How to finish the foot on an uneven natural edge bowl?

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Guys, I'm working on a natural edge burl that is quite uneven. I typically use a donut chuck to mount my bowls at the end and finish the footing, but due to the very irregular rim that's not working out too well this time. I suspect I'm going to come across this problem more and more as I continue with natural edge projects. What solutions are there for dealing with this situation? I basically need something that can hold the bowl securely in the headstock while completely exposing the bottom so I can clean up a recess or spigot.

Thanks again!
 

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Hey Dawson...could you post a pic of the bottom? Vaughn is the chuck master on these IMHO...but I'd go with a long cup on a chuck to fit the inside, a piece of shelf liner or sandpaper for some traction and have at it with low speed and tiny cuts.
 
I use a jam chuck mounted in my chuck. I turn the end to match the bottom of the bowl with some rubber drawer liner you can get from Wally World on the end for friction and to keep it from marring the bowl bottom. I put the bowl up against it and bring up the tailstock to finish the bottom. I finish the bottom until I have the nub as thin as I dare. I remove the bowl and carve off the nub and sand with a 2" disk in my drill press and then apply the finish. Works great.
 
Bernie pretty much described how I do similar pieces. I use whatever is handy for a friction chuck*, then finish cutting the foot, except for a little nub. Ill work that down as small as I dare (which is usually all the way through, these days), then finish sanding the bottom with the piece off the lathe. I will also sometimes use plastic stretch wrap to provide a little extra insurance to keep the bowl in place.

Here are a few pics from a bowl where I did that. The bottom of this bowl is completely rounded, so there's no foot, but the technique is the same.

Bowl 092 - 10  800.jpg Bowl 092 - 09  800.jpg Bowl 092 - 11  800.jpg Bowl 092 - 12  800.jpg

And just for grins, here's how it all came out...

Bowl 092 - 01  800.jpg Bowl 092 - 08  800.jpg

* A friction chuck (by my definition, anyway) is just about anything that the workpiece can fit into or over. It won't hold the piece without help from the tailstock, but it provides friction to turn the piece while finishing off the last few bottom cuts. More often than not, I find a roughed-out bowl that is a bit smaller than the bowls I'm working on. I'll mount the roughed-out bowl in my scroll chuck, true up the rim, the put the other bowl over it (face to face) and bring up the tailstock to hold it in place. I also use a similar idea when finishing the bottom of a hollow form, although in that case I'll find a bowl that the hollow form fits inside of.
 
Thanks guys, great replies. Vaughn, what type of spur do you use in your tailstock to hold it? It is a single point, three prong, or some type of screw?

Is the goal for the bowl to not move at all (friction chuck spins with the bowl), while the tailstock side spins freely?

Also, is there any strategy to make sure you have the bowl centered and aligned correctly? I found that you pretty much just had to do it by hand and sight?

And finally, your bowl looks great Vaughn. Out of curiosity, how did you do the graduated coloring (red to yellow) on the outside?
 
Having seen Vaughn's (same thing I use since he taught me) it's a 60 deg center...you are able to trim right up to the very point of the center. I use the same live center for pens and bases.
 
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Bernie's almost right...I've got a Oneway live center, but in these particular photos I was using the one that came with my Powermatic, which is essentially a clone of the Oneway. (BTW Jim, I don't cut to the point itself, but stop at the cup surrounding the point. Also, I think the point is sharper than the 60 degree centers for pen turners.)

live_center_250px.jpg

Dawson said:
Is the goal for the bowl to not move at all (friction chuck spins with the bowl), while the tailstock side spins freely?

I'm not sure I understand your question. :huh: The friction chuck is held by the regular chuck, then the bowl you're working on is pressed up against the friction chuck, with moderate pressure supplied by the tailstock to keep it in place. When the lathe is turned on, it all moves, but it moves together.

To answer your alignment question, when I make the tenon (when I first start turning the blank), I'm using the tailstock to hold the blank. The live center in the tailstock leaves a mark in the tenon where the point was poked into the blank. Later, when it's time to finish the bottom of the bowl, I use that little mark as a center reference when I do the friction chuck thing.

And thanks for the compliments on the bowl I showed. The shaded coloring was done with tinted clear finish applied with a mini HVLP spray gun. I've done similar things on smaller pieces with an airbrush.
 
"Bernie's almost right...I've got a Oneway live center, but in these particular photos I was using the one that came with my Powermatic, which is essentially a clone of the Oneway. (BTW Jim, I don't cut to the point itself, but stop at the cup surrounding the point. Also, I think the point is sharper than the 60 degree centers for pen turners.)"

That's right...we were using mine and I had the 60 with me. I have one with the small cone surrounding the point...would it be better than the 60...more stable maybe?
 
...That's right...we were using mine and I had the 60 with me. I have one with the small cone surrounding the point...would it be better than the 60...more stable maybe?

