Crofter
Addicted to ArboristSite
Here is a few pictures of a method of quick checking your bar rails for out of square. I use a welding rod here, but a chain file works dandy. Simply place it between chain and bar and tuck a chip or so on opposite side of bar to hold chain tight. Sight from end of bar and it will be obvious if one rail is higher than the other as the rod gives an extended dimension to the rails.
In the first picture I place a single thickness of paper on one rail to show what three thou out of square woould look like. The next two are checking top and bottom of bar.
In the first picture I place a single thickness of paper on one rail to show what three thou out of square woould look like. The next two are checking top and bottom of bar.