FILENAMES: Lineboring01.jpg Lineboring02.jpg Lineboring03.jpg DESCRIPTION: These are pictures of a line boring bar in use. Posted by Wayne Cook . The following description was provided: ================================================================= These pictures are of where I used a line boring bar to bore the boom of a track hoe. I used the same bar to bore the holes in the bucket. In Lineboring01 you can see a overall shot of the job. Starting at the left is the right angle air drill I used to power the bar. This drill is unusual in that it runs real slow for a drill this size. Even at that slow speed (about 200 rpm) I had some trouble with tool life. The drill is hooked to a universal joint and then the bar itself. The bar is simply a piece of 1 1/2" CR with some holes for lathe bits that are clamped with a setscrew. The original bar for this setup is much longer and has a lot of holes for the cutting tools but the holes are rather small and made for special HSS cutting bits. I had to make this bar to allow a larger carbide bit to be used due to the size of the hole being bored. As you can see I used a lot of C-clamps to hold the mounting flanges on. The box beam and lower angle iron where tack welded to the boom. The strange gearbox on the right is the feed for the bar. It is setup with gears so that the bar feeds at a much slower rate than the threads of the screw. There's also a quick release to allow pulling the bar out (it is released inthese shots). In Lineboring02 you can see the feed attachment better and the back side of the mounting flange. Notice the ball joint which the bearings mounting bar fits in. That is locked by turning the gear on the other side with the wrench provided (seen in #03). Just like a drill chuck. Even with the easy movement of the mounting flanges it can be a challenge to get the bar centered in the hole.