zzero for itsybitsy bits

[twelchPTM]

While working with a .015" endmill I quickly learned that the stock zzero routine snaps the tops off very easily... I know someone asked about this before so heres what I did....
in the Zzero.sbp file I added two lines, the first inserted at line 77 -
&new_Zmove_speed = .05
the second at line 93 -
VS, ,(&new_Zmove_speed )

now when working with tiny bits I comment the stock lines and uncomment the new lines, this moves the bit at the slowest possible speed and they don't break and when I'm done I change the comment makes back the other way.

I've read several techniques for zeroing the little bits but they only work with initial setup, when my partfile automatically calls the zero routine after a bit change I'm in the clear.

[garyr6]

Thanks. Those little bits are expensive

[dana_swift]

I have posted on this topic before.. I use 0.020 bits, and the way to zero them is to sightly lift the ZZero plate on once side until the first contact occurs, then set it on the material for the second slow "accurate" contact.

Then it should zero without any difficulty.

Hope that helps-

D

[David Iannone]

What supplier are you getting a .015 or .020 bit from? Also what size collet do you use to hold them?

[Brady Watson]

Your actual move speed will be .4 IPS unless you change the VR settings for Z Move speed. (2nd parameter in list) The default setting should be changed back to .4 again because cutting will be soggy and slow in the affected axis, and step timing can get dicey causing a COM error, although this is less prevalent in the newer versions of SB3. Your SBP can specify a .05 IPS move speed, but unless the 1st 2 parameters in VR are that value or lower, than it will never go that low.

All cutting diameter tools (end mills...not Dremel tools) less than .125 in diameter use a .125" shank.

-B