Manufacturing of the ER 25 collet chuck for the MH-80 lathe.

Shown is the manufacture of a collet chuck for ER 25 collets for the MN-80 lathe.
ER collets are widely used for clamping both workpieces and tools. They are good because they have two clamping zones, so the fastening is reliable and accurate.
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ER collets have many long slots, so the collets are flexible and resilient. Therefore, these collets, unlike standard collets, have a clamping range of whole mm.
For example, this Schaublin collet can clamp parts with a diameter of 14 to 13 mm.
The ER collet design was proposed in 1973 by Rego-Fix. The successful solution quickly spread and was unified by DIN 6499, ISO 15488 standards.
ER collets have 8 slots on each side, while standard collets have only 3 slots on one side. Therefore, ER collets have 16 lines of contact with the part or tool to be crimped.
Clamping the part in two zones along the axis does not allow it to deviate from the spindle axis. The clamp in one zone is less rigid.
The peculiarity of using these collets is that first the collet is inserted into the nut, and then, together with the nut, is inserted into the chuck.
I took this nut from the chuck with which I bought these collets. But the chuck itself has a KM3 shank and does not fit my machine.
Unfortunately, the MH-80 machine has a metric taper of 1:20 in the spindle, but of a non-standard size. And it is impossible to purchase a cartridge with such a shank.
That is why I made an ER collet chuck for my MH-80 machine.
To grind the cone, I unrolled the upper slide with rolling on the indicator along the inner cone of the spindle, into which this collet chuck will be installed. More details can be found here:
• ВТУЛКА ПЕРЕХОДНАЯ для ...
Now I can use these ER 25 collets. The maximum clamping diameter is 16 mm. And the standard set of collets is only 10 mm.
In addition, now I can put on the MH-80 not only parts for processing, but also tools: drills and cutters.