Collet help required

[Steve_MParticipant @steve_m58920]

[Steve_MParticipant @steve_m58920]

Hi All,>>

As some of you may know I recently required a Hobbymat MF65 lathe and BFE65 mill.>>

Being very new to the engineer I could do with some help trying to identify what collets I require. At the moment I’m well lost and confused. and not having the manual for the BFE isn't helping either.>>

I have 2 collet holders one that bolts on and one with the Mk1 taper.>>

Below is a selection of photos and measurements I have taken. I believe the collets for the mk1 taper are the wrong ones as they don’t seem to sit in the holder very well.

>>

and the 2nd one,

If someone could be kind enough to let me know what these collets are i.e. 5C, ER etc that would be great.

Kind regards

Steve

[jason udallParticipant @jasonudall57142]

Obviously you have two types here.
The 30 mm ones are a ER series..give me a mo and I will look em up
The other is a bit harder

[jason udallParticipant @jasonudall57142]

ER 20..
Now about the other..
Sorry there are a large number of similar and in some cases special to a gived machine tool supplier… I can’t help much there

[EmgeeParticipant @emgee]

Perhaps the MT1 shanked holder is for ES type collets, same taper and front angle as ER but without the removal groove.

Emgee

[jason udallParticipant @jasonudall57142]

Now those ER 20 seem to be modified to sort of fit ER16…
The max dia of the collet on a ER 20 is basically 21 And ER 16 is 17
Your seem to be 18..
and as you say a bit big for the holder

The length of er20 is 31.5 and them 16 27.5

[Steve_MParticipant @steve_m58920]

Thanks all for the quick replies.

I'm actually quite please you are having trouble working this out as I've measured them over and over and keep coming up with the same.

Am I right is say a ER collet recess should clip/sit into the holding nut lip? (hope you under stand that)

Also another photo of the holder nut diameter

Cheers

Steve .

[John PurdyParticipant @johnpurdy78347]

The first appears to have the same configuration as a Brown & Sharpe # 21 collet but from memory looks to be smaller. Sorry I don't have one any more to measure to confirm that.

John Purdy

[IanTParticipant @iant]

I don't have them any more (and I therefore have no measurements to hand or collets to check) – but I suspect that the second type of "ER" type collet is what I think of as 'Chinese' collets. Sets of them used to be sold with a matching collet chuck by the main ME suppliers before the current ER collets really caught on & became more affordable….10 years or so ago now?

Regards,

IanT

[IanTParticipant @iant]

My photo archives are still working – This is what my set of "Chinese" collets looked like.

They were a bit longer than the similar sized ER ones…. I don't seem to have a side-ways view of a collet I'm afraid.

Regards,

 

IanT

 

Edited By IanT on 27/11/2015 19:21:41

Edited By IanT on 27/11/2015 19:24:02

[Neil WyattModerator @neilwyatt]

Posted by jason udall on 27/11/2015 17:14:02:
Now those ER 20 seem to be modified to sort of fit ER16…
The max dia of the collet on a ER 20 is basically 21 And ER 16 is 17
Your seem to be 18..
and as you say a bit big for the holder

The length of er20 is 31.5 and them 16 27.5

They look like one of the many proprietary 'ER-a-like' types of collet, longer and thinner and fewer slits – as Ian's pic.

Neil

[JasonBModerator @jasonb]

Ian, the Far Eastern collets are quite a bit longer than Steve's, though I suppose thay may have done asmaller size.

[Steve_MParticipant @steve_m58920]

Thanks all, I'm really glad it wasn't me going mad.. I'm amazed at the wealth of knowledge out there.

I have found the first chuck collet details, which does look Chinese. Looks like hole diameter is set so I will just need to find a cutter of that shank size to fit it.

For the ER style I'm not sure which way to go now. May be buy a ER16 collet and see if it fits or cut my losses and go for a new MT1 collet holder. Problem is there isn't much choice out there for the MT1 stuff, unless some else knows different.

Cheers

Steve

Edited By Steve_M on 27/11/2015 21:14:05

Edited By Steve_M on 27/11/2015 21:41:52

[Ian PParticipant @ianp]

Steve

I cannot claim to be an expert on the BFE mill but I do have a brand new one still in its packing including the handbook.

My impression is that the collet holder that fastens to the flange of the spindle with three screws uses Prazi's own proprietary collets. They look similar to ER type and have a groove at the larger diameter end which aids extraction but I think that they designed to be left in the nut permanently so that each size collet has its own nut. Since presumably they are no longer manufactured I would imagine that both nuts and collets are like hens teeth.

The manual shows the method of installing and removing a collet in the nut, basically it involves closing the collet by hammering a short tube over the tines to reduce the OD of the collet groove so that it passes through the hole in the nut. The tube is then removed (more hammering!) to let the collet expand and engage in the groove.

I don't have the collet chuck but even if I did I doubt it would get used. (ER holder in the MT is your best bet.

Ian P

[Anonymous]

Posted by Steve_M on 27/11/2015 21:13:33:

Looks like hole diameter is set so I will just need to find a cutter of that shank size to fit it.

They're dead length collets to DIN6343 and widely available; it just so happens the datasheet shown is oriental. I'd be very surprised if they only came in one size. I expect that hole size quoted (round, square or hex) is the maximum for the particular size of collet.

Andrew

[Peter Lawrence 1Participant @peterlawrence1]

I have the Prazi lathe and mill which are very similar,

my lathe takes DIN-6341 k16-330E collets

I have not yet found any match for the mill collets

ER – have different taper and nose angle

OZ/SYOZ – have different nose angle

TG – have way too shallow taper

if you ever did find a match please let us know

thanks, Peter.

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