1$ DIY Cable Lug





Introduction: 1$ DIY Cable Lug

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The goal of this ible is to show you how to make a custom lug connectors for under a dollar. This is so cheap that you should be able to do this with leftover scraps from plumbing jobs.

Step 1: Material

You will need

Step 2: Figure Out Your Sizes

If you have cable sizing needs, then your connectors should match those requirements. Now resistance over distance is what matters, so if you are at a slightly lower gauge for the 1cm of your lug connector that happens to be thinner, don't worry too much. However, don't exaggerate, or that higher resistance point will become a fuse if you are wildly out of proportion.

First, use the wire gauge chart to figure out what

  1. the diameter of your wire (to know what size of pipe you need)
  2. the weight per foot, or surface area of the wire's face (depends on what calculations you prefer, surface area will be more accurate if there is a difference in the allow mixes; so err on the side of caution if you go by weight)

Next, use the pipe sizing chart to figure out (you are almost certainly using type M)

  1. look at the I.D of the pipes and figure out which one fits your cable size, with enough clearance to put in some extra layers as needed (see step 2)
  2. what the weight per foot is (to figure out how many layers of a given pipe are required to have the same weight per foot as the cable) or use the wall thickness and circumference to do a surface area calculation

For the record, for size 1 AWG, 2 layers of 1/2 or 3/8 pipe can be used, but 1/2 is easier to account for the layering necessary. This may take some trial and error for your other wires.

Step 3: Cut Your Pipe

First cut some short lengths of pipe (however long you want your lug + about an inch to go over the exposed wire). Add an extra half inch to this to account for hammering down. This will be your lug; cut a slit in it the length of your exposed wire if you are layering, just to make sure it goes on well.

Now cut some shorter pieces that will act as filler if there is too much of a difference between your pipe size and your wire. I needed 2 more inner layers to fill the gap. Make those the length of your exposed wire, and split them open on the length.

Step 4: Fit Your Copper Pipe

As you fit the filler pipes, use the pliers to crush and round out the layers. Once this is done, you may have to use the pex crimper on a smaller size than the rings you will be using, just to round out the copper, so that the rings will slip on.

Put on two rings, and crimp them. Once they are both well crimped, re-crimp the back one with a size too small.

Step 5: Cut and Flatten

Start by flattening the tip with a hammer, this will make it obvious where the wire ends. Where the wire ends(ish), cut a slit across the top of the lug. You can then flatten some more.

Step 6: Solder

Heat up your copper and shove some solder in there. The top slit also has the benefit of giving a good access to all layers and the wire, making sure that they can't just slip from one another.

You can also add a bit in the back, where you crimped harder there should be a small accessible lump. However, this will make the end of the cable a bit stiffer.

Step 7: Drill Drill Drill!

Make the hole the size you need it for your posts or bolts, and enjoy! You can also add a finishing touch by putting shrink tubing. What I like most about this is that I can colour code my cables so I know what's plugged where.



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    14 Discussions

    Did this this weekend when replacing a welding clamp. Yeah, I could have driven to Harbor Frieght and bought 2 for $3, but 1) I only needed one, and 2) when was the last time anyone went to Harbor Freight and only spent $3.

    Works great but I wish I read this before. Some good ideas--like reducing the size of the pipe and attaching to cable BEFORE flattening and drilling.

    13 replies

    Nice, thanks. It is good in a pinch or for pure hobby usage. I wish we had harbor freight here, I'd have to order directly from China and wait 3 months if I don't want to spend something like 10$ per terminal!


    Reply 1 year ago

    For low-voltage applications, there's nothing particularly 'unsafe' about this. Automobiles have exposed lugs similar to this for connections at the starter, the engine block, and sometimes at the battery itself. And if you have the tools to make your own lugs out of copper pipe, the savings in time AND money can be substantial. Premade cables with lugs like this are not particularly cheap, and there is time involved with getting into the car and driving to the vendor and/or ordering a 'proper' part. I used a similar strategy to build the cables necessary to get an old floor scrubber back into the fight; the manufacturer's cables would have taken like a week to get and cost nearly $80 apiece, and frankly, weren't much more elaborate than what I built.

