long thin spindles

Re: long thin spindles

Ed Davidson

Tremendous demonstration of skills, achieved by repetition and lots of practice...well done.

Excellent.  Most Impressive.

on a different scale

GaryG in MD

Funny you should mention.

Bit of a story here.

I want to make a tiny ladder, SW style -- won't say why right now -- save that for the future.

So I turned a foot of unknown wood down under 1/8" with the intent of chopping it into bits for the ladder. Did it an inch at a time with a very shallow 3/8" spindle gouge (almost Continental shape -- call it a bent skew with the edges turned up) holding it in a collet chuck and running it freely through the center of a pen mandrel live center.

But it would make a cool tall goblet stem! Can't bear to cut it up.

So I made another one to cut up. Now I have two goblet stems!

Can't win.

To be continued...

Sorry for the blurry pic -- my old "phone" won't focus properly.

Actually, it's a heart monitor, but that's another story.

Re: on a different scale

Jim Barbour

Nicely done. Can't wait to see the ladder ... errr ... goblet.

Great!

John K Jordan

I hope I know someone like you when I'm 91!

Very nice turning! That's with the bed extension, right? The longest one I've done on the PM with extension was with both the headstock and the tailstock just barely gripping their respective ends. I'm thinking of welding up a second extension from steel to put on the other end - I don't think it would be too hard. I think I can use two flat strips of mild steel with width and thickness the same as the lathe bed supported by a series of webs similar to the cast one on the lathe.

I turned a long one like yours but from dry hickory and it about wore me out! It was harder to do than the 26" pointers that taper down to 1/8". Some day I might break down and make a steady rest. Nah, what would be the challenge in that!

One thing I did find that helped with finishing "cuts" on problem spindles was a flat cabinet scraper held at an angle on the top of the spindle. I was too stubborn to give up and stoop to sandpaper! I have read that some people use a hand plane for cylinders and tapers but I never tried that.

Are you thinking of a wooden hook? It might be fun to make one from steel or brass but probably too heavy. I've got some thick aluminum stock if you want to try that. Might be light enough in weight. I also have both white and green HDPE if you want to try cutting a hook from that. (1" thick, big sheets) Hey, how about using some of that 1/2" titanium tubing somehow? That would be very light weight and I think it can be heli arc welded.

JKJ

Re: on a different scale

GaryG in MD

I turned a nice little goblet cup out of an Aussie bottle stopper blank of spiky burl, but it's too small for this stem, so now I need another cup AND a stem/foot appropriate for the small cup. Good news/bad news. :-) ...GG

Re: Great!

John C Lucas

I tried a hand plane on turnings back in my early days and again later just to see if it worked. On thick spindles it works. On long thin ones like this it chatters like the skew. You have.to counter the chatter with your hands but the weight of the plane meat you had to push too hard with your hand and it burns your fingers. My dad used to use a belt sander to do his rolling pins. He had a.shopsmith and its very hard to turn without chatter on that machine so he would sand and sand. One day he just pulled out the belt sander and had a dozen rolling pins done in nothing flat. Couldnt sand beads and coves tho.

Re: long thin spindles

Don Orr

Impressive John, but not surprising.

Re: long thin spindles

Dennis in Southern Oregon

John, I see that you turned the long spindle between centers. Better performance had be obtained by other mounting methods. For example, mounting the drive end in a chuck and using a live center at the other end will allow about 30% increase in spindle length for a given spindle diameter or about a 17% decrease in spindle diameter for a given diameter without chatter. Chucking both ends rigidly allows about a 60% increase in spindle length for a given diameter or about a 30% decrease in spindle diameter. A simple, effective, chuck for the outboard end is easily made by boring and tapping a bit of aluminum rod to fit on the threaded nose of a Oneway live center as shown below. These are easily made for any tenon size of interest. Its mass and moment of inertia are negligible compared to those of the live center itself, so it does not increase the risk of twisting off the tenon on start up.

The above performance numbers came from engineering calculations and direct experimental confirmation that were posted on the AAW Turning Forum in August 2016.

