I previously aligned my tail stock to the head, but didn't use a test rod. I knew it was a little off but put it on my list of ToDo's.
So I started off by making a 10" long test bar from 3/4" drill rod, This was about the largest diameter that would fit through my spindle bore of .787". With minimal stick out I faced, chamfered & center drilled each end.
I then made a dead center for the chuck. I cut the 60° angle with my compound set at 30° and a boring bar angled to the rear of the material. Running the lathe in reverse I cut .005" per pass using the compound for the cut & moving the cross feed out .005 per pass. This took a while until I had a sharp point. I used my fish scale to check the angle & was surprised that I had succeeded in getting the correct angle.
Next I made a light cut from the taper to the chuck jaws to check the chuck/spindle runout. This measured .0002" runout.
Next I mounted up the test bar & using a dial indicator I took a few measurements & found it was out of round by .008".
I took a couple of passes off the entire length from the tail stock to the chuck. Then I used a micrometer to measure the diameter of each end. The diameter at the tail stock end is bigger by .032".
WTH? - chuck end is .705" -- tail stock end is .737"
I measured several times at different points radially with my Mitutoyo 1" micrometer; same results.
Using a dial indicator perpendicular to the rod, I measured a taper of .001 plus about a third of the space between line. but... I started at 0 and it went to +1.3 at the tail stock.
The taper is measured with a near new Peacock dial indicator that has been reliable in the past.
So I'm thinking, maybe the cross feed shifted during the cut. I move the carriage & get a tool touch with the cross feed dial reading 15; I back off to 80. Move the carriage to the tail stock end, cross feed in to 15 then finally touch at 20.
On this lathe the cross feed dial is divided into 100, each division = about .002" (or so they claim). That would indicate a taper of .010".
double wth
I removed the test bar & brought the live center up to the dead center in the chuck
using a steel rule between, it held vertical & looked even horizontal.
Where am I going wrong?
Enco 3in1 lathe, minimal use, gibs reworked & adjusted, new cutting tool on centerline, new tight live center , tail stock was locked.
So I started off by making a 10" long test bar from 3/4" drill rod, This was about the largest diameter that would fit through my spindle bore of .787". With minimal stick out I faced, chamfered & center drilled each end.
I then made a dead center for the chuck. I cut the 60° angle with my compound set at 30° and a boring bar angled to the rear of the material. Running the lathe in reverse I cut .005" per pass using the compound for the cut & moving the cross feed out .005 per pass. This took a while until I had a sharp point. I used my fish scale to check the angle & was surprised that I had succeeded in getting the correct angle.
Next I made a light cut from the taper to the chuck jaws to check the chuck/spindle runout. This measured .0002" runout.
Next I mounted up the test bar & using a dial indicator I took a few measurements & found it was out of round by .008".
I took a couple of passes off the entire length from the tail stock to the chuck. Then I used a micrometer to measure the diameter of each end. The diameter at the tail stock end is bigger by .032".
WTH? - chuck end is .705" -- tail stock end is .737"
I measured several times at different points radially with my Mitutoyo 1" micrometer; same results.
Using a dial indicator perpendicular to the rod, I measured a taper of .001 plus about a third of the space between line. but... I started at 0 and it went to +1.3 at the tail stock.
The taper is measured with a near new Peacock dial indicator that has been reliable in the past.
So I'm thinking, maybe the cross feed shifted during the cut. I move the carriage & get a tool touch with the cross feed dial reading 15; I back off to 80. Move the carriage to the tail stock end, cross feed in to 15 then finally touch at 20.
On this lathe the cross feed dial is divided into 100, each division = about .002" (or so they claim). That would indicate a taper of .010".
double wth
I removed the test bar & brought the live center up to the dead center in the chuck
using a steel rule between, it held vertical & looked even horizontal.
Where am I going wrong?
Enco 3in1 lathe, minimal use, gibs reworked & adjusted, new cutting tool on centerline, new tight live center , tail stock was locked.