Thread: What is the Morse taper size ?

Just wondering what the Morse taper size of the spindle of My lathe would be ?

I have to buy some ER 32 collets for another machine which has a chuck for them already .
In that box there is a Chuck with a no 3 Morse taper . Is the hercus a 3 MT ?
And would this fit?

https://www.ebay.com.au/itm/Precisio...53.m1438.l2649


Rob

What model Hercus do you have?
My 2 Hercus 9" are both morse 3 in the headstock spindle. I've used ER collet holders in mine, no trouble. You do need to make a suitable draw bar to keep it all together. Of course, with such an arrangement, you can't turn long items that need to extend back into the spindle bore; in fact you are limited in diameter as well for any stock that needs to be housed in the (relatively short bore) M3 ER collet holder. On the upside, the ER collets work fine holding the end of whatever it is you are turning.



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Originally Posted by Silversprings

What model Hercus do you have?

Oh sorry, done it twice . Forgot the picture I prepared.
Model A

Originally Posted by Silversprings

You do need to make a suitable draw bar to keep it all together. Of course, with such an arrangement, you can't turn long items that need to extend back into the spindle bore; in fact you are limited in diameter as well for any stock that needs to be housed in the (relatively short bore) M3 ER collet holder.

Thanks , Ive been told about the draw bar . Didn't realize the limit to length or diameter though . I suppose the length possible is about the length of the chuck with a guess ? Or 70 % of that ?

Photo of the draw bar I made.
Because the draw bar takes up the spindle bore, you loose the ability to run the stock you are turning down the bore. The ER collet holder does have a bore of its own, but only about 80mm deep and around 10mm diameter. As I say all this is only a problem (limitation) if you are turning something long, and you need to have it positioned in the chuck/collet with some of the stock down the spindle bore.
I use my ER32 and ER20 collets often - they hold well, and have less run out than your average 3 jaw chuck (and mine is pretty average......)
Cheers, Tony
ER collet draw bar Hercus.jpg

Ill have to make one as well if I get the set. The main use for the collets is on another machine for holding end mills and it'll be a bonus if they work on my lathe as well . Even if the length of work is restricted I can still see uses for it . Thanks for the info.

Rob

I'd make a Collet Chuck similar to this one, can take long lengths and no drawbar required.
Hercus 260 ER32 Collet chuck.JPG
Hope this helps.
Kryn

What is it , an adaptor that holds the ER 32 chuck or is the whole thing a screw on chuck ?
Rob

Yes, a much better solution. The Morse taper ER holders are really for holding tools, but can double up to hold the 'work' in some applications, particularity if you have one in the workshop anyway. Making a dedicated ER chuck for the lathe is a good little project; making it on the machine it will be used on, should help in keeping the run out to a minimum. As one visitor to my workshop said recently 'you have every tool known to man', but he was wrong.....I don't have a screw on ER chuck for the Hercus. Must fix that omission!
Cheers, Tony

Its a whole chuck. Easy to make, good little project to do. Turn up a big bit of round to screw onto the spindle nose, with an 8 degree taper on the front of it. Cut the outside threads to match a nut off the shelf (or make your own if youre really keen) and away you go. Youll need to drill some holes to accomodate a pin spanner too. Itll be a lot more rigid than an MT3 adapted chuck, plus theres no limit to insertable length, much better solution.

Originally Posted by scottyd

......................... Cut the outside threads to match a nut off the shelf (or make your own if youre really keen) ......................

Testing my understanding ........... one can buy those black nuts as separate items on ebay / bangood ?

Wait ..... will google it

.......... varies between $5 and $50 on ebay

https://www.ebay.com.au/itm/ER32-UM-...8AAOSw8FRZsXta

Until it was pointed out in this thread I hadn't realised the difference between these chucks and using my collet chuck in the lathe ..... Much better idea. Thanks ............. another item added to the "make one of these" list. Just realised I can save $5 by cutting the thread to match my existing ER32 nut.

Wow, bit of price range! Normally they are pretty cheap, the $50 ones must be pretty special..... I have found a source of quite reasonably priced ER collet chuck nuts that have a rolling bearing in them. The theory says, these can be tightened and un-tightened easier and can put more pressure on the collet. I'm not sure it makes that much difference, but if you are going to buy one, the ER32 version goes for $14 plus postage (AU supplier).
I'm normally game to have a go at most things in the workshop, but an ER collet chuck nut would be a challenge, given the off-centre and undercut holding ring inside the nut. I think I'm not 'really keen' enough, especially when the price of a commercial one is so reasonable.
Yes, making an ER chuck to go on the lathe spindle sounds like a worthy project. I have a pretty big 'to do' list....don't we all.....must stop reading this forum and get turning.

I've found that with the Collet Chuck Nut, the threads vary, and are not interchangeable, had 4 nuts (from different suppliers) and none would screw onto other chucks, unless the nut came with the chuck or what I cut to suit. Just letting you know.
Kryn

Kryn, must admit I haven't had that trouble. The last one I bought was quite stiff to screw on, including the M3 Collet chuck it came with, and it proved stiff on my other chucks as well. I put it down to the price I paid (pretty cheap of EBay, so I figured I'd got a dodgy one). They are supposed to be the same thread, based on the ER standard. For ER32 it should be a 40mm x 1.5 thread. I have found the ones with the internal bearings I bought to replace all my non-bearing standard nuts, all screwed on OK. Maybe I was just lucky.
If you want to talk about bad luck and the hit and miss quality you get when buy cheap on EBay.....I bought a set of six 5C collets with square holes, which I thought would come in handy for some work I was doing. They arrived and I put one in the draw tube and didn't think much about the rather 'rattly' fit as I hand screwed it in; tried to tightened the draw tube up, and the collet fell out. I measured the thread diameter and it was 0.8mm undersize - enough to make the threads not engage. All 6 were undersized by varying amounts. I complained and they refunded my money, but what I really wanted was 6 useful collets.
Anyway, not disagreeing with you, just saying I haven't had the miss fitting of the ER nuts (yet...).
Cheers, Tony

Hi Kryn,

I'm surprised you have had problems - I thought all ER32 chucks were made to the same standard. I have three ER32 chucks, one Chinese and two shop made, and two Stevenson ER32 collet blocks from the UK. Only one came with a nut, so I bought 2 extra nuts from one supplier, and later 2 more from another supplier. All five nuts are good fits on each of the chucks and collet blocks without any problems at all.

Frank.