[garylb]

Hi,
Im using a 14mm 4xd u drill on an SL10 and am getting a 0.010" oversize hole on mild steel, 0.040" o/size on stainless steel and im also getting a pip in the centre of the hole. It does look like the web with the inside insert is rubbing as there are a few marks on the web. I placed a clock in the chuck and clocked around the dia of the shank and it was within 0.004". Is this too much? The turret is also 0.004" out over 3 1/2" in the x axis after a crash when i first got the machine. The thing is i have been using a 20mm u drill for years and have never had this problem with it. Could the u drill be vibrating too much and causing the issue?

[garylb]

im getting somewhere now. I have placed a shim under one end of the toolholder so the x is now parallel. I no longer get a big pip but the drill is still cutting o/size

[txcncman]

0.004" TIR would equal 0.004" over size. +/-0.004" run out would equal 0.008" oversize. Put a dial indicator down the side and across the front of the tool block for square in addition to checking shank. Adjust X axis run out in offset. Read the Haas manual on how to adjust Y axis run out.

[garylb]

0.004" TIR would equal 0.004" over size. +/-0.004" run out would equal 0.008" oversize. Put a dial indicator down the side and across the front of the tool block for square in addition to checking shank. Adjust X axis run out in offset. Read the Haas manual on how to adjust Y axis run out.

there was a 0.005 run out across the side of the tool block. I have now placed a 0.005 shim at one end and re clocked and is now within 0.0005. I clocked the face and it was 0. I then clocked the bore of the holder and it was within 0.002".
Next i inserted the drill and clocked the shank which was fine, i then clocked the tip of the drill on the web and it ran out by approx 0.005".
It cut 0.5mm o/size on mild steel with no pip, 0.75mm o/size on stainless with a pip. I have altered the x offset and can now cut without a pip but it still cuts 0.75mm o/size
I have tried the drill on my minimill and it cuts 0.25mm o/size on mild steel
I think there may be vibration due to the length of the drill which is causing part of the problem which would explain why it is worse on stainless

[txcncman]

Agreed. It sounds like drill walk. Does the problem increase or decrease with change of feed rate? If the flutes are aligned with the X axis, you should be able to compensate for size with X axis offsetting.

[garylb]

i was using 0.05mm per rev feed but havent tried any other feed yet. I have finished for the day now so will try different feeds when i get back on monday.
So would i have to alter the x axis in the - direction, if so is there a chance the drill will rub if i go too far?

[txcncman]

Most of the inserted drills I have used can be adjusted for size on X axis +/-0.010 with no problems.