1/4 of the way to a mill

[FanMan]

I'm in Manitoba and was looking for a mill. Very little to choose from so end up with a King PDM-30 basically a RF-31 (31N2F(BS)/25. The big thing that is not so good with this unit is a 1 phase motor (220v) and the belts that have to be changed for changing speed. That becomes a pain after a while. So I'm looking to converting it to 220v 3 phase. And oh by the way the motor is meteric at a 24mm bore. It says it 1hp but from the current on the label it's more like a 3/4 hp. The cost could be up to 1000 to 1500. Canadian to convert it. Also raising the head puts everything out of calibration. So will have to mod that somehow.

Look around for an old discarded treadmill and use the DC motor and controller from that... lots of threads here on the subject.

When you raise the head you don't lose "calibration, just the x-zero. There are ways to deal with that.

 

[DavidR8]

I'm in Manitoba and was looking for a mill. Very little to choose from so end up with a King PDM-30 basically a RF-31 (31N2F(BS)/25. The big thing that is not so good with this unit is a 1 phase motor (220v) and the belts that have to be changed for changing speed. That becomes a pain after a while. So I'm looking to converting it to 220v 3 phase. And oh by the way the motor is meteric at a 24mm bore. It says it 1hp but from the current on the label it's more like a 3/4 hp. The cost could be up to 1000 to 1500. Canadian to convert it. Also raising the head puts everything out of calibration. So will have to mod that somehow. Would I buy again, probably not and would go to a Model: KC-20VS-2 or better less power put more included options, especially variable speed control. That should be a given for a mill. Would have gone with busybeetools but shipping was horrible as there is no store in Manitoba.

I just converted my mill to 1.5 hp 3 phase.
I bought the motor and Teco VFD from e-motorsdirect.ca.
All in I’m under $600.
I now have forward, reverse and variable speed from about 100 rpm or less to over 2000 rpm all with the handy dial.
As far as losing position on changing Z height goes, there are easy ways to deal with that. Most simple is putting a dial indicator in place against the spindle before raising it and returning to the same position.

Sent from my iPhone using Tapatalk

 

[Bruce Billett]

So has anyone tried an autocollimator to realign the head back to it's original position?? I have not as yet, Don't have one small enough, but I have used these for years to align all sorts of thing with micron scale precision and it is not difficult. An autocollimator with a radical in it will bring you back to the same mark, doesn't even need to be anything special, out to ~100'. If your mill is bigger than that, well.....? Add a front surface precision ground mirror and you can get down right stupid perpendicularity!
Issues I have run into are,
1) These things are not free, Although I have found some salvaged from lasers and the like that are not to bad, but none with a right angle viewing head.
2) Finding a good place to mount it where you can still get your head in to look into it. I suspect an electronic one would work well.
3) Initial mounting. It would have to be mounted parallel to the columb center. Fine alignment would be easy, However determining if it is in fact parallel is an issue.

Any thoughts?

b

 

[DavidR8]

So has anyone tried an autocollimator to realign the head back to it's original position?? I have not as yet, Don't have one small enough, but I have used these for years to align all sorts of thing with micron scale precision and it is not difficult. An autocollimator with a radical in it will bring you back to the same mark, doesn't even need to be anything special, out to ~100'. If your mill is bigger than that, well.....? Add a front surface precision ground mirror and you can get down right stupid perpendicularity!
Issues I have run into are,
1) These things are not free, Although I have found some salvaged from lasers and the like that are not to bad, but none with a right angle viewing head.
2) Finding a good place to mount it where you can still get your head in to look into it. I suspect an electronic one would work well.
3) Initial mounting. It would have to be mounted parallel to the columb center. Fine alignment would be easy, However determining if it is in fact parallel is an issue.

Any thoughts?

b

I have absolutely zero knowledge about autocollimators but it sounds interesting.

 

[Bruce Billett]

Try looking them up on google search.
The basics are it takes the light going thru it and only allows light that is perpendicular to the lens through. So when you look through it all you can see is a target the size of the lens on the end of it. Result is you can see, I have at any rate, Up to about 150 feet just like you were looking at it in front of you. So The manual for the device at 150 feet was just as legible as it was in my hand, Downside? The lens was only about 1/4" Dia. so I could only see the letters in that 1/4" space. Makes for a LONG read.
Another feature is that if you project a light down through it to a front surface mirror should mirror now be perfectly perpendicular it will bounce off at an angle and you can't see it reflecting back. Putting the autocollimator through another front surface mirror so if the light bouncing back is CLOSE to coming back you will see a series of dots that lead off in the direction of error.
Google has much better explanations of this than I do. I only used them. Never designed one.
Hope you find this at least interesting.

b