Machining Titanium and Stainless Steel Jewelry

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Introduction: Machining Titanium and Stainless Steel Jewelry

Jewelry for body piercing is expensive and can be hard to find, particularly if you need an unusual or large size. I go through the steps of machining a barbell style piece from scratch. This project includes many operations typical of small scale machining on a lathe including facing, turning down, drilling, tapping, and polishing.

Step 1: Gather Materials

The first step, as in most projects, is to track down all the materials you'll need. For this barbell, we'll use titanium and 316L stainless steel. The titanium bar stock is 1/8 inch (3.2mm) diameter, and we'll only use a small amount of it. The screws are 18/8 stainless- still corrosion resistant, but stronger than 300 series. The balls are 316L ball bearings. All of this is pretty easy to find online. smallparts.com and onlinemetals.com are good sources.

Alternatively, you could use 316L for the bar. I've made quite a bit of stuff from titanium and in small sizes it's pretty much like working 316- I don't see much reason not to use the titanium and some people may have reactions to the small amount of nickel in 316.

I love using recycled materials for projects. I'm always grabbing scrap metal out of trash and my basement is, well, let's say it's full. This is one place where scrap materials are a really bad idea. For piercing jewelry I would only use 316L stainless, titanium, or gold. Use new materials from sources that know their stock. 'Stainless steel' rod from the hobby store or home center won't cut it, and is probably more expensive than buying good stock from a metal supplier. Anything else is risking nasty metal reactions and infections. The right stuff is not very expensive- all these materials should run under $10 and give enough for 5 or 10 pieces of jewelry.

Step 2: Facing Off the Bar Stock

The first step is to cut the end of the bar stock so it's square to the length. This gives a nice clean, smooth surface for drilling. Decide how long you want the bar to be, then add maybe a mm or two and cut it off. A jewelers saw works delightfully for this.

Chuck up the piece of bar in the lathe and take some light cuts to clean up the end. I'm using a carbide insert cutting tool, fairly moderate cutting speed, and no coolant.

Step 3: Turn the Bar

The next step is to turn the bar down to the diameter you want. You'll need to know what gauge piercing you want. In the US we use a bizarre system of measurement, of course. It's based on the Brown and Sharpe wire gauge measurements. I'm making an 10 gauge barbell, which comes out to 0.102 inches or 2.6 mm.

Take light cuts until you get down to the diameter you want. I like to make the last cut very light- just a couple of thousandths of an inch- at higher rpms. This leaves a smoother finish which is means less polishing. I finished this step with a diameterof 0.106, which leaves something to take off when polishing.

Step 4: Center Drill the End

Use a center drill to 'spot' the end of the piece. This leaves a little dimple right in the middle which will keep the drill bit in the right place in the next step. It's the same idea as center punching a piece of material before drilling it with a hand drill.

Step 5: Drill the Bar

Drill a hole through the bar. This should be the right size for the tap we'll use to cut the threads. I'm using a 1-72 tap, so it's a #53 drill bit which is 0.059 inch or 1.511 mm. As an interesting trivia point, number drill bits are measured using American Wire Gauge (AWG), which is completely different from the B&S; wire gauge for piercing sizes.

I drill the hole all the way through the bar, drilling half the depth from each end. I think this lets me do a better job of cleaning out cutting oil, chips, and general muck from the threads. Make sure to use some kind of lubricant on the drill bit and back it out frequently to clear out metal shavings.

Step 6: Tap the Bar

Using a tap, cut threads inside the bar. This is where the balls will screw on. Tapping small holes like this can be difficult- it doesn't take a lot of force to break the tap. If the tap is not perfectly lined up with the hole it will jam and break. I use the chuck in the tailstock to loosely hold the end of the tap while I turn the tap wrench by hand. Use lots of cutting lube, go slowly, and back the tap out more often than you think is necessary. I get into a rhythm of 1/2 turn forward, 1/4 turn back and then completely removing the tap every few turns. If you break the tap, you get to buy a new one and throw away the piece.

One fun trick though, in case you're working on a piece you don't want to throw away. The bar here is titanium and the tap is steel. This means that if the tap broke, you could put the whole mess in a bath of nitric acid, which would dissolve the broken tap piece but not the titanium part. Of course, when you were done you'd still have to deal with whatever problem made the tap break...

Step 7: Drill Your Balls

Chuck up one of the ball bearings in the lathe and use the center drill to start drilling it. The center drill does a good job of breaking through the ball's crunchy outer shell to the gooey center. Usually, ball bearings are pretty hard and difficult to drill without annealing. Stainless doesn't harden very well and I haven't had any problems with drilling them.

Step 8: Drill, Countersink, and Tap the Balls

Next, drill, countersink, and tap the balls. Drill a hole 2/3 of the way through the ball using the same bit you used for the bar. Then use a bit the same size as the diameter of the bar to put a short countersink into the ball. This will allow the bar to seat into the ball slightly when they're screwed together. This is the trickiest part of the whole thing. If the hole is too small, the barbell won't fit together right. Too big and there's a gap perfect for all kinds of biological nasties to live in. To make it more difficult, the bar is probably machined to some wierd size where you can't get a drill bit to match it (and drilling usually make the hole a little bigger than the bit anyway.

Once everything's drilled, tap the hole the same way you tapped the bar. Then screw one of the screws tightly into the ball and cut its head off. Leave enough threads sticking out of the ball that it can securely attach to the bar. I like to leave them longer than most commercial barbells.

Step 9: Rough Fit

At this point, we've machined two balls and a bar. All the components are done and it's time to check if they fit. Screw everything together- the threads should work smoothly. Check that the bar fits tightly into the countersinks. If it doesn't, you'll probably have to redo that ball. If everything looks good, then we're done with machining and ready to start finishing- in other words, we're about halfway.

