Thin wall MT3 to MT2 adapter?

[darkzero]

Thanks Will. I don't doubt at all that it is not thinner. We will find out 'cause it has been ordered and will be here in a few days.

I will carefully check out the dimensions and issues you point out before jamming that baby in there too tight.

No problem, but yeah you definitely don't want that sleeve stuck in your tail stock.

Here's some pics. These are both MT5-MT3 but you'll get the basic idea in size comparison between a spindle sleeve & regular sleeve (I only have the regular MT5 sleeve cause that's what ZLC originally sent me, they told me to just keep it). And as you can see, if you used this setup up as is, there's a big risk of ejecting the center out of the sleeve rather than both unless you are able to seat the center in the sleeve very tight & hope.

 

[NortonDommi]

Use open end,(drawbar),arbors and sleeves. Use a button head screw in the end so the arbor will knock out. If useing a MT2 arbor in a MT3 sleeve fit sleeve and screw through into the MT2 arbor this will make sure they come out together and it is easier to seperate them on the bench.
The only Tanged arbors I have are fitted with drill chucks but the lathe drill chuck has an open end arbor with a screw in it. Never had a problem with slip but I keep my tapers plugged if nothing is in them, Clean before anything goes in and I seat with a light tap with block of wood if not using a drawbar.
Here's some dimentions but they are in metrickery.

 

[Alan H.]

Okay, I received the Mt3/2 sleeve and it provided the basis of the solution I was after although it required a little modification by the addition of an extender. My new Royal Products Quad Bearing live center with MT2 is now fitted very well to my PM1340GT lathe.

The Z Live Center sleeve does have a thinner wall than my Sioux MT3/2 adapter. This benefit added to the other big advantage of the sleeve being much shorter than a tanged adapter yields a very good outcome.

I added an extender to the sleeve so that the assembly could be expelled by the tailstock quill adjuster screw as is normal. Without the extender, the sleeve on the live center would not be removed by backing the quill into the tailstock housing. The sleeve was about ~ 1/2" too short to engage with the screw to be pushed out of the socket. The extender I made solved that problem and this modified sleeve gives me what I was looking for. It is much shorter than a MT3 to 2 adapter with tang, has a thinner wall, and has almost no cantilever out the tailstock quill socket.

Here is the sleeve compared to the tanged adapter (the extender I made is shown here as well):


Here is the extender laying on the sketch I made for it. The dimensions specifically fit a PM1340GT tailstock, a Z Live Center sleeve and a Royal Quad Bearing live center.



The Royal, the sleeve and the extender ready to assemble:



Here's the Royal Live Center with the modified/extended ZLC sleeve on it:



Here's the projection of the Royal using a tanged MT3/2 adapter. The center is retracted to the point where the quill screw begins to expel the center. Notice how much cantilever there is even with the center pulled back as far as it will go. The wall thickness of the tanged adapter adds cantilever as well as the tanged end. This projection and cantilever is what I wanted to avoid:



Here's the Royal with the modified sleeve. Notice that it will retract all the way to the zero mark before it is expelled and there's no excessive cantilever. Both of these are the benefits I was after. The wall thickness and length are the ticket!



I have attached the drawing of the extender just in case it might help someone down the road. Keep in mind these dimensions are for a Royal Quad MT2 live center mounted in the the tailstock of a PM1340GT lathe. Please be sure to confirm the dimensions that would work for your machine and center.

 

[Alan H.]

I also meant to share the wall thicknesses of the two different adapters above.

The wall thickness on the MT3/2 tanged adapter (Made by Sioux) is 0.1355". The wall thickness on the MT3/2 sleeve by ZLC is 0.1255". So to my surprise the sleeve was significantly thinner which is a definite advantage for my application.

As pointed out by Will, the sleeve's real intended purpose is for use in a head stock. Perhaps that is why they are thinner to minimize projection.

 

[marcusp323]

Very nice. I see more fddlin' in my future yet again. Never ends really, does it ;-)
Mark

 

[NortonDommi]

Very nice design and finish.