How to Make a Metal Drill Bit
How to Make a Drill Bit from a Metal Pipe Nipple
A metal drill bit is a significant improvement over a PVC drill bit. After you drill a well or two with a PVC drill bit and you have to resharpen your bit
You will need a two inch galvanized metal pipe nipple for this. I'd suggest getting a four to eight inch nipple. A pipe nipple is a piece of pipe with two male ends that is normally used for connecting two pieces of pipe. Fortunately for our purposes, the threads on two inch pipe nipples match the female threads on two inch PVC female couplers, which in turn connect to our drillpipe.
Below is a picture of a six inch long, two inch diameter galvanized nipple as purchased. I got this one at Lowes, item 0024061. There is nothing special about buying this from Lowes. It is just the closest hardware store to my house and I like it. Ace Hardware, Home Depot, and numerous plumbing supply houses have comparable items.
TWO INCH GALVANIZED PIPE NIPPLE - SIX INCHES IN LENGTH
THREE WAYS TO MAKE A METAL DRILL BIT
To try to accomodate as many folks with different tools as possible, I am posting here three ways to make a metal drillbit that leave the middle of the bit open. It is necessary to leave the middle open if you are planning on slipping a wellscreen down through it at the conclusion of the drilling.
Quick review: the process in this particular technique is to completely drill/wash the hole with a larger drillpipe and then put a smaller wellscreen down through it. Most of the time this involves drilling with a two inch drillbit and pipe and then putting a 1.25 inch wellscreen and pipe down through it. After the wellscreen pipe is inserted and extended all the way to the bottom of the hole, the two inch drill pipe are raised up over the 1.25 inch wellscreen. The two inch drillbit and pipe should be taken completely out of the ground leaving only the 1.25 inch wellscreen and pipe in the ground.
The examples shown here are all two inch drill bits which anticipate a 1.25 inch wellscreen being installed after the hole is drilled.
The first technique is the easiest, provided you have a jigsaw. It takes about 10 minutes to make a drillbit using a jigsaw.
Be sure and use a metal cutting blade with your jigsaw. They are finetooth blades as shown below.
As you can see, the jigsaw cuts a very sharp drillbit. It is a quick, effective method and is my favorite.
A hacksaw creates a drillbit just as effective as one cut with a jigsaw. It just takes more effort to cut the bit. It generally takes me about 30 minutes to cut a bit with a hacksaw. Also, don' t do like me - put in a new blade before you start!
A grinder can make a very effective drillbit. It is not quite as high of quality as drillbits made with with jigsaws and hacksaws but it is perfectly servicible for our purposes. The technique here is virtually identical to the one described for PVC drillbits. It is just a little messier. Be sure and wear eye and hand protection.
Here are all three together so you can compare the results of the three techniques
The pipe nipple is then screwed into a two inch diameter female PVC adapter. One final step is necessary with all drillbits made from pipe nipples. Since we will be twisting the drill pipe back and forth we have to put a set screw through both the PVC piece and the metal drillbit so it won't loosen while we are "drilling."
The following video demonstrates the three techniques for making metal drillbits. Each technique results in a drillbit that will work just fine. Use whichever is best for you.
MAKING A METAL DRILL BIT