[m_mcgranahan]

Hi,

I am running my KMBX-1 via conversational programming and today I milled a hole that was supposed to end up 1.125" instead it ended up 1.130"! I have tripple checked all my settings and I can't find any reason why this would happen! My cutter in a true .500 mill and I set .500 as cutter. I put in compensation . I set .5625 as my radius setting for the hole I was milling.

Any idea what I am missing?

Thanks

God bless...
Mark

[Rich Carlstedt]

You don't say if the machine is new to you ?
Also assume the machine is older mill ?--condition ?
You don't say if you used a finish pass ?
Cutting oversize by that amount is weird.
Material ?

Run a check on loose ballscrew bearing and nuts ?
Also was X and Y axis the same ?

Rich

[m_mcgranahan]

Hi,

I have owned the machine for about 2 years now. T
he mill is older, it made Dodge transmission parts for decades...
I did not use a finish pass.
It is in Alum.

I don't know how to check for loose ball screw and nuts but I would love to learn how if you can pass that info on)

Yes x and y the same...

Also, just the night before milling this hole, is used a .375 mill and milled an identical hole (1.125") and it was spot on, 1.125" (I obviously used .375 as the cutter size for cutter compensation. It was almost like the .500 cutter compensation is off somehow???

Thanks

God bless...
Mark

[neilw20]

The cutter cuts oversize due to runout?
Put in some compensation (tell it cutter is oversize) and get it to cut the correct size.
Put a dial indicator on it. Each flute exactly the same?

[Dylwad]

Was it a climbing or regular cut? A heavy regular cut without a finish pass could make it oversize due to machine and tool flex.

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[m_mcgranahan]

Hi,

I will have to check that end mill to see if the flutes are the same. (That would make sense why it did it one one and not the other end mill)

[m_mcgranahan]

Hi,

It was regular cut going from 26mm hole to 1.125" hole. Cut was pretty slow (35 pecks to go 1.23" down)

Was it a climbing or regular cut? A heavy regular cut without a finish pass could make it oversize due to machine and tool flex.

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[m_mcgranahan]

HI,

SO I cut a new hole (Same cut into an atv swing arm I am sleeving) I found that I had about .002-.003 of play in the fixture I was using to hold the swing arm upright. I managed to get that down to about .0005 of play and slowed down the feed rates and got it to cut a perfect 1.125 hole. Thanks for the help.

God bless...
Mark

Here is a link to some video of this milling :-)

http://www.youtube.com/watch?v=2cqyf...bWj2vA&index=1

[neilw20]

I see you are doing conventional milling and not climb milling.
Usually climb milling will give a better finish, except in plastics.
https://www.google.com.au/search?q=c...w=1203&bih=762