[Marcwolf]

Hi.
We have been given a CNC machine by a departed member. We have finally got it running with MACH3, and have Aspire Pro.

It also came with a whole bunch of assorted but or different sizes and shanks. This has me puzzled.

1. Is it best to standardise on one collette size i.e. 6mm and purchase all bits to fit.. Or
2. Mix different colletes during a running job dependant on the bits being used.

This is to be used in out Mens Shed and so I want to try and make thing as easy as possible.

Many many thanks
Dave

[joeavaerage]

Hi,
post a photo of what you have.

There are dozens of different collets and collet chuck designs.

The real issue with collets is that the tool can, when under extreme load, 'pull out' wrecking the job. One common collet design that prevented that was one that had a
thread on the interior end into which the tool steel tool would thread. They work OK, but require tools made for that style of collet, and to my knowledge that includes tool steel
tools only. The collet will not work on smooth shanked carbide tools.

If you are buying a tooling system then you should look at ER collet chucks, depending on your machine ER32, ER25 or ER20. The collets 'close' at both ends and thus have
very good clamping, not a total solution to pull-out, but not bad.

These are my tool holders. They are HSK32, that is to say the taper which is pneumatically clamped into the spindle, while the 'tool' end is ER20, for the most part.
There are is one HSK32-to-ER25, a somewhat larger collet chuck, one that I can hold 16mm diameter tools, and four heatshrink tool holders. They are 6mm and 10mm.
As the name suggests they are heated (purpose built induction heater) which allows a carbide tool to slip in, but when cold the tool is clamped extremely tightly indeed,
probably the MOST secure clamping for a cylindrical tool. Downside is the induction heater can be many thousands of dollars. There is also once 1.5" Valenite facemill and HSK32 arbor.

My spindle is capable of 40,000rpm, but most of my work is done at 24000rpm, hence the predominance of small tools. These have 1/8th" shanks, and so naturally enough I have
a dozen or more 1/8th" ER20 collets.

Craig