Quote Originally Posted by Boyan Silyavski View Post
Normally cutters when new are spot on. Even Chinese. Check size though before inputting in CAM.


next step is 30mm circle in say 50mm square. 1mm depth, best i use Phenolic sheet as its very precise and holds incredible detail, same time not affected by temperature or humidity. As MDf is not right even 1 min after the cut/ i live near the sea.



If problems like in your case, then i go even simpler and do pure straight lines. dig 1mm deep and tell mach3 or controller to move 20mm. Then line will be 20+d of bit, easily measured with caliper. So its easy to figure whats happening and where.
Hi,

Cutting oversize ? If I read and understand correctly.
I would have a go at the step per given movement in Mach3.
Having said that i would also suggest that you do it over 85-90 % of axis travel
The quick and dirty way is the 3 4 5 triangle ( some maths involved to be within the limits of the shortest axis travel) but as big as you can get.
we mark out on a 3mm mdf fixed to the table and pin in tool on the spindle. does not have to be in the spindle , I have used darning needles fixed to the z axis. as long as it is constant position. Align the MDF to the long axis, errors will be the the diagonal and y axis
the test here is to see how close the DRO is to the measured distance marks. any variance in the x and y units will show up in the diagonal.
Regarding tool dia. Mach will let you put anything into the tool library for a tool dia. To me this this is the width of cut, the end of the day when of the all run-outs have had the effect. ( now having said, that I assume that the z axis is true perpendicular to both x and y .. it will effect the cut profile). I use off-cuts of corian I get it from the off cuts bin at the kitchen counter top factory. The bits they cut out for the sinks.
When swinging the z axis the bigger the radius the better. At this stage one can see if the x axis (for the purpose of this chat .. the long axis) are running parallel and flat to the bed. just move it to the corners of the bed at a fixed z height. If its out try jacking up the corner of the frame and leave it for a day. the colder the slower it beds it self in. A machinist level is the tool here level the x axis rails then the Y axis.
Sorry for the ramble, Public holiday afternoon here with a kit shelving job in progress lubricated with a very nice single malt.

Regards
Paul