1. ## G41

hello

2. There is no substitute to reading a book/manual.

In offset table you enter tool radius (edit the value if it is not correct), under D-column. Use geometry column. Have 0.0 in wear column.
I guess you are referring to a milling machine.

3. thankyou
G41 turn cutter radius compensation on left.and G42 is right.what is mean left and right?

4. When you move in the direction of feed motion, G41 shifts the tool laterally to the left of the programmed path, by an amount equal to tool radius, so as to cut the along the defined profile. G42 shifts to the right of the programmed path.
So, for example, if you want to machine a hole, use G41 for CCW toolpath, and G42 for CW toolpath.
On some controls, if you enter a negative value for radius in the offset table, the function of G41/G42 reverses.
There is a lot more to radius compensation. As I said, you need to refer to a book.

• imagine that the tool is a car you are driving and toolpath is the line in the middle of the road. If you are driving at the left of the line it's G41 and if you are driving at the right it's G42. But i'm agree with Sinha You should read a bit about G code programming instead of waiting answer from us.

• Here is an excellent source for learning about CNC all the way from a simple introduction to complete G and M code programming,

http://technology.calumet.purdue.edu/met/mfet/275/

• Another helpfull rule in a lathe could be:

external machinning (g42)
Internal machinning (g41)

Of course depending on the structure of the machinne and tool clamping system, but normally....

• Using thumb-rules on CNC can be dangerous. These might work in 99% cases, but you may belong to the unfortunate 1%. And you would realize it only after a crash. So, always try to reach a logical conclusion.
For example, G42 is indeed correct on a rear-type lathe during external machining, but if you need to machine left-to-right, you have to use G41!