Convert a manual grinder to auto feed?

[Flyinfool]

Anyone ever done this?
I have an ancient B&S No.2 Surface grinder.
These pics are are of it before I took it home and hauled it into the basement.
I have since cleaned everything, and replaced every bearing.
I would like to convert it from full manual to a auto feed in both the X and Z. The only thing I have found so far is a few old posts on various sites where someone said they did it, and a couple of YouTube vids of converted machines with no actual details.

Anyone have any details of how this was done?
I can figure out a way to make the table go back and forth at a variable speed, that will be the easy part. But I still have no clue how to make the table traverse a set variable distance at the end of each stroke.

 

[JimDawson]

You would do this by installing steppers or servos on the axes and controlling it like a CNC machine, actually make it a CNC grinder. Eventually I'm going to get around to doing mine, as soon as I get another project out of my way.

Theoretically you could hang a small 3 phase motor on the X and control it with a VFD and a couple of limit switches and a relay. You need something to be able to accelerate and decelerate at each end so it doesn't try to start & stop instantly.

 

[Flyinfool]

If I am going to do a CNC conversion it will be on my mill or lathe first.
The table drive is the easy part, how do I drive the traverse and tine it to the end of the table stroke and do it all mechanically. Right now I have a lot more time and material than money. How do the mechanical auto feed machines that are out there do it?

 

[JimDawson]

tine it to the end of the table stroke and do it all mechanically.

That's a great question. Maybe something like the ratchet feed mechanism used on a shaper?

 

[Toolmaker51]

Why? An 18" or 24"+ maybe. I can't imagine working out a .031 internal snap ring tool without full manual control; in each of 3 axis. Full auto is suitable for plate work, consequently bigger machines.

 

[JimDawson]

Why? An 18" or 24"+ maybe. I can't imagine working out a .031 internal snap ring tool without full manual control; in each of 3 axis. Full auto is suitable for plate work, consequently bigger machines.

Why would you not do one with full manual or full CNC control and be able to select which axes you want to control by what method for any given setup.

 

[MikeInOr]

A stepper motor controller can be really cheap. Hit a button and the motor advances x number of steps. Without having to have a computer or fancy micro controller... if that is not your thing... a cheap stepper controler plus motor seems like it would be the easiest path to go.

Another thought would be a automobile window motor on a timer. Press a button and the timer runs for .8 seconds. Adjust the on time for the increment you need. Look at timer relays for a pretty easily adjustable one component timer solution.

I use a timer relay on my rotary phase converter to energize the startup caps for 1.3 seconds then turn them off. The actual on time is adjustable with a knob on the top of the relay.

 

[Flyinfool]

The stepper motor and a switch sounds interesting. For both axis. But I know nothing about them or what I would need to make it work. I am good, and comfortable working with electronic stuff, I just have zero experience with stepper motors or programing. So wiring and setting it all up would be the easy part. All the electronic stuff I make (making small PCBs to do different things is another of my hobbies) is still old fashion logic chips. Having the stepper motors on the machine would also be a big step toward someday going full CNC with it. It would also give me some experience toward the eventual goal of converting my mill and lathe to CNC.

 

[JimDawson]

The stepper motor and a switch sounds interesting. For both axis. But I know nothing about them or what I would need to make it work. I am good, and comfortable working with electronic stuff, I just have zero experience with stepper motors or programing. So wiring and setting it all up would be the easy part. All the electronic stuff I make (making small PCBs to do different things is another of my hobbies) is still old fashion logic chips. Having the stepper motors on the machine would also be a big step toward someday going full CNC with it. It would also give me some experience toward the eventual goal of converting my mill and lathe to CNC.

I could write a whole book on the subject, but stepper motors are the most common method to driving machine axes in the home shop. Relatively inexpensive and simple to set up and control. The most common method is to buy a kit something like this example https://www.ebay.com/itm/USAFREE-2A...073160?hash=item4af7914708:g:E4IAAOSwCypWnd0Q

In its simplest form about the only thing that is needed with the above kit is a computer and Mach3 CNC software.

Since you already have digital electronics experience, building your own controller for a simple application would be pretty easy. The drives have 2 inputs; pulse and direction. The speed is controlled by a pulse train with a 50% duty cycle, the direction is just Hi/Lo. The inputs to the drive is TTL square wave. For a very simple application a couple of 555 timers and a bit of logic would do. You would only need to add some limit switch and on/off switch, and speed pot inputs to your circuit. The actual control of the stepper motor is all handled in the drive.

 

[MikeInOr]

I have used the Parker CompuMotor stepper controllers and have been very pleased with them. They used to cost several thousand dollars but can be picked up for a hundred bucks or so on ebay. The Compumotor will have everything you need in one package... power supply, stepper drivers, PLU (programmable logic unit) and a variety of built in I/O lines. They WILL require some programming to make work and they have their own ladder logic type language. Programming the controllers I used required a computer with an RS232 serial port. They have some custom programming/configuration software, I just used a hyper-terminal session. After the PLU is programmed the controller is stand alone... i.e. you do not need to have it connected to a computer to run it.

I used the SX6 and SX8 CompuMotor stepper controllers... they have the same PLU, the SX8 is just a higher power drive for controlling some REALLY big stepper motors.

Another route (a bit more modern) would be assembeling an Audrino or Raspberry pi system with a stepper controller, appropriate power supply and programming it appropriately. This would be quite a bit more flexible but quite a bit more work.... the Compumotor is pretty much plug, program, and play.

If you are going to CNC your grinder, mill and lathe JimDawon's suggestion above makes a lot of sense to me!

P.S. I am also an amature electronic hobbiest... there is quite a bit to be said for good old flipping and flopping!