Confused with spindle specs

[peter.van.haren]

My Yang 14x22 lathe spindle specs are in the attached picture.
What is the "Center" in Taper of Center - Morse Taper #3?
The Spindle bore is 1.77", and that is a lot bigger than a MT3.
There is also a Taper of Spindle Bore 1/30. Is the the inside taper of the spindle nose?
The tail stock taper is MT4.
(Happens to be a M48x20 LH thread at rear of spindle)
Thanks!
Peter

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[Cadillac]

You will need a mt5 to mt3 adapter unless it’s a oddball size. Looking at your measurements it might be bigger than a mt5. Pretty common

 

[peter.van.haren]

Yes, the hole might be bigger than MT5 (1.77" spindle bore vs 1.74" max of MT5). My measurements are certainly approximate and I don't have anything in MT5 to try it.
Still wonder why they write Center of Spindle as MT3??? Smaller yet!
Also the spindle nose being ASA A1-5, I can't see anywhere if the internal bore of that nose is a MT taper. Thoughts?
Thanks a bunch!!

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[Superburban]

Every bigger lathe I have owned, came with a taper adapter to fit the advertised taper into the spindle. Basically just looks like a 1/2 length MT 5 to 3 adapter.

 

[darkzero]

A1-5 & D1-5 size spindles usually have a MT5 taper. Not sure why that spec sheet lists those specs but lathes commonly come with a spindle taper adapter to match the tail stock taper. Not always I guess but usually it seems. But you stated your tailstock is a MT4 so I would figure your lathe would have came with a MT5 to MT4 sleeve.

But the reducing sleeves used in the spindle are not the same as reducing sleeves used for arbors that would go in a tailstock or drill press. They are usually shorter & have an open end, no tang feature. The sleeve for a drill arbor will still fit in the spindle but it most likely will stick out too far if used for turning between centers. Same if you just use a MT5 center instead of a the spindle reducing sleeve.

Reducing sleeve for a drill/tool arbor

Reducing sleeve for a center used in the spindle

 

[peter.van.haren]

Thank you Superburban and Darkzero,
I ordered a mt5 - mt4 adapter sleeve, so will know soon enough. Wondering if the spindle center mt3 is a typo? Entirely possible.
The 1:30 spec still has me baffled, but it is the spindle center that might be solved first.
More questions to come....ok? ;-)


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[rgray]

1:30 taper 1 inch of taper for 30 inches of length. Or 1mm for every 30mm of length.
On that lathe it's probably the metric.

 

[Stonebriar]

I have a 1440gt and it list the spindle as a 5 1/2MT taper. And who ever heard of that odd size. But it came with a 5 1/2 to MT3 adapter.

 

[peter.van.haren]

1:30 taper 1 inch of taper for 30 inches of length. Or 1mm for every 30mm of length.
On that lathe it's probably the metric.

Thanks. Yeah i figured the 1:30 means (only because I'm familiar with roof pitch/slope), just not sure what the taper of spindle bore 1:30 vs taper of the center MT3 (typo?) is. As my Thai business partner always says..."learning by doing"

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[peter.van.haren]

I have a 1440gt and it list the spindle as a 5 1/2MT taper. And who ever heard of that odd size. But it came with a 5 1/2 to MT3 adapter.

Good grief! Hope its not a odd size like that! Anyway, didn't get an adapter, but can always ask the importer if "we" get stuck, I guess. By the way, its a Used import from a Taiwanese school.

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