Brent H
Ultra Member
Well this tapered gib for the compound was quite the project. Cast iron is a hard material. When you have a cutter that is a bit out of round - well it is harder to cut. Couple that with a sudden horrible back gear sound and things can get exciting! So after finding out my 30° end mill was out 0.0015” but being without options I slowed my feed and shifted to a slower mill speed. Then came the grinding sound that was not the bit cutting a hair out of round - it was the Bridgeport back gears growling away.
With everything set up and measurements on the money I proceeded to tear the head off the mill to access the back gears and see what was amiss. I found that the gears were not engaging fully with the main drive gear and also there was a need for more grease. After packing a half tube of grease Into the head I had one of my boys hold the main gear in position and set the lever up on the side. Then reassembled and started milling again in a much quieter environment.
I milled the blank to thickness and then used a 60° cutter setup (sort of a hodgepodge or cutter and holder) to cut the angle on the straight side of the gib.
once that side was done I set up with my jig for cutting the taper and just about screwed the whole thing up! I set the compound up and used it to turn my vice to the angle required for the gib. I used a test indicator to dial it in to 0.0000”. Total excitement and then it dawned on me that it would cut my angle opposite to what I needed - crap, what to do......my vice has the swivel base still on it so I set a dial indicator up at zero on one edge of the vice. I then moved the table over to the other side of the vice and swivelled the vice until my indicator came back to zero - sweet! I did a few other checks and things looked good!
roughed in the angle with a roughing mill and then cut the 30° bevel with my out of round cutter.
After milling I had several hours of scrapping and lapping and some grinding
Yep- the front of my compound is some chowdered up still, even after welding repairs - BUT!!!!!! The dang thing runs butter smooth now without end play !!! Yeh me!!! And my mill back gears are all set properly as well !!
With everything set up and measurements on the money I proceeded to tear the head off the mill to access the back gears and see what was amiss. I found that the gears were not engaging fully with the main drive gear and also there was a need for more grease. After packing a half tube of grease Into the head I had one of my boys hold the main gear in position and set the lever up on the side. Then reassembled and started milling again in a much quieter environment.
I milled the blank to thickness and then used a 60° cutter setup (sort of a hodgepodge or cutter and holder) to cut the angle on the straight side of the gib.
once that side was done I set up with my jig for cutting the taper and just about screwed the whole thing up! I set the compound up and used it to turn my vice to the angle required for the gib. I used a test indicator to dial it in to 0.0000”. Total excitement and then it dawned on me that it would cut my angle opposite to what I needed - crap, what to do......my vice has the swivel base still on it so I set a dial indicator up at zero on one edge of the vice. I then moved the table over to the other side of the vice and swivelled the vice until my indicator came back to zero - sweet! I did a few other checks and things looked good!
roughed in the angle with a roughing mill and then cut the 30° bevel with my out of round cutter.
After milling I had several hours of scrapping and lapping and some grinding
Yep- the front of my compound is some chowdered up still, even after welding repairs - BUT!!!!!! The dang thing runs butter smooth now without end play !!! Yeh me!!! And my mill back gears are all set properly as well !!