Agree with Tbombz & Bruce. Not always ideal for regular BB'ing exercises. More attention is usually focused on the grip rather than exercise performance. Exercise bars, being thinner, can be better adapted to most exercises. Need not be concerned about the grip when doing pushing exercises.
Thicker bars aid the grip greatly when doing partial DL's from a PR. With the pins set about mid thigh level. This way you can use much more weight than normal.If the grip slips, the bar will not drop down very far. Also try a thumbles grip at times. Loading up a pair of DB's can work the grip well. Holding along the sides, try curling up the fingers/grip.
Doing heavy weighted chins can really tax the gripping power. The focus would be using chins as a gripping movement only. Just hanging from a chinning bar, with a couple hundred pounds strapped on, for 15 to 30 seconds (static hold) is a outstanding movement.Or try short partial reps this way. Also might try one arm hanging chins, doing static or partial reps. These exercise can be done thumbles (false grip)
Gripping overhead wood rafters develops all around gripping strength, both one or two handed. Used the same way as the above chinning exercises. Lot more stress is put upon the thumb strength. Good Luck.