Are there any Dremel experts out there? I have a question about the collet of my new and annoying Dremel 4000....
My new 4000 kit came with a lot of accessories and I was immediately able to load a cutting disk on an 1/8" (sorry, I know you're European) mandrel and cut a gap in a rail for my lift-out track section. But now whenever I try to load any 1/8" accessory the collet either won't open enough when the nut is threaded on or if it's open enough I can't engage the nut in the threaded part of the tool.
If its like my dremel you have a screw on piece at the end which you finger tighten to hold the rod .This can also be unscrewed to replace the collet with bigger/smaller one .I find with mine that when I have finished a job and undone with the key I have to do a light tap on the end to release the rod .
Have you taken the collet off and inspected it ?perhaps it has a lump of something in it .
Excuse my non-technical terms but I hope you understand what I mean .
Hi Tom,
Thanks for the consideration, but I'm long enough here to cope with Imperial measures. We had them too when we were an empire 100years ago or so. So it's just old-fashioned to us... :laugh: :laugh: :laugh:
Chucks with 3 clamp pieces
(if you have 4 read below)
This sounds like your collet is not properly assembled. As Alan explained, the collet can be taken off the drill spindle (to attach other tools or collet sizes).
You have a 'base', the part that fits onto the spindle. You screw the conical sleeve (the actual collet; I think the whole assembly is a chuck, or not, or is this American?) onto it that forces the 3 clamp pieces onto the shaft to clamp your tool. A spring normally will make these clamp pieces retract as you unscrew the sleeve. Normally on Dremel collets the 3 pieces are identical, but mark their position before screwing apart, so they go back whence they came from.
By the sound of it you have either of 3 problems:
1. the spring is defect and doesn't release the shaft.
2. the assembly is gunged up so that the spring can't push the clamp pieces apart.
3. if you have a hollow spindle (like mine) the base sits askew (that has happened to me)
Step 1:
First take the chuck off the spindle (you might need the spanner supplied for that) and shine some light down that bore of the chuck. If you're lucky you see the base dislocated. That you can fix with a small screw driver or so by pushing on the high side; the collet has be screwed loose (but not off) to give you room to play. If that's not the case move on:
Step 2:
Unscrew the sleeve until the clamp pieces are nearly vanishing into the sleeve: are they sitting equal in the chuck, or is one further in or out than the others? If so, your problem is a sticky clamp piece, or two. I had a couple of Dremel chucks with that problem.
Step 3:
Having marked the clamp pieces, unscrew the sleeve completely, trying to keep everything else in place with your fingers. Have a very good look (or take a snap) so you know how to get it back together. Once you let go the clamp pieces should fall out of their slots in the base (at that size there might not be slots), and a spring ring or 3 small spiral ones underneath the clamps (design dependant). Make sure they are not lost!
Now you can check that their is no gunge or dirt blocking the clamp pieces, and there are no burrs. The clamp pieces must move freely in their slots, and in the sleeve. Check for burrs (on all parts, including the sleeve), etc., and a slight oiling, and reassemble.
Hopefully that will have fixed your problem.
Collets with 4 clamping pieces
I have worn-out collets, especially smaller ones with a brass clamping piece, but you say yours is new. You can easily spot if yours is one of those: it'll have 4 clamping prongs instead of 3. As these are one part actually, no need for marking (and their won't be a spring either).
Then your term is probably more accurate as the whole assembly comprises 2 pieces:
1. the conical sleeve that screws onto the hollow drill spindle.
2. the clamping tube, which has 2 cross-wise cuts about 3/4 down its length to form 4 clamping prongs.
However, in that case your tool shaft was too thin, and the 4 clamping prongs have been permanently bend. That's why they don't open fully any more. In which case just unscrew the sleeve and an oddly shaped tube will fall out, with cross-wise slots. Take a knife and carefully open the slots, just enough that they are even width along the length, Don't overdue it as the prongs might break off!
Try to use a smaller collet to avoid the problem.
These collets are made to a budget, so it's 'you gets what you pay for'.
Hope this helps
Waldschrat
Possibly 'daft' but don't these come with TWO sizes of collet ?
Yes Pete -thats why I mentioned bigger/smaller
I wonder Tom if you were using the wrong size collet and forcing the rod in which caused the problem ?
If I remember rightly the drilling /cutting tools use the smaller collect and the slitting disc rod the bigger one .
Alan
I have 4 collet sizes, and I have clapped out collets; talking the 4-clamp design, where mine are brass. The 3-clamp design (Jacobs chuck) has steel clamps, which cope better with cutting operations. You need only a few spins in the brass collets to 're-size' them. :laugh:
Anyway, if you did as suggested, i.e. force the shaft into a collet that's too small, unscrew the collar all the way, and you should be able to grab the brass collet (preferably without pliers) and pull it off the shaft.
Cheers
Waldschrat
Big thanks to Waldschrat, Alan, and Pete for their inputs.
I never solved the mystery despite carefully absorbing their guidance. I've confirmed the kit only comes with one collet (so I don't need to keep looking under the fridge for a lost one) and I KNOW I made one cut in my rails on day one... so it's pretty clear that the problem lies somewhere between the Dremel and my chair.
SO I just bought a Dremel 4486 chuck for 329 Ukrainian Hryvnia (less than 10 quid) which works perfectly and should be the way Dremels always load accessories.
Sounds like a good resolve; keep the collet for tight spaces, but use the chuck as a default.
Cheers
Waldschrat