Thread Repair Inserts - Stainless Steel Wire Thread Inserts, Metric M7 to M10, 1D to 3D Lengths, 10 & 20-Piece Packs

These stainless steel thread repair inserts are coiled wire thread inserts that rebuild stripped or worn internal threads in metric sizes M7, M8, M9 and M10. Each option is one size, one pitch and one length, sold in a 10-piece pack (two sizes also come as 20-piece packs).

You drill out the damaged thread, tap the hole with a matching insert tap, then wind the insert in. The finished thread takes the original bolt size again. The supplier lists use on steel, cast iron and aluminum parts, including engine and automotive repairs.

Specifications

• Type: wire (helical coil) thread repair insert
• Material: stainless steel (supplier-listed)
• Sizes: M7 x 1.0, M8 x 1.0, M8 x 1.25, M9 x 1.25, M10 x 1.0, M10 x 1.25, M10 x 1.5
• Lengths: 1D, 1.5D, 2D, 2.5D and 3D (not every length in every size)
• Pack: 10 pieces, or 20 pieces for M8 x 1.25 x 2D and M7 x 1.0 x 1.5D
• Package: inserts only; tap and installation tool are not included

How to Choose Size and Length

Match the bolt: an M8 x 1.25 bolt needs an M8 x 1.25 insert. The length is a multiple of the nominal diameter, so 1D on M8 is 8mm, 1.5D is 12mm, 2D is 16mm and 3D is 24mm. The option names show the length in mm. Longer inserts give more thread engagement, which helps in soft metals like aluminum.

Best For

• Stripped bolt and stud holes in engine and automotive parts
• Repairing threads in aluminum housings, cast iron and steel parts
• Shops that already own the matching insert tap and tool and need refill packs

FAQ

Do I need a special tap?
Yes. Wire thread inserts need an insert (STI) tap made for that insert size, not a standard tap. It is not included.

What does 1.5D mean?
The insert length is 1.5 times the nominal diameter. On an M10 insert, 1.5D is 15mm long.

Are these coarse or fine thread?
Both. M8 x 1.25 and M10 x 1.5 are coarse pitch; M8 x 1.0, M10 x 1.0 and M10 x 1.25 are fine pitch.