5C expanding collet

[Sshire]

I just got a few 5C expanding collets.
I'm not sure about the correct adjustments. After turning, screwing, unscrewing, etc. I can make one work but I don't know what I did to accomplish this. When I tighten it in the chuck it expands. Can't make the others expand. Help!! I know the front SHCS expands the shaft but have no idea what the rear SHCS does.
I'd like to know what to do and what I did to make one work.
Here are pix

Thanks
Stan

 

[Blogwitch]

Stan,

Don't panic, they just need a bit of understanding.

Don't play about with the cap screw on the bottom, that is just there to hold the threaded bit in position, the threaded part should be able to move backwards and forwards slightly.

Put the expanding collet into the chuck and tighten up a bit, until the collet is actually starting to tighten, but not fully.

Now put the piece you want to grip over the end fingers (the bits that expand). Tighten up the the front centre screw until it just starts to grip the part, but you can still take the part on and off. You now have the expanding collet set correctly for that part. Just tighten up your collet chuck and the fingers will expand, gripping the part, ready for machining. If it doesn't grip enough, slacken off the collet from the chuck slightly, and just tighten up the centre screw a bit more.

Now what you never get to hear from the retailers.

These are classed as disposable items, that is, you machine them down to fit the part. So eventually, they will be no use for gripping anything except the last part you machined on them.
So if you can, machine in steps on the sticky out lengths. That way, you will get more life out of them, in fact, you might find that once you get a few steps on there, you might be lucky, and most times they will fit most parts with the adjustment available.

I think there are two versions of these sets, one longer than the other, so maybe if you have bought the longer set, you may be able to get four steps on them.

Just an aside, they only expand about 0.5mm to 1mm, so don't expect too much, if the part is too loose, you will need to use the next size up, and machine it down to fit.


I hope this makes it a little clearer.


John

 

[Sshire]

John
Marvelous!
Worked perfectly. (Worked a treat??)
The problem was, since I had no idea what to do, and loose screws just seem wrong, I had tightened the rear SHCS and the rear threaded collar could not move. I looked at the one that worked and it was a few turns loose, allowing the collar to move. A with most things, once you know.....
I assume with a blind hole one would keep removing the part to be worked on, adjust the front screw, replace the part and keep at it until you have a snug sliding fit. Then tighten in the collet.
Again, thank you.
Best
Stan