Coring 101

Coring Beads with the Impress Beadliner


Coring, or lining, beads means to place a metal tube with riveted ends through the hole, adding decorative “riveted” ends to the bead. The Impress is a very popular way to do this. It’s easy!

The fact that the Impress is screw based gives you a big advantage. Each turn of the Impress’ handle moves the cone downward exactly 1.25 mm, so you’ll know at each step exactly how far you’ve gone, without having to judge it by how hard you are pulling a handle, etc. This allows you to do each side of each bead exactly the same way.

You have considerable control over the look of your rivet ends by varying the length of the tubing, and how far you turn the handle at each stage of the process. Once you decide on a tubing length and a look that you like, it will produce the same or very nearly the same results every time. You can keep a notebook of “recipes” for styles you like and make any of them again.

What you’ll need

Not all of these are absolutely necessary, but each is either essential, or highly recommended for best results:

  • Impress Beadliner
  • Dave’s Debur Tool
  • Digital Caliper (Get one with steel jaws, not plastic! Nothing too fancy, a cheap one will be fine.)
  • Mini Tubing cutter
  • Small rawhide or plastic mallet, 1 inch diameter or so.
  • Tubing that fits your bead holes.  (Sterling Silver, Copper, Brass, Aluminum will all work. Some copper brands must be annealed before use; some don’t need it.)


  • Impress accessories such as extra centering pegs for other sizes of tubing you’ll be using, riser kit for longer beads,  Little Phil screwdriver/wrench for quickly changing pegs.
  • Bead Caps (Washer-shaped parts that are riveted to the bead ends along with the bead.)
  • Buffing equipment (Usually not needed when using Sterling tubes. The hardened and polished surfaces on the Impress burnish the metal as it is being formed so it comes out shiny.)

Getting Started

Before lining your beads, you’ll have some shopping and preparation to do. Read the following first!

Choosing a Pipe Cutter

Choose a good quality mini pipe cutter, one that is about 1 inch square or so. Don’t pick a big honkin’ one. They are awkward for small tubing and will not provide any better results than the little ones. Choose one that has two rollers in the bottom, not just a V shaped trough. Preferably, look for one that has replacement wheels on the rack, right beside the tool. A sharp wheel makes a big difference in the quality and look of the finished rivet. There are many good quality brands. Don’t skimp. Get a good one. It will probably cost somewhere between $11.00 and $15.00. There are certainly more expensive ones out there, but any cutter that has a hardened wheel, and tracks straight will be fine. If it tries to cut a spiral instead of a circle, it’s junk. Take it back to the store and return it!

Choosing a mallet

You want a very light weight tool for this. A little rawhide mallet is my preferred type, but plastic is fine too. If you’re careful, you can even use a very (very) small steel hammer, as long as your bead has no “bumpies” close to the rivet.

Choosing a Digital Caliper

There is no way I would ever want to do this work without a digital caliper. It makes it so easy, you’ll thank yourself every time you use it. Harbor Freight sells a very nice one in two different lengths at a very modest price. For this work, the smaller 4 inch one will be fine, but I prefer the 6 inch since it is so handy for other things as well.

The Parts of the Caliper and How to Use it

The caliper has three buttons:

  • (1) On/Off – (It will also turn itself off after a period of disuse, but why waste the battery?)
  • (2) mm/inch mode – Very nice for conversions!
  • (3) Zero – This sets the reading to Zero, regardless of where the jaw is. This will come in very handy, as you’ll see below.

There is also a little metal knob at the top. Turn this to lock the caliper’s jaws at any width.

There is a little thumb wheel at the back that helps to move the jaws open or shut by very tiny amounts. You can use that, or simply push or pull the jaws for longer excursions. The wheel feels loose. That is normal. Push it against the slide with your thumb to engage it.

The long thin thing that slides out the end is a depth gauge. You can stick that into a blind hole and slide the tool down till the butt end contacts the top surface, and the reading will be the depth of the hole.

Using the Caliper to Measure and Mark Tubing

Let’s say you have a bead that is 9.6 mm wide, and you want to cut your tubing 4.2 mm longer than that to make a fairly wide rivet.

Close the jaws of the caliper, and press the mm/inch button so it reads mm on the display. Press the zero button if it does not read zero already. (Always be sure the caliper’s jaws are clean, so you are not measuring a bit of metal or grit, and calling it zero. 🙂

Now, measure your bead at the widest point. (9.6 mm.) Next, rather than doing the arithmetic, turn the locking knob to lock that position, and then press the zero button again. Now loosen the lock, and slide the jaws open until it reads 4.2 mm. Lock the jaws. Now your caliper is actually set and locked, to 9.6 mm + 4.2 mm = 13.8 mm, but without having to do the math.

The caliper’s jaws are hard steel, and very sharp at the tips. Put one end of your tube against the tip end of the back jaw, and scribe the tube a short distance with the other tip. You now have a very accurate mark exactly where you should cut. Now you know why you want steel jaws. Much more accurate and consistent than a sharpie!

Cutting Tubes

Always debur the inside edge of your tubing before you cut it. (See below) It’s easier to do with a long piece. Then you only need to do one end after the cut, holding the short piece in thumb and finger.

Place the tubing into the cutter with the wheel at the scribed line you made in the step above. Screw the adjustment wheel GENTLY.

