X axis on a G0704

I have the di touching the fixed jaw on one side to the four inch vice jaw. Every turn on the crank moves the x axis .100 and during every turn on the x axis there is no movement of the di for .060 and the on the last .040 of the turn the di moves +.00075 and then returns back to zero. This happens on every turn of the crank. Why would it run true for 2/3 of the travel then move off for the .040 and then return. I probably am expecting to much from the mill but would like to know why this happens

Any ideas
 
Woa, that's not what I was describing on mine. I have no idea what that is other than maybe a bent lead screw?
 
You could start out by tightening the X-axis gib (look on page 41-42). You have tapered gibs with an adjustment screws on both ends.

I also suspect that Bill is right, your lead screw is slightly warped, and it is causing the table to deflect in the y direction. Tightening your gib may solve this problem, but for that slight amount of movement, it probably isn't worth it.

To be blunt, you are expecting too much. You are talking about less than a thousandths error. Even a $15000 bridgeport is only going to give you accuracy to 0.002". The machinists I trained with said trying to exceed that accuracy is a waste of time unless you really have a critical part (and that is where cylindrical and surface grinders come into play).

If I push on one end of the table on a bridgeport, I get 0.001-0.002" deflection. Cutter deflection under load can cause a similar amount of error (ie. 0.0005".)
 
Last edited:
Bent lead screw! I had mine replaced under warranty! Easy to check remove screw and roll on flat surface!
 
You must log in or register to reply here.
Back
Top