I have a 20 inch sugihara bar for my 372 that I just can’t get to cut straight. The trouble started after a BL cutting session with too dull of a chain. By the time I caught myself muscling through the cuts the bottom of the bar had become discolored and the enamel was burning off. After many passes with my bar rail dresser, it is now flat and the gap is fairly consistent but it still pulls to the left when in any larger cut. I have ruled out the chain as the culprit because when I flip the bar my cuts are arrow straight. I’ve already determined that the lightweight bars are not for me and will be replacing with an OE 20 incher but am not quite ready to scrap this one. I’ve watched all the you tube videos on the subject but was hoping some helpful user here might have the solution.
Do you have another 20" bar to use for a test, with the same chain? If it cuts straight, then it's the bar. If it cuts crooked, then it's the chain.
If you or someone you know has a bench top sander of any kind, it could be used to make sure the rails are perfectly true. Like this: Lay it flat on the round disc sides table. What I would recommend is you try a brand new chain with the bar oriented with the “bad” side down to make absolute sure. It’s very easy to get a chain cutting crooked if you don’t use a progressive depth plate on the “rakers” or depth gauges. When you flip that bar, if that sides rails are off a little, it could offset the problematic chain.
I had a chain that cut straight. Then I filed it with one of those 12v powered files. I fudged thst thing up so bad cuts so crooked. learned to just tap the chain with it. Might be filed uneven
Make sure the chain gauge is proper . I have seen where someone mixed up a chain and was running either a .050 in a .058 groove or an .058 in a .063 groove (can't recall which one it actually was) but this didn't cut straight . Swapped to proper chain and straight as an arrow.
I would say its your rails, make sure the top edges aren’t flared/mushrooming then find a perpendicular belt sander, use some dykem or a black maker to mark the tops of your rails then lightly sand them. Its not a bad idea to check the angle of the dangle on the sanding table as well.
This is the one I have. Only used so far on one bar but it got things squared up. The pferd one is kinda pricy. There are others on Amazon.
I’ve used mine a few times and it’s done a great job. Amazon is just a glorified Harbor Freight when it comes to non name brand tools. Some of the broken English and BS on some of the descriptions is pretty comical though. A description on some batteries I bought recently for my night vision scope.
I was running 050 chain in that 22" Carlton bar not realizing it was 058 until it started cutting crooked. Bar got scrapped.
Actually somewhere in the shop. I think the groove inside got worn. Tried flipping bar and tried different chain and nothing worked. The bar came with a saw i bought so i dont think the former owner knew it either. I wasnt buying an 058 chain either.
Thx for replies everyone. So far I like the disc sander idea best because I get to buy a new tool. I have the hand tool mentioned above and have removed a fair bit of metal already. With the bar flipped this chain cuts like butter but a can see how uneven rails might bring out sharpening inconsistencies so will try a new loop to see if that helps. Starting to think the whole bar has a slight warp or twist to it but don’t have any surface flat enough to verify. At least not in the shop. Granite countertop might do.
