The legendary Lionel Ivan Orozco has a great tutorial about making do-it-yourself armatures on his site broken into three parts: open hole double ball joints, drilling holes in metal balls, and brazing balls onto rods. These are the tuts I used to make my Ahab armature, which works surprizingly well actually, even though the holes I drilled in all those balls were crooked as the day is long. Well, I now have the capability to quickly and easily drill out as many balls as I want, perfectly centered and trouble-free, thanks to a method suggested on the message board by Ted Sydor. And now, valued reader, I share with you this ancient secret.

Ted said that if he were drilling stainless steel ball bearings on a drill press (not the best method, but a very affordable one - and who has a lathe laying around in their home workshop anyway?) - what he would do is get a good sturdy vise that can be bolted down securely to the drill press table and just drill straight down into the jaws, making a hole the same diameter as the ball you'll be drilling. This was one of those ideas that just sunk in and took root, and I decided I had to do it. So I started buying drill press vises... had to go through several before I found a good rock-solid one with soft steel jaws (one was almost perfect, but had hardened jaws that I couldn't drill into, and several others would "lift" or shift in some way as I tightened them down). I ended up with this one:


Click the image to go to the Enco site's description.

If the link isn't working, go to www.use-enco.com and enter model# 891-4155 into the search engine. In the picture, you can just see, there's a thick steel rod running under the jaws that keeps them perfectly lined up, which is what makes this vice so sturdy. No free play at all! And the price is right... currently they're charging $33.75.

Here's how you want to set it up;
First you need to stabilize the adjustable drill press table so it doesn't tend to tilt when you put the pressure on it, as they will generally do. For this you can just put a piece of wood under it and crank the table down onto it until it's firmly braced, and then lock everything off. You want it set up so with the vise in place you have an inch or two clearance. Ok, that done, take a piece of thick cardboard, maybe folded in half if it's kind of thin (or a piece of paper folded over 4 or 5 times), and secure it between the jaws. This will help you clearly see the center line, and also separates the jaws slightly, so the hole you drill will grab the ball securely... otherwise the it will just spin when you try to drill it. Now. with the screws slightly loosened, adjust the vise so the center line - clearly demarcated by the edge of cardboard, is precisely centered under the tip of the drill bit. Pull the bit down until it makes contact, so you can see exactly where it's going to touch. When everything is lined up, lock off the vise.

Use plenty of cutting/tapping fluid and drill the hole... setting your depth finder so it's slightly more than half the diameter of the ball. My most common ball size is the 1/8" diameter, so for that you'd set the depth slightly more than 1/16th". This way half of the ball will still be showing over the top... making things much much easier on yourself than if they were buried down inside the hole. Here's a picture of my setup:



You can see the ball is in place in one of the holes, almost half of it showing above the top of the vise jaws. The second hole is a different diameter, for drilling smaller balls. You can put a few holes in the vise jaws, but no more than two or three, and keep them pretty close to the center so they don't throw off the clamping action.

You can also see I have the drill bit pushed as far as possible up into the chuck. I did this to minimize flexing, which can make the bit "walk" across the surface of the bearing rather than biting in dead center. People have since told me this might not be a good idea, I think because the metal shavings can't clear... they want to go right up into the drill chuck rather than emerging out the spiral slot in the bit. It worked fine for me though, but I did have to pull some spiral metal filings from the chuck after each ball. Another thing that really helps to keep the bit centered is to file a flat spot on the top of the ball after you get it clamped in place.

When you set out to drill some balls with this jig, it's a good idea to do a whole bunch of them at one sitting. It might take a few balls just to zero-in your vise and get it perfectly centered... I generally have to adjust slightly after each of the first couple of balls until they're coming out perfect. When you do get it centered, it's time to go to town! I can drill approximately a ball a minute with this setup. A good bearing to use is 302 stainless steel, which Lionel recommends on his site. While you're at Enco picking up the vise, you can get a hundred lot of balls too. (Model #240-2445 if the link stops working).

Click below if you have questions or suggestions, or if you spot any mistakes on this page:

Comments

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OUCH! That poor drill vice.
Hey Mike, that looks like a good trick for drilling balls without many tools. My only suggestion would be to make removable jaws. Most drill vises like that have removable jaws. It would not be much more work to add some 1/4" thick aluminum bars as soft jaws to drill into. That way your original vise will remain intact. You could make one set for each different size ball you want to drill.
But overall good tutorial, drilling balls seems to be one of the hard parts for folks starting out with armatures - You just made it a lot easier. ~Mark Fullerton

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Hmmm... yeah, that would work. A lot less stressfull on the ol' vise too I guess. ~M







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