Chucking up a pre-fab

hazmat · Post by **hazmat** » Wed May 24, 2006 1:21 pm

Anybody have any helpful hints on properly chucking up a pre-fabbed stem? I seem to be hit-or-miss when I do this and it's starting to cost me in wasted stems(but at least I'm not exploding them any longer!!). Just wondering what some of you fellas who are using pre-fabs may do in this regard. Any help, as always, greatly appreciated!

Matt

btw.. I'm using a smithy with a three-jaw chuck.

custom300 · Post by **custom300** » Wed May 24, 2006 2:14 pm

I've been dealing with the same issue the last two days. What I did, was the chuck the stem as close to center as possible, but with a very slight play around the stem. Then I move the tail piece with a live center right up to the tenon on the stem so that it presses the stem back into the chuck. As the tail piece applies pressure on the stem, I then tighten down the chuck. Once it is tight, i turn the lathe on with the live center still inserted into the draught hole on the tenon. If it looks like it is tracking straight I back out the tail piece and begin my shaping work.

I should point out that I have a one-way chuck with spindle jaws on a Delta Midi Lathe.

It seems to work pretty well. However, I have only done two stems in this manner.

Post by **KurtHuhn** » Wed May 24, 2006 2:17 pm

The easiest way to ge it close is to stick a drill bit that fits snugly into the stem's airhole, and chuck the drill bit in your tailstock. That way the hole is roughly centered and you can move the tailstock up to the chuck and tighten it down and get things close. It will never be exact, but you can remove a lot of the drama associated with trying to get them straight enough to work on.

Another hint, I never re-drill pre-fabs on the lathe while they're chucked in. I alsways drill those by hand with the bit (tapered bit, always) spinning in the headstock, and slowly and patiently advance the stem while holding it in my hand. Vulcanite is soft enough that you don't have to have a grip like a gorilla.

hazmat · Post by **hazmat** » Wed May 24, 2006 2:29 pm

Thanks to both of you.

Kurt.. I've been doing exactly what you're talking about.. most times it's right on, other times I get a bit of wobble. I guess it's all just a matter of getting it as close as you can.. I just hate when I start to turn the tenon and can see that my turning puts the stem's air hole off-center from the tenon itself... I also think the lathe I'm using is just a bit of overkill. If you're familiar with a Smithy, they're rather large affairs...

ArtGuy · Post by **ArtGuy** » Wed May 24, 2006 2:58 pm

What I used to do on my taig is take the stem and wrap the button end with several layers of masking tape. I then chucked it loosely in a 4 jaw scroll chuck (tape helped prevent the jaws from marking the stem) and bring my live center up to the airway on the tenon side. My live center has a spring in it so it will give a little. I would mess with it until everything was seated and turning true and tighten the chuck.I would Then I would turn the tenon down with the live center still in place.

hazmat · Post by **hazmat** » Wed May 24, 2006 3:12 pm

okay.. pardon my lathe ignorance here... what is a live center? I don't believe the lathe I'm using has one(it's not my lathe)... and my only recollection of using one was way back in wood shop...

LexKY_Pipe · Post by **LexKY_Pipe** » Wed May 24, 2006 3:40 pm

A live center is a center that fits in the tail stock (or head stock) and is set into a ball bearing so it spins with the item being turned.

A dead center is a center that is pointed only, so when the work piece turns, the center holds it by friction and does not turn with the work piece.

Hope that makes sense.

hazmat · Post by **hazmat** » Wed May 24, 2006 3:52 pm

Makes perfect sense.. and that's what I thought it was. Unfortunately, I don't think there's a live center for this lathe in the shop.. but there are dead centers. I'm assuming that can be used to at least chuck up the stem...

LexKY_Pipe · Post by **LexKY_Pipe** » Wed May 24, 2006 3:58 pm

Yes for alignment purposes.

For my pre-formed stems, I follow a procedure I learned from Ronni B at Night Owl Pipe Works. I've made a small tool out of 1/2" aluminum rod. I chuck the rod into my lathe chuck. I mounted a 5/32 screw in the end of the rod. So you have a rod sticking out of your chuck with a 5/32 screw sticking out of the rod. I then drill and tap the pre-formed stem. Screw the stem on the rod. With a live center, I hold the the botton side of the stem. And voila. Centered every time.

mahaffy · Post by **mahaffy** » Wed May 24, 2006 9:11 pm

Using a four-jaw independent chuck: insert a close-fitting long-shank drill in the stem. Fuss with the 4-jaw chuck until the drill bit aligns with the tip of your tailstock live center when you rotate the lathe slowly by hand. If you can get it to point dead on without moving off center, you can redrill to your heart's content. If not, don't.

stevalla · Post by **stevalla** » Fri May 26, 2006 2:46 pm

For what its worth, Tom Johnson of LunaPipes makes a great tool he calls the Spinner. Check out his site, lunapipes.com. I've been using this to help me cut tennons for several years , it has been a blessing.
Alan Stevenson
N. Central WI

hazmat · Post by **hazmat** » Fri May 26, 2006 3:37 pm

Thanks, Alan.. I've seen this jig in my internet wanderings..