ER25 MT3 thread?

[-steves-]

I wonder if anyone can help me out before I end up buying a new collect holder?

I needed an MT3 ER25 collet set, so purchased a set which included the collet holder. I needed an M12 thread, but unfortunately didn;t read the write up that well and ended up with a collet holder which my thread on my mill doesn't fit

So, I went down the local hardware store who have LOADS of threaded rod in stock as the holder I bought was listed as 3/8 BSW. So I bought one foot of 3/8 BSW threaded rod together with 2 nuts so I could use the incorrect holder. Got home, it doesn't fit by miles?? I took the holder down there and the closest thread they had was an M10 Extra fine thread, though this was marginally loose and didnt quite seem like the right thread, even though it screwed all the way in.

1) Does any one know what actual thread is in my collect holder which was supposed to be 3/8 BSW, but isn't as its fine thread?

2) Am I better off replacing the entire collect holder for an M12 threaded one at £40 or should I continue trying to find out what thread this actually is?

If anyone has any helpful suggestions on this, I will be only too glad to hear them as I am at a bit of a loss? The set came from Chronos and is listed both on Ebay and their website in a red box if anyone wants to read up on it. Is it worth going back to Chronos and saying the stipulated thread maybe wrong and ask them if they know what it is and try to do a deal on the coeect holder???

Thanks
Steve

[Bluechip]

If it was sold as 3/8" BSW, that's what it should be. I would contact Chronos and get a correct item.

Not that it's any help to you, I once had a 2MT blank end arbor threaded 3/8" x 24 TPI UNF.
Quite why, I don't know. Except it's the same thread as [ some ] drill chucks.
It got dumped ..

Has the studding supplier got any UNF studding to try? Long shot but ...
I would still contact Chronos.
They are a reputable supplier, if it's wrong they will swap it OK.

Dave BC

 

[doubleboost]

Hi
Steve
UNF Is a common thread on draw bars for some strange reason 
John

[Bluechip]

Hi
Steve
UNF Is a common thread on draw bars for some strange reason 
John

There you go Steve .. from someone who knows ....

John DB ... I only ever met that one, thought it was an odd-ball.
It came with all the curiosities when I bought the Myford ..

So I decided to check it's aeronautical qualities ...

BC

[doubleboost]

Hi
Just checked all my R8 tooling is 7/16 UNF thread
I think they use a fine thread so it wears out quickly
It is like most pipework is still BSP

[-steves-]

I think 7/16 UNF would be too big for this one as its something like a 9.5 ish internal on the thread.

At the local hardware store (quite a good one as it goes) they tried every threaded rod they had and absolutely nothing fitted, as I said, the nearest was a 10mm Extra Fine, but that felt a litle loose in the thread. If I were a betting man (which I am not) then my money would be on it being 3/8 UNF, but I am not sure how to tell. Sometimes it would be nice if things just fitted 

[David Jupp]

I agree about getting the supplier to swap it for what was advertised.  If you ask nicely and an M12 version is available they may even swap for what you should have bought!

Failing that, find out what the thread actually is (UNF, BSF,...?)  A local nut & bolt specialist may be able to supply threaded bar, or it may be simpler to buy a die and thread the end of a piece of bar to suit - that way you are not limited to having the same thread at both ends of the draw bar.

If feeling really brave you could try drilling out and tapping to a larger size - but of course you wreck the holder, you are in trouble.

[Fergus OMore]

All that you need to do is find a bit of wooden dowel or pencil or whatever. Ram it into the hole and use something to get an imprint.
Take it out and measure the 'thread' that you created.

It's not in the book but the old engineers would have probably inserted a rod 'dead on undersize' and tinned it, and twisted it into the hole.

Rather nice to send it to whoever- and say, 'up yours- or words to that effect'

Regards

[Stilldrillin]

Steve.
I think it's 7/16UNF....... Tapping size is 9.8mm....... My R8 collets are that thread.

Never heard of MT being tapped that thread before. 

Give Chronos a ring, I'm sure they will be sympathetic. 

David D.

[-steves-]

Steve.
I think it's 7/16UNF....... Tapping size is 9.8mm....... My R8 collets are that thread.

Never heard of MT being tapped that thread before. 

Give Chronos a ring, I'm sure they will be sympathetic. 

David D.

Hi ya David

Well I gave Chronos a ring as you suggested and they were very helpful. They are sending a courier to pick up the entire set and have already issued a full refund. Its not what I exactly wanted, but it does give me a no cost option and I can start again. They would have changed the holder over, except they dont have an MT3 12mm in stock.

Hey ho, back to square one and on the look out for an ER25, MT3, 12mm drawbar collet set from 1mm to 16mm 

[Stilldrillin]

Hi Steve.

I thought they would be quite fair with you! 

Arc Euro have the holder, at £38....   And a 6 collet starter set at £71 .......      http://www.arceurotrade.co.uk/Catalogue/Collets/ER-Collets-Collet-Chucks/ER25-Collets-Collet-Chucks

RDG have  holder at £39.50 .....    http://rdgtools.co.uk/acatalog/ER25_COLLET_CHUCKS.html

And, a full set of 15, (don't think you really need the full set), collets, at £72.50 ......   http://rdgtools.co.uk/acatalog/ER25_COLLET_SETS.html

David D

[dvbydt]

I have used this supplier on several occasions and their quality and service is very good.

http://www.ctctools.biz/servlet/StoreFront

Delivered price is about half the cost of uk suppliers. No connection, just a happy punter!

Ian