ER 25 straight shank holder.

[Lee RogersParticipant @leerogers95060]

I’m looking for a 1″ straight shank ER 25 collet chuck in the UK.

Plenty of metric ones to be found in the usual places

but 1 inch seems to be only available from the USA

at an arm and leg price. Thanks in advance.

[DC31kParticipant @dc31k]

See:

https://www.mscdirect.co.uk/interstate-er25-x-1in-straight-shank-extension-eri-48370b

MSCdirect, having a US parent, is one of the few UK sources for imperial stuff.

Try finding an imperial shank edge finder here…

Outside chance is Gloster Tooling as they sometimes have imperial stuff.

[DC31k]

On DC31k Said:

MSCdirect, having a US parent, is one of the few UK sources for imperial stuff.

Try finding an imperial shank edge finder here…

Outside chance is Gloster Tooling as they sometimes have imperial stuff.

Zoro UK, aka Cromwell, has a US parent and imperial edge finders.

And imperial straight shank ER25 collet chucks.

[DiogenesParticipant @diogenes]

Can’t you stick a standard one in a capstan sleeve?

EDIT – RDG and Chronos both occasionally have Imperial ‘oddities’ kicking around, might be worth calling esp. RDG

[Martin ConnellyParticipant @martinconnelly55370]

Having put threads onto the parallel shanks of ER16 collet holders I would get a Ø32 one and reduce it to 1″ if you can find one with a solid shank. Alternatively cut it down in length and thread the stump and fit a 1″ shank to it.

Martin C

PS if you are going to put a new shank on it get one with smaller shank if it is cheaper, thread that and put the new shank over it may be an option, but may be less rigid.

[Martin Connelly]

On Martin Connelly Said:

…put the new shank over it may be an option, but may be less rigid.

That raises the question of ‘how much less rigid?’.

Let us say we had a 25mm solid shaft; we can calculate the second moment of area.

Now assume that shaft is made from a 16mm solid bar with a 4.5mm wall tube shrink fitted over it. Where would we find the maths to determine its I value?

[DC31k]

On DC31k Said:

[…] Where would we find the maths to determine its I value?

Start by calculating the stiffness of the tube

Then add the [much lower] stiffness of the shaft

BUT … the tricky-to-calculate bit would be the risks of

1. slippage between the components
2. stress-raising at the region where the shank abuts the chuck

To a first reasonable approximation, however, the stiffness of the tube would probably suffice.

FEM at this level is probably within the scope of a modern CAD package.

MichaelG.

[Lee RogersParticipant @leerogers95060]

Thanks to all for the input which has as usual prompted some novel solutions.

I think that the MSC option at £60 ish will be my best bet . It’s going on to a Quorn T&C grinder

so accuracy for end mill sharpening is my goal. I will be giving them a ring to confirm that it is

actually 1 inch because if you scroll down to the spec section it is described as 25mm , odd that!

I’ll post here if the conversation is more interesting than it should be.

[ianjParticipant @ians]

Hi Lee.

I’m in a similair search for my Quorn. At the moment I have a 2MT ER25 chuck in a 1″ od capstan sleeve which is ok. The closest I found were ER20 OR ER32 with 1″ shank chucks from CTC tools,https://www.ctctools.biz/er-collet-chucks/?sort=featured&page=2

 

I think the one from MSC will be £82 + postage.

 

Let us know how you go on.

[VicParticipant @vic]

What about sleeving a 16mm or 20mm dia shank ER25 chuck? Plenty of cheap ones on eBay.

[Michael GilliganParticipant @michaelgilligan61133]

It’ not like you, Vic to overlook a whole chunk of the earlier discussion

MichaelG.

[ianj]

On ianj Said:

…from CTC tools

…who are not in the UK, which we must at least acknowledge was a specification of the original post.

I say this as a satisfied customer of CTC.

—

On further reflection of the lower rigidity of a sleeved item, if either the sleeve or the inner item were of a stiffer (higher E-value) material than the solid original, the bending stiffness could be increased over that of a homogonous solid item.

The crux of the matter is the behaviour of the connection between the two, which is still a mystery.

[JasonBModerator @jasonb]

Why not bring the Quorn upto date and future proof it. Get a second casting from Reeves and bore it out to 25mm rather than the existing 1″. Or just cut an new one from solid, fabricate or 3D metal print.

[DC31k]

On DC31k Said:

[…] The crux of the matter is the behaviour of the connection between the two, which is still a mystery.

Unless they are truly locked-together at a molecular level, the safe assumption is that there will be slippage … hence my suggestion of simple addition of their stiffnesses.

MichaelG.

[JasonBModerator @jasonb]

Now that we know the holder is being used in a Quorn does rigidity really really come into it? The work (cutter) is just going to be kissed by a grinding wheel not be used to take heavy milling cuts.

Concentricity would be what I’d be looking for.

[Michael Gilligan]

On Michael Gilligan Said:

On DC31k Said:

[…] Where would we find the maths to determine its I value?

Start by calculating the stiffness of the tube

Then add the [much lower] stiffness of the shaft

[…]

As everything else is constant … we only have to juggle with the fourth powers of the numbers 25.4 and16.0

To a first reasonable approximation, however, the stiffness of the tube would probably suffice.

416231.4256 – 65536 = 350695.4256

Q.E.D.

.

.

MichaelG.

[Martin ConnellyParticipant @martinconnelly55370]

For the Quorn, why not buy some 0.2mm shim stock to fill the gap between 24.4mm bore and 25mm shank? Less than £3 for a sheet 100mm x 100mm.

Martin C

[duncan webster 1Participant @duncanwebster1]

DC31K suggestion of significantly higher youngs modulus would work if you could find such a material. Sounds like unobtainium.

Even if there were slippage between a sleeve and a shank, you can just add their I values. In fact if the sleeve was shrunk or loctited on I doubt you’d get slippage under the light loads from grinding and so could just treat it as a solid shaft. A more expensive solution would be to get a 25mm shank plated and then ground to 1″. Probably cheaper to import from USA

[martin haysomParticipant @martinhaysom48469]

why not do as i did and buy it from China. cheap, quick delivery  and well made. got two in my Bonelle.

[martin haysomParticipant @martinhaysom48469]

should have said only one is er 25 with a 1″shank the one in the grinding head is a bit smaller

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