this may sound like a dumb question, but calibrated or not, the movement should REPEAT over any length of travel.
skipping steps while not under load?
What does the carriage do if you turn the screw BY HAND and work to a specific screw position (like with a hand-wheel)? does it repeat?
Ball Screw Question
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- Bill Shields
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Re: Ball Screw Question
Too many things going on to bother listing them.
- SteveHGraham
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Re: Ball Screw Question
It will be a while before I get back to it, so I don't know the answers right now.
Every hard-fried egg began life sunny-side up.
Re: Ball Screw Question
I would probably use my dial caliper by clamping the fixed jaw to the tool post, extend the movable jaw all the way out toward the chuck, and use the depth feature against the chuck to get a full 6" travel.
Or something similar by laying the DC on the ways, maybe stabilizing with clamps or magnets.
Or something similar by laying the DC on the ways, maybe stabilizing with clamps or magnets.
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...
- Bill Shields
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Re: Ball Screw Question
just put a dial indicator against the carriage and move it AWAY for a few inches and bring it back to the same programmed point.
Does it repeat?
Does it repeat?
Too many things going on to bother listing them.
- SteveHGraham
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Re: Ball Screw Question
Can I expect a Chinese indicator to reset to the same point after tension has been released and reapplied? I suppose I could check that on my mill.
Every hard-fried egg began life sunny-side up.
- Bill Shields
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Re: Ball Screw Question
it should, Chinese or not...it is just a rack and pinion....
now...do it 10,000 times and country of origin may be a problem.
now...do it 10,000 times and country of origin may be a problem.
Too many things going on to bother listing them.
Re: Ball Screw Question
I've had good luck with all my dial indicators/calipers. My expectations are not that high, but I feel OK splitting a division at best, on a good day...
I remember the first thing I did when setting up my mill was to get control of the motors before I even mounted them to the masheen. Of course the mechanicals were verified manually as well.
I remember the first thing I did when setting up my mill was to get control of the motors before I even mounted them to the masheen. Of course the mechanicals were verified manually as well.
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...
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Re: Ball Screw Question
I Agree with Dave, FIRST check to see if there is backlash. Looseness in your system that drives the screw. Nut loose against the thrust bearings? Is the ballscrew nut secure to the crossslide? Motor or screw pulley loose? Belt excesively loose?Dave_C wrote:Steve,
If you are missing steps the measurements you take should not repeat! Lost steps should give you random readings...
Of course there is also backlash issues, loose thrust bearings, bad (cheap) ball nuts and all that stuff. Without seeing some of the parts and the setup I can't really offer much else that will help.
Dave C.
Can you put an indicator on the slide and push against something in the spindle, head in, preload the indicator, zero it, zero the axis on the control, then set your machine to jog in .0001", and back out a tenth at a time until the indicator needle just moves. Stop as soon as you see the needle move. Look at your DRO, see what it reads, that is your backlash. (That is provided you have your motor steps per revolution set correctly)
"Jack of all Trades, Master of None"