Re: long thin spindles

John K Jordan

>>>...mounting the drive end in a chuck and using a live center at the other end will allow about 30% increase in spindle length for a given spindle diameter...

A simple, effective, chuck for the outboard end is easily made...

...The above performance numbers came from engineering calculations and direct experimental confirmation that were posted on the AAW Turning Forum in August 2016.

I'm the different John, but I absolutely agree with what you said about gripping at least one end tightly. I use either a chuck, or for small diameter spindles turn a morse taper on the end, and teach the same. I certainly can believe the numbers - in my experience holding one end rigidly makes the first 1/3 or so more rigid. This depends somewhat on the wood - some are inherently more flexible than others. You can actually feel the huge difference by flexing the spindle with the hand.

I never thought of making a jam chuck of sorts for the tailstock. That will certainly be an upcoming project. I've threaded lignum vitae for tailstock pieces - that might work as well as aluminum, at least for thin spindles.

One wand here shows the morse taper I cut for the headstock. They should be even easier with a matching one for the tailstock, at the expense of another 3/4" or so of wood.

JKJ

Re: long thin spindles

Dennis in Southern Oregon

Nice wands there, John! You might be interested in another result when one adds tension to the spindle. I ran some experiments in which I anchored the tenon in the tailstock "chuck" by threading a screw crosswise through them and then applying 55 pounds of tension using a spring-loaded contraption that I won't attempt to describe here. After turning the spindle down in diameter just to the onset of chatter without tension (about 0.5 inches), I applied tension and continued turning until chatter began to develop again. This occurred at a diameter of about 0.4 inches. This translates into a reduction of achievable diameter of about 46% compared to that obtained when turning between centers. I can visualize practical means for applying tension in a production environment, but I don't know if it would be worth the effort. Maybe someone would like to set a record in the the Guiness woodturning book or records.

Re: long thin spindles

john lucas

OK now the spring sounds interesting. Many years ago I attempted to put a chuck on the tailstock end. I ran into 2 issues. One was the that I needed a draw bar to hold the live center with chuck into the morse taper. That proved difficult because of the movement of the quill. The other problem was the starting inertia for the tailstock chuck simply twisted my spindle apart after it got thin. a spring contraption and a lightweight aluminum jam chuck might solve both problems. A good experiment for later on.

wands and things

John K Jordan

>>>Nice wands there, John! You might be interested in another result when one adds tension to the spindle. ...

Thanks! I've made hundreds of wands - made one just a couple of days ago on a request.

I experimented once with tension (in my mind) and convinced myself it would in fact work well. However, I have zero problems with turning these spindles from any wood I've tried so far using the morse taper jam chuck method. I use the "left hand steady" technique with skew or gouges, cutting to left, right, or even underhand like this:

I hold the tool close to the tool rest with one hand and jam the end of the tool handle into the underside of my forearm so the skew is kind of an extension of my arm. My left arm rests on the top of the headstock.

If there is any chatter, it is almost always controllable by adjusting tailstock a bit, changing the speed up or down, or grabbing a slightly different tool.

This method works so well I don't want to add the complexity of the tension. Also, I'd have to use some method on the headstock other than the short MT2 under compression. I don't like to use a chuck since the morse taper give me more clearance around the end. (Another reason to NOT use a chuck is when turning these on the Jet mini lathe - the lathe is just barely long enough to hold the blank with the morse taper - using a chuck would make the wand pretty short. Harry Potter book release time:

(Oops, sorry, I got carried away with photos again!)

When turning longer, thinner spindles I had to use a 1/4-20 drawbar in a threaded hole in the morse taper end to hold the wood securely in the lathe spindle since any tension from the tailstock introduced chatter. I did the most of these with the right end completely unsupported except from my hand:

These are blackboard and whiteboard pointers, 25-26" long, tapering to about 1/8", pine shelving board from Home Depot and walnut.

Short versions of these are conductor's batons:

Good clean fun!

