Bent bar? Crooked cuts

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August76

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Im pretty sure this bar is bent . I swapped chains and still making curved cuts in 16 inch wet ponderosa pine.
I havent had this issue before.20181112_155022.jpg
 
Is the new chain a brand new chain ? How tight is the chain ? Are you using the dawgs and forcing it threw ?


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I was using this saw and the dolmar. Both use same chain. I was making straight cuts with dolmar . I figured the chain was just sharpened un evenly. But after switching only the dolmar cut straight. I seem to recall this bar cutting funny on my dcs6421. Its off that saw.
 
It should be easy enough to tell if the bar is bent . When I see a saw do this it’s because the chain is loose,dull, and I was using the dawgs to “force” it threw


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Remove the bar, give it a wipe with a shop towel and put it on a perfectly flat surface. You will see right away if it's bent.
At least that's what I do, albeit in all these years I've found a single not obviously bent bar and it was on one of those black Echo bars so it was probably a case of the eye being fooled by a different color...

But more often than not crooked cuts are due to some problem with the chain itself.
 
Remove the bar, give it a wipe with a shop towel and put it on a perfectly flat surface. You will see right away if it's bent.
At least that's what I do, albeit in all these years I've found a single not obviously bent bar and it was on one of those black Echo bars so it was probably a case of the eye being fooled by a different color...

But more often than not crooked cuts are due to some problem with the chain itself.

This is not advice, so absolutely no help at all. BUT, when my saw/saws cut all goofy it's usually a barley soda overload, combined with a loose nut located behind the operator presence safety lever. Just saying
 
You’ve pretty much proven it’s not the chain.
Give that bar a good dressing with a flat file to square it up and also remove any burrs along the edges.
Don’t go crazy, just dress it.
If the bar’s not bent, this might very well be your issue.
You should also turn your bar over occasionally. It’ll wear more evenly.
 
As others have said, it is not your chain, and it is quite unlikely that your bar is bent. But it IS your bar - the grooves are worn. Several possibilities - the top edges are worn unevenly, the internal edges are notched or worn into an hourglass shape, or just the top inside edges are worn into a V shape.

The first and easiest test is to simply try and rock the chain side-to-side on the top and bottom of the bar - you should not get much movement at all (compare it to the saw that cuts straight). If the chain flops around, you either need to dress the bar to fix it, or just replace the bar if you do not want to mess with it.

And remember to WEAR GLOVES! A worn bar can slice you to pieces real quick.
 
It should be easy enough to tell if the bar is bent . When I see a saw do this it’s because the chain is loose,dull, and I was using the dawgs to “force” it threw


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The bar came with my dcs6421 former home depot rental saw.
As others have said, it is not your chain, and it is quite unlikely that your bar is bent. But it IS your bar - the grooves are worn. Several possibilities - the top edges are worn unevenly, the internal edges are notched or worn into an hourglass shape, or just the top inside edges are worn into a V shape.

The first and easiest test is to simply try and rock the chain side-to-side on the top and bottom of the bar - you should not get much movement at all (compare it to the saw that cuts straight). If the chain flops around, you either need to dress the bar to fix it, or just replace the bar if you do not want to mess with it.

And remember to WEAR GLOVES! A worn bar can slice you to pieces real quick.
Thanks ill check . You aren't kidding about the bar being able to slice the crap out of you. I got cut before.
 
I probably should find another bar for the saw I didn't like the 28 inch bar on it which is now on a difference off but I like a 20 inch bar over a 28 so I guess I should look into where to get a cheap affordable decent bar I don't need nothing special and I can dress this one and fix it if it's not bent it's of course a black bar so it could be hard to see anything but doesn't look real old but being a rental it's been abused
 
Greeting August. As ThackMan and others have said it is likely that your blade needs dressing. That means the rails are uneven so the chain is leaned to one side. I would recommend fixing this by taking the blade to a saw shop that has a Bar Shop or a bar rail grinder and having the blade ground true. This should cost anywhere from free to $15.00 or so.

For the future buy yourself a hand held bar rail dresser (a short file held in a hand sized jig) and dress the blade every time you take it off the saw. The best way is to clamp the blade in a vice but even a few stroke while you hold the blade will help if done often enough. You could also buy a bar rail grinder and mount it in your shop or on a plank that can be clamped to a bench top. Like most actions your first results may not yield much success but after 6 months you'll be a pro.

