The need to cut internal threads in holes in wooden parts may arise when performing various types of work, for example:
- during assembly furniture;
- when constructing shelves or stands in utility rooms or garages;
- when assembling structures that require connecting wooden elements to each other or to metal parts.
If you do not have the opportunity or desire to purchase the tap necessary for this in the store, I suggest making this tool yourself from an unnecessary bolt. You will spend no more than 5 minutes to complete this work and will be very pleased with the result.
Required tools and materials
We will need:
- angle grinder (grinder);
- clamp or vice;
- sharpening machine (emery) with a fine-grained stone;
- drill;
- a bolt or screw of the required length with a thread of the desired size.
Giving the future tap the required shape
If you are using a bolt or screw, cut off the head of the bolt or screwdriver. If you find it, you can immediately take a threaded rod of the required size. This will allow you to use the tap with a drill or screwdriver in the future.
Next, you need to create a small cone at one end of the thread. I did this on a benchtop sanding machine. During the grinding process, the bolt must be constantly rotated to ensure an even taper.
To do this, I recommend clamping our headless bolt (or stud) into the drill chuck and grinding it, turning on the drill at low speed. In this case, the bolt must be oriented relative to the plane of the grindstone at a slight angle, ensuring the desired taper. In this way we will obtain a centered, correctly shaped cone of our tap.
When performing this stage of work, the threads should not be completely ground off even in the initial part of the tap.
We cut longitudinal grooves on the tap
We fix the tap with a clamp or clamp it in a vice. Using a grinder, we make 3 or 4 longitudinal slots, evenly spaced around the circumference of the tap.
The cut grooves will allow you to remove sawdust during the threading process, and the sharp edges of the threads formed by the grooves will easily cut into the wood.
Cleaning the Tap Threads
Take a nut with the appropriate thread and, screwing it onto the tap, run it several times along the thread in the forward and reverse direction. As a result, small burrs that will inevitably arise when cutting longitudinal grooves will be removed.
Now you can clamp the tap into the drill chuck and make sure it works correctly. If you are afraid that the drill chuck will be scratched by the threads of the non-working part of the tap, grind it off using sandpaper. I did not do this and did not notice any damage to the cartridge. In fact, bolts are usually made of a softer steel than the drill chuck.
We produce thread cutting
Drill a hole in the wood whose diameter is slightly smaller than the internal diameter of the tap thread.
When cutting threads, move slowly, after 1 - 2 revolutions of the tool, turn on the reverse and, pulling out the tap, clear it of chips. This will allow you to cut the thread without flaws.
Keep in mind that threads cut in wood are not as strong as metal threads, but in some designs they are quite strong enough.
Original article in English