Step 10: Polishing Fun!

Now it's time to make it all shiny. I use some 600 grit wet/dry sandpaper to remove any tool marks from machining. Don't overdo it- you don't want to change the dimensions too much. Then use a rotary tool with a felt pad and polishing compound to get a mirror shine. In the picture below, the bar is screwed onto a brass fixture to hold it in the lathe while it's polished.

I finish off with an ultrasonic bath to remove polishing compound and and residue from cutting oils, then passivate in a citric acid solution for 10 minutes. Passivation is a process of using an acid bath to remove any little bits of iron that might have rubbed off from the cutting tools. For the stainless bits, it also helps to remove iron from the surface layer of the part and make a good corrosion-resistant surface. Finally, it gets washed again and it's done!

Step 11: And We're Done

Here's a picture of the finished product, showing a couple of common problems. First, it's hard to tell from the photo but the surface isn't quite where I'd want it. It's smooth and shiny, but not quite there. So it goes back for some more polishing- not a big deal. Second, and more seriously, the ball on the left has too big of a countersink. This shows well what I was warning about earlier. Nasty gunk can get caught in there and it gives a great place for bacteria to grow. This might be good enough for a healed piercing, but I still redid it.

I put a picture of my 'shop' at the bottom. The point I want to make is that you don't need a lot of space or massive machine tools to do this kind of work. The lathe is the biggest investment, and that was about $300 from harbor freight. It takes me an hour or so to make one of these. The first one took more like three hours, but I made 4 or 5 balls before I was happy with them.

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    34 Discussions

    Can anyone advise me how to HAND drill an 1/8" hole in large stainless taper for body jewelry. I dimpled it with a punch, however 2 @ Dewalt cobalt drill bits and an 18 volt Makita drill didn't even begin to cut into it. (I'm hoping I don't need to go buy a $500 lathe tool setup.)

    Thanks in advance for your replies.

    You are aware that the "L" in 316L is lead? Is there any concern of that leaching?

    2 replies

    No its low carbon, 316l is implant grade stainless. Its used in the food and medical service widely.

    As an idea, you can machine the bar to any size you want, so why not make the balls first, pair them off, and then make the bars to the right size for the holes. That way you won't have nay issues with the countersinks being the wrong size. Nice instructable. :-)

    3 replies

    Thanks! That's a good idea. It ends up not making a lot of difference what order you make them in. You have to machine the countersinks in the balls to match the diameter of the bar. If you want to match standard gauges (and there's no reason you have to), then you already know the numbers to shoot for- otherwise you pick a number and make them all the same. It's easier if you pick sizes that match bits you already have. For 8 gauge, I can cut the countersink with a 1/8" endmill. There's enough runout in the chuck that it ends up being the .128 I want. Otherwise, you have to start fiddling around with really little boring bars.

    Hello I was referred to you by an asscoiate . My name is everton and I dont small time acting and promoting. I have a custom piece that need to be made that I belive you can make. I had a gentleman in texas that use to make custom spikes for me. I have dermal implants in my head that allow me to screw a metal spiked mohawk in over that last year of going to events and getting drunk I have lost a few of them. I can send you one to use as a example and or email you pictures . They ones I have now are 6-8 guage -80 pitch . If you can help me out this would go alone way and I will compsensate you. If you have someone you can refer me to please do so thanks

    Everton Watson

    evertonwatson@gmail.com

    Bump! just kidding. An actual tip. Instead of an appearent counterbore(or was this an illusion o fthe photo?) use an actual countersink.(I'd use the center drill again, for a hole that small) When machining the bar, make it a few thou over the size of the outside o the countersink. Put a taper on the end of the bar that matches your counter sink. If your tools are sharp, and your eye keen, this should give a "seamless" joint, as long as the tapped hole in the shaft is deeper than the threads on the post.

    Awesome job I've been making body jewelry for 5 years (nothing threaded) mostly just custom bends and other designs..this is a good instruction on how to make a barbell! thank you so much for posting this!

    316L is available at most weld shops as tig filler rod. Standard sizes are .035, 3/32, and 1/8. Thicker can be ordered.

    What grade of Ti are you using. Commercially pure?

    As for your lathe work a couple things. You may get better performance from HSS bits, Cobalt even better. You can get a much sharper edge on HSS than carbide. Especially with the TNMG inserts you are using. There is also a company that offers HSS and cobalt TNMG inserts that should work with your holders. It looks like you are using TNMG21.51?

    Second is work holding. Try to get a collet chuck of you can. Better runout and repeatability especially when using small barstock like this. Littlemachineshop has some setups for your lathe.

    Third. Either use a dead center or follow rest when turning long thin materials. This will reduce the spring cut you need to take. A follow rest is available for your lathe.

    Fourth: Center drill are for making the pilot hole for centers, live or dead. Use a spotting drill with a split point to spot before drilling. They will not wander like a center drill will. Alternatively use a split point screw machine length drill and drill in one go.

    Fifth. Use an actual counterbore bit to counterbore. They are available in many different sizes and pilot sizes.

    Sixth. Tapping, look up the drill size for 50% threads. You shoudnt need anything more than that and this will reduce tap breakage. Also give the form taps a try.

    Dont set youself on a Hardinge. There are a lot of machines as good or better than a Hardinge and many times cheaper. A Monarch 10EE is a good choice. Better runout than a Hardinge from the factory and weighs more as well (Mine is about 3500LBS) I used to have one of the lathes like yours. Great little machine. But the lower belt cover on my machine weighs as much as your lathe. More mass = Less Vibration = Better Finish = Happy Operator

    0
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    okto

    12 years ago

    Nice job. Any tips on creating curved-bar jewelry? I'd like to make some custom stuff for my eyebrow.