Everyone has experienced a stripped bolt or nut. It can leave you feeling helpless – unless you have a good tap and die set handy. Kobalt introduced its 46-piece Tap and Die Set to take away that dilemma and provide you with the tools necessary to fix that nut or bolt right up. Of course, you can also use a good tap and die set to take a bare piece of steel rod and turn it into a threaded one. For most, however, you’ll use this to fix a bad bolt, nut, or threaded socket – and those are the tasks for which this level of set is best suited.
Kobalt SAE Tap and Die Set Build Quality
The kit comes complete with a Kobalt blue case that latches closed and has integrated tiers for the drill bits. The case isn’t very robust, nor is it confidence-inspiring. In our kit, two of the retaining pieces for the tiers were either broken off or in the process of breaking, which scattered several of the drill bits and taps throughout the interior. In addition, there are also molded inserts for the wrenches and hex dies. These are very thin and cheap, and in fact arrived already broken in several areas. From what we can tell, if your kit isn’t broken when you buy it, it will only be a matter of time until even minor handling will tear it up – a good blow mold case would have been a better choice for this tool set. The case also doesn’t stand on end for storage, but must be laid flat. This is one area where Kobalt can spend a little more money, especially given the competition in this area.
Contents
The Kobalt 46-piece Tap, Die and Drill kit comes with an assortment of SAE taps, dies and drill bits. The size arrangement is limited, but does indeed hit some of the more popular sizes you are likely to encounter in normal use. Since taps and dies vary in both the teeth per inch (TPI) as well as diameter, it would take a very large (and expensive) kit to hit all of the possible permutations. Here are the specific sizes included with this set:
Tap & Hex Die Sizes:
- 6-32 NC
- 8-32 NC
- 10-24 NC
- 1/4-20 NC
- 5/16-18 NC
- 3/8-16 NC
- 1/2-13 NC
- 10-32 NF
- 1/4-28 NF
- 5/16-24 NF
- 3/8-24 NF
- 7/16-20 NF
- 1/2-20 NF
- 1/8-27 NPT
Drill Bit Sizes:
- #36
- #29
- #25
- #7
- F
- 5/16
- 27/64
- #21
- #3
- 21-64
- 25/64
- 29/64
Using a Tap and Die Set
Since we like to educate as well as inform, let’s jump into actually using the tap and die set. First off, “tapping” is when you cut, or recut threads into a hole or nut. Anyone who has worked on You use a “die” to cut or repair threads onto a bolt. Before we could start spinning away, we first had to determine the number of threads per inch (TPI) in either the bolt or the nut. Most tap and die systems, and Kobalt is no exception, include a gauge that has a number of different “blades” which can be used to calculate the TPI of a bolt or nut. It looks a little like a small pocket knife. After determining the TPI of a bolt, we selected the die that corresponded to it – in this case, the 1/4NF28. Both taps and dies are tapered so that they can ease into a bolt or nut and gently re-carve the threads as they were intended. The Kobalt die fit into the special wrench that held it fast, giving it leverage to spin it around and guide it on its cutting path.
As we indicated, we used the die to fix the threads on a 1/4-inch 28 TPI bolt that had become cross-threaded. We needed to secure the bolt, and accomplished this by using a vice, taking care to not further damage the threads. It helps to position the bolt in the vice such that it is not grabbing onto any threads you intend to use. Carefully align the die so that you don’t go down on an angle, but straight down the bolt. When we began to rethread the bolt it started to heat up – something that is inevitable when tightly rubbing two metals together – and more apparently when you engage in longer thread distances. We recommend you use a little cutting oil to lubricate the die and keep it cool during use. Since the wrench provided by Kobalt has an open top, this is pretty easy to do without having to remove the die. This also extends the life of your tap and die set. As we threaded the die down onto the bolt we could feel it quickly begin to catch. Every few turns we had to back the die out a bit to clear the threads and allow it to cut better. This was expected and reminded us of drilling into wood with a large bit. Once the die made it far enough down that the bolt stuck through the top we knew we were done.
Using a tap to thread (or re-thread in our case) a nut was just as easy. If doing this apart from a matching bolt you would use the gauge to select the correct size for the nut or hole you wanted to thread. We knew the nut was matching our existing 1/4-inch threaded bolt so we were all set. For those doing a nut on its own, you would want to use the actual matching bolt to set the size, keeping you from needing to try and muscle the gauge into a worn out bolt. Also, if the threads are completely damaged, the other solution is to drill out the hole and re-tap for a slightly larger bolt size. We placed our tap into the Kobalt-provided wrench and secured it. We then placed the tap into the nut and began turning it down by hand – being cautious to keep it perfectly straight to the hole. As with using a die, adding oil is a must and we backed it out frequently to get rid of debris that built up in the threads.
Conclusion
In no time we had tapped and died our cross-threaded nut and bolt. Putting them together we found that they fit like a glove. We also felt that the Kobalt tools looked ready to go another round and were no worse for the wear we had put them through. These seemed like a set of tools you can get a lot of use out of if you treat them with care. The vast amount of competition and a flimsy case does put this set at a disadvantage. However, the tools themselves performed admirably and we felt they would stand up to much wear and tear, though we feel they might not be suitable for use on harder stainless steel due to their construction. For most, this won’t be an issue and we can recommend this set, especially if you can find it on sale at Lowes.
