Just bought a speed increaser off Ebay and from the picture both myself and the seller thought it was on ER25 collets but on collecting it today it appears not.
After a bit of searching it appears they are DIN 6388A series and type410 or 415. The only difference between these two is one is single split and one is double. Here's a spec sheet, we are looking at the top two. Does anyone have any of these laying about ? Looking for small sizes ideally 2.5mm and 3mm for starters.
Yes I could get the nose machined out for ER's and make a new nut but I'm not. Worst case is to make some collets up and get them hardened professionally but I like to explore the S/H collet option first.
John Stevenson Nottingham, England.
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