Introducing the Cobalt SAE Tap and Die Set
Have you ever experienced the frustration of dealing with stripped bolts or screws? It can leave you feeling helpless, unless you have a reliable tap and die set. Cobalt has introduced a 46-piece tap and die set that addresses this issue, equipping you with the necessary tools to secure bolts and screws properly. While you can also use it for threading bare steel rods, most people will find it most useful for repairing damaged bolts, screws, or threaded sockets – tasks that are ideally suited for this kit.
Quality Build of the Cobalt SAE Tap and Die Set
The kit comes in a cobalt blue box that can be closed and features an integrated drill coating. The case itself is not too sturdy and does not inspire confidence. In our kit, the two-tiered holder was broken or missing, resulting in several bits and taps being scattered inside. Additionally, there are mold inserts for wrenches and hex sockets. However, they are flimsy and cheap, and some have even cracked in places. As far as we know, even if your kit is not damaged when you purchase it, it’s only a matter of time before even minor handling will tear it apart – a good blow-molded case would be a much better choice for this kit. The case also cannot be stored upright and needs to be kept flat. This is an area where Cobalt could spend a little more, especially considering the competition in this space.
Contents of the Cobalt 46-Piece Tap, Die, and Drill Set
The Cobalt 46-Piece Tap, Die, and Drill Set comes with a variety of SAE taps, dies, and drills. The range of sizes is limited but covers some of the more popular sizes you may encounter in normal use. Since taps and dies vary in threads per inch (TPI) and diameter, a very large (and expensive) kit is needed to achieve all possible permutations. Here are the exact sizes included in this set:
Dimensions for Taps and Hex Dies:
- 6-32 CNC
- 8-32 CNC
- 10-24 typically closed
- 1/4-20 CNC
- 5/16-18 CNC
- 3/8-16 CNC
- 1/2-13 CNC
- 10-32 Fine
- 16/5-24 NF
- 16/7-20 NF
- 1/8-27 NPT
Sizes for Drills:
Using the Tap and Die Set
Let’s dive into how to use the tap and die set. First, “tapping” refers to cutting or recutting threads into a hole or screw. Anyone who has ever worked on a project involving screws has used a “die” to cut or repair threads on a bolt. Before we can start tapping, we need to determine the number of threads per inch (TPI) on the bolt or screw. Most tap and die systems, including Kobalt, provide a gauge with multiple different “blades” that can be used to measure the TPI of the bolt or screw. This gauge resembles a pocket knife. After determining the TPI of the bolt, we select the appropriate die – in this case, it’s 1/4NF28. The tap and die are tapered to easily fit into the bolt or screw and carefully recut the threads as intended. The Cobalt die is mounted on a special hex wrench that securely holds it, allowing it to rotate and guide it along the cutting path.
As stated earlier, we used the die to hold the threads on a 1/4″ 28 TPI bolt that had cross-threaded. We needed to secure the bolt, and we did so by using a vise, being careful not to further damage the threads. This helps position the bolt in the vise so that it doesn’t catch the desired threads. Carefully align the die so that you don’t tilt downward but stay straight down the shaft. As we began to tighten the bolt back, it started heating up – an inevitable result when rubbing two metals tightly together – more noticeable when using a greater thread distance. We recommend lubricating the die with some cutting oil and keeping it cool during use. Since Kobalt supplies an open-top hex wrench, this can be easily done without removing the die. This also extends the lifespan of the tap and die set. As we threaded the die onto the bolt, we could feel it starting to bind fairly quickly. Every few turns, we had to back the die off slightly to clear the threads and let it cut better. This is to be expected and reminds us of drilling wood with large bits. We knew we were finished when the die moved far enough for the bolt to pass through the top.
Tightening (or in our case, retightening) the nut is just as easy as tapping. If you’re doing this without a matching bolt, you’ll use the gauge to select the right size for the nut or hole you’ll be inserting it into. We knew the nut fit our existing 1/4″ threaded bolt, so we were ready. For those making their own nuts, you may want to use an actual matching bolt to set the size so you don’t have to try and force the gauge onto a worn bolt. Also, if the threads are severely damaged, another solution is to drill out the hole and retap it to a slightly larger bolt size. We inserted the tap into the provided hex wrench by Cobalt and secured it. We then inserted the tap into the nut and began threading it by hand – being careful to keep it straight and aligned with the hole. Like the die, oiling is a must, and we often poured oil to clean out the accumulated dirt from the threads.
In no time, we successfully tapped and tightened our cross-threaded nuts and bolts. As we brought them together, they fit like a glove. We also felt that the Cobalt tools looked ready for the next machining round and didn’t worsen from the wear and tear we experienced. It seems like a set of tools that you can rely on if you treat them with care. The high level of competition and the film case truly make this series less lucrative. However, the tools themselves perform exceptionally well, and we believe they can withstand a lot of wear and tear, although they may not be suitable for use with harder stainless steel due to their construction. In most cases, this is not an issue, and we can recommend this set, especially if you can find it at Lowes.