The Home Machinist!

Hi All,

I am new to this forum and would appreciate some help with this concern. I have an EZ-Trak with the servo motors, cabinet and console removed. I need to install all the original handles and bearing brackets to be like a manual mill. I want to install a Servo 150 on the X axis. My question is can I do this with the original ball screws or are they to long and probably do not have threads on the left end of the lead screw for the handle. Also, I have a spanner nut up against the bearing on each screw is that a left hand or right hand thread.
Thank you
Dan Yoder

Boy! what did you do to garner so many rapid responses?
The only caution I know of when using ball screws manually is to be careful when climb milling, the ball screws don't offer as much resistance to tool induced motion as regular screws.
"My question is can I do this with the original ball screws or are they to long and probably do not have threads on the left end of the lead screw for the handle."
Unless you can supply pics and other specs., only you can determine whether they are too long or have threads (R or L hand).

I would say you could adapt manual handles to the ball screws and you may not even have to remove the servos but if this is the only machine you have it would be difficult to make parts on it manually while it is in pieces awaiting the mods you are trying to make.
I hope you get better responses (and more of them), good luck.
Steve

All I can do is offer a hearty "welcome" to the forum. I would not be able to answer any of the questions about the conversion.

However, I do agree that the use of ball screws for manual machining can be troublesome.

Harold

_________________
Wise people talk because they have something to say. Fools talk because they have to say something.

I have been using a Sharp with the centroid control at work, so I can use it either way. I am really getting to like the ball screws for manual machining as I can make heavy cuts while climb milling.

The one thing you might check is the lead on the ball screws. I have seen only a few of the ball screws and some have a long lead, so the factory dials won't read right.

If it were me, I would leave the CNC on the X and Y axis if it has the option for manual or CNC operation. I don't know if you have the parts to allow this.

The more I use this Sharp with the CNC on the X & Y and the Centroid control, the more I want one.

Richard W.

What kind of luck do you have when you rely on the screw(s) for holding a dimension in the opposite axis? Are they able to resist the forces of the cut, or is it mandatory to lock the given slide? Without a motor to hold the screw on location, seems you'd wrestle with that issue.

Harold

_________________
Wise people talk because they have something to say. Fools talk because they have to say something.

Harold it hasn't been a problem and the control works as a DRO as well. Back lash isn't much of a problem either since the ball screws have it pretty well adjusted out. It's nice when you need to counter bore a hole and you don't have the right size counter bore. You just tell it to cut it with an end mill. I think you would like it once you used one a bit.

Richard W.

Thanks, Richard.
In regards to using an end mill in place of a counterbore, that's one of the features of the Haas tool room mill I purchased a couple years ago. It makes so many things easier to accomplish, and lowers the need for special tooling. As much as I've resisted moving to CNC, I must admit I quite enjoy watching mine do its thing, albeit having it sit idle for the most part. I hope to see that change when I'm finished with the building project, however.

I fear the CNC is going to spoil me, so I'll start looking for a CNC lathe, too.

Harold

_________________
Wise people talk because they have something to say. Fools talk because they have to say something.

Hi All,

Well Steve I believe it is God's favor. I ask for His help all the time and He sometimes uses His people to do that for Him. I will post some pictures next week. I am a ProE Designer and a machinist from the old school. I have 12 years experience as a job shop machinist and then 6 more as a maintenance machinist at GE Lamp Plant in Winchester VA.
For the past 14 years I have been a mechanical designer using AutoCAD, SolidWorks, and now ProE. I have been given the responsibility of running our machine shop and being the sole machinist. I was left with (2) Bridgeports a 1985 2J 1 1/2 HP and a 1999 EZ-Trak 2J 2 HP with burntout servos. When the machinist quit he was in the process of ordering a Centroid S400 system that costs 12,000. I had the CAR cancled and started to remove all the CNC equipment. Now I know you guys are starting to squirm and say what a stupid thing to do. I have three reasons for this: 1) the costs 2) part quantity 3) I perfer to use my old skill set. The money that I saved I can use to buy a rotary table, 90 degree angle head, and a 2 Axis Acu-Rite DRO VUE system and a 150 Servo power feed on the X axis. I do have CNC experience on a Mazak and a Bandit retrofit to a bridgeport. I do not like running machines that I can't touch, feel and become part of the creation process. I was wondering if I could remove and modify the ball screws and reverse engineer them to the specs of the old acme set. I noticed that when you order lead screws that they have two p/n one for a power feed and another without. I would like to get a set of prints for these screws. If I pull the ball screw assembly can I unscrew the tha shaft, catch the balls, and then feed them back into the bracket?

Well Cadmandu, If you're able to obtain divine intervention, I'm outa here.
When I wrote the following,

I should have typed "only" in bold caps!
I now know another caution and that is, that the ballscrew pitches are computer linked and therefore may not have a manually friendly pitch.
Having doubled my knowledge I am still woefully out of my league on this subject.
Good luck and I'll be following the thread in hope of learning more.
Steve

The ball screws that I have used were built for other duty. So I may be off on this, but may be something to look for. The ball nuts we used had recurlating tubes clamped to them. When tore down and cleaned you had to count the balls and drop them in and remount the tubes. The ones we used had 3 sets of tubes. My memory may be a little off as this was close to 30 years ago.

The other ball nut we used came assembled with a tube in the center. There were no threads on the tube, but the tube was used to hold the balls in place during assembly. The idea was you slide the ball nut and tube against the end of the ball screw and as you turned the nut on the screw the tube was pushed out the other end of the nut. This meant no ball counting and everything was in place as set by the factory. Now if you make a tube to the right diameter you can take it apart and not loose any of the balls and not have to mess with counting balls on reassembly. You will need a hole in the tube large enough to slide over the largest diameter of the fits in front of the threads. (Fits being bearing or sealing surfaces.)

Then again I may be off for your application? But you now know some of the things to look for.

Richard W.

I was wondering if you were concerning yourself with the ball screw only and not taking into account the weight of the table and friction of the sliding surfaces when you wrote the above?



With a DRO the pitch would not make a difference as there becomes no need for dials on the machine. The addition of a power feed intended for a 5 TPI pitch screw put on a long lead screw (Say a 1 TPI pitch screw) becomes a problem as you loose your slow feeds. Also dials would most likey have to be made if you wanted them?

Richard W.

Hi Richard and Steve,

We all have divne intervention just some are aware of it and some are not. Great input with the ball capturing tube idea Richard. I was looking at the ball screw yesterday and it looks like a normal acme thread pitch of 5 tpi. I will take a picture of it on Monday. What do you guys think of the Acu-Rite VUE DRO?

http://www.rockfordballscrew.com/manuals.htm

http://www.practicalmachinist.com/vb/ge ... ew-237323/

http://www.practicalmachinist.com/vb/br ... ew-217313/