[FritzX]

Hi,

I just want to show you this German guy's self-designed lathe turret:




By a friendly request, the Designer (his name is Dieter),

might send you the complete drawings by email free of charge. Please note: The Dimensions are metric !

You will find his email address somewhere at http://www.cnc-projects.de/

Regards,
Fritz

[DennisCNC]

Bablefish his site!!! Some nice machines he built!!!

The auto toolchanger spindle is ..... killer!!

[Ken_Shea]

Fritz,
Did you get the cad files from Dieter?

He graciously sent them to me but they are not the CAD files, rather .pdf for viewing only.


His work looks more like art then mechanical.

In my life I know only two people (Personally) that do such beautiful machining, I, unfortunately am not one of them

Thanks
Ken

[JH-Q]

I have just began building mine, build log here: http://www.robosota.fi/foorumi/viewtopic.php?t=935
Sorry it is in finnish but there are some pics to see
Lots of thanks for Dieter, his design has saved incredible amount of designing!

[CNC-Joe]

The direct link to the drawing file is:

http://www.cnc-projects.de/CNC-Revolver.html

[TheMillMan]

i down loaded the design and find it vary well thought out great job to the designer! i was thinking of using this design in my lathe, but i don't want to use air to unlock the turret and i want to be able to cut towards tho tail stock. has anyone got ideas on what i should use to set up the tool changer in that way?

thanks

[Guldberg]

What do you want to unlock the turret with instead? Why cant you cut toward the tailstock? If loaded with powerfull enough springs, I doubt you will un-pop the head on such a smale scale turning if you cut towards the tail stock

[TheMillMan]

i was thinking of using fluid power since i have a lot of surplus hydrolic parts and my machine is 3 hp and is being built from steel plate so i will need to scale up the design. i like the design so the only thing i would change for my purposes is the unlocking mechanism and scale.

i think you are right about the springs, but a heavy cut at 60 percent hp could in theory unlock the turret. i may be missing important factors in my reasoning but then i am always thinking of potentialities.

however hooks law times four springs could apply a lot of force.


the designer did an extremely good job and has made a nice contribution to my project because i will use his ideas. but i am new to CNC and still have a lot to learn so i was soliciting ideas, there is a lot of talent out there.


thanks for your reply

[Guldberg]

I use belleville washers instead of regular springs, take a look at the latest pics http://www.cnczone.com/forums/showth...=51688&page=26

My motor is also 3hp, but since i doubt I will do any serious production runs, if I ever cut against the tailstock I dont mind slowing down the feedrate. Have you calculated how much force it would take to unlock it with a given depth and feedrate?

[TheMillMan]

no, i haven't done calculations on this because i do not have any data on the springs used, also the Z component force the tool will generate (cutting tool apposition) to unlock the tourret i do not know how to calculate.

horse power at the cutting tool is known and at motor, but what this translates to the tail stock and turret along Z axis is something i will need to find out.

which is a good question, dose anyone know how to calculate component forces (using Full Body Diagram) an a lathe?

[keebler303]

I think you mean "free body diagram"

Unfortunately, its a little more complex than just calculating a couple force vectors. The cutter geometry, material, speed and feed will all affect the amount of axial force.

I am sure it could be figured out mathematically using the shear strength of the material, blah, blah, blah. If I wanted to find the force "good enough", I would put a torque wrench on the handle for the z axis and do a couple quick calculations (I think finding the pitch diameter on the drive gear would be all you need) to get a good idea of what forces I was seeing.

Matt

[jasminder]

What do you want to unlock the turret with instead? Why cant you cut toward the tailstock? If loaded with powerfull enough springs, I doubt you will un-pop the head on such a smale scale turning if you cut towards the tail stock

hello guldberg,
your turret design is awsome. but i was thinking about using 1 or 2 pins to lock the turret position while keeping the turret stationary (forward/backward)
I want to use 2 angle contact bearings back to back on the tool plate that will give the turret a 0 tollerance and the pin will lock into the rotating turret.

