R8 collet problem

I had the same problem with some R8 tooling in my ZX-25 mill/drill. I figured out that the grooves on some of them were, as mentioned, too shallow. I ended up grinding the pin down just enough to fit the worst of the tools. I've never had any trouble since.

Because the outside diameter of all R8 shanks is the same, within tolerances, the top edge of the groove is in the same place. Works fine with a slightly shorter pin - just not too short.
 
I finally got some time to get to the mill and the collet issue is no more. Thanks to you guys here and to Matt who responded to me by email.

After I unscrewed the ''spindle cap'', I realized the pin was in fact some set screw that can be adjusted so no more questions about it: any reasonable keyway depth will fit in there. One would simply have to adjust the setscrew if another tool had a deeper or shallower slot.

After this happy discovery, I had time to clean and install the vise on the table. I think I did a fair job at ''indicating'' the vise but still need some practice.

Don't know if «indicating» makes sense to you guys I am french and some times I am not sure if I choose the correct words to be understood.:dunno:

Again thanks guys, hey, I just made my first (home made) chips! :thumbsup:
 
Cool, I didn't know the pin was adjustable. I'm not sure what the spindle cap is though. Can you post a picture? Thanks,

John
 
The spindle cap is the round threaded cap that is just below the lower spindle bearing. There are 3 dimples in the cap that can be used to unscrew it. I used a small punch and gently taped in the dimple so the cap would turn counterclockwise. It was easily unscrewed

Here is a pic of the opened cap (Thanks to Matt's email) You dont see the actual cap but you get where it is installed. The set screw is visible.

Spindle cap.jpgPS.: Spindle Cap is the name I gave it, it might no be the official name:)

Spindle cap.jpg
 
OK, that makes sense. I'll have to adjust mine a little bit too. Some of my collets are still a bit tight going in. Thanks for sharing that information!

John
 
Hey Guys, glad to see you are all fixed up.

Just remember, that pin in there is NOT what keeps the collet from turning when running the machine. I don't even have them in most of my own machines, I take them out. Because the taper of the R8 is what holds it. I've spun R8 tooling in spindles before, and when you go to take it out, its stuck, because it sheared the key off and turned a bit. With the key not in there, you never notice it, and just take the tool out.

But if the pin is in there, it can shear off, and get stuck, if your collet is a little loose, or you are using a bigger face mill or larger drill something and it twists in the taper.

So my advice? (Not just for this machine, ANY R8 Taper) Take the pins out completely. It can save you a headache from getting a stuck collet out, and they really serve no purpose for locking, that is what the taper does.
 
Thanks, I checked our two machines here at work and they both miss the pin so I guess its no big deal after all!
 
First thing I did was remove the pin but was reluctant to mention it here fearing a flurry of contrary opinion but, the cat's out of the bag. As long as you have a double nut arrangement on the top of the drawbar, there's no way it will get stuck with no way to loosen it. Just unlock one nut against the other and the thread comes loose then, tap it down and the spindle attachment comes out. Just always make sure you have plenty of thread engagement in the spindle attachment.

Ray

qualitymachinetools said:
Hey Guys, glad to see you are all fixed up.

Just remember, that pin in there is NOT what keeps the collet from turning when running the machine. I don't even have them in most of my own machines, I take them out. Because the taper of the R8 is what holds it. I've spun R8 tooling in spindles before, and when you go to take it out, its stuck, because it sheared the key off and turned a bit. With the key not in there, you never notice it, and just take the tool out.

But if the pin is in there, it can shear off, and get stuck, if your collet is a little loose, or you are using a bigger face mill or larger drill something and it twists in the taper.

So my advice? (Not just for this machine, ANY R8 Taper) Take the pins out completely. It can save you a headache from getting a stuck collet out, and they really serve no purpose for locking, that is what the taper does.
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