Dressing bars
Hi Chad, First I want to explain the reasons why this should be done & I believe should be on all bars, not just carving bars. When you first start running a new bar of any make you get the black grinding swarf spitting off of the bar tip, the chains quite often run a little rough with resistance immediately which I used to chalk up to a break in period. After learning about carving bars & how to create a minimal resistance path for the chain to run upon I started studying new bars, both sprocket tip & carving bars to see what quality of finish the rails actually came from the factory with & found some major mechanical flaws in all of them no matter who the manufacturer was & most of the defects could be dressed out rather quickly leaving only the initial break in of the chain in relation to the bar rather than the bar causing the resistance initially with defects in the path of travel of the chain. Some of the defects I have seen are from just a general rough textured surface on the rails to actual notches in them that the manufacturing process has totally missed.
To dress the rails with just a rough surface, I use a Red Indian stone which is about 800 grit with a thin lubricant such as WD-40 or any thin lube which can be sprayed on the stone to keep it clean. If the damage is more severe I have a low speed (200 RPM) vertical belt sander which has a table which is set square to the belt & run the rails across this to true them up but still removing minimal material & then follow with dressing with the Indian stone. All rail edges should be either radiused or beveled very lightly to allow the "burr" that builds up normally to "shed" itself off of the edges of the rails. You must pay as much attention to the inside of the rails as you do the outside also & study the path which the chain travels such as the "lead in" where the chain comes off of the drive sprocket & enters into the rails. Sugi Hara has always created a great "lead in" whereas the heal of the bar has a tapered opening design on the rails & also if viewed from the side, instead of an almost square, they radius this surface also. These are all areas where the chain will impact causing damage to the lower sides of the tie straps & also possibly the drivers themselves, which in no time at all will damage the bar prematurely.
I hope this helps & if a person studies the path of the chain on any bar & limits the resistance by dressing & creating the "path of least resistance" their bars/chains will operate much cooler & last longer?
Thanks, Robbin
