I have a Silvey model 300 sharpener that I use for chisel, semi-chisel and chipper chain and it always seemed to work well until just recently. I seem to have one cutter being ground more than the other which is abviously causing me some trouble. I e-mailed Silvey and the gal said I needed to shim the chain bar. Before I screw everthing up, has anyone had a problem like this? Howd ya fix it?