Test Holes are tapered

[charliem]

Hello Everyone,

I have a 6040 Router that I replaced the stock drivers and motion control with a G450 and Uc100 and Uccnc software.

After calibrating all the axis I did some test cuts in first wood and then plexiglass. The hole size and shape is good enough, but one thing I did notice is
The hole is slightly bigger at the top then at the bottom. I have confirmed this with a gauge plug. What I am doing is cutting a pocket .625. I check the size with a .625
gauge plug and at the bottom of the hole the fit is what you would want. At the top the gauge plug is a tad loose. I readjusted the Spindle tram to with in .004 in the X and Y. any other ideas as to what might cause this? Thanks.

Charlie

[Robertspark]

a coupling loose?

[ger21]

Flex in the machine is probably the only thing that could cause a tapered hole.

[Robertspark]

is it stepped or tapered?

[charliem]

Thanks for the replies.

Its not stepped. the pocket is just looser at the top then at the bottom of the pocket. At first i was using a 1/8 bit. the feed rate did not seem too fast 40 ipm.

I changed the size of the pocket to .625 and then using a 1/4 in bit retested. its no as bad. Thanks for the suggestions.