Spindles and Chucks

As a beginner, I am confused at the different spindle sizes and chuck mounting. Where can I find something to explain the most popular spindle sizes and how you obtain chucks to fit. Maybe spindle dimensions or various ways of chuck mounting would help me.
Mostly I hear a spindle described by diameter and then I hear about a 5C spindle and 5C tooling. so you can see how confusing it is to someone like me. Gene

You did not mention machine type, but I will assume you are referring to lathes.

5C is a collet system, has nothing much to do with the topic.

There are threaded spindles - from teeny to huge. The largest spindle nose threads I can think of are about 14" OD. This is the oldest way to hold a chuck on a spindle.

There are maker or proprietary spindle noses - Hardinge taper nose comes to mind - no threads.

There are "standard" spindle noses used on larger industrial machines. These range from small to huge. These are in several "types", or designs. Three types are "A", "D" and "L"

John Oder

genejohnson said:

As a beginner, I am confused at the different spindle sizes and chuck mounting. Gene

Click to expand...

Gene,
Once you have determined the mounting setup for your lathe it is a matter of determining what chuck will best hold the work you wish to turn. Most people will interchange several types of chucks and the advantages of each have been debated several times already (4 jaw, 6 jaw, 3 jaw, 5C, etc.) Size just adds another variable which makes the group even larger. I would say that quality is another important component, it typically matches the quality of the lathe. A cheap holding device usually does not work as smoothly and accurately but then it may be better than doing without.

Raymond

Here's a page that shows the dimensions of A, D and L spindles:

http://shopswarf.orconhosting.net.nz/chuckmt.html

But your question isn't super clear. There's isn't a lot of need to know all about spindle types. A given lathe has a given spindle, so if you have a lathe, you only need to worry about that one spindle.

Most common from what I've seen are

-threaded as John mentioned, denoted with simple OD size and thread pitch

-"long taper" which are denoted L00, L0, L1, etc

-"camlock" which are usually denoted D1-3, D1-4, D1-6, etc.

This isn't all-consuming, but encompasses probably 90% of what's out there.

As far as workholding, I'd concentrate first on a 4-jaw chuck as that's most versatile. Collets are a nice secondary addition. The 5C collets are the most widely produced and thus the most economical to buy. There are untold numbers of other lathe collets out there, I'd say 2J collets are probably the next most common, after that they go pretty quickly into rare birds, harder to find and thus usually more expensive.

As far as workholding with a collet, you need something to "clamp" or "close" the collet. This can be something like a Hardinge/Sjogren "speed chuck" which attaches to the spindle, it can be a hollow tube with threads on the end which closes the collet into the spindle nose (or usually an adapter) via screw pressure, or a lever closer which starts with the same hollow tube, but uses an over-center locking device to actually close the collet.

These two sites have some decent pics which will help with visualization and some numbers too.

http://www.shopswarf.com/chuckmt.html

http://www.shopswarf.com/collet.html

Spindles usually have internal features and external features. In a lathe, the internal features are made to fit a solid center, various adapters or collets directly without an adapter. The external features on a lathe spindle are designed to accept a chuck or faceplate.

A 5C spindle is a spindle that has internal grinding and a key into which a 5C collet or other 5C tooling will fit directly without an adapter. Most Hardinge lathes had 5C spindles. Hardinge made lathes with other size spindles, but they all take collets directly without adapters. By eliminating adapters, Hardinge got higher precision in their machines. This design concept goes back to around 1870 and was first used on Moseley watchmaker lathes. Other companies made similar lathes to directly accept various types of collets.

Most other lathe spindles have internal grinding with a Morse (or other less popular type) taper, so that a solid center with a Morse taper shank will fit directly. More often, the lathe came with an adapter with a large external Morse taper to fit the spindle and a smaller Morse taper to fit a smaller solid center. Collets, like a 5C collet, can be used in these lathes by means of an adapter with the external large Morse taper and an internal grind and key to take the collet. These taper bore spindles are described by their internal diameter because that determines the maximum bar stock that will fit clear through the spindle and also lets you know what collets can be adapted to fit. For instance, you need a spindle bore of about 1.38 inches or more to be able to use 5C collets with an adapter and a drawbar collet closer.

Lathe spindle exterior features are as John described.

Of course, other machine tools and fixtures have spindles, and some, like dividing heads, have internal and external features very much like lathes. Hardinge dividing heads use the same collets and chucks as their lathes. B&S type dividing heads have B&S taper bores and threaded noses for chucks.

Larry

Gene, beyond the matter of suitable chucks, nearly all lathes provide some means to utilize collets, (5C is a collet). These hold the workpiece with their ID's while the OD is drawn into a taper, clamping the part tightly and concentrically. Most are considered "spring collets" and have radial slits that allow reducing their diameter.

Some lathes just have a cylindrical boring precision ground into the chuck end of the spindle, these then accept a collet adapter. The OD fits the spindle ID and the ID of the adapter is tapered to fit collets compatible with that particular taper.

Other lathes have tapered spindle ID's, no "adapter" necessary. The tapers can be 5C, one of the Morse Taper sizes and proprietary tapers. These can be fitted with compatible collets or a suitable "collet chuck" with a shank to match the spindle taper.

There is also a class of collet chucks that are affixed to the projecting spindle nose OD, instead of a 3-4-etc. jaw, standard type chuck.

Now we're both confused.

Bob
Edit; OK, I'm slow!