JKJ

Re: long thin spindles

Dennis in Southern Oregon

John, the following picture shows the device I made to provide tension on the spindle. You are correct; you need a drawbar to keep the live center in place. The make-up of the unit, reading left to right is as follows: a nut to fit the piece of all-rod used for the drawbar, the aluminum “chuck” threaded to fit the nose of the live center, the live center, the tailstock (not shown), a fender washer, a shop-made aluminum bearing outer retainer, a ball thrust bearing, a shop-made aluminum bearing inner retainer, a spring that requires a measured 55 pounds of pressure to fully close it, a fender washer, and finally a wing nut. All of the added parts are light weight and of small diameter so do not add a lot of moment of inertia to the basic live center.

To use it, I chuck the spindle between a Vicmarc chuck with pin jaws and the shop made aluminum chuck attached to the live center and drive a small screw through the aluminum chuck to lock the tenon in place. With tailstock unlocked, I extend the live center a few inches (more than the amount of compression that the spring will experience). Then, I lock the tailstock in position, run the wing nut up against the washer and the inner bearing retainer, and retract the live center until the spring is completely compressed.

Re: wands and things

mikeee12345

I can see the wands being just as addictive as turning tops.

Nice work!

thanks Dennis- saved it

Clever!

John K Jordan

This John is saving your picture too. In fact, I took most of what you wrote in this thread and put it and the pictures into a Word document to save in my Thin Spindles document folder. Very clever design, thanks, and a lot simpler than I imagined. I suspect lots of readers are saving this.

Do you remember the bearing you used for those who go to buy one?

This will be simple to make for those who have metal-cutting lathes. (For those who don't, remember you can always machine aluminum on the wood lathe with standard woodturning tools!)

You could probably make and sell these (in your spare time! )

A question about your shopmade aluminum "chuck". When I saw the hole in the side of your tailstock chuck and assumed it was for a rod to fasten and unfasten it from the live center:

Then you mentioned you "drive a small screw through the aluminum chuck to lock the tenon in place." Is that hole in the side for the screw?

I also wonder if the aluminum sleeve could be threaded all the way through. Then a tenon slightly oversized could be force-threaded into one end. I often make taps and dies by cutting slots across the threads of nuts and bolts with a Dremel or a triangular file. This works well for threading wood. I've notched the end of my 1/4-20 drawbar for this reason, to tap threads in the little morse taper on spindles to keep an unsupported piece tight in the headstock taper.

I may just have to try turning that 48" long 1/2" to 1/16" taper now!

JKJ

Oops Oops

Dennis in Southern Oregon

As I was headed to bed last night, I realized that the above procedure was incorrect in part. I ran these experiments a year and a half ago and forgot some of fine points. Here is the correct procedure (I went to the shop and verified it this morning):

1. Mount the spindle in the two chucks and secure them. The wing nut should be just started.

2. With the tailstock unlocked, extend the live center as much as possible. Then lock the tailstock.

3. Temporarily put a pin through the locking hole in the live center so the latter will not turn.

4. Turn wing nut to compress the spring fully (or the amount that gives the desired tension).

5. Retract tailstock until spring is barely compressed. (Any further may pop Morse taper out of its socket.)

6. Repeat 4 and 5 until 5 will not extend spring any more.

7. Extend tailstock a tad so that any load that it is bearing transfers fully to the spring.

8. Remove locking pin from live center.

Re: Clever!

Dennis in Southern Oregon

John thanks for your interest. I bought the bearing at my local Ace Hardware Center. I chose it from among lots of alternatives for its size and apparent strength to hold axial loads. I do not recall whether the store display indicated its intended use. It is a Chinese unit marked as follows: 508Z FIT-435. I am not a bearing specialist, but maybe these mean something to you. The size is as follows: OD 0.865-in or 22mm, ID 0.313-in or 8mm, W 0.29-in or 7mm.

Following is another shot of one of the aluminum chucks showing the pair of holes for a retaining screw and a larger hole for a toggle bar to tighten it onto the live center. These and the bearing/spring retainers were made from a piece of 1-inch round bar stock. All boring, tapping and machining were done on my wood lathe with mostly woodturning tools and a Jacobs chuck in the tailstock. I see no reason why the chucks could not be threaded all the way through or even with different diameters and pitches on the two ends.

I look forward to seeing your record-breaking long, skinny wand!