic below is representative of all .050 chain. Note that the drive link in the center of the picture has a destintive line across it- that is the line that is created by this flatening process- so the drive link at the rivet is .058 on both .050 and .058 chain. The drive link in the top of the picture is a .058 and note no line. The presets that come either .050 or .058 chain is for both- no difference.

 

[jsikkema1]

chain stretch...

My point above has to do with chain stretch and that the stretch actually occurs due to rivet and drive link hole wear and not side strap stretch... I have taken chain apart that has seen heavy use and the holes in the drive links have shown quite a bit of elongation due to the relative movement between it and the rivet. The side straps don't stretch...

 

[Stumper]

Perhaps the straps don't stretch but.....I've taken apart chain that didn't show much slop at the pivot points but needed a link out. a few thousandths at each hole does add up but it didn't seem like enough to account for the total chain elongation. Maybe I just misguessed the number of thousands that wear was averaging. Of course, EVERYTHING expands with heat so the tiestraps do get longer albeit temporarily.:angel:

 

[Crofter]

Stumper: The wear at each rivet drivelink meeting place sure accumulates. 4 faces per drive link at say 5 thou each is 20 thou times 60 drive links is almost 1 and a quarter inches on a 16inch 3/8 chain. The same pin and bushin internal wear shows up in tracked dozers, fellerbunchers, excavators etc. There the pins and bushings are routinely pressed out and given a half turn and reassembled with the unworn surfaces that were on the slack side, now under tension. It restores the chain to new factory pitch.


Frank

 

[Qatanlison]

jsikkema1,

That's quite some trip you made up north in Sweden! Lucky you, I've only been halfway up; I live in the very south...

Thanks a bunch all the rest of you for making my choice easy, 3/8 seem to be the way to go...

/O

 

[Tony Snyder]

Crofter, where are you getting the four wear surfaces per drive link, I only count two?

 

[Crofter]

Tony: There are two rivet holes in each drive link so there is a wear surface at each hole and a wear surface at each rivet for a total of four surfaces that get worn per drive link.

Frank