backlash info

[hmcl281]

do u have to adjust backlash every time u change direction of the table? sorry for a milling machine

[smiller6912]

You need to compensate for backlash to return to a given location.
The "take-up" between the lead screw and its nut happens each time you change direction, so, you can not just back up .XXX amount, you need to backup past it (I always go a full turn, just for ease of remembering) and then come back to your required position.
Adjusting for backlash only minimizes it and only needs to be done when it becomes excessive.


( Does that even make sense, I read it thrice and I'm still not sure)

[Fasttrack]

You have to be aware of it ... you don't have to "adjust" for it neccessarily. Just crank the dial two extra revolutions when you change direction to "take-out" the backlash. If you need to reverse direction, reverse two full reveloutions plus the amount you need to go, then move back in two revolutions. Or, on a mill, you could lock the table and then crank the dial until the backlash is gone but it's not a wonderfully precise method.

[hmcl281]

You have to be aware of it ... you don't have to "adjust" for it neccessarily. Just crank the dial two extra revolutions when you change direction to "take-out" the backlash. If you need to reverse direction, reverse two full reveloutions plus the amount you need to go, then move back in two revolutions. Or, on a mill, you could lock the table and then crank the dial until the backlash is gone but it's not a wonderfully precise method.

sorry, forgot to mention it was a milling machine. i might have to try the locking the table. doe backlash only happen when u r moving on the x axis? does in only affect the z axis or both but u only notice the y because the x has already been cut into?

[smiller6912]

...doe backlash only happen when u r moving on the x axis? does in only affect the z axis or both ...

Backlash is the movement (or lack of) due to the clearance between the lead screw and its nut. It exists in all lead screws. It can usually be adjusted to a minimum amount but can never be eliminated completely.

[smiller6912]

PS. a good way to check the backlash on your machine is to lock down the axis and see how much the handle turns. That is the backlash. You just need to remember to compensate for it.

[Forrest Addy]

Competently handled. Nothing I could add except to praise the clearity and brevity of responses.

[SGW]

Don't try "adjusting" or "compensating" for the backlash, as it probably varies depending on where you are on the leadscrew and you'll go crazy in short order. As others have said, just always take up the backlash in the same direction, then it doesn't matter how much or how little the backlash is.

[John Lawson]

This is one of those things in our trade where "Good enough for Government work" is allowed. And, heed the advice above about variations on different parts of the lead screw, especially on Chinese machines.