Need Help!- Bridgeport CNC Series 1 BOSS 4 (5?) Retrofit

[mbshopman]

I ended up with a 1979 Bridgeport Series 1 CNC rigid ram in very good mechanical condition that I am looking to retrofit with new controls. I have a lot of experience with small scale machines like sherline to large bench or even specialty machines for robotic control, pick and place, etc. I've done scratch builds of smaller scale CNCs of many types, shapes and sizes but nothing on a BP size.

I would like to get this going to be operated by EMC on linux which I am familiar with and is suitable for the types of projects that this will be used for. I happened to have 3 phase power available where the machine is to be located and the machine is mostly wired for that already (though I want to gut the current electronics cabinet). I don't care about a standalone DRO and I am happy with a dedicated system/screen running EMC.

I've been a longtime lurker and I did a lot of googling but could not find the information I needed, if there is such a thread please feel free to point me there.

I have 3 ametek 99vdc motors that were looking for a project and I think this is the right one. They need encoders though, I was intending to use the E5-500-250-N-S-E-G-2 from US Digital. I was debating either the gecko 320X or is there something else I should be looking at?

My experience is primarily with stepper controlled CNC so I am struggling with some of the aspects of getting the servo control going. I was hoping to get some feedback on questions I have:

*Is there any compelling reason to use different encoders than that? What calculation should I be doing to determine cpr/ppr for this mill?

*What is the best way to mount the encoders to that motor or just make a mount? There is the extended rear shaft already but I don't think the existing holes line up with the us digital encoder.

*I have some pulleys for the ameteks from another project but I don't really know how to compute the proper pulley ratio for this project to see if they are appropriate?

*The mounts on the BP are for the old NEMA 42 steppers and the ameteks have a very different mounting profile. Is there some existing mount plate I should buy or just drill one up?

*What power supply setup do I need to have for the ameteks for this project?

*Is there any downside to using 3 phase power on this over a VFD? The existing cabinet does have wiring for 3 phase and does power on the spindle but I don't really trust the 30 year old electronics hardware in there or should I? What is a suitable replacement if not?

Thanks a bunch for any feedback, I hope that isn't too many questions in one post.

[ccoleman]

I'm certainly no expert here, but I'll throw in my 2 cents.
I did a retrofit on a Series II of the same vintage and kept the original steppers with great success (I think I wound up with 60IPM rapids at a lower than optimum voltage which I was plenty pleased with). I'm sure you'll find a ton of posts on that subject in these forums. As for the servo side of things, I'm in the middle of an R2E3 retrofit and have gone with the amt 102 encoders from AMT modular encoders | CUI Inc I believe these were recommended by Marriss at Gecko. They are pretty slick and are fully adjustable as you'll see in the documentation. I'm running a G320 (that I had laying around) on the Z, a G320x (cuz I wanted to try one) on the X and a Dugong on the Y. All of them are working just fine at 500PPR (I'm running them all at a low voltage 36V for now). The Dugong is about the ugliest thing from a fabrication standpoint, especially when set next to the Geckos, but seems to work very well and I'm planning on swapping the X out for another Dugong once I setup a higher voltage supply. I'd check the AMT documentation to see if their mounts match your motors.

On the SII conversion I did, I used all of the existing 3 phase contacts, etc and simply wired in the CW/CCW relay/contactors/whatever you call them to be switched from Mach3. Worked great for me.


Best of luck.
Chris
Stuff - for the beginning of a build log on my R2E3

[grigsby]

Hello,
I am looking for some old boss 4-5-6 boards, Especially LSI-11 board.
We have some boss bridgeports and would like to have some parts that you would like to get rid of. Email me with what you have. thanks grigsbyatwowwaydotcom