In short, in your turret design, the turret comes forward to the chuck, then moves and locks back to the tail stock. But in my design the locking pin will move only. So i don't need to worry about the spring tension and the power of pneumatic cylinder. Just an outcam or spring will move the locking pin.
I hope you had this idea before cuz it is very simple. But what made you think that complicated. Any drawbacks of my design?

[Guldberg]

Hi Jasminder

It should be doable but you need some really tight tolerances to keep the turret locked firmly. Im not sure why, but it seams that most professional lathe manufacturers chooses the same locking mechanism as the german designer

[The Blight]

Jasminder

Thats what I made for my lathe. It can't hog away big chunks of metal, but it does work ok.

http://www.cnczone.com/forums/showthread.php?t=56549

The locking pin is also spring loaded.

[jasminder]

Jasminder

Thats what I made for my lathe. It can't hog away big chunks of metal, but it does work ok.

http://www.cnczone.com/forums/showthread.php?t=56549

The locking pin is also spring loaded.

Nice work Blight.
but i hope your turret will have less tolerance than a german revolver (guldberg's design) because there are taper bearings. In german revolver there is a keyway that the turret uses to travel on. And i don't see any keyway without 0.002 of clearance (play). If i am not wrong then Guldber will be receiving 0.001-2 thousands of errors in his tooling and offsets.

BTW the locking pin drives the screw using a coupling? or uses a rack and pinion like thing? in which the taper pin works as a rack?

and do tell What motor and VFD you are using on your machine?
I am looking for cheap spindle control for my lathe. near 2HP
nice work on your machine Blight. Congrats.
jasminder

[The Blight]

Thanks

I have not really done much measuring on the slop in the turret. I can't see it move any while cutting, but I will have to put a dti to check.

Furthermore. I don't think there is more slop in guldbergs design. I think there is less actually.

The pin works like a screw. Motor is connected directly to it.

It's just a regular X2 spindle motor and controller. I am however thinking about replacing the motor with a 2+kw brushless rc motor. Doesn't cost too much, and I need more rpm to work on smaller parts.

[Guldberg]

The key doesnt really have a lot to do with the tolerances. The turret locks it self on the skewed faces of the locking ring. It can be misalligent more than 1mm and it still finds it way.

0.002 ~ 0.5 seams like awfull sloppy machining also :-)

[The Blight]

Thats what I was thinking.

Also. You missed a 0. Its supposed to be 0.05mm

[jasminder]

The key doesnt really have a lot to do with the tolerances. The turret locks it self on the skewed faces of the locking ring. It can be misalligent more than 1mm and it still finds it way.

0.002 ~ 0.5 seams like awfull sloppy machining also :-)

hi guldberg,
sorry for late reply and thanks for your support. BTW how do you make the skewed faces on the turret. I mean that accurate dividing?
Did you use cnc for the same or a manual milling?
The good news is that I have started building a cnc lathe too after i got inpired from your slant bed design.
Here is the post:
http://www.cnczone.com/forums/showth...457#post788457

i wish you to comment and help me.
And i saw in a youtube video that you have made a cnc lathe using linear bushing also? But the project is not on cnczone.

regards,
jasminder singh

[jasminder]

Thanks

I have not really done much measuring on the slop in the turret. I can't see it move any while cutting, but I will have to put a dti to check.

Furthermore. I don't think there is more slop in guldbergs design. I think there is less actually.

The pin works like a screw. Motor is connected directly to it.

It's just a regular X2 spindle motor and controller. I am however thinking about replacing the motor with a 2+kw brushless rc motor. Doesn't cost too much, and I need more rpm to work on smaller parts.

Hi blight,
your machine seems very rigid to me. And i would like to know about the motor configurations and rapids you have, if you don't mind.
And luckily i started a cnc project too here :
http://www.cnczone.com/forums/showth...457#post788457

Please see and comment. Do you think that the things will make a good cnc?

regards,
jasminder singh