They look to be similar to an er series collet and this would be common with collet sets adapted to a mt spindle.
Milling machine collet types.
Also check out tg75 series collets.
With a full set of er collets you can hold any diameter that is in the clamping range of the set.
It may be used to hold a workpiece or a tool.
A collet ˈ k ɒ l ɪ t is a subtype of chuck that forms a collar around an object to be held and exerts a strong clamping force on the object when it is tightened usually by means of a tapered outer collar.
The collet can be squeezed.
An external collet is a sleeve with a normally cylindrical inner surface and a conical outer surface.
In a milling machine the cutter is rotating due to this workpiece is fed against it this can hold more than one tool at a time.
On a benchtop milling machine or router the body of the collet will be incorporated into the spindle of the machine.
Rdgtools er32 collet spanner for er 32 range c type milling tools.
A lathe for example has a rotating spindle in its headstock to which one may want to mount a spur drive or work in a collet another example is a drill press to which an operator may want to mount a bit directly or using a drill chuck.
Toolholder bt30 er16 er20 er25 er32 cnc milling machine clamping collet chuck.
Rdgtools 5c collet round imperial sizes 3 8 1 milling lathes collet chucks.
A wide variety of milling machine collet types options are available to you such as new.
Machine tool operators must be able to install or remove tool bits quickly and easily.
Install into a 100 tg collet chuck or holder to tightly grip round shank tool bits in milling machines.
Suggest you google for er collet dimensions recheck your dimensions and see if there is a match.
Virtually all milling machines from the oldest manual.
The collet sits in an internal tapered shaft which matches the taper of the.
Er collets have a wide clamping range and high accuracy.
While they are designed for tool holding they work great for work holding in small lathes.
However your dimensions indicate something else.
The collets snap into the nut which is then screwed onto the main body or spindle the tool is inserted into the collet and the nut is then tightened.