Bar rail wear/gap.. what's acceptable??

[SawGarage]

Did a search, with no luck



I got a few bars here, some are USED and some have 95% of the paint left...

what is FACTORY rail gap, and what is acceptable bar wear?

I have a LIGHTLY used .058" bar that shows about .070" gap... seems like a lot, as I measured a NEW .058" bar, and it measured JUST about .061" or so... (not sure if there was paint in there??


SO.... what is acceptable, and what should be trued?? (It might be time to invest in a rail true-er... the hammer and .056" ga. stainless metal inserted in the bar method didn't seem so perfect on the bar i tried it on


Thoughts welcomed...

J

 

[minnnt]

This happened to my first and second bars on my 346. Not sure what the gap was, might measure it and check. There is quite a bit of movement on the chain with this bar, which basically makes it unuseable Not sure what is acceptable, if you're running 1.5mm chain then why not try 1.6? Might make the bar a bit more useable for a bit longer.

BTW, what makes them do this?

 

[steven1955]

Boy I'm glad you posted this question. I was going to because I too failed at searching and finding an answer.

I have a Homelite SLXA, just given to me and just overhauled, that came with a hard nosed 0.050" bar. The gap is 0.059" to 0.061" top and bottom, and 0.054" to 0.056" on the nose. I thought this was pretty bad, but of course I didn't measure it until after I tried sawing a few cookies. They were more like waffle potato chips.

By the way, the chain drive links were 0.049" to 0.050", and the chain was just sharpened.

I was going to replace the bar, but wanted to know what the new gap should be both and how wide the gap can be before the bar needs servicing or replacement.

 

[Trigger-Time]

How they wear so fast IMO, is not enough oil, low quality oil, low quality bar steel, or bar isn't tempered correctly.

Or cutting in the dirt or any thing else abrasive.



TT

 

[pioneerguy600]

We have always used a bar up as much as possible, as the groove wore wider we moved up in gauge of the chain until even .063 became too sloppy, then closed the rails for a little more running, this was back when we ran slower turning saws. With the higher speed saws it seems we needed tighter chain control on sprocket tipped bars but we still start out with a lot more .050 bars and chase them up through .058 and then .063 gauge chain paying more attention to the chain drive link clearance than previously. If my chains have .010 starting out then I would run that bar and chain until the cutters showed excessive sideways rocking, then move up to the next wider gauge.

Pioneerguy600

 

[minnnt]

We have always used a bar up as much as possible, as the groove wore wider we moved up in gauge of the chain until even .063 became too sloppy, then closed the rails for a little more running, this was back when we ran slower turning saws. With the higher speed saws it seems we needed tighter chain control on sprocket tipped bars but we still start out with a lot more .050 bars and chase them up through .058 and then .063 gauge chain paying more attention to the chain drive link clearance than previously. If my chains have .010 starting out then I would run that bar and chain until the cutters showed excessive sideways rocking, then move up to the next wider gauge.

Pioneerguy600

good cost effective useage!!!

 

[LAndrews]

I think it depends a lot on what you're trying to do. For simple cutting of small trees, it doesn't matter that much if the chain can move around. For long cuts and especially milling, controlling the chain is critical to getting straight cuts without a lot of chatter.

My 395 originally came with a really tired .063 bar/chain. Cuts wanted to twist and there was about 3/8"/10mm of wave to the cut. Was pretty ridiculous. New bar/chain straightened up the cuts and the surface was surprisingly smooth.

my 2c.

 

[ray benson]

Out of an Intertec Chainsaw Service Manual.

 

[spudulike]

Out of an Intertec Chainsaw Service Manual.

Spot on - belt it with a hammer along the edge, just don't wallop it too hard or it will pinch the chain.

This will get a lot more wear out of the bar and will ensure straight cutting and no chain roll!!

Spud

 

[steven1955]

Does it make any difference if the gap between the bar rails is too wide due to wear as opposed to the rails being spread?

From memory my old Homelite bar appears to be worn instead of spread, but I'll need to double check.

Now to find something I can use as a 0.054 shim. I've got the anvil and ball pein hammers.

 

[retired redneck]

I use a bar rail closer, sold by baileys.....

 

[Sagetown]

SawGarage; I had the same question. Found a saw manual that recommended the Bar should be changed after every Second Chain replacement. Wow ! Have I been cheating or what ? :chainsawguy:

 

[heimannm]

Retired is right, the bar rail closer from Bailey's is not too expensive and works pretty well once you catch on to using it.

Check often as you go along though, or you will need a "bar rail spreader" as well.

I will first dress the rails on a disc sander to insure they are square and even, then close them if needed with the bar rail closer. I have yet to find a single bar that has worn to the point the drive links don't have enough clearance but you do need to check to make sure.

Mark

 

[SawGarage]

I use a bar rail closer, sold by baileys.....

This is what I was thinking...seems to make the most sense...the rails DO NOT LOOK spread apart...just that they have MORE TOLERANCE than I would have expected...


seems the rail closer makes the most sense...

RR- how does it work?? set the gauge AND roll it down???


thanks!

J

 

[heimannm]

There are two bearings that run against the rails, and a screw type adjustment to close them. No real dialing it it, little adjusment, pull it over the bar a time or two, check the chain fit, then repeat as needed.

Mark

 

[svk]

Does anyone have a chart showing the factory dimensions of distance between rails for the various chain gauges? Or even just the numbers? IIRC it is about 2-4 thousandths over the stated driver width.

 

[svk]

Just to follow up on this. I was given a used but clean bar that was originally .058. Consistently measures .065 though the rails with a feeler gauge. Just throw a .063 chain on it and call it good?

 

[heimannm]

Once a groove has a lot of wear, it will be difficult to every make it really right again. That said, most of the work at keeping the chain flat as it goes around is accomplished buy the rails, most but not all. I found I had trouble making a straight cut when I accidentally put an 0.050" gauge chain on an 0.058" bar. Closing the bar rails will help some but can't take all of the wobble out.

Mark

 

[Deleted member 149229]

From a machinist view point, if the gap is wore and you’re trying to narrow it then you will still have a problem because the methods available will will only work towards the top of the groove. Both sides of the groove (keyway) must be parallel to be effective. If you push the sides toward each other it will be tapered in the groove, once the top wears you will be back to original problem.

 

[pioneerguy600]

Does anyone have a chart showing the factory dimensions of distance between rails for the various chain gauges? Or even just the numbers? IIRC it is about 2-4 thousandths over the stated driver width.

2-4 is fine, I have never closed a bar rail but we always bought .050 gauge new and when they wore we would re broach them up to the next size gauge, these were older solid bars not the wimpy laminated bars they sell today.