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Frank&Earnest
6th September 2009, 02:36 PM
Just in case I am not the genius I think I am :rolleyes::D and it is a case of reinventing the wheel, does anybody know how to make this? Nobody around here did, but Adelaide is not really the centre of the world...

No rigs needed, just the chuck and a piece of sacrificial wood with a bit of double sided tape.

If indeed it is not straightforward, making one could be the subject of the next challenge...:D

jefferson
6th September 2009, 02:44 PM
F & E,

A guy turned something very similar to this piece down at 's den last year. Double sided tape from memory and off centre. A nice bloke too.

Perhaps can enlighten us? :p

Frank&Earnest
6th September 2009, 03:27 PM
I have seen a cruder version (flat back) turned on a rig by the president of the nearest turners' club, that's what spurred me to do better...:wink:

Tony Morton
6th September 2009, 03:37 PM
Hi Frank and Ernest
August issue of Woodturning has the full details.

Cheers Tony

Frank&Earnest
6th September 2009, 04:09 PM
Hi Tony. Are you saying that the article has the full details of how to make the pendant convex both sides or of how to make the rig I have seen? Could you mention the author, please?

Tony Morton
6th September 2009, 04:23 PM
Hi Frank and Ernest

Someone copied this pic from article but only one side convex writen by John Lucas.

Cheers Tony

Frank&Earnest
6th September 2009, 06:27 PM
Thanks Tony, that's what I imagined. Maybe I will write an article for the next issue of Woodturning, then.:D

artme
6th September 2009, 09:03 PM
Look up th International Association of Penturners site and get into the "Other things we Make" forum.

tea lady
6th September 2009, 09:08 PM
Looks like some interesting things here. Haven't had a proper look yet.:cool:

"http://www.penturners.org/forum/tags.php?tag=pendant"

Frank&Earnest
6th September 2009, 09:59 PM
Thanks, Artme, very informative site. It confirms that "those" pendants are flat backed and drilled instead of fully turned both sides, so I am reasonably confident that the method I have developed last week is a genuine innovation. Turning is not exactly rocket science, I am sure that anybody who really wants to can think out different ways of doing things. Time then sorts out what works better.

Using a drill and a rig makes it easier to produce multiple copies, I suppose. Which is exactly why the flat back solution to me appears ... well, more "flat" aesthetically, especially for earrings that are meant to be seen also in profile. In the end, though, if given the choice most people would not care, doing it my way would just become a futile exercise of turning oneuppery.

rannndy
7th September 2009, 03:30 AM
try this
http://www.woodworkersinstitute.com/page.asp?p=594

photo 34 is the wrong one, all you are missing is screwing the backplate in the offset hole
john

Happy amateur
7th September 2009, 06:02 AM
A demonstrator at our club showed us how to do it.
I will try and replicate his method.

1. mount blank between centers. I use a small steb center.
2. turn to shape required.
3 Make a set of wooden jaws as in picture. This is a nova chuck with pin removed to allow jaws to be removed.
4. I use 1 and 3 jaws. insert jaw 1 onto chuck and do 3 turns oc the scroll before mounting jaw 3. This give you the offset required. One more turn gives a greater offset.
5. & 6. The revolving center shows the offset .
7. one I made but think the hole is too big.
8. if chuck jaws mounted as standard then an insert both sides of contrasting wood or plastic can be inserted

Fred
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Frank&Earnest
7th September 2009, 10:37 AM
Thank you Rannndy and Fred.

The method described in the linked site is exactly what I have seen demonstrated. The rig I have seen was more permanent and effective, though, the offset was achieved by swiveling and re-screwing the wooden piece holding the pendant against the piece held in the chuck.

The method you use, Fred, works but requires modifying the chuck and the jaws. Stabbing the centre of the piece to start with also requires the stabbed part to be removed by the (large) hole, is that correct? Whatever the limitations of each method, though, this proves that the task in itself is not too difficult and that somebody has already seen the biconvex shape as a desirable improvement. :2tsup:

Ozkaban
7th September 2009, 11:46 AM
Similar method used here:
http://www.sawg.org.nz/Projects/Pendant%20Jewellery.pdf

Their site is excellent - it's in the woodies startup links thread. Lots of cool projects and how-to's.

Cheers,
Dave

Ed Reiss
7th September 2009, 11:54 AM
cool project !!!!:2tsup:

Frank&Earnest
7th September 2009, 01:36 PM
Yes, this seems the best method so far that requires drilling and rigging. Still has the limitation of the central drilling dictating the size of the final hole.

