Ball Screws in Bridgeport mill?

Iggy,
If it were me, I would save the ballscrews until you run across some stepper or servo motors, and then install the screws and motors. The direction I would be heading is to have a machine that can run manually or CNC. In the past you showed an interest in writing scripts and cranking the handles like an etch-a-sketch to machine shapes. The CNC can save hours of setup time for getting different angles and radius' that you would need a rotary table for.
Since you're already comfortable with Linux, you could get up and running with EMC2 software
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for free. If you timed it correctly, you could take your controls to the annual EMC get together and get help if you had any trouble configuring it for what you want to do. Anyway, a couple of motors and ballscrews can replace a lot of tooling and setup time.
I bought a CNC lathe and couldn't get the controls running so I converted it to EMC2 control. I wrote a little program to turn and thread the end of a hydraulic cylinder rod. It turned down 1" dia stainless steel to 3/4" X 3" long and threaded 1-1/2" on the end for 3/4-16 UNF thread. This with a manual tool change took about 3 minutes without trying to push it or run the coolant pump yet. All those operations are easy to do on a manual lathe except the 3 minute cycle time. I also ran the Pawn chess piece example program included with EMC2 and has various radius' and angles. It also took about 3 minutes, that would have taken a lot of tool changes and compound settings to do on a manual lathe.
RogerN
Reply to
RogerN
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Roger, this is great and I looked at EMC2 closely, installed it etc. In the end I decided to keep the Bridgeport as a manual mill. The downside is just too great. That's as pertains to me personally. I admire people who convert manual machines to CNC, but in my very personal case, I think that the downside is greater than the upside.
i
Reply to
Ignoramus16228
There is a downside if you can no longer use it manually. My Bridgeport CNC mill has handles so I can flip a switch to turn the motors off and run it as a manual mill. I don't know the details of your ballscrew ends, but I was thinking of you installing a timing belt pulley and the handles for running manual control. That way, switch the motors off and you have a manual mill, switch the motors on and you have a CNC mill. In manual mode, motors off, the friction of the motors would help hold position so the table wouldn't backdrive so easily.
I'm guessing that the loss of manual mill control is what you are considering the downside. Other than that the downside is the cost of the motors, drives, interface, and a space for the computer to control the CNC part. Motors and drives can be found on eBay or old machines with bad controls. Anyway, you don't have to give up your manual machine to add CNC capabilities.
RogerN
Reply to
RogerN
If you look up Anilam on eBay and look at the knee mills, you can see they use handwheels that the handle folds in.
Also a small picture here.
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That's the way my Bridgeport is set up, I can use it as a manual mill just by flipping a switch that allows the spindle motor to run while the servo motors are off. This makes the downside very small.
RogerN
Reply to
RogerN
You CAN use ballscrews in a manual mill, although you need to lock and unlock the axes all the time, as the ballscrews offer no resistance to back driving.
Most likely, what these are for was other outfits bought manual mills and retrofitted them for CNC use. Centroid, Bandit, etc. did that. The BOSS CNC frames were only made available to maybe a few other machine builders on a limited basis.
The ballscrews have no backlash, and don't develop the pattern of wear in the center that happens with the steel screws on bronze Acme nuts, leading to inaccuracy.
Jon
Reply to
Jon Elson
My own main concern is that while doing the conversion, I will somehow break something and make the mill unusable, due to my inexperience. That's the downside that I have in mind. If I had more money, and more space, I would get myself a ProtoTrak or some such or even try a manual conversion on a spare mill. As it stands now, I cannot afford to be left without my mill.
Also, with the DRO, I can do the things I usually need to do. Right now, CNC is interesting, but not very necessary. So why risk losing what I have and need, for something that I do not really need.
Reply to
Ignoramus26369
Ok, I was wondering what this downside was. The only time you would loose manual use of your mill would be when installing the ballscrews. I've had similar concerns about changing my machine controls. My lathe control never worked since I owned it so I didn't have anything to loose in doing an EMC2 conversion. For the mill, I plan to use the same connectors as the existing control. That way if I have difficulty getting things going, I can just plug back into the original control and run until I get the bugs worked out.
I don't know your goals of your metalworking but I remember your milling from coordinates. I thought it would be nice to have the motors move to the coordinates for you. It's something to keep in mind in case you have more of a need for it someday.
RogerN
Reply to
RogerN
If you have servos or steppers and a control, , you can easily use Jog to move the slide around, if you have ball screws when doing one off cutting.
Its not rocket science
Gunner
"They couldn't hit an elephant at this dist..." Maj. Gen. John Sedgewick, killed by a sniper in 1864 at the battle of Spotsylvania
Reply to
Gunner Asch
Iggy, I found this example of a model engine flywheel that was machined on a hobby CNC mill.
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Just think how many operations and tooling such a part would take on a manual machine.
RogerN
Reply to
RogerN
I agree. On the other hand, it would be a lot easier to do on a manual machine -- an evening's project -- if the spokes were straight.
Reply to
Ignoramus25152
Casting would be the ticket. Make a wood one and then cast Al. Clean up as shown. Martin
Ignoramus25152 wrote:
Reply to
Martin H. Eastburn

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