Originally Posted by
Glidergider
...until we closed in on the back of the long axis bearing mount. It turns out that on the back side of that mount, there is a MDF block, which appears to be an adjustment feature or just a structural backup block. Its detail 21. Its also shown on assy07.
Can you shed some light on its purpose?
Are you sure you got the drawing number correct. According to my PDF plans CNC_dtl21 is a GANTRY - CORNER BLOCK. Are you talking about the ANTI - WHIP BLOCK SPACER (cnc_dtl24) and the corresponding ANTI - WHIP BLOCK (cnc_dtl23)? If you are, then the purpose is to help keep the long axis leadscrew (1/4"-20 x 43.50") from 'whipping' around like a jumprope while moving. This is apparent at higher feed rates (motor RPM) and the farther you get from the drive motor. The sound is horrible and results in reduced accuracy and repeatability. The A-W Block Spacer also seems to help stabilize the gantry a bit.
If you used 3/4" Delrin/HDPE for the ANTI - WHIP BLOCK (cnc_dtl23) you wouldn't need the A-W Block Spacer (cnc_dtl24). If you're converting to a larger ACME leadscrew the A-W Block is one of the parts that requires modification.
HayTay
Don't be the one that stands in the way of your success!