Here’s the short story: I have a Bridgeport knee mill that I converted to CNC a few years ago. I’ve since acknowledged to myself that everyone who said that knee mills are bad CNCs were right, and I set out to find a better option.
Long and short, I found a siber hegner RB1 for cheap, and bought it.
The situation is this:
1. I’m a hobby guy, holding .001 is definitely good enough. I don’t need to make perfect parts and I know when to hire pros.
2. I don’t expect this to be my be all end all machine, but it is a step in the right direction. It doesn’t have to be the last thing I ever do.
3. I want to do a good job, but I don’t want to be ridiculous. It’s a used bed mill with dovetail ways. I don’t need 400IPM rapids 24/7.
So, here is my conundrum. The mill I bought was in an auto shop where it was used as a drill press with a fancy table. The head was dead. I guess the vari speed bushings died and then they ran the motor with the rattle until the motor shaft has .375” of wear on one side. Yes, you read right.
The ways are scratched - mostly the upward facing ways on the bed.
The upward facing ways are hardened. The column ways are hardened, and the top of the saddle is hardened.
The gibs were never scraped and the dovetails were never scraped.
I tore the whole mill apart, and soda blasted all the parts clean of goo, schmoo, and crust. I then inspected.
Essentially, the ways on the vertical y axis and the column ways have hardened surfaces that are badly scratched. Other than that, everything seems flat to +/- .0015. Before tear down, things moved freely and nicely.
I took the saddle off, stoned the surfaces that mate with the scratched bed ways and then scraped it in. I’m going to have a local shop dust the top of the saddle to ensure it is cleaned up nicely.
Here’s the questions
1. Should I worry about about scraping the ways on the table? They were ground and are in great shape, but have no oil grooves, scraping, or flaking.
2. How should I treat the scratches in the y ways on the bed? A carbide scraper won’t bite, and my precision stones are going to be inadequate to just buff high spots.
Long and short, I found a siber hegner RB1 for cheap, and bought it.
The situation is this:
1. I’m a hobby guy, holding .001 is definitely good enough. I don’t need to make perfect parts and I know when to hire pros.
2. I don’t expect this to be my be all end all machine, but it is a step in the right direction. It doesn’t have to be the last thing I ever do.
3. I want to do a good job, but I don’t want to be ridiculous. It’s a used bed mill with dovetail ways. I don’t need 400IPM rapids 24/7.
So, here is my conundrum. The mill I bought was in an auto shop where it was used as a drill press with a fancy table. The head was dead. I guess the vari speed bushings died and then they ran the motor with the rattle until the motor shaft has .375” of wear on one side. Yes, you read right.
The ways are scratched - mostly the upward facing ways on the bed.
The upward facing ways are hardened. The column ways are hardened, and the top of the saddle is hardened.
The gibs were never scraped and the dovetails were never scraped.
I tore the whole mill apart, and soda blasted all the parts clean of goo, schmoo, and crust. I then inspected.
Essentially, the ways on the vertical y axis and the column ways have hardened surfaces that are badly scratched. Other than that, everything seems flat to +/- .0015. Before tear down, things moved freely and nicely.
I took the saddle off, stoned the surfaces that mate with the scratched bed ways and then scraped it in. I’m going to have a local shop dust the top of the saddle to ensure it is cleaned up nicely.
Here’s the questions
1. Should I worry about about scraping the ways on the table? They were ground and are in great shape, but have no oil grooves, scraping, or flaking.
2. How should I treat the scratches in the y ways on the bed? A carbide scraper won’t bite, and my precision stones are going to be inadequate to just buff high spots.