Drill through anything (conductive) with Electrical Discharge Machining

I show how to build an EDM drilling machine, describe how it works, and where to buy parts.

[smartereveryday]

Drilling through a lathe cutter is impressive. I've never thought about EDM for drilling. This is genius.

[coastmansscenicproducts]

Not only is this impressive machining, he provides an articulate and thorough explanation of how it's accomplished. Accolades!

[ThisOldTony]

when I was younger my kid used to tell me stories of homemade EDM machines that I always dismissed as urban legend.
I've seen that baxedm stuff around, great to see it implemented. Looking forward to seeing your wire feeder / tensioner. I talk alot when I'm excited; moral of the story: Amazing work!!

[petemoore]

A lot of years ago, I used one of these machines to remove broken drills, taps and hardened steel pegs from materials. It was extremely good at doing this and due to costing, worked out cheaper than re-machining the whole part again - mainly because I worked cheap.
For fun, I used to make strings of ball bearings, similar to pearls, from worn out bearings.

[Thepiecat]

>It'll be too conductive
>water your plants with it

It's got what plants crave. (Electrolytes)

[jimbaritone]

When I was in Grade 8, a buddy and I built an EDM drill starting from an article that had been in Popular Mechanics. I got a section of a many-splined transmission shaft to use as a "tool" from a shop that fixed Kenworth oilfield trucks. That was pretty hard, high-grade steel, and it was able to drill a close-fitting hole through a piece of 1-1/2" mild steel or aluminum plate. The plate being drilled was submerged in Kerosene in a clear Pyrex dish, so that the arc discharge was actually covered by the liquid. Raising/lowering the head for the cutting tool was a vertical slide made of maple, both the track and the movable head that ran in it. The maple slider holding the "tool" was raised and lowered by fly line running through a multi-line block & tackle made with Meccano pulleys. We got a very slow-turning gear motor out of a junked Timex watch display, which very slowly un-reeled the line, lowering the cutting tool. The speed for lowering the cutting head was one of the hardest things to get right. The winding motor wasn't variable speed or reversible - a hand crank raised the cutting head.

We cobbled up a circulating pump using an automotive-type mechanical fuel pump with the actuating lever arm moved by a maple cam on a bolt chucked in a 1/4" electric drill. We put a diode in one leg of the power wires to slow the drill down. We made a tapered glass tubing nozzle for the hose where it "squirted" at the workpiece. That flushed the cuttings away from the tool pretty well, although not as nicely as if we'd had a tool head with a hollow center to pump the Kerosene through. The cuttings built up quite quickly, and we discovered that things didn't work so well if the liquid was full of metal cuttings. The solution for that problem was to drain the kerosene full of cuttings into a reservoir. Some settled out, and the pump output ran through a Diesel engine fuel filter. Our high voltage supply was 120 VAC going through a voltage doubler or tripler power supply, using some big capacitors, some big incandescent light bulbs for current limiting, and some high-rating diodes we obtained by writing to a solid-state component manufacturer. They sent us a box with 2 or 3 sets as well as some heat sink material free of charge, which was good of them.

All this back in 1969 - 50 years ago - hard to believe. Later I became an electrical engineer, and belatedly learned just how dangerous this setup had been. But, ignorance is bliss, and we never had any shocks, big arcs, fires or major problems or failures, and it actually did cut really complex shaped holes through thick steel and aluminum. A buddy and I built this contraption and won 2nd prize at a regional science fair. We attended a really small school, with teachers who really didn't understand (fortunately) what we were doing very well. We figured we'd done OK, since about 80% of the parts were junk/scrap, begged, or donated, and the only "guidebook" we had was a Popular Mechanics article.

We bought the big capacitors from a motor & genset rewinding shop that worked on oilfield equipment. They got interested in what we were doing, and donated the mechanical fuel pump, a bunch of hoses, and a diesel engine filter housing and filters along with the fittings to connect it all up. They thought using an electric drill to drive the pump showed "ingenuity." We were pretty lucky to have people help us out with things like that, and the high voltage diodes.

