What are ER Collets?

ER collets are used on CNC spindles. Different sized spindles have their own collet size. Typically the bigger the spindle (power and size) the bigger the ER collet.

How to use an ER Collet?

IMPORTANT NOTEs:

Always keep your collets clean and free of debris. They will not crush evenly with debris build up in the slots. Do ensure you blow out the male and female thread (spindle and nut) as swarf or debris will damage the thread and replacing the spindle shaft or iso/bt tool holder is not cheap!

Consider that collets are actually a consumable which need to be replaced after a time, how long will depend on how much runout has begun to creep in due to chatter, extended use, mistakes and of course the quality of the collet. Often collets are cheaper than the tools you entrust them with so clean them every tool change, replace when showing signs of age or damage and lastly try not to use the full crush – ie a 6mm stool should be used with a 6-5mm collet even though yes you could put it in a 7-6 and get it to work – the collet and the seat in the collet nut will suffer.

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Thanks for reading

–3DTEK