# Atlas lathe versus Atlas mill Morse taper



## JPMacG (Jan 16, 2015)

So my Craftsman/Atlas 12x24 lathe has a Morse taper #3 on the head but the Atlas milling machine that I am thinking of buying takes a #2.   

I would rather not get two sets of collets.  If I were to use a #3-#2 taper reducer on the lathe would I run into problems?


----------



## Mondo (Jan 16, 2015)

JPMacG said:


> So my Craftsman/Atlas 12x24 lathe has a Morse taper #3 on the head but the Atlas milling machine that I am thinking of buying takes a #2.
> 
> I would rather not get two sets of collets.  If I were to use a #3-#2 taper reducer on the lathe would I run into problems?



I think only to the extent that each additional part or adapter can and will introduce some small measure of added TIR.  Add to that the further out from the headstock bearing the work piece or tool is held the larger the deviation caused by run-out and vibration will be realized.

Exactly how much these added deviations will be depend on the quality and accuracy of the parts involved and how well they fit together.  Use the best quality you can obtain and you can probably minimize the deviations.

Spiral_Chips


----------



## Ulma Doctor (Jan 16, 2015)

i guess that would depend on how much precision is necessary for your work.
any time you use an adapter, you are inviting runout.
if you are using the adapter for roughing, there won't be any consequence.
when doing fine work is where problems might be more apparent.

i don't think anyone of us are building stuff to land on Europa, 
so you'd probably be ok buying the adapter, you just may have to plan ahead when doing very fine work to tolerance.


----------



## Terrywerm (Jan 16, 2015)

If I were in your shoes, I would consider making an ER32 collet chuck for the lathe, and purchase an MT2 to ER32 collet adapter for the mill. Then you would only need one set of collets.


----------



## JPMacG (Jan 16, 2015)

Thanks everyone.   

Would the ER32 to MT2 adapter take up more room on the mill?  The Atlas is tiny.   I've never actually seen an ER32 collet chuck; I'm just looking at photos on the Shars website.

And what is a collet chuck?  Something that screws onto the spindle in the same manner as a 3 jaw or 4 jaw chuck?

Thanks


----------



## wa5cab (Jan 17, 2015)

JP,

Although I'm not sure that there is any publication or standard anywhere that defines the terms, a collet chuck usually is a gadget that attaches to the spindle.  In all Atlas cases it would screw onto the spindle nose threads.  

A collet adapter, also called a collet closer, would stick into the spindle, in this case 2MT for the Atlas Mill and 6" lathes and 3MT for the larger Atlas lathes (9", 10" and 12").  An end mill or cutter holder also usually sticks into whatever taper the machine has in the spindle bore.  Using these definitions, the collet closer for traditional pull-type collets like 3AT and 5C costs very little table space.  But neither will fit on an Atlsa 6" or mill.  2MT collets will.  The collet adaptor (on a 2MT arbor) and the collet chuck for ER collets have a compression nut on the front which will take up something like an inch or more of table space.  I don't think that anyone makes a collet chuck for a 5C collet that will fit the mill or 6".  I have one for my 3996 and it sticks out about as far as my Pratt Bernard 3-jaw and is about 4" in diameter.  So much too large to make to fit the mill or 6".

Sorry, but I do not have any of the ones that you might be interested in to take a photo of.

Robert D.


----------



## master53yoda (Jan 17, 2015)

I have been using a ER25 mt2 on my mill/drill conversion with good success.   For my 12 x 36 craftsman I have just ordered a mt 3 to mt 2 adaptor for use with the mt2/ERr25.   I only have about 3 collets for the ERr25.

I am ordering a MT2 to ER40 with a full collets set, i can get this for 185.00  it will fit anything from .115 to 1"   I am planning on making a collet adapter for the spindle of 12 X 36 for the ER40   The following website is a article the shows the build for the collet adapter for 618.      http://www.deansphotographica.com/machining/atlas/ER25/ER25.html


the MT2 to ERr25 adapter in the mill is about the same size as the mt2 drill chuck.  it looks like the mt2 to er40 will be about the same size as my 5/8 chuck is.

Hope this helps

Art B


----------



## JPMacG (Jan 17, 2015)

Thanks Robert and Art.  That is all very helpful.  The help that I get on this forum always amazes me - no comparison to other sites that I visit.

I plan to pick up the Atlas mill on Monday.   Once I have it in my shop I can get a better feel for  how much room I have and what to do about a collet.  

I really like the range of the ER25 collets.  I think they would be very useful for my Atlas 12x24 lathe.   Maybe for the mill I will just get two or three MT2 collets in the standard endmill shank sizes.


----------

