[chevelless502]

We have a Haas SL30T lathe. We are trying to drill a .234" hole in a solid .500 dia piece. The part is 3.375" long. When the hole is drilled it will be nearly on size at the back end of the part but on the turret side, (entrance side) it is running between .020" and .030" larger dia. No matter what we have done we cant get this out of it. We have also noticed it a few months ago on a par that was about 2" long that we were putting a hole thru then tapping it 5/8-11. We did some measuring and the turret has about .015 run out on it when you rotate it around. Is there a way to shim the turret in order to get that out of it?

[machinehop5]

...easy to check Alignment (with manual) looks like on page 57.
https://www.haascnc.com/content/dam/...ual---2004.pdf

[deadlykitten]

hy it seems o5 hole in 12.5x85mm stock

0.5-0.7++

pls share photo with setup; its a matter of overhang + coaxial aligment / kindly

[chevelless502]

hy it seems o5 hole in 12.5x85mm stock

0.5-0.7++

pls share photo with setup; its a matter of overhang + coaxial aligment / kindly

Not sure I understand all you are saying but part of it I do. At first we had about 1" hanging outside of the jaws of the chuck. We tried to put it back where less than .500" was out of the chuck and still had the same troubles.

[deadlykitten]

is the drill coaxial with the spindle ?

[Jim Dawson]

I had a similar problem a few weeks ago. 0.250, 135 deg., split point, cobalt stub drill. Cross drill 0.250 - 0.253 thru about 0.475 diameter, 303SS. Was getting 0.255 - 0.258, and a taper, tried about 6 different new drill bits. Then went and bought some new bits from our local vendor, different brand (and more expensive). The problem went away and we were back on size, with no other changes.

Given that you are drilling almost 15 diameters deep, you may need to use a gun drill and properly prep the starting hole. Is the tool holder aligned with the spindle centerline? Both axial and radial? Are you spot drilling the start?

For a 5/8-11 I would rough drill then bore to minor diameter. Then thread mill. Depending on the material I thread mill in one pass. I make hundreds of 6061 parts this way, 1''-8 thread, 2 inches deep, one pass.

Is that axial or radial runout on the turret? You should be able to compensate for axial and radial runout. If the runout is conical then it gets more complicated.

[chevelless502]

is the drill coaxial with the spindle ?

That is the problem. We dont think it is and need to try to adjust the turret if possible.

[chevelless502]

I had a similar problem a few weeks ago. 0.250, 135 deg., split point, cobalt stub drill. Cross drill 0.250 - 0.253 thru about 0.475 diameter, 303SS. Was getting 0.255 - 0.258, and a taper, tried about 6 different new drill bits. Then went and bought some new bits from our local vendor, different brand (and more expensive). The problem went away and we were back on size, with no other changes.

Given that you are drilling almost 15 diameters deep, you may need to use a gun drill and properly prep the starting hole. Is the tool holder aligned with the spindle centerline? Both axial and radial? Are you spot drilling the start?

For a 5/8-11 I would rough drill then bore to minor diameter. Then thread mill. Depending on the material I thread mill in one pass. I make hundreds of 6061 parts this way, 1''-8 thread, 2 inches deep, one pass.

Is that axial or radial runout on the turret? You should be able to compensate for axial and radial runout. If the runout is conical then it gets more complicated.

The tool holder is aligned with the spindle centerline we made sure of that. We are spot drilling first then drilling after that.

Not sure how to best describe it but the centerline of the spindle appears to not be perpendicular with the face of the turret. You can face a part off on the end and it will clean up the part with no bump or numb but its when you go to drilling into a part is when we have the issues.

[deadlykitten]

don't worry, such things can happen even on a machine with good alingment

replace the drill with a solid shank, same diameter and length as the drill

use a dial to check that it is paralel to z axis, in xz plane, then in yz plane, thus on 2 generators at 90* phase shift; deviations are allowed, is not critical to hit 0.0000etc, and values can be adjusted by rotating holder, changing tool chuck, changing screws order, using shims, etc

after that, use a coax, to check that tip is as close to spindle center as possible

an y turret will help, otherwise it will be a bit more chalenging

something tells me you have not been throw such a simple yet life saving procedure so far ...

Not sure how to best describe it but the centerline of the spindle appears to not be perpendicular with the face of the turret. You can face a part off on the end and it will clean up the part with no bump or numb but its when you go to drilling into a part is when we have the issues.

such things are not always related; for example is possible to face and get a clean part, but still have problems with drilling, etc

if you wish, i will go deeper into such things

for specific details, pls show an image of tool + toolholder; is late 4 me, keep in touch

Given that you are drilling almost 15 diameters deep

hy jim it may not be required to spot drill before, i know cases of even longer l/d ratios that worked without internal coolant, for a long series setup, hss drill being changed once at few days ... just be sure that toll is new, in good condition, etc / kindly

[chevelless502]

don't worry, such things can happen even on a machine with good alingment

replace the drill with a solid shank, same diameter and length as the drill

use a dial to check that it is paralel to z axis, in xz plane, then in yz plane, thus on 2 generators at 90* phase shift; deviations are allowed, is not critical to hit 0.0000etc, and values can be adjusted by rotating holder, changing tool chuck, changing screws order, using shims, etc

after that, use a coax, to check that tip is as close to spindle center as possible

an y turret will help, otherwise it will be a bit more chalenging

something tells me you have not been throw such a simple yet life saving procedure so far ...



such things are not always related; for example is possible to face and get a clean part, but still have problems with drilling, etc

if you wish, i will go deeper into such things

for specific details, pls show an image of tool + toolholder; is late 4 me, keep in touch



hy jim it may not be required to spot drill before, i know cases of even longer l/d ratios that worked without internal coolant, for a long series setup, hss drill being changed once at few days ... just be sure that toll is new, in good condition, etc / kindly

See the attached pics. The drill bit was no longer in the holder as we put a dowel in it but it is held in a collet style holder. The drill bit is a solid style cobalt material bit. We have tried 3 different bits all brand new and had the exact same results.Attachment 475014 i

[Jim Dawson]

That is the problem. We dont think it is and need to try to adjust the turret if possible.

As crazy as it may sound, it is not important that the turret face is aligned with the spindle, only that the tool holder is aligned and the carriage moves perfectly parallel to the spindle axis.

See the attached pics. The drill bit was no longer in the holder as we put a dowel in it but it is held in a collet style holder. The drill bit is a solid style cobalt material bit. We have tried 3 different bits all brand new and had the exact same results.

From my post above '' Then went and bought some new bits from our local vendor, different brand (and more expensive). The problem went away and we were back on size, with no other changes.''

Not saying it's the bits, but worth a try. I would also drill about 3 or 4 diameters deep with a stub drill, then finish with the long bit.

[deadlykitten]

hy chevelles, pls check attached i tried to explain it nice, get a cup of coffe/tea, go through it maybe with your colegues, etc

That is the problem. We dont think it is and need to try to adjust the turret if possible

such adjusments are needed, but not on the turret; once you understand them, you will see that there are faster alignment methods that don't involve the turret

even more, based on this, there exist special holders and sleeves, designed to allow faster alingments for such situations that are similar to yours / kindly

As crazy as it may sound, it is not important that the turret face is aligned with the spindle

hy jim, yup, this is very true ... is possible to setup up a misslainged turret/spindle for deep drilling / kindly