How to account for difference in m/f matching part

[lrheimpel]

I am a new shopbot buddy owner, machining my first parts.

I am trying to machine 2 matching parts that fit/couple each other male/female type fitting using a circle 2.25 inches in diameter.

On one piece of material I machined a path on the outside of the circle to make the male component. The resulting piece is 2.26 inches in diameter.

On another piece of material I machined a pocket (also tried a path on the inside of the circle) inside the 2.25 in circle. The resulting pocket is 2.24 inches in diameter.

The 2.26 in male part does NOT fit the 2.24 in female part.

How do I account for this so my parts end up matching each other? Why does this happen? Is my cutter a hair under its 0.25 in diameter size?

[jerry_stanek]

What software are you using. If you have Vcarve pro 5.5 or partworks you should have the inlay tool.

[srwtlc]

Luis,

The most likely thing that is happening is that your 0.25" bit is deflecting into or away from the intended cut path (depending on what direction you're cutting and whether you're using an upcut or downcut bit).

You can leave an allowance on the cut (0.015" - 0.020" or so) and follow up with a final light pass to get the right size. For inlay or mating type work, it's best to allow a little play so that the parts can fit without having to force them together.

Try a 0.375" cutter.

The other possibility would be that your unit values for your tool may be off a bit, but I'm guessing that they're just fine and your bit is deflecting in the cut.

[lrheimpel]

Jerry, I am using PartWorks 2.5

I am not using the inlay tool, will take a llok at it this afternoon. Any tips?

[knight_toolworks]

the easiest way to do it is cut the male part cut the female pocket test the fit if possible before the part is cut out and dial it is.
Therew is no hard rule to deal with the slop of the machine. it depends on bit size cut speed cut direction and material.
if you are cutting the normal direction the outside of the piece will tend to small and the pocket will tend to be small too. so I will cut the male piece cut the pocket teast the fit till perfect and off I go. you can also cut the maple piece with a tapered bit and it will be easier to fit it.

[jerry_stanek]

I just cut 16 inlays and I had to use the off set to get it just right.

[lrheimpel]

Jerry, Scott and Steve:

Thanks for your comments and tips. I used the inlay tool in PartWorks 2.5 but that still did not do it. While reading about it I noticed the tolerance factor variable.

In the end, I cut the male part as is (an outside profile cut) and when cutting the female pocket, increased the tolerance amount until I got it just right. The machine makes the cut a tad smaller or larger depending on the +/- sign and the amount of the tolerance value.