Holding face turnings with a through hole

[Phil Hopkins]

Hello all wise woodturners.

I'm turning some drop spindles. I like them to be edge weighted so that they are lighter and spin well. That means that I hollow out the middle except for a center post that the dowel goes through and the edge. These are 2 1/2" - 3" in width and 3/4" to 1 1/4" in thickness usually. I drill the 3/8" through hole first and then turn them. The problem I'm having is with the thicker ones.

I've tried any number of ways to hold these. I've tried glueing them to the dowel first and clamping that in a chuck. I've tried turning a wooden faceplate with a dowel epoxied into it to register the dowel hole on the piece I'm turning and using double sided tape to hold it to the faceplate.

But these are small, and I'm hollowing pretty deeply without a lot of room and catches happen. When they do, the piece usually is knocked off-center and I have to sort of start over with it. Not to mention the damage done to the dowel if I've glued the whorl on already and am holding that dowel to turn.

I've thought about this a lot, and I don't recall seeing any other way to turn these whorls except for making a little tapered wood button pin and hammering that into the dowel hole and clamping the other side in a chuck. My worry is that doing so will wallow out the dowel hole a bit, and I'd rather use 3/8" birch dowels that I taper for these rather than turning a shaft from scratch. So, the dowels are just under 3/8" already. I don't have any more room for slop. And the button would get in the way of hollowing, making it hard to turn the center post cleanly.

I don't know if a 3/8" collet chuck might do a better job of holding it securely while I turn if I glue the whorl on the dowel first. But I don't have a collet chuck anyway!

Here's my current idea, and I thought I'd run it by y'all and see if you have any critiques or other suggestions. I suspect y'all will know of ways I just haven't come across yet.

I'm thinking of expoxying a length of 3/8" threaded rod into a 1" dowel I turn so that I can clamp it in a chuck, say one with 70mm jaws so there's a nice register for the face of the piece I'm turning. Then, I could drill a hole through a short length of 1/2" or 3/4" dowel as a bushing and put a washer and nut on the other side, so that when I tighten the nut, I clamp the piece I'm turning between the jaws of the chuck and the wood bushing in the center in front. Would this work?



Is there a better way to do this, short of learning how to use my bowl gouge better so I don't have catches?

 

[Richard Coers]

One of your issues will be that 3/8" threaded rod is not 3/8" diameter. It is slightly smaller diameter because of the threading. You'll get runout issues. You'll have to use a rod that has a good fit, and then either tap the rod for a smaller bolt, or thread just the end.

 

[Phil Hopkins]

Yeah, that's an issue. Maybe I should try a bolt that I can epoxy into the dowel that goes in the chuck if I can find one with a full 3/8" shaft. I suppose I could just use the bolt itself. I think my pin jaws minimum diameter is 3/8" Does it hurt the jaws to clamp onto steel instead of wood?

Went out to the shop and I have several 5" bolts that seem to be high quality. The shafts are 3/8" and they are straight. I put one in my pin jaws and it mounts on the lathe spindle well and doesn't seem to have runout.

Just worried about clamping it in the chuck, since the pin jaws seem to contract to 6mm so they are holding the bolt on the corners of the jaws.

This is where I need a collet chuck, I'm thinking.

 

[hockenbery]

I did a bunch of pulls that were going to be covered with fabric for custom drapes.

I drilled a through hole. I have a stepped dive center with the correct diameter and a small cone on the tailstock.
This should work for these.

Matching wooden mandrels would work well too.
The tailstock can be the desired diameter of the center

2. double sided tape is great for holding small pieces like these. A slightly concave wooden drive with a center pin and 2 srtrips of tape.

 

[hockenbery]

I’d probably make an 1/8” tenon on the flat face.
Grip it with real dovetail jaws. For the hollowing

The reverse chuck it a remove the dove tail

 

[Chris Hoehle]

Maybe a pin chuck?

View: https://youtu.be/Odu1cT3AwUE?si=EW8r6lYHyPEjF6r3&t=45

 

[Phil Hopkins]

Matching wooden mandrels would work well too.
The tailstock can be the desired diameter of the center

I don't have a stepped drive and tried the double-sided tape method, without full success.

Can you say more what you mean by matching wooden mandrels? Are you talking about two slightly tapered shafts held in the headstock and tailstock in some way?

I could probably do the tenon method. But the shape of the hollowing and outer diameter don't lend themselves to reverse chucking. Unless I do so on a mandrel of some sort.

 

[Phil Hopkins]

Maybe a pin chuck?

View: https://youtu.be/Odu1cT3AwUE?si=EW8r6lYHyPEjF6r3&t=45

Well, that's interesting. I don't have a metal lathe or milling machine, but could perhaps grind a flat on a steel rod and make something like this. I'd like to see it in action before going to that much trouble.

Also, as I said, I don't have a collet chuck yet. But this might work with a regular chuck in compression.

Again, I'm not sure about clamping onto steel with chuck jaws. I worry about wear should there be a catch that puts lateral loads on the jaws.

 

[hockenbery]

I don't have a stepped drive and tried the double-sided tape method, without full success.

Can you say more what you mean by matching wooden mandrels? Are you talking about two slightly tapered shafts held in the headstock and tailstock in some way?

I could probably do the tenon method. But the shape of the hollowing and outer diameter don't lend themselves to reverse chucking. Unless I do so on a mandrel of some sort.

