View Full Version : lathe chuck fittings

Alistair Hosie
08-02-2003, 05:43 PM
What does D1-4" or D1-3" camlock fitting mean on a lathe chuck etc and can a D1-3" fitting backplate be removed and a D1-4" fitted instead and are they all standard so that all D1-4" fitiings are the same the world over . Alistair

Alan in Oz
08-02-2003, 06:41 PM
The attached link should help in your quest for info on chucks of varying descriptions www.workholding.com/prattadaptor.htm (http://www.workholding.com/prattadaptor.htm)

08-02-2003, 08:08 PM
D1-4 or D1-3 camlock is the spindle type. A backplate that fits that spindle can hold either a faceplate, collet chuck, or lathe chuck. It is just a matter of fiting the backplate to the chuck properly. You cannot interchange them however - A D1-3 will not fit a D1-4. There are adapters made for this but they are not recommended as they add overhang to the chucks.


Alistair Hosie
08-04-2003, 01:01 AM
Dave what is the difference between a D1-4 and a D1-3 that's what I am trying to fathom and what do these numbers mean is it 4inches against 3inches between pins or four pins against three pins or what.what do the letters and numbers signify? Alistair

Alistair Hosie
08-04-2003, 01:20 AM
It seems that D1-3 and D1-4 are both with three pins distanced three and four inches apart and all others have six pins distanced in inches according to their numbers I.E D1-6 would be six inches apart and D1-8 would be eight inches apart if I am reading the chuck advice you sent Dave is that right.Alistair

Alan in Oz
08-04-2003, 03:55 AM
The following link may help explain the differences a little better

08-04-2003, 07:56 AM
A quick check, center of spindle to center of pin;
D1-3 1.391"
D1-4 1.625"
D1-5 2.0625"
Pin Diameter;
D1-3 0.5937" (3)
D1-4 0.6562" (3)
D1-5 .7815 (6)

Alistair Hosie
08-04-2003, 09:46 AM
Can anyone tell me what doe D1-3 mean what does D signify what does 1 signify and what does-3 signify then I can work it out maybe. There must be a reason why these numbers and letters are being used surely it's not to make life more complicated for the (no nothings) like myself http://bbs.homeshopmachinist.net//biggrin.gif http://bbs.homeshopmachinist.net//biggrin.gif Alistair

Forrest Addy
08-04-2003, 11:21 AM
Like most standardized stuff lathe spindle nose confugurations have designations that hint at certain features.

The question had to do with the A1-3 and A1-4 spindle nose and what the last number really meant. Not much, realiy. The designator has nothing at all to do with the CD of the D-1 cam-lock pins or the A-1 bolt circle. It's just a number like for a dress size or a fish hook.

In the A-1 series the number designator kinda means the interger number of inches in the diameter of the flange. It doesn't refer to some actual dimension. As the designation number gets bigger the spindle nose bets bigger overall and in rough proportion.

Here's a website to Cushman Industries for A-1 series spindle nose demensional data.


And for the D-1 series


A budding machinist should study the many standards and commit the essential features of standards used every day to memory. Among these are the spindle nose standards to be found in chuck manufacturer's catalogs as applied to your equipment.

With a little practice, a casual glance at a lathe spindle from across the shop will cause "D1-6" or "A1-11" to pop into your mind.

Where I used to work we had an old Lodge and Shipley oil country lathe that had a 21" hole through the spindle and a chuck at each end. It was a large powerful machine whose highest speed was 110 RPM and whose massive gearing inspired awe even from from jaded gawkers.

The chuck bodies were shot thanks to 30 years of use and negligence and new jaws and screws wouldn't solve the problem. I was instructed to look into purchasing new ones.

The spindle was an A1- something but it didn't fit any standard I could find. The S-2 gage diameter of the short taper is taken from the theoretical intersection of the taper cone with the mounting face. That size was something like 22 1/2" but I can't recall exactly. It was so big therewas no standard that applied ot it. I imagine Lodge and Shipley simply stretched a D1-11

Phone calls and letters (rememeber snail mail?) went back and forth. Cushman offered to make us a pair of 42" oil country chucks for $17,000 in 1973 dollars; probably a reasonable price for a special but out of the question for that year's budget.

Well, (the reasoning went) we had at our disposal a perfectly good machine shop and foundry so why couldn't we make our own?

We moved the rear chuck to the front and sent the front body to the pattern shop. The pattern shop built up the old body with linoleum and filler to make a pattern and the foundry poured us a couple of new chuck body castings of their excellent 60,000 PSI malleable iron.

We ordered new jaws, screws, T handle etc from Cushman to suit one of their standard chucks and we put a promising apprentice to machining the chuck bodies. All told $3400 and change.