Bridgeport R2E3 solid spindle?

[Jake2465]

I was thinking about getting a power drawbar for my mill, but noticed that this plug/ spline looking thing is blocking the path through the quill. Has anyone seen this before? I was under the impression that Bridgeport Quills were all through hole. Mine has the Erikson quick change system on it.

 

[JimDawson]

Yup, that's the end of the spindle down there. The splines are the drive system. Looks like there is a center drill hole in the end. Definitely not a through hole.

The counter bored pocket in the quill (3rd pic) is where the quill stop normally attaches on a manual machine.

 

[Jake2465]

No pneumatic draw bar for me .

 

[derf]

Drill it out! That's what I did to mine.

 

[Jake2465]

Can the spindle come out without taking the head apart?

 

[derf]

The spindle is the easiest thing to remove on that whole machine. There is a 1/4" set screw on the back side of the quill, about 1/4" up from the spindle nose cap. Remove the set screw and then use a drift or a spanner wrench to unscrew the spindle nose cap.(right hand thread) Once the nose cap is off, the spindle assembly slides out the bottom. The "assembly" is like a cartridge, with all the bearings and etc. contained within.
It will probably take you longer to crank the knee down for clearance than it took to remove the nose cap.
To drill it, the best way I have found is to clamp one end in the chuck and support the other end with a steady rest right on the bearing sleeve so it rotates on it's own bearings.
The spindle itself is only case hardened, about .020" deep. I started with a 1/2 carbide drill to break through the case, and after that used a standard HSS extended drill bit. I also drilled from both ends and met somewhere in the middle. Once the hole was drilled to max depth with the carbide, I clamped the extended drill in a tool holder and used the carriage to push the drill. Once you have it set up, it will take about 2 hrs.

 

[Jake2465]

The spindle is the easiest thing to remove on that whole machine. There is a 1/4" set screw on the back side of the quill, about 1/4" up from the spindle nose cap. Remove the set screw and then use a drift or a spanner wrench to unscrew the spindle nose cap.(right hand thread) Once the nose cap is off, the spindle assembly slides out the bottom. The "assembly" is like a cartridge, with all the bearings and etc. contained within.
It will probably take you longer to crank the knee down for clearance than it took to remove the nose cap.
To drill it, the best way I have found is to clamp one end in the chuck and support the other end with a steady rest right on the bearing sleeve so it rotates on it's own bearings.
The spindle itself is only case hardened, about .020" deep. I started with a 1/2 carbide drill to break through the case, and after that used a standard HSS extended drill bit. I also drilled from both ends and met somewhere in the middle. Once the hole was drilled to max depth with the carbide, I clamped the extended drill in a tool holder and used the carriage to push the drill. Once you have it set up, it will take about 2 hrs.

Referencing one of my pictures, is the spindle nose cap that brass colored piece just above the quick change spanner nut?

Did you end up going with 1/2" as a final size for the hole? I have not taken any measurements, but I would think that the spline shaft would get pretty thin with a 1/2" core removed. I would have to take it to a shop as my lathe probably does not have the bed length to accommodate the spindle and a long drill bit in unison.

 

[derf]

1/2" worked fine, as the drawbar is slightly undersize. I drilled mine on a 13-40 Jet with no problems. That's why I clamped the extended drill bit in a tool holder, and just kept moving the bit out about 4" at a time and re-clamping.

 

[Jake2465]

View attachment 264775
1/2" worked fine, as the drawbar is slightly undersize. I drilled mine on a 13-40 Jet with no problems. That's why I clamped the extended drill bit in a tool holder, and just kept moving the bit out about 4" at a time and re-clamping.

I see. And, do your tool holders use the 1/2 x 13 thread? I am not sure what the major diameter of a 1/2 x 13 thread is, but I can only guess that it's right around 1/2".

 

[derf]

All the Erickson and NMTB 30 tool holders use a 1/2"-13 drawbar. The threaded portion of the drawbar measures .490", and the un-threaded portion is a little smaller, probably because the threads are rolled on.