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Frequently Asked Questions

  • How to use RAPI-COIL® Thread Repair Kit ?
    Steps to follow to repair your thread Step - 1 Driling :- First the damage thread is cleared with a standard drill. All kits up to 12 mm include correct drill to be used. No pre-dealing is required to repair a spark plug thread, if using the special Spark Plug Tap. Important – for using flute less Taps bigger holes are required. Step - 2 Tapping :- Special STI (Screw Thread Insert) Taps to be used for cutting the holding thread into the cleared hole. It is recommended to use Suitable branded cutting oil. Note : Thread and pitch of the tap to be checked with the bolt pitch and thread before tapping. Step - 3 Installling the Insert :- Insert is to be placed on Installation tool and the adjustable ring positioned in a way so that the insert tang is centered in the tang slot. Insert to be winded in with a llight downward Pressure until a half turn below the surface. Step - 4 Tang Removal :- After finshing the above, Installation tool is to be lifted up and tang is removed using the Tang Break Tool provided in kits up to 12mm. For bigger sizes and spark Plug Taps, Long Nose Pliers Are used for removing the tang. RESULT- THE NEW REPAIRED THREAD IS STRONGER THEN THE ORIGINAL.
  • Is it necessary to buy kits every time you make a purchase?
    No, but when placing the first order you need to buy a kit as it contains a complete set of tools required for installation of wire inserts. Once you have the complete kit, Later, you can place your order for any spares as per your requirements.
  • Is RAPI-COIL® an Indian brand?
    Yes, RAPI-COIL is an Indian-based company whose manufacturing unit is in Delhi NCR and our offices are in Mahilpalpur, Delhi and soon opening new office in Gurugram.
  • What is the material of the inserts and its grade?
    It is made from the high quality Stainless Steel and its grade is AISI-304 / AISI-316.
  • What is the material of the tap and its grade?
    It is High Speed Steel - M2 grade / HSSE – M35 Grade.
  • Do you provide repairing services or any demo if needed?
    Yes we do provide thread repairing services at your doorstep and have also posted tutorial videos on how to use our Kits on our YouTube channel, Rapi-coil Screw Thread Solutions, and we strive to respond to any question people ask us about using thread repairing inserts.
  • Will the new thread be stronger than the previous one?
    Yes and it will last longer than the previous one.
  • Is it similar to Helicoil?
    We are the Indian manufacturer and supplier of stainless steel wire thread inserts, whereas Helicoil is a foreign based company. A handful of the services we offer are comparable to theirs, yet we differ greatly in many other ways. Our products and services are reasonably priced and of high quality too.
  • Is the tap provided a standard one?
    No, we only offer STI (Screw Thread Inserts) taps for usage with the designated tools.
  • Are they similar to springs in any way?
    No, the thread repair kits and other related tools that we offer have nothing in common with springs and cannot be used as springs.
  • For inspection purposes, how does one accurately measure the insert diameter and length of a wire thread insert before installation?
    The outer diameter (OD) of a wire insert can only be measured in its free state by first measuring the free coil diameter (FCD) and then counting the number of coils from the notch of the tang to the top of the insert determines its length. The free coil diameter and the number of coils per a specific size insert can be found in the manufacturer’s literature, or generally on their website. Note that wire inserts come in five lengths, each a multiple of the diameter (i.e., 1.0, 1.5, 2.0, 2.5 & 3.0 X diameter) — and that length is the installed length of the insert.
  • Can a user use a standard drill and tap combination with wire thread or key-locking inserts?
    The answer is yes for standard drills but no for tap for wire thread inserts. Wire thread inserts require the use of screw thread insert or STI taps only and standard taps cannot be used for installation of a wire thread insert. However standard drills can be used as per Drill size recommendations will shown in the manufacturer’s literature, typically, on their website. For key-locking inserts, standard taps may be used but the drill and tap combination is not standard. A slightly larger drill size must be used so that the keys of the insert can be driven into the parent material.
  • Why use a wire thread insert instead of a key-locking insert?
    Cost is a major factor. Additionally, using a wire thread insert allows for a thread to be repaired maintaining the integrity of the original assembly, meaning that no major additional material is removed from the parent material. When using a key-locking insert, additional material must be drilled out of the parent material to allow for the external threads of the key-locking insert’s outer wall. In cases where space is critical, only a wire insert can be used.

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