A few TBC questions from a new pen turner

[Cavediver]

Hello all,
After turning my first few pens on a mandrel, I'd like to take a stab at turning between centers.

Is turning between centers suitable for someone so new to the game? My overall lathe experience is also pretty limited, and I don't want to set myself up for more failure than necessary :wink:

Aside from the wear and tear issue, is there any reason I can't use a collet chuck and some 3/4 oak dowel to make a (temporary / trial) dead center?

How many digital calipers will I want? I've got one set and figure I can make that work for now, but am willing to expand my inventory if it'll save me some frustration.

It seems like a lot of folks turn their own bushings from Corian, Delrin, or some other non-stickish materials. Is this reasonably easy to do on a wood lathe? If so, are there any guidelines for tool usage on the different plastics? (I've tried cutting some nylon rod and did not have much success. I've looked around for this info, but either my search terms sucked, or there's no info out there. I'm betting on the former :biggrin: )

Thank you, and sorry for yet another TBC thread :redface:

 

[Ed McDonnell]

Everyone has opinions, here's mine in response to your questions:

1) You are never too new to start turning between centers. If you use TBC bushings sized to your kit, it will be no different than turning on a mandrel, with the possible exception of not having to deal with bent mandrel issues.

2) You can make a dead center yourself from whatever you want. But a decent dead center can be had for less than $10. It's really not worth the trouble unless money is very tight. Getting the angle on the dead center to match the angle in your bushings is kind of important. If you make your dead center with too small an included angle the bushings will not run true. If your included angle is too big, you will only contact the bushings at the rim. They will run true, but will be prone to stopping spinning if you cut too aggressively.

3) One caliper is adequate, although I have a couple in the shop. I only use them one at a time.

4) I make finishing bushings from Acetal (aka Delrin), but there is no reason they couldn't be something else that will resist the solvent you will have to use to clean them periodically. Plastics turn very easily with wood turning tools that have a sharp edge and are used with good technique. I prefer steel or aluminum for bushings when I am turning the blank to size. Even when I'm using undersized bushings on custom pens. They just seem to last longer. But plastics would work.

Ed

 

[monophoto]

1. Turning between centers is basic to all spindle work. The only thing that makes turning pens between centers more challenging is the desire for precision. Pen mandrels were invented for convenience, but in my opinion, mandrel turning is neither better or worse than TBC turning. Like everything else, the 'best' approach for you is the approach you are most comfortable using.

2. There is absolutely nothing to keep you from using a pointed dowel as a drive center. It will wear over time - but if its wood, you can easily renew the point. At the other end of the spectrum, you could buy a steel dead center. Somewhere in between is the option to make a dead center from aluminum rod you buy at the hardware store. And by the way - you don't have to have a collet chuck - you can hold the rod using pin jaws in a scroll chuck, or in a Jacobs chuck (be sure to use a drawbar). And its not that difficult to make a morse taper on the other end of your pointed dowel, especially if you are working in wood. And for a one-off project, just whittle down the end of a small billet until it starts to fit into the taper, tap it in, and then turn a cone on the exposed end.

3. I have two calipers - one digital and an ancient analog (so old that it is only imperial - inherited from my father-in-law). I use the analog for day to day applications, and the digital for applications where I need greater precision. Would I like more? Sure - but I'm descended from a long line of Scottsmen who were notoriously cheap.

4. I routinely make various things from HDPE. I bought some cheap cutting boards at a discount store (dollar store, surplus outlet, etc) that I cut up for raw material. Use ordinary wood turning tools - the stuff cuts reasonably well, but doesn't scrape well at all, and forget sanding. Be advised that the shavings stick to everything in the shop, so in that sense, its a PITA to work with. I mentioned making an aluminum deadcenter - you can also turn aluminum on a wood lathe. Carbide cutters seem to work best on aluminum for me - as well as patience cuz the stuff works far more slowly than wood.

 

[BSea]

I've been turning pens for about 4 years, and have never owned a pen mandrel. If that's the way you want to go, why spend money on things that you won't use?

The only problem I see making a dead center is that with wood, it will deform a little every time you use it. so getting it to run true would be an issue I think. If it's off by even .001", it can be felt. So you would have to true it from time to time. Maybe most times.

