TBC questions

[silent soundly]

I was just getting frustrated with my pens being off center (mandrel woes) when I happened upon IAP and began reading everything I could. One thing it looks like I should do is turn between centers and ditch the pen mandrel. I already have the 60° live and dead centers, so why not give it a shot. I figured that I could just use my digital calipers to turn to the proper diameter and ditch the bushings. My question is, how do you set the proper tension on the tail stock. too loose and the blank will spin on the centers, too tight and they will likely expand the brass tube. My first attempt, I thought I was doing ok. Didn't notice any slipping (I had rounded the blank on a pen mandrel before changing to TBC) but there were brass shavings inside the tube and it was chamfered at one end. Any tips from the masters? Should I chamfer the ends before I start to give more contact to the centers? I don't have any sort of countersink tool yet.

 

[TonyL]

PM Sent. But I am sure you will get lots of excellent advice. I set my "pressure" just tight enough so that the blank doesn't stop rotating when I touch it with my skew to turn it. Sometimes a 10th of a rotation of your tail stock is all you need (even less). I like keeping my tailstock as short as possible while still firmly gripping the live center to keep run-out and vibration to a minimum. Again, you will receive lots of great advice - most superior to mine .

 

[JimB]

When I TBC I still use the bushings. That way I don't need to worry about over tightening. I remove the bushing to apply my CA finish. I use the standard bushings. There are others who buy special bushings for TBC. They get them from some IAP members who make them.

Based on what you have said about your mandrel and the brass tube I would say you have a tendency to over tighten.

 

[flyitfast]

The best tool to clean and slightly chamfer the tube ends (in the blank) is this tool from Harbor Freight. It is a cheap, but effective, plumbers tool and works great.

Reamer/Deburring Tool

I use on every pen. Not only cleans the tube end, but with a slight chamfer the pen parts tend to center and slide in more easily. I use it after tube is in the blanks and after squaring the ends.

Gordon

 

[KenV]

Nick -- Out of Round -- especially severe out of round can be frustrating. Heavy hand with the tail stock or not having a good clean square end on the blank are likely causes.

I have tried the deadcenter/livecenter without bushings, and the tailstock screw on my lathe is not sensitive enough to pull it off -- There is too much slack in the tailstock screw mechanism to handle the "light touch" needed. I am turning on a big lathe though, and smaller ones tend to be more sensitive.

I use bushings with turning between centers and a "mandrel saver" style live center when using a mandrel.

If you struggle with TBC without bushings, it is OK to give it a try with regular bushings or get some custom TBC bushings.