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Author Topic: Drill chuck reference on lathe table!!!  (Read 155 times)

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Drill chuck reference on lathe table!!!
« on: March 10, 2020, 12:24:49 PM »
It seems with out switches on mach 3 turn you can not restart your machine and have a reference home.  I do not have a tail stock on my lathe.  So when I want to drill something I need to have something to bring back the tool post to proper x axis to be centered.

In researching switches it seems that they can be less than accurate unless you spend alot. 
This a hobby for me.  The closet thing I have been able to come up with is getting the drill post centered and making that machine cordinate x0 z0.   When I restart the machine the machine cordinates are the same as when you turned the machine off.  If I get the machine coordinates back to zero it seems to be at center.  This method requires you never change the machine coordinates.

Any ideas on best way to be able to call back the drill center?  Would home mechanical switches be OK ? 

Thanks in advance
Tom
« Last Edit: March 10, 2020, 12:36:24 PM by TomWh »
Re: Drill chuck reference on lathe table!!!
« Reply #1 on: March 10, 2020, 02:05:21 PM »
Hi,
I use good quality roller plunger snap action microswitches for home switches on my mill and achieve 0.02mm or
better repeatability. Home switches and index homing are required if ou wish to do better than that.

https://nz.element14.com/honeywell/bzc-2rq18-a2/switch-basic-top-roller-plunger/dp/1525198

Craig
My wife left with my best friend...
     and I miss him!

Offline RICH

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Re: Drill chuck reference on lathe table!!!
« Reply #2 on: March 10, 2020, 03:10:15 PM »
Have you considered probing?
I don't use switches on any of my machines. For the lathe I use probing for numerous tasks;
populate the tool table, measurements  / reverse engineering of turned forms, BUT, most importantly to
locate X axis center of the lathe.

A touch off fixture that is removable / can be re-positioned, easily attached to the lathe bed can be made to do what you want at any time. Thought ...it's just a tool setter and you use the probing feature.

I have found probing to be very accurate; typically 0.0001" or .0002" repeatable.


RICH



   

Re: Drill chuck reference on lathe table!!!
« Reply #3 on: March 11, 2020, 10:02:01 AM »
Hey Rich

Did a far amount of searching on probing but mostly found getting touch off points and reverse engineering part tracing.  Not sure how you would reference a drill chuck to x center point after you start the machine.  If there is somewhere to look to find more information or you could give me the procedure you would use to center this chuck after a start up, I would appreciate it.  Also are you using a touch plate device or a probe with internal switching? 

I am not rapping my head around with out a reference point how you can hit a button and have the machine take the tool post to a certain position. 

Thanks
Tom





















Offline TPS

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Re: Drill chuck reference on lathe table!!!
« Reply #4 on: March 11, 2020, 02:38:49 PM »
IMHO there are two posibilities depending on the Motion controler and Motors (servos/Steppers) you are using.

1st: precise/indexed homing 
      -if you have a Motion controler witch supports index homing and servo Motors you have normally a real good Chance to do a precise
       homing (zero pulse from servo resolver)
      if you use Steppers the possibilities of an precise homing are very "limited"

2nd. as Rich sayed a probing Input would be a Option (does not matter witch Motors you have) to get a "accurate" x-axis Position.


sorry for my bad bavarian english
anything is possible, just try it.
if you find some mistakes, in my bad bavarian english,they are yours.