G'day,
I bought an end mill the other day and it came with a thread on the end.. I was under the impression that endmills used collets, or mill holders to be mounted to the spindle. Realising that i can still do this, I am curious as to the purpose of the threaded part. What does the commercial system look like which uses that thread? Any online pictures, descriptions? advantages over collets, or mill holders?
Thanks, Des
This is a UK system, the collet chucks are Clarkson Autolock. The endmill is screwed into the rear of the collet and the centre in the threaded end of the endmill abuts against a centre fixed in the holder. As the endmill is abutted, if it slips when cutting, being threaded into the collet this forces the collet down against the retaining collar and therefore tightens its grip on the cutter. The advantages of this setup is that only light pressures are needed to tighten the cutters. If you're interested in the original patent, in the US it's #551065 you can access it here:
Brain fade! Too eager to get to the dinner table!
#551065 was the UK patent #2367988 is the US version..
Tom
What kind of person runs around with patent numbers in his head?
Lane
Advantages: More precise positioning, unlike end-mill holders and collets. Since it uses a form of collet to hold it, runout is minimal, unlike end mill holders. Won't pull out under load, unlike regular collets.
Disadvantages: Requires special holder, more expensive, not as convenient to change cutters.
Popular in some CNC applications, etc.
Since you have one, as long as the thread isn't larger than the shank you can still hold them in conventional holders and collets. You may need to grind a flat relief spot in the cutter shank where the setscrew in a holder engages it.
Dan Mitchell ==========
Des Bromilow wrote:
Patently, memorable? :-)
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