[Bird_E]

I'm in the process of converting my X3 mill to CNC. I'm going to replace the standard AMCE lead screw in the Z axis with a ball screw. Since I will be driving the ball screw from a servo at the top of the column do I need to support the lower end of the screw with a radial bearing or can I let it hang free? Of course the current screw is supported from the bottom because it driven from the bottom not the top.

Here is a picture of the stock setup:

[cncadmin]

You could punch a hole in the top of the square colum and install a bearing block and run a motor directly to the screw.

[cncadmin]

Have you come up with a solution? I'm gonna be in the same boat very soon. I'm going to drive it right from the top, and re-machine a new ball screw.

[Bird_E]

Yes, I can up with a solution.

I punched a hole in the top of the column and mounted a bearing plate on top. I then made a new mount for the ball nut, and a cross piece. I then machined the other end of the ball screw so that it will slip through the lower exsisting bearing mount. I removed the thrust bearing and replace them with simple radial bearings just to support the floating end. I can, if I want, put the crown gear on the loose end of the shaft so that I can still use the hand wheel if I desire. I tried it and it works perfect, although I have since removed the crown gear, no need to drive all that other friction if I don't need too! I was able to move the head up and down with ease from a 12 volts 1.5 amp supply at 1 :2.5 belt reduction.
I can send some pictures if you would like.
I also lowered where the gas spring connectes to the cross plate, by lowering it about 1.5" it give me more z travel going up. With the gas spring you don't need to worry about the weight of the head back driving the screw it holds it in place with no problem at all.
Bob

[cncadmin]

Yes please I'd love to see some pics.

[Turbo1zz]

I too wpild love some pictures if you have some to share.

Would the new X3 mills have a problem now that they no longer come with the strut installed?

Thank you,
Jeffrey Park

[MIKE JEFFERS]

pics would be good, should take delivery of an x3 in the next 2 weeks, can't wait
mike

[Bird_E]

:devious:

[Turbo1zz]

Oh Boy!!! Those are some reeeeeeeeeeealy big images.

Looks really nice. I only hope to do as well as you have. Did you make the gears on the servo motors and the ends of the srews?

Thanks,

Jeffrey Park

[Bird_E]

No I purchased the belts and pulleys from Stock drive Parts.
Bob

[jfong]

Hi Bob,

Your X3 conversion looks pretty good! I'm planning on converting my X3 and have the same clifton servo motors. Some questions if you don't mind.

What gear ratio did you use? Do you have the part# from SDP? What is your max rapid speed? Did you ebay or purchase your ballscrews from a supplier?

Regards,

Jim

[Bird_E]

I'm using 2.5:1 ratio in X and Y and 3:1 ratio for z. I'm easliy running rapids at 125 IPM. It may go faster but for a mahine this size it's more then plenty for me. It has more then enough power with the cliffton servos. I can break 3/8 end mills and it keeps going like nothing ever happened! I purchased a 6 foot section of ball screw from Industial Hobbies, along with ball nuts and angular contact bearings. I made preloaded ball nuts from the plans Jeff Davis offers.
Their price for the screw and nuts was really good. Of course I had to cut and turn the ends down for the bearings.

The ball screw is the same 5/8 screw that you can purchase from Mcmaster car.

[jfong]

Thanks for the quick answers. I noticed you did a belt drive conversion for the spindle using a red link belt. How is that working? The stock gear drive is very noisy on the X3. Did you get a increase in spindle RPM?

I also noticed you have a nice lathe in the background too.

Jim

[Bird_E]

Jim,
Yes, In fact I just did the belt mod this weekend. I ripped out all the hi low gear stuff and now I have a direct spindle drive. It is SOOOO much quieter and smooth. Hardly any vibration at all. The RPM is just about 2000. But is seems to have a little more power now that its not driving all those gears. I plan to change the motor over to a 1/2HP AC VFD drive in the near future, but for now it is working much better then stock.
The lathe in the backgound is a Harbor Freight 9X20, I used that lathe to turn down all the ball screw ends and all other round work for the machine conversion.

Bob

[Bird_E]

I made the pictures smaller! Should be easier to view.
Bob

[Willyb]

Hi Bird E

Nice pictures of your CNC Mill setup. Is that your own designed controller box? Would like to hear some details on it and maybe a picture or two of the insides if possible. What do the Meters measure? Wouldn't be currant would it? Interested to hear what's in that box. :-)

Willyb

[Willyb]

What are the maximum travels of your Mill setup? The Lathemaster Factory specs for the Sieg X3 Mill are: X - 16" Y - 5-3/4" Z - ???

What is your maximum Z travel? Can you squeeze anymore travel out of the Y Axis? To me this is the limiting factor of using this Mill. The rest of the travels are great.

Does your X Axis Servo Motor not hit the front of your vertical column if you move your table to the maximum of -X and +Y ? From the pictures, it looks like it would hit the column?

Did you ever consider CNCing the larger Square Column Mill? What was the main reason for picking the Sieg X3 Mill? I am trying to decide which of these two Mills to buy? I basically want to do the same as you. I am going to swap out the Motor for a 3 phase unit and install a VFD.

Thanks for your help with my questions.

Regards
Willyb

[Bird_E]

I don't know exactly what my travels are. However.. I think my X is around 18".

Y is 6-3/4 to 7" Doing the ball screw conversion I was able to squeez more travel

Z travel I have plenty... I was able to adjust the travel again by doing the ball screw conversion. The limiting part was using the same gas spring. If I used a different gas spring I could get more travel.

I purchased the X-3 specifically because the Z axis was easy modify to ball screw, and the price of the mill was good. And it was the right size for what I was looking for.

I did design and built the entire control box. I will try to take some pictures tonight. Under the hood is a nice big toroid transformer, 3 gecko 320's, heat sinks, fan, filter caps, bridge and a Bob campbell break out board. The meters on the front measure current for each axis and provide a nice indication of load on each axis. The digital panel meter displays the output voltage for power supply. LED's are Axis Fault lights and reset switches.

I had fun building the control box. If you are ever interested, let me know I may be willing to build another one!
Thanks!
Bob

[Bird_E]

WillyB,
Here is a site that I started to document my conversion, I never finished it but it may give you some ideas. http://www.rlberg.com/CNC.htm
Also, I did model the whole conversion in solid works so that I could check for interfereneces. So as far as the x-axis servo is concered, no it will not hit the column, it's close, like .050" clearence but it won't hit! The reason why I did it this way is because I didn't want the motors to hang way out in front of the mill, I would think they would always be getting in the way and more prone to damage, etc.....
Bob

Bob

[Willyb]

WillyB,
Here is a site that I started to document my conversion, I never finished it but it may give you some ideas. http://www.rlberg.com/CNC.htm
Also, I did model the whole conversion in solid works so that I could check for interfereneces. So as far as the x-axis servo is concered, no it will not hit the column, it's close, like .050" clearence but it won't hit! The reason why I did it this way is because I didn't want the motors to hang way out in front of the mill, I would think they would always be getting in the way and more prone to damage, etc.....
Bob

Bob

Hi Bob

I am glad to hear that you have enough clearance for your X Axis Motor. I wasn't trying to be smart it's just that the picture makes it look like there might be a problem. Using Solidworks is the greatest thing for checking fits and clearances, isn't it. When you start machining the parts, you know for sure that everything is going to fit. Great job.

Willyb