ER40 thread size

[Martin CargillParticipant @martincargill50290]

ER40 Collet Nut

Does anyone know what the thread on an ER40 collet nut is? or does anyone know if its possible to get a die nut for repairing the threads on an ER40 tool holder?

 

Thanks

 

Martin

[JasonBModerator @jasonb]

M50 x 1.5

Depending on the damage you may get away with a thread restoring file. Or set up in the lathe and rotate by hand while set up for screwcutting 1.5mm pitch.

[bernard towersParticipant @bernardtowers37738]

A tip I was told is to set up for screw cutting and engage half nuts and drive the saddle so play is taken up set crosslide to zero and with toolholder in place loosen toolbit screws and push toolbit forwards to fully engage thread, that should give you a guide to depth and as Jason says turn by hand. Best of luck!

[old martParticipant @oldmart]

https://www.cgtk.co.uk/metalwork/data/erThis link may help, from google:

Bernerd’s method is exactly how I would do it if you can set 1.5mm pitch.

If there was a die nut, it would likely cost more than a new er40 replacement.

 

 

[mgnbukParticipant @mgnbuk]

repairing the threads on an ER40 tool holder

If the threads are damaged, I would replace the holder.

Had quite a few ER holder threads fail when I was working – though most “picked up” and it became impossible to remove the nut. Best case scenario then was to use a slitting wheel to cut the nut off the holder to retrieve the collet. Even if the cuts were made such that no further damage was inflicted on the holder, the thread damage was usually substantial & the assembly would not have been as secure if the thread was cleaned up.

I do appreciate that when you are paying for the replacement bits, rather than ordering them on a company account, that this is rather painful.

Nigel B.

[Neil LickfoldParticipant @neillickfold44316]

What damage are you talking about on the thread?

Some holders are case hardened and the threads are ground. A diamond triangle file can usually be care fully used to repair the damaged areas.

When I make the holders, I use a 1.5mm pitch partial form ground insert. It has slightly less cutting forces than the pressed inserts.

Bernard’s mention of how to easily pick up an existing thread works very well. Just make sure that all backlash has been taken care of, especially in the top slide. Hand rotate or a speed close to 90rpm will work. Just check that the tool being used has a matching root radius or a slightly larger root radius. I also recommend colouring the thread with red or blue marker pen to be able to easily see where the recutting is taking place.

Check that the Nut thread is still in good condition.

[Martin CargillParticipant @martincargill50290]

Thank you for all of the information and replys. The damaged threads are on two rivet “ripping” machines, used in the cooperage industry (they punch out the old rivets on hoops for barrels). The customer asked me to look at one of them a couple of weeks ago because one of their employees had cross threaded the nut while changing the punch tool. The damage is mostly to the male part but the nut has suffered some damage as well.

The male part is the end of a hydraulic ram and has an ER40 collet system to hold a punch which is approx 10mm in diameter.

I bought a new nut for the machine but whilst waiting for it to arrive the boss man phoned me to say that their second machine had also been damaged in the same way.

I had intended to try and use a thread file to try and sort out the damage but as there is now two machines to fix it may be worth buying a die nut, hence the reason for asking about the thread dimensions.

 

Martin

[Martin Cargill]

On Martin Cargill Said:

I bought a new nut for the machine…

As ER collet nuts are cheap, cut the end off it and then put some hacksaw slots into the threads. That can give it some die nut-like, field-expedient clean up abilities.

One has to ask why they need to remove the nut to change the tooling. The only reason would be to change the collet. Might it not be better to standardise on a universal shank size for all the tooling, so a change just requires loosening the nut, pulling out one tool and inserting the new one.

[Martin CargillParticipant @martincargill50290]

The tools are shaped like a nail, hence the reason for having to remove the nut and the collet

[bernard towersParticipant @bernardtowers37738]

Change the workforce!!

[Martin Cargill]

On 5 September 2024 at 19:58 Martin Cargill Said:

… anyone know if its possible to get a die nut for repairing the threads on an ER40 tool holder? 

…

Certainly is now the thread’s been identified as M40 x 1.5

You could buy a £539.20 + VAT Presto die from Cutwel.  This is the real McCoy, built to cut hundreds of threads in 40mm stock from scratch, which is hard on the die.

Or, this tap and die from Amazon for about £95.   The die is unlikely to as last as long as a Presto, but there’s a high probability it’s adequate for tidying up an existing damaged thread.  Correcting threads is much less stressful on taps and dies.

Having a tap and die might be helpful if male and female are both damaged.   If necessary, the end of the tap can be ground flat to fit inside the nut.

Also needed will be a tap and die wrench.  M40 is quite big, and I couldn’t see one on Amazon.  Plus a tapping fluid like CT90, though a dash of engine oil will do at a pinch.

Taps and dies are operated with a two turns forward, quarter turn back action to clear swarf.   May not be necessary for a simple thread clean up.

Dave

[SillyOldDuffer]

On SillyOldDuffer Said:

On 5 September 2024 at 19:58 Martin Cargill Said:

… anyone know if its possible to get a die nut for repairing the threads on an ER40 tool holder?

…

Certainly is now the thread’s been identified as M40 x 1.5

On no it hasn’t.  How would you get a collet of 41mm OD  into an nut with M40 thread? M50x1.5 Dies available from £30

Large dies like that do not need a 1/4″ turn back. Any die only needs backing off by 1 / No of cutting edges so about 1/8th in this case and if repairing I doubt it needs backing off at all

[Tony Pratt 1Participant @tonypratt1]

I have just measured my ER40 thread, its M50 x 1.5. You could use a die for £30 that would be worth a go. My holder and all others I expect are toughened but not dead hard so are very likely to ruin the die. The nuts are so inexpensive they are not worth repairing.

Tony

[JasonB]

On JasonB Said:

On SillyOldDuffer Said:

On 5 September 2024 at 19:58 Martin Cargill Said:

… anyone know if its possible to get a die nut for repairing the threads on an ER40 tool holder?

…

Certainly is now the thread’s been identified as M40 x 1.5

On no it hasn’t.  How would you get a collet of 41mm OD  into an nut with M40 thread? M50x1.5 Dies available from £30

Large dies like that do not need a 1/4″ turn back. Any die only needs backing off by 1 / No of cutting edges so about 1/8th in this case and if repairing I doubt it needs backing off at all

Hells bells!  Between reading M50x1.5 in Jason’s answer and typing my own a few minutes later I somehow misremembered the thread as M40x1.5

Apologies to one and all for this error of fact. The world needs to know the truth, even though my sensitive and delicate pride is now dented!

Dave

 

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