Tree mill collets not releasing?

tobnpr · Apr 19, 2020

Learning the ropes on using the Tree collets- seems there's a fine line between getting the collet tension tight enough so that the cutter won't break loose under heavy cuts, and not so tight it won't release. The paperwork I have says to snug the collet nut by hand, then back off a half-turn. That doesn't work, so I tighten until I feel moderate resistance as it cams over.

More often than not after cutting, I need to "tap" the end mill with a rubber hammer (after releasing the collet), and then it falls right out. Not a big deal, but obviously not the way it's intended to work. No burrs or other imperfections in the taper and the collets are in good shape.

Is this expected, or is there something here I haven't figured out?

thermite · Apr 20, 2020

tobnpr said:
Is this expected, or is there something here I haven't figured out?

No klew, here. Or no "Tree", anyway!

But "packrat memory" recalls a thread on successfully tuning up Tree's special collet system "Right here, on PM".

Search for that if you have not already read it.

Prolly need Go Ogle to do it from the "outside", as it was a while ago, already, and PM's own search is a tad less effective.

jwaples11 · May 7, 2020

Hello tobnr -

I have had the opposite issue on my Tree 2UVR (collet won't stay closed) and although the forum has some very helpful posts, none of them explained EXACTLY how the inner workings of the collet closer worked. Since I still have the spindle apart I can provide some good close-ups that may help you and other future users.

As you know, when you pull the collar out to capture the shifter sleeve and move the quill lever down, the collar forces the shifter sleeve (M-1005) up which should unlock the collet. When you move the quill lever up, the shifter sleeve moves downward and if you have the collet nose adjusted properly, you will feel the lever "cam over" with the tool locked in place.

The diagram shows the collet closer shifter sleeve (M-1005) in the locked position. When the shifter sheeve moves upward to the unlocked position, it allows 31 ball bearings (M-1006) to drop downward and inward which in turn allows the collet closer adapter (M-1004) and collet closer nose (M-1003) to move down enough to loosen the grip on the collet.

There is nothing else going on in there. If the collet is not letting go it may be worn out or perhaps the tapered ground surface that mates to the upper half of the collet is dirty.

So lets talk about the details of the collet closer shifter sleeve (M-1005) The sleeve is a close fit over the spindle and nose that comes into contact with the ball bearings is chamfered. This surface needs to be clean and undamaged. This was not the case on my mill. You can see that the chamfered nose of my shifter sleeve is heavily damaged with dents from the ball bearings all the way around it's periphery. This means that depending on luck of the draw, you could not get it to "cam over" if the balls fell in the pre-existing dents. (Note that this material is VERY hard, must have been quite a chore to damage the shifter sleeve this badly.)

Finally, if you do not find a simple root cause to your issue and end up removing the spindle this is what you get with it out of the machine. The new shifter sleeve is installed and held in place temporarily with clear tape so that the ball bearings can't fall out. (Note: disassemble and reassemble it in some kind of tray so that you do not lose the bearings.) Note that the spindle bearing nut that retains the assembly is shown and it is 1-1/2 inches across the flats. You will need to make a super deep well socket to remove it - at least 5-1/2 inches deep. My spindle bearing nut (M-1014-A) was cross threaded - for posterity the thread size is 1-3/16 in. and 24 tpi. If you need to make one, use steel that is relatively soft so that it sacrifices itself rather than the spindle threads if you cross-thread it.

Mold God · Nov 7, 2020

I used a 2UVR and a 4 VGC for 10 years, I wish I could be of help. My experience was that the main problem with the Tree collets was that they would let loose under heavy load. I loved the flexibility of the system, being a moldmaker, I had lots of tool changing going on. I agree with the chap who opines that the collet or quill (or both)might be dirty. A trick to keep tools in that seem to walk out while being used: a little chalk on the tool to collet surface will sometimes give enough traction to get the job done.

Rick Hand · Nov 10, 2020

I've had the same problem when attempting to release a tool. The mill isn't mine, I help a friend when I have time. We have never looked into it and enjoy this thread.
Thanks,
Rick

LoShel · Feb 4, 2024

jwaples11 said:
Hello tobnr -

I have had the opposite issue on my Tree 2UVR (collet won't stay closed) and although the forum has some very helpful posts, none of them explained EXACTLY how the inner workings of the collet closer worked. Since I still have the spindle apart I can provide some good close-ups that may help you and other future users.

As you know, when you pull the collar out to capture the shifter sleeve and move the quill lever down, the collar forces the shifter sleeve (M-1005) up which should unlock the collet. When you move the quill lever up, the shifter sleeve moves downward and if you have the collet nose adjusted properly, you will feel the lever "cam over" with the tool locked in place.

The diagram shows the collet closer shifter sleeve (M-1005) in the locked position. When the shifter sheeve moves upward to the unlocked position, it allows 31 ball bearings (M-1006) to drop downward and inward which in turn allows the collet closer adapter (M-1004) and collet closer nose (M-1003) to move down enough to loosen the grip on the collet.

View attachment 287812

There is nothing else going on in there. If the collet is not letting go it may be worn out or perhaps the tapered ground surface that mates to the upper half of the collet is dirty.

So lets talk about the details of the collet closer shifter sleeve (M-1005) The sleeve is a close fit over the spindle and nose that comes into contact with the ball bearings is chamfered. This surface needs to be clean and undamaged. This was not the case on my mill. You can see that the chamfered nose of my shifter sleeve is heavily damaged with dents from the ball bearings all the way around it's periphery. This means that depending on luck of the draw, you could not get it to "cam over" if the balls fell in the pre-existing dents. (Note that this material is VERY hard, must have been quite a chore to damage the shifter sleeve this badly.)

View attachment 287813

Finally, if you do not find a simple root cause to your issue and end up removing the spindle this is what you get with it out of the machine. The new shifter sleeve is installed and held in place temporarily with clear tape so that the ball bearings can't fall out. (Note: disassemble and reassemble it in some kind of tray so that you do not lose the bearings.) Note that the spindle bearing nut that retains the assembly is shown and it is 1-1/2 inches across the flats. You will need to make a super deep well socket to remove it - at least 5-1/2 inches deep. My spindle bearing nut (M-1014-A) was cross threaded - for posterity the thread size is 1-3/16 in. and 24 tpi. If you need to make one, use steel that is relatively soft so that it sacrifices itself rather than the spindle threads if you cross-thread it.

View attachment 287816

My shifter sleeve M-1005 moves up and down freely. does this mean all the M-1006 balls are gone? did you get a new M-1005 shifter sleeve?

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Tree mill collets not releasing?

tobnpr

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thermite

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Mold God

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Rick Hand

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LoShel

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