    The only thing I did differently was to heat-shrink where the lugs crimp to the wires to minimize corrosion. I didn't even use a crimping tool, just a hammer, punch, and vice.

    In a 12v car battery, low voltage isn't the concern, it's the massive current the battery can supply, coupled with the inconsistent resistance provided by these makeshift lugs. I'm all for suitable replacements when the manufacturer's replacements are grossly overpriced, but I really don't believe this is the answer for that. If you can save $8 and you only need a couple, bite the bullet and spend the extra cash. If you need a lot of these in your day-to-day work, the I hope your only doing repairs like this on your own property, because there's a reason these lugs are built the way they are. Take that $8 each you're not spending on proper lugs, and save it. You might need it when your car insurance refuses your claim, hehe.

    Actually, if you look closely at the commercially-available lugs, you'll discover that they're made pretty much the same way - stranded copper wire crimped and soldered into flattened tubing. Oh, sure, the parts-store variety is prettier and has a shiny zinc finish on it, but it's the same basic construction. The 'inconsistent resistance' is only an issue if you DON'T use solder, as it is possible for moisture and corrosion to seep in and compromise the contact between the cable and tubing.

    I work with these every day, and no, they are not the same. If you want to do this in your own garage, that's fine by me, but suggesting that these are equivalent is irresponsible, ignorant, or both.


    Welp, I just ran them in my spot welder; vaporized aluminum no problem, but the lugs stayed cool as a cucumber. Did not go up from ambiant temperature by more than a degree C

    Yup, at 5 minutes per lug (after the first one where I fiddled for the while of course), it saves me 8$ each and the drive out. I just ordered some heat shrink that would fit actually, because my 1/2 rubs on the sheathing when I put it on, sufficiently to heat up and tighten :p no way I would go over my lug at the moment. What did you use the punch for? I was tempted to crimp using the screw driver to jam the pipe down at first, but I was worried the stranded wires would still slip out.

    Actually, it was a cold chisel, like you'd use to knock welding flash off of a metal object. I'd start by flattening the tubing slightly into an oval shape. Then I'd insert the stranded wire, and use the chisel and hammer to crease the tubing enough to grasp the wire. Then it was a simple matter to just tighten the vise down to close the crimp. A little solder, a little heat, and some shrink tubing, then all that was left was to flatten the end and drill the hole.

    I don't even buy premade battery cables any more. I just buy the bulk wire/cable and some copper tubing and make my own.

    Nice, probably easier than my outer crimping with the rings. What size pipe to wire did you use? Ps. Thanks for the participation, I've sent you a pro membership voucher.

    To be honest, I just size them according to what I need. I have copper tubing in a couple of sizes on hand, I find something that's as close as possible to the wire gauge I'm running. If I have to use a piece of tubing that's significantly larger than the cable, I'll either fold the wire back inside the area where I crimp it or cut the tubing lengthwise so that i can crimp it smaller. For very small gauges of wire, I use the regular Radio Shack-type pre-made lugs, since they're inexpensive (particularly in quantity) and easy to keep on hand.

    I haven't had one of my home made lugs fail yet, and I've used them on everything from lawnmowers, to the aforementioned scrubber machine, on up to diesel-powered dump trucks. The first one I ever made is still in service, 20-odd years later, in my old Ford hot rod.

    That said, I would not use them to, say, wire a house - not because I believe they're unsafe, but because electrical codes are very specific about what is and isn't acceptable for utility electric.

    Oh absolutely not for anything in-wall I agree; but anything I DIY / salvage? Heck yeah! Just tested mine at roughly 350A yesterday, and it worked like a charm.