A set of ER25 metric collets along with 3MT and parallel shank chucks.
The parts as they arrived. 25 collets, 2 chucks and 2 C-Spanners not shown here. All of the parts came in sealed plastic bags and well oiled and these were all inside individual plastic boxes.
An ER25 collet and 3MT chuck shown next to a 3MT direct collet. The direct collets reduce the overhang on the spindle, but they are not as convenient to use as the ER collet system.
A nut as viewed from the back. Note that this shows the offset ridge that the collet sits in (this is not poor machining, they are meant to be like this so that you can easily get the collets out).
The collet is firstly placed in the nut. If you wriggle the collet around it will locate on this ridge. You can now offer the collet up to the spindle and thread the nut on. Do not tighten the nut without a tool placed in the collet.
You can see the collet is hanging on the ridge that is formed with the offset machined feature in the nut. If you push the nut more firmly then it will centre in the taper of the nut. This ridge also serves to pull the collet free when you release the nut and remove it.
The ER chuck does mean the milling bit is further away from the bearing than when used with a direct collet, but the ER system is more convenient to use.
The advantage is this extra length does allow the head to more easily reach the table.
I decided to also buy a chuck with a parallel shank (this cost approx. £10).
You can see below this chuck mounted in the 3-jaw chuck of the Warco WM240B.
Using collets in the lathe is a great way to get a repeatable accuracy and a good way to hold a circular part that is delicate as a collet will support the whole circumference of the part. The only problem with 2 chucks is the overhang, this is rather large and so I’ve now moved to a dedicated ER25 lathe chuck.
Conclusion – this complete set was rather good value at ~£80. There was a quite hefty charge for postage and we reduced this by buying two sets with a colleague and so sharing the costs.
This set is very good value for money and would highly recommend it based on the quality of parts. The nuts are different with one having the location ridge more eccentric than the other. Also, I received two 12mm collets and did not get an 11mm collet, but considering this set is half the price of any others I have seen I cannot really complain.