I like the cone (or cup) style because it prevents you from driving the live center in too deep, which can cause the nub to split once it gets whittled down. You want the tailstock pressure to be firm, but not so hard that it breaks the nub. The cup helps distribute those forces over a larger area, reducing the chance of something going south.
 
Vaughn how brave to you get? Do you cut thru the nub or just stop short. I cut thru the nub a couple of time (tool had just been sharpened) but didn't really disturb it's postion so all was good but one I kind of slipped and it knocked the nub out and it got exciting real quick. Lots of words were spewed.:rofl::rofl: Thankfully it had a couple of small dents that I hand sanded out. Just had to ask as it broght that thought of me messing up to mind.:D
 
Vaughn how brave to you get? Do you cut thru the nub or just stop short. I cut thru the nub a couple of time (tool had just been sharpened) but didn't really disturb it's postion so all was good but one I kind of slipped and it knocked the nub out and it got exciting real quick. Lots of words were spewed.:rofl::rofl: Thankfully it had a couple of small dents that I hand sanded out. Just had to ask as it broght that thought of me messing up to mind.:D

Lately, I've been pretty brave, and I cut most of them all the way through as long as the wood is cutting cleanly. I've got a shallow detail gouge that works great for those fine, final cuts. I also have my remote on-off switch close at hand so I can shut things down quickly if necessary. I know what you mean about getting exciting real fast, though. A few nights ago I was taking the tenon off a mesquite bowl and I exposed a hidden bark inclusion that was inside the tenon. I was down to the last 3/4" or so and a big chunk of the tenon left the lathe, with the bowl trying real hard to follow it to the floor. This was an important big bowl for a wedding gift, so yes, some bad words were said. :doh: It banged up the rim on the headstock bad enough that I had to un-reverse the bowl and hold it with the vacuum chuck to re-do the rim. :rolleyes: Saved it, though. Pics to follow once the finish is done.
 
I tried the jam chuck concept today with a smaller bowl that fit inside of this one (just like Vaughn illustrated) ... worked great and was exactly what I needed.

Next question: How do you guys cut completely through the nub? I figured as soon as you cut through that, your tailstock would lose pressure and the bowl would start going out of control.
 
Vaughn, I just took a look through your pictures again and now I've got a couple more questions!

1 - I noticed that your finished bowl had a few cracks in it. From an experience woodturner's perspective and a customer perspective, does it matter if the bowl has cracks like that? I don't mind the look of it (in fact, sometimes it looks better), but does it affect a persons perception of quality?

2 - Your bowl also had an uneven natural edge, but it looks like your finished rim is the exact same thickness everywhere. In my current bowl, the uneven rims slopes away at different angles and the edge "appears" to be thicker in spots (more bark is shown). Is this just the nature of the wood that you start with?

Thanks! It's been a cold winter up here in New Brunswick (Canada) and I'm looking forward to getting a few more projects started.
 
...Next question: How do you guys cut completely through the nub?...

Verrrrrry carefully. :D

Seriously, most folks try to avoid cutting all the way through the nub, and instead get it down to the last 1/8" to 1/16" holding on, then they take the piece off the lathe and make the final cut with a sharp bench chisel or skew. I've done it that way, and still do sometimes.

The cup center on the tailstock end does help in the event that you do cut one all the way through while it's still on the lathe. If your cuts are very light, you can cut through the point of the cone that the nub becomes, and the cup center will still support the base of the cone. The cone point will still be touching the bowl, it just stops spinning once it's detached. I'll try to get some pics (hopefully tonight) to better explain when I mean. I don't recommend trying it on any important pieces, at least not until you've become comfortable doing it on practice pieces.
 
I use a jam chuck mounted in my donut chuck. That way you don't need the tail piece. I have an adapter that lets me mount the scroll chuck on the Oneway live center and mount the turning in the donut chuck before I remove the scroll chuck. It's simpler than it sounds.:)
 
I use a jam chuck mounted in my donut chuck. That way you don't need the tail piece. I have an adapter that lets me mount the scroll chuck on the Oneway live center and mount the turning in the donut chuck before I remove the scroll chuck. It's simpler than it sounds.:)

:huh::huh: My brain just shut down :eek:;):eek:
 
:huh::huh: My brain just shut down :eek:;):eek:

Picture a donut chuck with a domed piece of wood in the center of the flat back plate that's tall enough to keep the rim of the bowl from touching the back plate. Then you attach the scroll chuck to the live center on the tailstock long enough to hold the bowl in place and tighten down the donut. (It's like using the dimple in the tenon to get things re-centered when you reverse a bowl, except you're using the whole scroll chuck instead.)
 
This also sounds like a good approach. It would be nice to have the bottom completely exposed and not need to worry about the tailstock at all. Are there any downfalls to using this method?

Also, do you guys favor donut-chucks over the jam chuck method when you have flat rim? In other words, do you only use a jam chuck when required due to an uneven / natural edge?

What is the special adapter that's required to attach the scroll chuck to the tail?
 
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