Neck Turning Part Three, The Inside, Tool Preparation, Ready to Turn

[bikemutt]

Got to the point of no return today, tomorrow will be inside turning for real 

I changed the single-use neck holder preparation; the center bore was omitted, only the 3 bolt holes are drilled. Why I thought I could drill a hole on one machine, then bore the hole to final I.D. on another machine is beyond me , I know better.

Here's a picture of the permanent holder with the single-use neck holder mounted in the lathe chuck, ready to drill and bore. The neck holder is about 0.3195" thick.



First step is using a 1/8" spotting drill to mark the center of the chucked assembly. The bit is allowed to wonder; it always wonders to dead center  .





1/4" hole drilled, ready for boring.



Here's a video of the hole being drilled, have to tall ya though; it's boring 

0.25: Hole Drilling

The last step is to bore the hole to neck O.D. which is 0.2900". I did not video this part because, for me at least, it requires undivided attention. The idea is to keep checking work with gage pins, then make the final pass to size. Here's the finished piece with a .290- gage, and an outside turned neck. The fit is superb which is the only adjective I can think of, I'm sure there's a technical term for the feel of a good slip-fit.





Here's a snapshot of the finished holder with a dial test indicator made live on the inside diameter, and set to zero for reference, this will come in handy later.



Here's a video which aims to quantify the axial and radial excellence achievable by making a holding part on the lathe. Radial runout is in the low 10 thousands of an inch, axial runout likewise as seen when the indicator tip traverses the length of the bore. At the very end of the video the lathe spindle is placed in neutral and motor turned on, that's the noise floor of the machine. Anyway, I think this one's worth watching for those interested in the subject, music courtesy Blake Shelton  .

https://drive.google.com/file/d/1LOqhXOXmzMVDqI8OyWNPqplcpPW6Q49C/view?usp=drive_link

Here's a picture showing the brass ready to inside neck turn. It takes just seconds to insert the piece into the holder and secure it for turning.



Finally, recall the picture showing the dial test indicator (DTI) zeroed on the holder I.D., here's one showing the same DTI touching the inside of the outside-turned neck. I'd estimated taking 0.0009" off the wall, this picture indicates it's 0.0008"  . The wall thickness here is 0.0133", always nice when the math adds up 

[gman47564]

Chris I commend you for your efforts to achieve perfection...

[DHuffman]

Chris I commend you for your efforts to achieve perfection...

Agree with Grant 100% on this.

It's amazing to me to watch how far many of us (myself included) will go down the "hole" to single out a part of a process and chase absolute perfection.

I'm living vicariously through Chris and many of you for the time being and the distraction is welcome.