Happy amateur
7th September 2009, 06:06 PM
The holding marks on the pendant does not dictate the size of the offset hole,
as they are only surface marks and not all the way through.
There may be other methods but this is the one I use and find it is the least technical.
One thing important is that when the pendant is reversed in the chuck, the orientation is important. This can be achieved by a pencil mark on the chuck jaw and the pendant or a short length of tape on the pendant lined up with the mark on the chuck jaw then folded over to the other side of the pandant and again lined up with the jaw mark.

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Fred

Frank&Earnest
7th September 2009, 10:08 PM
Thanks Fred. Orientation is indeed important, I do it with a notch on the sacrificial wood, which also serves the purpose of facilitating detaching the piece from the tape, and a pencil mark on the piece.

As regards the holding marks, even if they are not very deep, you confirm that they have to be removed and therefore have to be comprised in the area turned out. An alternative would be to start with extra thickness to allow for flattening before turning the hole, which means another operation on the centre before turning off centre... is this practical?

I am forming the opinion that, in the end, it boils down to a choice between the predictability of making a rig to produce many pieces of a specific size and shape against the capacity to make virtually any shape and size within the limitations of the chuck and the basic design. Your solution of wooden jaws and modified chuck seems to offer a bit more flexibility than a fixed rig.

Happy amateur
8th September 2009, 03:58 AM
The modified chuck allows the size of the pendant to vary. It is possible to turn quite small ones for a matching set of earings and pendant.
I cannot say that it is the best way it's the only way i know.
My proplem with double sided tape is getting the damn thing off.

Fred

Frank&Earnest
9th September 2009, 03:19 PM
Fred, your method seems to allow a figure 8 design by reversing the orientation. It could be a bit dicey because it does not provide support in the centre, though. Would you like to try?

My example, in the picture, is a bit asymmetrical because I did not bother to measure it properly, just a first attempt to carry the discussion forward. Interesting that nobody in Australia seems to have done it.

Happy amateur
9th September 2009, 07:14 PM
Have not thought about it, Will give it a try and see what happens.

Fred

Happy amateur
10th September 2009, 06:52 AM
Frank. You are really pushing me now. Maybe a good thing as I am not the best turner in the world looking at what has been produced on this forum. bUT YOU GOT THE BRAIN WORKING.
Yes possible figure of eight see picture but if you can turn a figure of eight why not go further and do one for the Irish. Three centers for a shamrock shape. See picture. Bothe sides photographed of each.

In the case of the shamrock i found it easiest to drill a small hole in each center before starting to turn. It is an indicator as to how deep you are turning. For a single hole it does not really matter as the depth is not so critical as all it means is the hole may be bigger or smaller than intended when the second side is finished.

These are just from the tool (Spindle detail gouge fingernail grind) with no finish. A spray finish might be best due to the fragility of the center especially the shamrock one.

Fred

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NeilS
11th September 2009, 12:17 PM
Yes possible figure of eight see picture but if you can turn a figure of eight why not go further and do one for the Irish. Three centers for a shamrock shape.

I get it, an Irish button!

Says he who descended from the Irish of County Donegal....:B

Frank&Earnest
11th September 2009, 02:10 PM
Excellent Fred! :2tsup:So now you can get one further up and have a cross shape with 4 holes! :D
Now I am working on the idea of a spiral of increasing diametre holes, will let you know how it pans out. You can do it too by progressively changing the offset of the jaws.

As regards the finish, the easiest could be brushing with lacquer as they do for the flat rigged ones. So far I have used Shellawax burnished on the lathe for the single hole type and rubbed on and buffed (not really wonderful) for the multiple holes types.

Happy amateur
11th September 2009, 07:28 PM
Neil, I am Irish from Leitrim.Been in UK for over 40 years.

Frank, Have only a little brain and you are trying to fry it.
With my chuck there is only three different centers available from the centre out.
Thinking about it it might be possible using jaw 1 with jaw 2 opposite then jaw 3 and 4 due to the thread position on the carriers. hope that makes sense.The centers would be very close together. Let me know if you try it.

When I was shown the basic pendant, the demonstrator used gripper jaws which had a series of internal teeth to hold the blank. I tried it with Nova chuck and found that the teeth were cut as a thread and not concentric. I don't know if other gripper jaws would be suitable. Would negate making wooden jaws.

Fred

Frank&Earnest
11th September 2009, 11:01 PM
Hi Fred, be honest, you are enjoying the challenge, a working brain does not fry!:)
You are right, probably the distance off centre achievable with the jaws is not sufficient to produce more complicated patterns. On the other hand we are talking only about a 30mm radius for the whole pendant, so no great distances are needed. I have never pulled a chuck apart yet, so at the moment your guess is definitely better than mine.

