R8 pin dropped

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rronald

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After fighting with some R8 tapers, I decided to remove the locating pin in my PM-833TV mill spindle.

Unfortunately, I goofed up and the pin dropped off inside the quill. Feel free to abuse me for being foolish enough to drop this piece. I've had it out before with no issues, but I obviously didn't exercise sufficient care. DOH!

A picture of the quill opening that provides access:
Spindle pin access.jpg
Two questions:

1) Any suggestions on how to extract it w/o taking everything apart? I thought about putting a small magnet down to grab it, but with all the spindle being steel, it seems unlikely to work.

2) Is there any risk to using the mill with the very small set screw loose in there.
 
You'd be surprised, a magnet might work if you can keep it centered in the gap between the quill and the spindle. Some magnetic pick-up tools have the magnet in an aluminum sleeve, that helps keep the force directed forward.
Also, there are those retractable-claw type, grabbers.
No, I wouldn't leave the pin in there.

For reference:
 
I agree with @Eddyde. Give a magnet a try or any other creative solutions others come up with.
I absolutely would not leave that set screw in there.
 
Ow, that sucks. I would definitely get it out - there's no telling what it could do in use - anything from galling to jamming up.

Can you see the pin or have any certainty where it is? With a strong enough magnet you may be able to apply the magnet to the outside of the quill and drag the pin up to the opening (slowly, slowly). Otherwise it's magnet on a piece of wire (so you can push it down far enough, it won't fall).

Are you able to rotate the head to an upside down position? (If you try, I'd take precautions to make sure it can't move past the hole and get lodged higher up.)

Good luck!

GsT
 
@rronald Another data point you may want to consider is permanently removing that pin. The locating pin for R8 collets has come up in conversation before and the general consensus is that it is not required. The taper of the R8 is what keeps the collet from spinning in the spindle under load, not the locating pin. I am not really sure what that pin even does.
 
I removed mine very early in the game. They seem to work fine on high end collets, and the cheap imports tend to bind up on them. I just removed it. Fish it out of there and dont put it back in is my vote...but ABSOLUTELY get it out of there. Like someone said before, it may be easier to tilt the head just past 90 degrees clockwise, and see if you can fish it out with a greased long Q-tip or something. Then Re-tram.
 
Ironically....I was permanently removing it. But I did it badly.

Just spent an hour trying to make an old el-cheapo borescope work on a couple of really old phones since my newest phone has USB-C and the borescope has micro USB). I think I sighted the set screw, but the 7 or 8 year phone battery decide 15 minutes of run time was all I could have.

I also tried removing it with some small plastic hose and a vacuum pump. If it was directly below the access point, I'm pretty sure the vacuum would hold the set screw at the end of the hose. Unfortunately, it's hard to snake around the spindle within the quill.

I'll try again with the borescope when the battery comes back up.
 
7milesup said:
and the general consensus is that it is not required
Click to expand...
The consensus amongst professional machinists, and machine rebuilders is that the pin is required.

You can do without it, but I would never remove mine, and I've installed several for people. If the collet sticks on the pin, it is not made to spec. Fixing the collet isn't all that hard.

The pin is there for repeatability. It is not there for prevent the collet from turning under load. It does assist during the first threads of the drawbar, keeping the collet from moving while tightening (hands free).
 
rronald said:
Ironically....I was permanently removing it. But I did it badly.

Just spent an hour trying to make an old el-cheapo borescope work on a couple of really old phones since my newest phone has USB-C and the borescope has micro USB). I think I sighted the set screw, but the 7 or 8 year phone battery decide 15 minutes of run time was all I could have.

I also tried removing it with some small plastic hose and a vacuum pump. If it was directly below the access point, I'm pretty sure the vacuum would hold the set screw at the end of the hose. Unfortunately, it's hard to snake around the spindle within the quill.

I'll try again with the borescope when the battery comes back up.
Click to expand...
Good luck! If you can not get it that way, I would definitely try to tilt the head 90 degrees to isolate the pin to a known position (bottom of a curved cylinder) and fish it out then, before I removed the spindle.
 
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