If your chain is sharpened unevenly, or the rakers are not at the same height from side to side, or the chain is simply sharper on one side this will cause the cut to sweep. It also starts uneven groove wear again. Another cause can be too much pressure on the cut from a dull chain or being forced to curve due to pivoting on a single bucking spike.

It is my opinion that some cheap blades wear much faster the others. I think Cannon makes the best blades followed the Stihl. Stihl blades are very reasonably priced too. (They are about the only reasonably priced thing Stihl makes). Old Oregon blades have very hard rails and are a great find if you're lucky. Newer Oregons… not so much but many loggers love them.

If all else fails send the saw to me and I'll send you a gift card to Home Depot and you can buy a new saw.
 
Greeting August. As ThackMan and others have said it is likely that your blade needs dressing. That means the rails are uneven so the chain is leaned to one side. I would recommend fixing this by taking the blade to a saw shop that has a Bar Shop or a bar rail grinder and having the blade ground true. This should cost anywhere from free to $15.00 or so.

For the future buy yourself a hand held bar rail dresser (a short file held in a hand sized jig) and dress the blade every time you take it off the saw. The best way is to clamp the blade in a vice but even a few stroke while you hold the blade will help if done often enough. You could also buy a bar rail grinder and mount it in your shop or on a plank that can be clamped to a bench top. Like most actions your first results may not yield much success but after 6 months you'll be a pro.

If your chain is sharpened unevenly, or the rakers are not at the same height from side to side, or the chain is simply sharper on one side this will cause the cut to sweep. It also starts uneven groove wear again. Another cause can be too much pressure on the cut from a dull chain or being forced to curve due to pivoting on a single bucking spike.

It is my opinion that some cheap blades wear much faster the others. I think Cannon makes the best blades followed the Stihl. Stihl blades are very reasonably priced too. (They are about the only reasonably priced thing Stihl makes). Old Oregon blades have very hard rails and are a great find if you're lucky. Newer Oregons… not so much but many loggers love them.

If all else fails send the saw to me and I'll send you a gift card to Home Depot and you can buy a new saw.
The bar is off of the saw that came from Home Depot Home Depot doesn't sell 372xp haha it's definitely the bar because I switched the chain and put it on the other saw that was cutting straight and it continued to cut straight and the chain from the other saw on this one cut crooked I just need to dress out the bar and make sure everything's good and I do need to find another bar so that I can take the 28 inch bar off of the other saw I don't ever need a bar that big I've got two saws that use the same bar but only one bar
 
The first thing that comes to mind for many when a b/c cuts crooked is a bent bar. Its almost always not the case. Looking closely with your eyes will solve the mystery.
It appears because of the way the tree was growing it caused the saw to veer one way or another. sort of like internal knot . but it does have a tendency to cut a little funky today I took out different saws and they all did well
 
Of course I cut myself while trying to get all the goofy burrs off this bar it does appear to be slightly bowed when laid on a flat surface there is a part number on this bar and it says 35020mk72TR I don't know what that correlates to just some goofy crap that Home Depot orders up on the cheap?
 
Well it was doing ok. Till i came to some knotts. Its like it tries to turn a corner.
I guess the bar is just worn bad
 
You never commented on how much wear you found on the bar, particularly if there is any side-to-side flop with the chain. If you had significant burs on the edges, it is quite likely that your bar groves are worn or spread too. That can be fixed too, but it is somewhat more complicated than just dressing the rails. Regular bar dressing will prevent this problem by lowering the edges a little each time, and that removes the most worn inner part too, but if you have a lot of flop now, you have to grind a lot off to get back down to straight groove walls. If the inside of the groove is notched on either side instead of just spread in a V shape, you do not have any choice - you MUST grind off enough of the rails to get down to the bottom of the notch.

There is a special tool that uses rollers to squeeze the rails back together, but I do not have that. I have learned how to repair that type of wear with a hammer and vice - it is not hard, but it does take a while, and you have to have some finesse; if you just start wailing on the bar with a hammer you will ruin it real fast!. I have also heard of some folks putting on a thicker gauge chain to use with a worn bar instead of trying to repair the groove shape.
 
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