Best Thread Metric Inserts & Repair Kits of 2025

"After discovering stripped bolt holes on my engine, this kit saved the day. It includes various sizes suitable for most machinery needs. The thread inserts have held up well, and I achieved a perfect repair on my first try. It's more affordable than other thread repair sets but performs just as effectively. I'm very satisfied with this purchase."

"I utilized this kit on an engine block, and it worked excellently. Everything needed is included in the box, which is my favorite aspect."

"This set provided all the tools I needed for installing around 40 M6 HELICOIL's, along with the flexibility to tackle different sizes. It's truly a great purchase with excellent value."

"I had stripped out starter bolt holes on my wood splitter. This tool worked like a charm! I rethreaded the holes, and now the starter is secure and the machine runs like a champ."

"I don't typically leave reviews, but this product is fantastic. I repaired a stripped nut in my VW, and the kit made it so much easier. Take your time drilling and it works perfectly."

"Using this kit was straightforward. I added WD-40 for cutting assistance. It includes everything needed, and the quality parts make it a great addition to my toolbox."

"I used this kit to repair two stripped threads on my GX470's belly pan. After 17 years of wear, it worked just like new. The bolt threaded in smoothly, and I saved an hour of labor compared to a shop visit. This kit easily paid for itself."

"This kit was perfect for my aluminum intake manifold repair. It took me only about 20 minutes to fix the problem, and I highly recommend this brand. The tools were sharp and effective, making it a nice addition to my tool chest."

"I purchased this kit for repairing threads in an aluminum block, and I was impressed. The drill bits were sharp, and the tap cut effortlessly. I even used it on steel exhaust later, and it worked flawlessly. For the price, I am truly blown away by the performance of this set."

"I've used heli-coils before, but for this repair, I wanted something more reliable. This kit was well-packed and worked smoothly, providing a near-perfect finish. Although it was a bit pricey, it was definitely worth it for the task at hand."

"I repaired a snapped injector rocker bolt on my 2003 ALH Golf, and it worked like a charm. I took my time drilling out the old bolt, and the results were excellent."

"This product is much stronger than regular helicoils. I had a manifold bolt break on my Jeep, and after using this kit, the new bolt fit perfectly and held tight. I highly recommend it!"

"I am really impressed with the quality of this kit and how sharp the bits and cutting tool are. It was money well spent."

"I purchased this to fix my machine threads, and it performed the task perfectly. It's the best value and the best little tool I've used."

"This kit has saved many projects from disaster. It works well for repairing stripped aluminum threads. Just be sure to keep the tap straight to avoid sloppy threads. I wish it had a tap wrench included for convenience, and the size indexing could use more contrast for easier identification. Overall, having all the necessary sizes in one kit is very convenient, and the tools work well with aluminum."

"I ordered the helicoil set to repair a stripped threaded hole on some machinery. Despite it being my first time, the process went flawlessly after watching some YouTube videos. The hardened steel coil creates threads that are unlikely to strip again. Highly recommended for those with average knowledge of tapping threads."

"This thread repair kit is great for the price. I highly recommend it."

"I found the kit to be as described, but when I tried to use it, the included tap for the 1/4-20 coils was incorrect. The inventory on the lid confirmed it should match, but it didn't. After contacting Stanley Tools, I was told to return the kit for a replacement. The kit's tap should have been Helicoil part# 819-4, but I received part# 570-6."

"This kit was a lifesaver for me! I had a broken trans pan bolt, and after some damage to the threads, I was worried. Using this helicoil kit, I managed to fix it perfectly. The instructions were helpful, and I was able to torque the bolt to spec, and it has been holding for weeks now!"

"I had two stripped threads in my intake manifold, and this product was just what I needed. It worked wonderfully, but I struggled a bit with the installation tool. A T-handle would have made it much easier in tight spots."

"I couldn't believe my luck when I found this kit! After a broken valve cover bolt in a tough spot, I thought I was out of options. This helicoil repair kit saved the day! It created new threads without much hassle. I only wish it came with both tapered and bottoming taps."

"I used this kit to repair stripped transmission mounts on my 1980 Mustang. The kit is complete and definitely worth buying for DIY projects."

"While reinstalling the governor on my Ford 8N tractor, I found that one of the threads in the aluminum mounting plate was stripped. After following the enclosed instructions, I achieved an excellent repair with no oil leaks."

"The kit arrived too late for my immediate needs, but upon comparison with another brand, I found this one to be of better quality and more robust than what I had purchased earlier. I’m sure it will come in handy soon."

"I was thrilled to find this Helicoil kit in a metal storage case, which is a huge bonus for me. The quality seems high, as the drills and taps are made from HSS. Having everything required for a Helicoil repair in one place—drill bit, tap, inserts, and installation tool—is just perfect! The only downside is that the Helicoil inserts come in plastic bags. Once you open the bag, they become loose in the case pocket, so I have to be careful when moving it. However, I don’t think this is worth deducting a star from an otherwise high-quality kit."

"I’ve used helicoil arrangements before but usually bought kits piecemeal. This set has many of the sizes I need, all in a sturdy metal case that fits nicely in my toolbox. The tools feel well-built and show minimal machining marks. My only gripe is the instructions—they’re poorly translated and hard to read. But if you’re familiar with thread repair kits, you probably won’t need them. Overall, I’m very pleased with what I got for the price."

"This kit is incredibly handy and comes with plenty of extras. I can't tell you how often I’ve been in a bind without it. Having this on hand saves me from spending a fortune on new parts due to messed-up threads. The thin metal case is nice, and the price is excellent. I’d definitely recommend getting this kit before you find yourself in a tough spot."