Round dial / square dial Taper Attachment photos and differences.

[mooserov]

I have been piecing together a taper attachment for a while now, and I wanted to provide some photos and measurements to those seeking info about it. I see very few differences overall, and looks like only mounting hole spacing would keep you from using one from a different style machine.

Here are the parts I've collected. I don't have two of everything, but at least I can measure the main castings.







Here it looks like the round dial part is a little beefier, but all the critical dimensions are the same. these parts appear to be interchangable between the two main castings.





These parts are identical



Round dial on top

square dial top-row mounting hole distance. Note measurement starts on 1" for every shot with the ruler.

round dial top-row mounting hole distance.

square dial top-row mounting holes are centered on the same plane,

Round dial top-row mounting holes are NOT on the same plane.

 

[mooserov]

the round dial casting is shorter, putting the slide lower.

but the measurements from the top of the slide to the center of the mounting holes are the same.
this is difficult to photograph well, but I have 1" to center from top of bar on each casting.

Vertical mounting holes..
Square dial, coplanar

round dial, not coplanar.



I only have 1 'skate' , but it fits in both castings. I only have one set of the eccentric shafts/bearings, but they fit in each casting.

The chip guards that cover the bottom bearings have the same hole spacing, but the outer set of holes is set 100 thou back on the square dial set. I made a set.



Buyer beware, I might be incorrect on which parts are round dial, and which ones are square dial. especially on the adjustment parts. I accumulated these parts from all over, including here, so please correct any mistakes you see.
If there is any other thing someone needs me to measure/photograph, please speak up. this has been educational.
Cheers,
Gary

 

[Cal Haines]

What you're calling a round-dial taper attachment is from a Sundstrand drive era machine, correct? Motor/generator era TAs are like those assembly on the right:

 

[Cal Haines]

Here's the TA on my '43 MG round-dial:

 

[mooserov]

honestly Cal, I don't know what it is from. I got some 10ee taper attachment castings from a member here, and the one in white is what was sent. I'd like to know when they changed to the style like you have, obviously before the square dial came out.
from what I can tell the only real difference is a couple of holes here and there, and the height of the TA bridge.


rimcanyon said this in the first thread I made:

on't work unless you plan on installing a round dial cross slide. The square dial cross slide is too long for that 1940 TA. I even had a round dial cross slide with a rear dovetail (which is the same length as a square dial cross slide) that I tried to fit to my 1940 10EE, and it would not work. The longer cross slide runs into the TA bridge, shortening its travel by a couple inches at least. Sell the TA to someone with a 1940 or older 10EE.

Also the height of the casting is different for a 1940 TA. Which means the location of the threaded rod for the bed stop is different. Which means you need a different bed stop than the later TA. Also, the location of the mounting holes may be different, I don't recall.

 

[Cal Haines]

The change appears to have happened when the 10EE was redesigned for the inline exciter motor/generator. Here's the TA for EE8815, a Sunstrand drive machine, built July 1940:


Here's the TA for EE10110, an early inline machine, built June 1941:

 

[mooserov]

That's great cal, thanks. I'm kinda dense sometimes and that cleared it up for me.

 

[pob2]

Thanks this is really interesting. I've been looking for a taper attachment for a CVA lathe, British Monarch 10ee clone, for a while and wondered if a Monarch attachment would fit. Here's a photo of the mounting holes on the back of the CVA saddle - which are different. The spacing between bottom holes is approx. 10 3/4 inches

Pat

 

[mooserov]

Cal, do you have a closeup of the wiper holders on the 'skate' ? do they hook around the bottom, etc. I'm missing that and will have to fab it.

 

[rimcanyon]

My guess is that the change occurred as a result of the introduction of the rear dovetail cross slide. That cross slide is longer than the regular round dial cross slide, and there was not enough travel to support the use of a rear toolpost, so they redesigned the TA to allow more cross slide travel.