|Chris Trice||11/11/2017 02:05:26|
973 forum posts
Gently tap the drill shaft near to the collet as it's rotating. I find this often seats everything where it should be before tightening it a little more. In theory, it shouldn't make a difference. In practice, it often does.
|Chris Trice||11/11/2017 02:11:13|
973 forum posts
... or use the tail end of a boring tool and advance it until it just touches the shaft of the drill near the collet in the same way that you can use a boring bar to steady a drill bit to drill centrally without resorting to a centre drill. Again, in theory it shouldn't make a difference but in practice it sometimes does.
12049 forum posts
That is not a spotting drill, this is not tried the sherwood but as you were looking at Cromewll's I used one of theirs to link to.
This is a KEO one though they are imperial, don't be put off by ythe photos they actually ;look like the Cromwell ones at 1/8" x 1.25"
Edited By JasonB on 11/11/2017 07:30:52
|Men Ifr||14/11/2017 17:33:02|
|73 forum posts|
The ER20 collets arrived from RDG and to my dismay the 2mm hole does not look to be in the centre of the collet (where the split lines cross) this is what I could see with the chinese one I had before. - Maybe it is my imagination but I don't think so. They do seem to be machined/ground though and the chinese ones aren't but you can also see some manufacturing errors.
Anyway 1st test I check the run-out setup the same as the video I posted earlier and I get 0.045 - so only slightly better than the Chinese one.
I'll go and measure some-more and re-check the collet holder in case that's a long way out...
What's the consesus on oil on the collet and tightening torque - I'm giving a reasonable nip with a 300mm spanner I may try a few 'tightnesses' and see if things seem to get better or worse.
Only 1 more thing - I'm using a drill bit and measuring on the shank, I'm assuming that should be a reasonable method. - also it means this is likely the best possible result as the run-out is likely to get worse further away from the collet (i.e. at a drill bit tip where it actually matters...)
Edited By Men Ifr on 14/11/2017 17:33:52
|718 forum posts|
Wonder if you are using a drill shank the same size as the maximum collet capacity and not oversize.
My collet tapers and threads get a very light coat of oil before fitting the tool.
|Men Ifr||14/11/2017 19:47:43|
|73 forum posts|
Typically I've been measuring like for like i.e. 2mm collet 2mm drill bit shank.
I've been getting 0.045 - 0.07 across the set so far. I'll ring them in the morning to see what they say.
I ordered a drill chuck plus abour at the same time - I'll measure that - I wouldn't expect it to be more accurate but given the poor results from the collets you never know.
The other possibility is even through I can measure the collet holder at + 0.01 maybe the way it holds the collets makes them inaccurate..?
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