1. If you have a worm screw with your chuck that may be a simple and effective hold. The ONEWAY worm screw is 10mm but will screw into most woods with a 3/8 hole. You are gluing in a shaft so it should make a good bond and hide the thread marks.
The worm screw can be shortened with a plywood spacer made from a small square with a hole in the middle.
Try this if you have a worm screw.

2. You can make a screw center run a lag screw through a block of wood mounted in the chuck.
I like a slight concave on the face this lets the out edge make solid contact.



3 this is a digram of pin drive and a pin on the tailstock end. Lots of ways to attach pinst to different tail centers.
If you have a ONEWAY center or the copies that have the threaded nose drill a hole and wrap a couple turns of masking tape over the threads for a pressure fit. Or glue in a nut.

This is what you can duplicate in wood. I would use a metal pin on the drive side


Wood can look something like this.

 

[Phil Hopkins]

Thanks, Hockenbery.

I do have several worm screws. I never thought of using them, or a screw center because I was thinking the threads would mess up the hole for the shaft. But, as you say, there's a good chance the shaft will cover the threads and having threads might actually make the bond stronger if I use epoxy. This is worth a try, I think.

And thanks for the diagram on the pins in drive and live centers. After you wrote, I was trying to think out how to do this. I have the Nova live center system so can mount a variety of shapes custom turned in it. I'm thinking two pins with a little taper might hold tight enough, one turned on a piece of scrap in the chuck and one mounted on the screw in the kit and turned to match and then placed in the tailstock.

I do have a pen mandrel, and thought about mounting it up and turning a bushing on it to fit in the 3/8" hole and a larger bushing to tighten against the piece. I could use a spacer on the headstock side with a slight concavity, as you suggest.

I've got lots of ideas now!

I still think the bolt would work, but am nervous about clamping it hard with my pin jaws.

 

[Lou Jacobs]

I’ve made a few drop spindles (my wife is a weaver and my daughter is a spinner) though not hollowed as deeply as you are planning. I’ve done some with the whorl attached, and some with it turned separately. You are proposing turning deeply enough that (if the hollowed side is facing down, towards the shorter end of the shaft) I don’t see the shaft getting in the way of the turning tool. I’d think you’d be using a scraper for this hollowing, or perhaps some sort of carbide cup tool. They’d pretty much be entering the work parallel to the shaft. I’d use a collet chuck and only taper the spindle after the whorl is turned.

 

[hockenbery]

I've got lots of ideas now!

Great. A lot of ways to go with these.
Have fun and make lots of yarn

 

[Don Wattenhofer]

Imade a bunch of drop spindles about 10 years ago. I didn't go as deep as you are proposing and I didn't use dowels. The first step was to round out the whorl blank outside diameter by holding it with a wood worm screw. I had made some wood inserts for my dovetail jaws so i could finish both faces including a tapered hole for the spindle. The spindle blank was square and held on the drive end in a chuck then turned round with some of the drop end details and the tapered fit for the whorl and the remaining length turned to about 3/8" diameter. The next step is to glue the spindle into the whorl ( the taper if matched up correctly will fit without gaps and is self clamping and does not scrap the glue off). The pin jaws on my old Nova chuck were just about perfect for holding the assembly to finish the edges of the whorl and the final details on the bottom of the spindle including the metal hook.

The chuck inserts did double duty as this is shown with a spinning top whorl and as you can see both faces can be worked.

 

[Phil Hopkins]

Great. A lot of ways to go with these.
Have fun and make lots of yarn

Okay, worm screw doesn't work. For an already drilled through hole, it doesn't align the piece concentrically very well. Fine for starting a bowl, but not so good for this application. Since I'm turning a post around the center hole, it needs to be precisely concentric. I'm sure a spacer would have helped, but I think there are better options.

About to turn some bushings for the pen mandrel to see how that works. I'll head into town later and get a nut for the bolt I have to try that method as well.

 

[Phil Hopkins]

Okay, worm screw doesn't work. For an already drilled through hole, it doesn't align the piece concentrically very well. Fine for starting a bowl, but not so good for this application. Since I'm turning a post around the center hole, it needs to be precisely concentric. I'm sure a spacer would have helped, but I think there are better options.

About to turn some bushings for the pen mandrel to see how that works. I'll head into town later and get a nut for the bolt I have to try that method as well.

Success!!!



It's nice to get some use out of this mandrel. I made a few pens a decade or two ago and just never have used it since.

 

[Leo Van Der Loo]

YES TOO LATE AS I SEE, but here is my idea of how to get there.

I've turned some what I call a "ring caddy"

Not drop spindels of course, but pretty similar to what you are wanting to make .


I have one in a Oneway Talon chuck, so to show how, I start turning the piece held in the chuck and steady it with the tailstock center, turn the outside of what will become the cup and a shallow recess in the bottom end, so I can hold the piece with the recess on the chuck, (later I remove some of the wood that made the recess as shown here, but maybe not for what you want.

Flip the piece end for end and start removing the wood for the pillar to hang the rings on, then using a Oneway Termite end-grain ring tool I hollow the cup, it will hold the watch and earrings etc




This is what I need for what I want to make, you can change this of course to what you want to do at this point, drill it or change the pillar shape or length



Good luck.