It's sure a long, long way from where EDM technology is today. I went to an industrial trade show once, where some EDM equipment was being demo'd, and told one of the sales reps about the Grade 8 science fair project. He had a good laugh, and told me we'd been complete idiots. Which wasn't really fair - we built it with almost no adult help, solved all the problems, and made a working machine that actually drilled a 1"-1-1/4" splined hole through thick steel plate. We nicknamed the beast the "Spitzensparken" for obvious reasons. My friend's dad was a ham radio operator, so he knew something about high voltage wiring and insulation. We were pretty lucky in some respects. How many school science teachers today would let a couple of 13 year-olds build a project like this in the school lab?. We had parents who kept an eye on things but trusted us enough to be careful when fooling around with what was a pretty crude rig.

[FFLFFS]

I had need for such a machine several times in my shop life and only guessed that such a machine existed. Not till now has the concept been shown as being practical and affordable. Thank you.
Opens lots of new doors.

[TrasteIAm]

Ben's wife: "Honey why is the sauce pan leaking?"
There is now a tiny hole in every conductive thing in Ben's home.

[glenshort]

You sir, are brilliant. I don't usually leave comments, and this has nothing to do with anything I would ever be involved in, but I found this very fascinating and articulate.

[needleonthevinyl]

I think hobbyist level EDM is going to make a large impact in the small/precision capabilities of the home shop

[treverwolverton]

Not to mention he very clearly walks us through every step, so that novice to expert is in full understanding of form and function, as well as what and where to go-to for parts and programs for running it. Impressive. He clearly watched ALOT of Mr. Wizard as a youth. Thank you Obi One....

[electronash]

The complexity and variety of projects that Ben works on is amazing.

Always so thoroughly explained, too.

Every video is a must-watch for me. Keep up the good work. ;)

[matthiaswandel]

Makes me want one so I can drill random holes through random hard metal objects, just because I can!

[pepper]

I once had a conversation with an engineer - he talked about a project he was working on. It was about EDM machining; they used a wire about the thickness of a human hair. It was so precise that when you put two freshly separated pieces of metal back together and left them for a while, they'd fuse back into one piece. Since EDM is pretty slow, they'd devised a system which was able to re-inject a new piece of wire using a jet of water should the old one have broken when running unsupervised during the night or over a weekend. Fascinating stuff!

[wessmall]

Suddenly everything in his shop has dozens of tiny holes

[jamesdavis]

Of course ben makes his own EDM machine! I expect a fully functional fusion reactor by the end of the week.

Maybe you should give that a shot!

[nerdanderthalidontlikegoog]

I EDMed a 1/2" wrench once while replacing batteries in a room sized UPS. A few hundred amps is all you need.

[donpollard]

The local engineering shop that I frequented during my formative years on the farm had one of these units, and you could 'eat' out a broken off bolt/stud/whatever - it used what looked like a 1/2 horse electric motor, that had been reconfigured to be an electromagnet; the circuit ran through the armature and back through the work piece.
When you applied the lever and brought the tungsten electrode into contact with the work piece, it energised the armature and the the electrode was pulled away from the work piece and created your arc, thus eroding the part a little.
Repeated application of the electrode kept eating away at the part until it was (most;y) removed, allowing the broken part to be extracted.
Magic!

[AllanDee]

"Honey, where's my large mixing pot?"
"You mean the large colander?"
"No, I mean my big mixing bowl from the KitchenAid mixer"
"Yes. You mean... the colander."

[ProlificInvention]

*Applied Science* I collect Niobium and Ferro-Niobium, would love to see you drill through the crystalline as well as solid bar forms using the EDM method. You are also the one guy who may be able to melt it in the home shop. Usually an electron beam welder type device is used to melt it, I had always wondered if a carbon arc mini foundry would be capable.