Happy amateur
12th September 2009, 05:21 AM
Frank

Yes enjoying it. Takes somebody to push me to try something out of the ordinary.

Any chance of seeing your method,

Fred

Frank&Earnest
12th September 2009, 11:24 AM
No problem, just give me some time to take photos and document the steps. I am thinking of working this into a broader discussion about chucking.

Frank&Earnest
18th September 2009, 10:37 PM
OK, here it is. Sorry it took so long, a change in medication did not help.

By using wide jaws to hold a flat square piece it is easy to produce a biconvex blank without the marks of the centre stabs. Squaring the piece is important because it has to be reversed to achieve a biconvex shape. Starting with a size of about 65x65x10 mm, the round blank is obtained by forming a convex line from the centre to the circumference, a couple of mm inside the square, down to slightly more than half the thickness. The piece is then reversed and the process repeated until the round blank separates. A couple of mm waste is all that’s needed for the square to remain firmly secured in the jaws. A touch of sandpaper to remove any wisps of wood around the circumference and the pendant blank is ready.
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There is no need to build cumbersome jigs for turning off centre such a small piece. A piece of scrap wood and a few spacers will suffice. In this case the scrap is a 90x90x35 mm piece of radiata pine rounded in the same way. The notch serves two purposes: to provide a reference point for rotation and to help lifting the blank held in place with double sided tape.

To make the conventional pendant with an off-centre hole it is now sufficient to insert a spacer between the sacrificial piece of wood and the jaws. The distance of the offset is half the height of the spacer (radius = ½ diameter).

The shape of the recess does not need to match exactly the shape of the pendant, provided the concavity is deeper than the convexity of the pendant there will always be a circumference where the tape can touch both sides. Of course, if it is close it is better.

Once turned the hole on one side, mark the reference point with a pencil and reverse the blank to turn the other side. It might be worth replacing the tape. The piece can now be finished on the lathe.

To show the simplicity of the concept, the spacer used here is just a corner off cut, but using something as simple as 1mm thick aluminium stripes any off centre distance allowed by the size of the chuck can be achieved with precision.
Marking the holding piece with a protractor allows rotation and reversal of the piece with an amount of precision adequate for handmade craftwork.

This means that the conventional one hole design can be vastly expanded: three hole shamrock shape, four hole cross shape, other shapes only limited by your imagination: here is the design for a spiral, for example. If you leave the surface flat, it could be overlapping rings or lattice work instead of holes. Unfortunately, though, the lathe only makes round things.:D

To save you the bother, if you want to try, for a 60mm pendant in an 80mm holding piece in 110mm internal diameter jaws, the measurements anticlockwise are:
Ø hole height spacer rotation
(mm) (mm) (approx degrees)
20 30 0
16 26 90
12 22 150
10 20 195
8 18 235
6 16 270
4 14 290
3 13 310

Of course, if you want to be really creative, start carving! :U

NeilS
19th September 2009, 12:38 PM
Frank - thanks for the tutorial on your offset method. Logical, now that we can see it...:U

Happy amateur
20th September 2009, 05:38 AM
Frank

Yes would agree that your way of turning the blank is excellent if a mark in the centre is to be avoided.also the method of getting the offset is excellent provided that the blanks are all the same size.

With the modified jaws the blank size is not critical and as I said before if you wanted to make a set. a pendant and matching earrings then different sizes would be required.

I do think your varying the size of the holes in a spiral is good and if filled with a colour, silver or brass would be nice. I will give it a try when I get time.

As with most woodturning what works for the turner is the correct way if it is a safe way.

Fred

Frank&Earnest
20th September 2009, 12:37 PM
Sorry for not making it clear Fred, the idea behind this method is that any piece is unique, but you can make it whatever size you want. You can make more than one of the same size and keep the same recess in the holding piece of wood, but when you change the size you have to modify the recess. If it is just a bit larger you just make the recess larger, if it is smaller you flatten again the piece (as you can see in my example it protrudes quite a bit from the jaws, not only for ease of working but also to provide for more than one use) and make a smaller recess. It takes only seconds anyway, once you have the base measurement you can stop the lathe and check the fit a couple of times. That's why I called it a sacrificial piece of wood and not a jig, hope I have not been confusing. If it is more convenient for large runs you can have a few holding pieces with different size recesses, but if you are happy with just a couple of sizes and you are already set up for them that's obviously the best way for you.