Bridgeport as a lathe

[ka67_72]

For those of you trying to decide between a mill and a lathe, here's how to have your cake and eat it too. At least until you need a steady rest. I mostly use my little 4" R8 chuck for drilling but you can turn with it too.

Kevin

[studemax]

Never done it myself, but I've seen it done.... and I was nervous as can be for the guy doing it.

[squirrel]

You can also use a lathe as a mill, South Bend made an attachment.

[ka67_72]

I really would like to have a Swiss type lathe. They can do everything.

Kevin

[DanStokes]

When we got our CNC Bridgeport at work our machinist used the rotary table to do a LOT of what he used to do on the lathe. It was something to see the Bridgeport making perfect circles with the handles spinning themselves this way and that. But that machine was PRICEY!

Dan

[studemax]

Anyone here ever operated a die mill? (aka rotary head mill)

Imagine a 3-axis Bridgeport-type mill with the head on a rotary table. That's how many tools and parts were made before CNC. I used to run one in the tool shop at Beechcraft many years ago. Even though it worked perfectly, they sold it for scrap and bought a Bridgeport with digital readouts. Of course, the Bridgeport had fewer capabilities.

Here's a rather bad video of a die mill being demonstrated. Note that the milling head can be driven in a circle. You crank it in and out to set the radius of the circular cut. It also has X and Y, with Z functions in the head (you can bore with it, drill or mill), and the knee is power operated in Z. VERY versatile machine.

https://www.youtube.com/watch?v=9CwQx0RYJ7A

[Loren]

Pretty neat video, never seen one. Nice to be able to do arcs without screwing w/ part position on the table, as w/ a rotary table.

[DanStokes]

Never seen one either. Nice tool - yet I could see me confusing myself for weeks.

Dan

[studemax]

Did not take me long to figure it out. You just really had to plan your job out beforehand (just like if you were writing a program for CNC). Made some really cool bearing plates with it for a welding jig, and some neat assembly line tools.

[ImpalaSam]

We did that at one place I worked on a CNC mill, put the stock in a collet however. With two vises you can use 4 lathe tools.
Programming is a little tricky and you don't have the constant surface speed option that is available on a turning center.

[ka67_72]

We did that at one place I worked on a CNC mill, put the stock in a collet however. With two vises you can use 4 lathe tools.
Programming is a little tricky and you don't have the constant surface speed option that is available on a turning center.

I was thinking about doing this in my machining center to make a shaped tool for some finish passes. I haven't got up the nerve to try it yet. I can't really afford to fix it if I break something.

Kevin

[ImpalaSam]

I was thinking about doing this in my machining center to make a shaped tool for some finish passes. I haven't got up the nerve to try it yet. I can't really afford to fix it if I break something.

Kevin

Just go slow. Run the program 2 or 3 inches high to prove it out.

[ka67_72]

I am way cautious with new code. I'm currently using Sprutcam 8 but I've had some bad experiences with the free CAM programs I was trying to use before. I usually run without a tool, then I cut the part from foamular, then in metal.

Kevin

[ImpalaSam]

I personally would not even try to use a CAM system to program something like that. I would just manually write a G-code
program. Remember this is only going to be a 2-axis program. Use work offsets for each individual tool so that the spindle
C/L is on center with the tool, just like a lathe, probably will be the "Y" axis. The program will only be in "Z" and "X", just remember
you will not be programming in diameter like a lathe, and the RPM will need to be changed manually to match the diameter
that is being cut.

[ka67_72]

I personally would not even try to use a CAM system to program something like that. I would just manually write a G-code
program. Remember this is only going to be a 2-axis program. Use work offsets for each individual tool so that the spindle
C/L is on center with the tool, just like a lathe, probably will be the "Y" axis. The program will only be in "Z" and "X", just remember
you will not be programming in diameter like a lathe, and the RPM will need to be changed manually to match the diameter
that is being cut.

That makes perfect sense. I do CAD design regularly at my day job, but have no machining experience other than what I've learned in my own in the garage. All our parts get sent out for machining. They let me keep some of the sheet metal work in house. The part I've been working on at home is 3+2 and 40,000-ish lines of code. I hope to figure out the simultaneous programming soon and make finishing easier. I just got stuck in the CAD/CAM mindset.

Thanks,
Kevin