Turning between centers question

[mmayo]

Is there any advantage turning between centers instead of using a pen mandrel.

Yes, you get great pens every time

 

[mmayo]

I'm on my third set of centers, and about to replace them. The brass tubes seem to carve little rings in the surface after not too long, even with my sad attempt to use blue tape to protect them.

What are some good centers you would recommend?

Use the correct TBC bushings and do it correctly

 

[jrista]

While just a few years ago, there were solid carbide dead centers (IIRC) but I can't find any now. The only one with a large carbide tip is on Amazon and it is somewhat pricey: $75+

https://www.amazon.com/Center-08016-Oversized-Carbide-Morse/dp/B008B83GIG/ref=sr_1_3_sspa?crid=CECLTAVJKNYU&keywords=wood+lathe+carbide+dead+center&qid=1693260694&s=industrial&sprefix=wood+lathe+carbide+dead+center%2Cindustrial%2C108&sr=1-3-spons&ufe=app_do%3Aamzn1.fos.006c50ae-5d4c-4777-9bc0-4513d670b6bc&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

Aye, a bit spendy...

Hank, do you know how well carbide holds up to the rigors of TBC pen making?

 

[jrista]

I'm on my third set of centers, and about to replace them. The brass tubes seem to carve little rings in the surface after not too long, even with my sad attempt to use blue tape to protect them.

What are some good centers you would recommend?

Have you ever looked at TBCBushings.com? Most of my TBC bushings are from him. Others I managed to get from the manufacturer, or from the place I bought the pen kits from. If you haven't used TBC bushings before, then I think you will find they resolve most of the issue. I have a set of centers that I use with my TBC bushings. I keep them as groove-free as I can, and the TBC bushings dont introduce grooves themselves (they have a 60 degree internal angled surface to properly mate with a 60 degree center). The TBC bushings DO mar the surface of the centers, but that is easy enough to sand out periodically. TBC bushings with a decent (doesn't have to be a great) set of centers gives me very true turning.

My biggest issue with trueness is the quality of my lathe, I think. I'm still fiddling with optimizing my tailstock, headstock, leveling of both, alignment and centering of both. The Wen lathe is not top of the line, but its a good workhorse lathe, and a lot easier to use for pens than my huge Powermatic. But its lack of precision in the ways and such, has certainly given me a non-trivial task of getting everything optimal. I've got things pretty close now, though not perfect, and that has resulted in better turning overall. I still have some issues, haven't quite narrowed down exactly from what yet. It may be that a higher quality live center that doesn't have any wobble at all in the bearing, may be a piece of the puzzle.

Anyway...TBC bushings took me from wobbling and vibrating bushings while turning (which are guaranteed to give me nonconcentric turns), to pretty much dead stable spin on both bushings the vast majority of the time. Sometimes, I think there might be a mating issue between one set of bushings, and one or both of the centers, but its pretty rare.

 

[leehljp]

Aye, a bit spendy...

Hank, do you know how well carbide holds up to the rigors of TBC pen making?

They hold up well, IMO and My experience.

I personally use bushings on the blank between centers to get it round or to shape, and very close to the needed size; then take the bushings off and finish sizing it. This way there is very little slippage, no rings in the drive center and I don't flair the tubes. I have been using TBC that way since 2008.

 

[egnald]

I'm on my third set of centers, and about to replace them. The brass tubes seem to carve little rings in the surface after not too long, even with my sad attempt to use blue tape to protect them.

What are some good centers you would recommend?

Are you sure that you are just not seeing galling of the brass on the center? Brass is softer than steel so I would assume that any friction might cause galling. If it is, then you should be able to clean it up by using some emery cloth/paper with a hard backing (I recommend a plastic pen blank). Even if the 60-degree angle is changed slightly I don't think it will have an impact on anything else you might be using the center for.

Using TBC bushings should also help resolve this as you would go from a point contact between the center and the tube to a full face contact between the bushing and the center and between the bushing and the face of the blank instead of just the inside edge of the brass tube.

Dave