Tuesday, November 30, 2010

COPPER

Copper is increasingly being used by many jewelry artists now that silver has become more and more expensive. Now, copper itself is likely to increase in price. I recently read in "Bloomberg Businessweek" that thieves are making off with copper stolen from cell phone towers, foreclosed and empty houses and many other places and selling the loot at salvage yards. The salvage yards chop up the copper and then sell to companies that ship it overseas, mainly to China, ending up in electronics, etc. that are shipped back to the US. Authorities are trying to stem this looting but are fighting a losing battle.

Will copper dramatically increase in price? I don't know. Should you increase your stock of copper? I don't know that, either. For myself, my stock of sheet metal is adequate for my needs.

Plus, having had a new furnace and air conditioning system installed earlier this year, I managed to salvage quite a lot of old copper pipe, plus some new. All this has been cut up into smaller pieces which I will cut a slit down through the side of the pipe with flex shaft and cut off wheel and then open up the pipe and flatten it out. With the rolling mill, I can make thinner gauges of sheet.

Saturday, November 27, 2010

The Pepe Tube Cutting Jig

Here is an article I posted on JewelryLessons.com

Pictured is the Pepe Tube Cutting Jig with a piece of copper tubing in place. The photo is deceiving in that my thumb is missing from holding down the thumb clamp. That's the gray colored thingy in the center of the jig. I didn't have a good way to hold the camera and include my thumb at the same time. Sorry about that.


Anyway, the jig is adjustable for length, up to 13 cm, and for stock up to 6 mm in diameter. The wood handle is obviously for hand held operation. I found this to be rather difficult for me to do, even bracing the jig against a bench pin.


A couple other things to know about the jig. By removing two screws on the saw guide ,and by using thin brass sheets (shim stock), the width of the saw slot can be adjusted for larger or smaller width saw blades.


The other thing is that everybody says you can't use the jig in a vise. Phooey! The photo proves this contention as wrong. But, there is the fact that you may have to remove the jig from the vise in order to change the setting for a different length. Only a minor inconvenience.


As you can see, the jig is firmly and safely secured in a vise, albeit a small, one inch jaw width, machinists vise. I won't say that is the only vise that will work. A small vise like that is always handy to have around. So are C-clamps! Very handy.


If there is a drawback to the tube cutting jig, it's that it can be a tad difficult with the way I've set it up to retrieve very short lengths of cut off tubing from the jig. But, a pair of sharp point tweezers or a fine point awl (aka bodkin), will do the trick. I suggest that you also have something under the jig to catch the cut off as it falls from the jig. I'm still searching for one that got away.


Now, a cautionary reminder. Very thin tubing may require some sort of support inside the tubing, or the tubing could collapse from the pressure of sawing. So a wood dowel, bamboo skewer, or a round toothpick inserted inside the tube should do the trick.


The saw cuts will produce some burring, so you can remove these with a fine file and sand paper as you cut, or do it later, whichever is easiest for you. Tumbling with stainless steel shot will remove some, but maybe not all of the burs. Remember to lube your saw blade and have the blade tensioned properly. I really didn't need to remind you of that, did I? I use bees wax. You can see a lump of it in back by the saw. It's only about 70 years old and is like the Energizer Bunny. It keeps going and going. I lube the back of the blade, not the teeth. I find it's better that way.


Why would you need one? Dunno. What can you make with one? Same length spacer beads. Any length metal beads. Within reason, of course. Danglely things for necklaces and earrings. Decorative add-ins on metal pieces. Tube rivets. Tube settings for stones. Cups for enameling on metal backing. Et cetera, and so on.


The Pepe Tube Cutting Jig is available from several on-line jewelry making supply companies. Mine was purchased from The Contenti Company. I have no affiliation with Contenti other than as a customer.


Thank you and good luck sawing whatever you saw.


John



Thursday, November 11, 2010

An update (this is a revised version).

What's been going on with old John? This week has been sawing, sawing, sawing. It is also goodbye to couple of old friends. I have two, very old jeweler's saw frames that I had to retire. After repairing them numerous times, it became impractical to do so anymore. The metal which the frame was constructed was a strange kind of alloy. I had encountered it only once before. I'm just guessing that it was a kind of bronze. Anyway, the wear and tear of unloosening the thumb screw, wore out the threads. It meant drilling out the worn threads, re-tapping threads and replacing the thumbscrews, only to go through this again, and again. Now, they are replaced with new, modern saw frames.

So now to the sawing. I bought several 12" x 12" sheets of copper, brass and nugold (bright brass), and have been sawing them down to what for me are workable sizes. Since my bench shear has only a 4" capacity, the sheets have to have one, 4" dimension.

To saw the sheets, I took a piece of Baltic birch plywood (about 18" x 24"), and marked out a 6" x 6" square in one corner of the plywood, extending one of the lines across the 18" dimension. Then drilled a 3/16's" hole in the corner of the square where the lines intersect.
That's relief for the saw blade when unloosening it from the saw frame. This is necessary when the saw frame's throat is only 5 7/8's inches. The using an electric jigsaw and a guide, I made a saw cut along one of the lines from the edge of the board to the hole.

This layout allows all around support for the metal sheet. You don't want to have the sheet extending outside as it will vibrate from the sawing and cause gloom, despair, and agony and break saw blade after saw blade.

I marked out 6" x 6" rectangles on the sheets with rule and scriber, and drilled a hole in the metal sheet where the lines intersect. Lining up the scribed line with the saw cut and the extended line, I taped the sheets to the sawing board with blue painter's tape. I have to do this to secure the sheet to the board. Otherwise, it moves around too much. Then began sawing. I took the 6" x 6" and cut those down a little smaller, leaving a 6" edge on some in case I might need that length for a project. Dressed down the sawn edges with 320 grit paper on a sanding stick, marked the gauge on the pieces, wrapped them is salvaged packing paper, put them in a ziplock bag, marked with the gauge and type of metal.

All this may not be economical for some. Since I don't make jewelry as a main source of income, the time used really doesn't matter.

Til next time, John