 

[UCLAJediKnight]

hey everyone, quick question about TBC. I'm also very new to turning.

What is the purpose of the bushings when TBC? To protect the live/dead centers?

 

[TBCbushings]

I personally prefer TBC but I started with a mandrel and still use on kits I haven't made TBC for.

 

[Edgar]

My thoughts (and this also answers UCLAJediKnight's question)..

First, I agree with everything that's been posted above.

Personally, I normally use bushings on a mandrel for most of my tubed projects. As has been noted many times around here, bushings will get you close to the final diameter, but since bushings can wear and kits can vary, you should always use calipers for getting your turning/sanding down to the exact size for the best fit.

I do have 60˚ centers that I sometimes use for TBC when I don't have the bushings for a particular kit & don't want to buy them or wait for them to be shipped. In this case, I turn without bushings and start using calipers when I get within a couple mm or so of the target size.

If you do have TBC bushings, they should be used just like mandrel bushings - as a guide to get the turning close to the desired diameter. In general, bushings will make it easier to get close to the finished diameter than just eyeballing, but if I'm only making one or two of a particular kit, that's not really a big deal.

Regardless of whether I turn on a mandrel or TBC, I like to use delrin bushings for sanding & finishing after I get the turning down to the desired size. This keeps metal filings from the bushings or centers from getting into the blank & keeps finish off the bushings & centers.

 

[Cavediver]

I gave this a shot last night after disassembling one of my first two pens; the lower barrel was horribly shaped and both ends needed to be trimmed. Also, both halves of the pen were out of concentricity, though I didn't know that while I was turning it..

I chucked up a piece of oak and turned it down to an approximate 60 degrees to mirror m live center. I placed the barrel in and immediately felt how far off center my cuts were. It was terrible! I was able to even things out for the most part, and I trimmed down the center of the barrel to something a little less offensive. I suffered a tiny bit of blowout at the trim ring end, but that's not a big deal (it's a tester pen, right?).

End result: I ordered a steel dead center today, and I made a return trip to Peachtree Woodworking to pick up a few more pen kits and a couple of less-plain blanks for this weekend. They didn't have any of the non-stick bushings for finishing, so that'll be yet another order, or maybe my second trip to Woodcraft for the week...

Thanks to all for the help and advice!

 

[toddlajoie]

I do my CA finishes between centers without any bushings. It works like a charm, and all you need to do when you are done is either chip any CA that got on the centers off (it comes off pretty easy) or (if you are lazy like me, find a small container that they fit in and soak your dead center in it to dissolve the CA (I'm not sure if soaking is a good idea with the live center considering the bearings inside, so I never did... In the end I don't see too much buildup on the centers unless I am VERY sloppy with the CA...) I've also NEVER had a blank get attached to the centers, but I have had the bushings get connected pretty firmly, so I don't do THAT any more...:wink:

 

[Edgar]

They didn't have any of the non-stick bushings for finishing, so that'll be yet another order, or maybe my second trip to Woodcraft for the week...

Thanks to all for the help and advice!

Another alternative is to buy some delrin rod and make your own bushings. It's also useful for other things like a tube insertion tool.

Here's one ebay source - there's several others:
Natural Acetal Delrin Rod 1 2" Dia 1 ft Bushing | eBay

You can also buy it from Zoro Tools (a division of Grainger) & they also sell on ebay
Shop for delrin at Zoro

I usually keep a few 1' lengths of 1/2" & 3/4" rods on hand - comes in very handy from time to time

 

[UCLAJediKnight]

They didn't have any of the non-stick bushings for finishing, so that'll be yet another order, or maybe my second trip to Woodcraft for the week...

Thanks to all for the help and advice!

Another alternative is to buy some delrin rod and make your own bushings. It's also useful for other things like a tube insertion tool.

Here's one ebay source - there's several others:
Natural Acetal Delrin Rod 1 2" Dia 1 ft Bushing | eBay

You can also buy it from Zoro Tools (a division of Grainger) & they also sell on ebay
Shop for delrin at Zoro

I usually keep a few 1' lengths of 1/2" & 3/4" rods on hand - comes in very handy from time to time

How do you make your bushings? Do you drill it out, cut to length, and then TBC to desired size?