Help identifying spindle taper

[Hathaway98]

Hi, new here. I’m having trouble identifying what spindle taper is in my Nardini ND1760E lathe. I’m pretty much a novice machinist. I went to Trinidad State gunsmithing school, and know the general functions of lathes. I chambered 20 rifles while I was there, and machined various simple tooling. Unfortunately, I never had a class that taught more specifics on lathe parts, tooling, standardized parts, etc. I ended up buying a lathe after graduating, and never got power to it. It’s been setting a couple years, and I’m now looking at getting things running. I’ve got most all the tooling I need, but having trouble ID’ing my internal spindle taper. Thought it was an MT6, but only about an inch of the dead center fit, and it’s obviously the wrong taper as well as size.(light Ring formed on dead center where contact stopped the center). Way too large for mt5. I have some rough measurements on the taper and just wondering if anyone could recognize it. I believe it’s a D6 camlock spindle nose casted to the spindle. Anyway, here are the measurements, forgive my lack of proper terminology.

Large side taper dia.: 2.200”

Small side taper dia.: 2.075

Taper degrees: 2*

Taper length: 2.75 roughly

Spindle standard dia: 2”

Any help would be greatly appreciated. Also, if you know of a good machinist handbook with this sort of info, I would love to hear your recommendations. Also have a sharpe lmv 9x42” vertical mill. Sorry about the lengthy post….

 

[deltap]

Get a Machinery's Handbook. It should have all the info you need on standard tapers. If mt5 is way sloppy you could turn an adapter for a 5. For temporary service chuck a piece of round stock and machine a dead center on it. I have one I marked the number one chuck jaw on and it is repeatable for most jobs.

 

[johnoder]

Assuming the length is nearly what you wrote, it comes out to .545" taper per foot on dia

(Its also fairly close to 3mm taper on dia. in 70mm of length)

less taper than Morse (and Jarno) and more taper than B&S

Lots less taper than the American Standard which is .750" per foot on dia.

Handy info here

Standard Tapers

have fun

 

[Hathaway98]

Hey guys, thanks for the info and tables. Ya it’s a funky taper, not very handy. I’m planning on building an adapter when I get the machine running. Hopefully I can keep the TIR to less than .0005”, but we’ll see. Thanks for the other info as well. Would still love to know what Nardini threw in there, are there metric tapers as well? Can’t find much info on them. I’ll get that book ordered, looks like it’s pretty much the industry standard.

 

[Bill D]

A little searching says the tailstock is MT4. in my limited experience I would guess MT6 in the headstock. Probably a cut down short version of the taper.
The Nardini 1440 lathe is MT5 for the headstock.
Bill D

 

[L Vanice]

The 5C lever collet closer maker called "JFK" has apparently undergone a change of address and website usefulness. I recall they had a very long list of 5C headstock spindle adapters (including dimensions) that would fit almost any lathe. I think that the list included some that were called 5-1/2MT, a size not included in the original list of Morse tapers for drill bit shanks. But JFK also had a number of different "gage diameters" available for the 5 and 6MT tapers because the various lathe makers never standardized their products. Their current website is useless, though one could try asking them what 5C adapter will fit that particular Nardini.

Larry

 

[L Vanice]

Of necessity, Morse was adopted into Metric-world. ISTR they call MT out as KT?...

I think you mean MK. The M would still be for Morse, but the K would be a German term for taper, Kegel (cone).

Larry

 

[Hathaway98]

Thanks all for the conversation. It’s not an mt6 cuz it’s to small and the wrong taper angle.(tried bison mt6 dead center) Not an mt5 cuz it slips right past the taper, and on into the spindle, as well as being the wrong taper angle again.(tried a mt5 adapter sleeve there)So I don’t think it’s a short Morse taper. For starters here, the main use would be a dead center, which as others said, I can build an adapter, and use a sacrificial center in the mean time. A 5c or possibly R8 collet system is hopefully in my future down the road. I used 5c with a handwheel constantly during my time at school. It is indeed an mt4 live center in the tail stock. Just don’t understand why they wouldn’t have just cut an mt6 or mt5, and skipped a tolerance stacking adapter bushing…. Not sore about it, but seems foolish.

 

[Bill D]

I have no idea what was common in Brazil 30 years ago. maybe they were told that the taper used was the coming thing in world wide lathe production and they better get with it or be left behind in the dust.
I remember as a high school kid hearing the USA had to metrify or petrify. That was some 45 years ago, still waiting to see more metric then English nut and bolts in a store.
Bill D.

 

[Bill D]

My understanding is the MT was supposed to be a nice ratio like 5/8 per foot. I think it varied by size? But Morse could not measure that accurately, before micrometers were invented etc, so it is off a little bit and everyone keeps making it to match. Jurno does make sense and it is modern enough that it really is a whole number taper.
Bill D