Don’t be in a hurry to finish your cut. Never turn the wheel so far that it dents the tubing even the slightest bit! If the wheel is sharp, it is cutting, but you probably won’t see it. Turn the cutter’s wheel just till it is good and snug, and no farther. Spin the cutter three times or so, (you should feel it getting loose as it cuts,) and snug it up again. repeat. It will take maybe three or four repetitions, and the tube will suddenly snap off all at once, perhaps before you even think you’ve cut it halfway through. When properly done, the tube will separate with a definite snap, and have a clean square edge. If instead it separates only partially, either your wheel is dull, or (most likely) you are turning the cutter adjustment too hard.

Debur the other end.

Using Dave’s Debur Tool

There is more to this tool than meets the eye, and almost everyone who tries to get by without it comes back to art in the round very soon to buy it. If you have it congrats. If not, go get it. OK, sales pitch over.

To use the tool, simply insert the cutter into the end of the tube, press gently, and turn a few times. You’ll see a thin sliver of metal curl out, and a shiny beveled edge is formed on the inside. DO NOT cut more than about half way to the outer edge. Less is better. Get it too thin and your tubing might split, and even if it doesn’t, it will have a sharp edge. Unlike filing or sanding which leave a square edge, the tool makes this 60-degree angle on the inside edge. This edge will be the outer top edge of your rivet after coring. During flaring it is smoothed out some, leaving a gently curving slope down to the bead. Without this treatment, you would see a square-edged rivet that looks, in my opinion, more like hardware than finished jewelry!

Using the Impress to Line a Bead

Finally, we’re here!
Please read all of the instructions above before trying this.

This will produce a slim to medium width rivet with a slightly domed lip. The process takes about a minute to complete, after you are up to speed and confident of your technique.

  • Cut a tube 3.6 mm longer than the bead width at its widest point.
  • Deburr the inner edge of the tube on each end.
  • Place the tube and bead onto the alignment peg.
  • Screw the cone down till it contacts the tube, but apply no force at this point.
  • Slide the bead to the mid point between the top and bottom, and keep it there with thumb and/or forefinger as you perform the following steps:
  • Screw the cone down till it is good and snug, but not enough to begin flaring the tube.
  • Don’t forget to  keep your bead near the center of the tube, away from the part that is being stretched by the cone, or it will crack. Glass does not flare very well!

It helps to imagine a clock face with twelve o’clock placed at whatever position the handle is in at the beginning of each turn.

(1) Turn the handle 3/4 turn. (9 o’clock)
(2) Flip bead and tube together, end for end. Snug it.
(3) Turn 3/4 turn.
(4) Flip. Snug.
(5) Turn 1/2 turn (6 o’clock)
(6) Flip. Snug.
(7) repeat steps 5 and 6 three times. Don’t try to make it completely tight on the bead…yet.

With a soft mallet such as rawhide or plastic, or a very small smooth faced metal hammer, gently tap the edges of the rivets down all around the circumference while turning the bead, until the core is tight. With a little skill. you’ll be surprised how hard you can hit it without damage to glass bead or metal, but go slow at first till you get a good feel for it.


Each time you re-flare a previously flared end, the flared edge curls slightly downward toward the bead. The more repetitions, the more the curl, and hence, the higher the dome. (You can actually curl it all the way back on itself!) On the other hand, larger turns will make for a flatter rivet. But I’ve found that anything over about 3/4 to 1 turn as the first step, may rip the tubing. You need to get it curled down some first, so the stretch is not focused at the raw edge of the metal.

You can also stop at any point, and use a hammer, then optionally go back to the tool, etc.

You can add length to the tube, or take smaller turns, to increase the number of repetitions possible on a given bead. Smaller steps on the same length tube will make a higher dome with a narrower lip. Experiment, and give me and others some feedback on what you discover. It is a work in progress, with many as yet untapped possibilities. Try longer tubes, larger turns, or small, then large, then small turns, to shape the dome differently, etc.

Your tubing should slide easily down the peg and fully contact the anvil post without any force being applied. If it stops before hitting bottom, you have done one of two possible things wrong, and you should correct that before proceeding…

(1) You didn’t deburr it well enough, and there is a metal edge inside the end that is smaller than the normal tube width. Remove it.

(2) You tightened the pipe cutter too tight on one or more passes, which squeezes it inward, reducing the diameter. If either one of these has occurred, you can push it down with the cone, and the tapered peg will stretch it back, but, your tube will probably stick, and you’ll have to tap it (and your bead!) carefully with your soft mallet, or the plastic end of a screwdriver handle to knock it off the peg. It is therefor better to stop, and deburr the tube till it fits without any force being applied. This is why I belabor the issue of proper technique when cutting your tubing.

Don’t forget to  keep your bead near the center of the tube, away from the part that is being stretched by the cone, or it will crack. Glass does not flare very well!

Due to small errors in length of your cut or measurement and symmetry of your bead, you may need to do only a 1/4 turn for the last one or two pairs of turns.

Always try to judge how far is left to go and plan your turns to allow an equal number for each end, or your lips will be slightly different sizes.

Take your time, and turn the bead between steps, looking to make sure you are stopping before hitting any high spot on the bead.

Don’t try to use the press to get the rivet tight against the bead. Use a small mallet for the final tightening. Stop using the Impress when the rivet has a total gap about the thickness of the metal, or a little less.