Not blaming my tools Robin, forced to use them at numerous other peoples one was an engineering firm who saw fit to replace with R8 collets after.
The nature of what i do i have to be able to frequently change cutters quickly increasing productivity and have accurate grip ie three cutter changes in 2 mins wouldnt be uncommon. Work it out less than 8 secs to change a cutter with R8 or MT2,3 against how long it takes by other means, excluding hydraulic and air types.
Maybe i am spoiled being brought in to milling with an engineering company using R8 collets, if i didnt know any better i would probably be a lemming your loss. I would never own any ER or Clarkson collet setup, why settle for second best, but would invest in the 5C for other purposes if need arised.
Take the Clarkson - Remove nut, find collet and screw in cutter, place collet with cutter in and adjust depth of cutter by rotating in the thread then tighten up nut. I have known them to run out even visually with the cr, the less parts in the setup and distance from original spindle fixing the better! My dislike is they take an eternity to change cutters, same with ER and other similar types along with cutter slipping or dropping. Just by the time the nut is removed i could have in a new collet and cutter fully tightened up.
A good tip while i think of it is make up a spindle lock if not fitted whichever type of rotary clamping system used.
Now i may have figured the source of the ER and CMD cutters slipping and dropping problem with all chinese and proper expensive English and German made examples. The nut binds and theres a limit to how tight the collet will go. You will know this when you have a cutter drop and the nut is tight still!
It doesn't rely on pinching the tool shank to hold it vertically, only to hold it concentric at the bottom of the collet.
The tool extension and tool concentricity at the top is set by the collet centre entering the centre pip on the back of the tool. You can change tool without adjusting the Z.
Because the tool extension is set there is no way on God's green earth it can slip vertically in the collet.
If there is runout then that usually means someone didn't understand how the collet operated, inserted a grub screw and tried to pinch an unthreaded tool thereby nadgering the chuck centre which aligns the tool top. The collet is a loose fit in the chuck so you need to preserve the centre.
To set a Clarkson you do the nose up gently, screw the tool in until it hits the pip, back the nose off a quarter turn, screw the tool in tight. Tighten the nose. No huge spanners required, you aren't gripping the tool, merely supporting it.
Now't wrong with a Clarkson except you need tooling designed for it. A good choice for facing with an end mill.
Last edited by Robin Hewitt; 06-09-2010 at 11:36 AM. Reason: Didn't explain it very well
I can see the advantage of the Clarkson specific type, i never said they slip!
The runout would or could have been before my time, dont know whether spindle, or Clarkson shank, nut or collets were out. Set up like you say backing off around 1/4 turn. The point i make here is, whatever runout there is due to extra additional parts with subsequent machinings, amplifies the further out the spindle the cutter is.
My actual grievance is the time it takes to change a cutter.
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