V-COIL Inserting Tool UN 1.3/8 x 8, 1/2 inch square drive

A wire thread insert inserting tool transfers torque to the coil while it winds into a prepared tapped hole. This VÖLKEL model covers the UN 1.3/8 x 8 thread size only. The mandrel carries the matching thread form, so the insert stays guided during installation. A 1/2 inch square drive shank sits at the rear end. That connector accepts a ratchet, a wrench or a suitable power tool.

Thread repair on UN sizes follows a fixed sequence. The damaged hole is drilled, tapped and cleaned first. A V-COIL wire thread insert is then wound in with the mandrel until it seats. The tool is listed under works standard and supplied as one piece. Because the size range is fixed at UN 1.3/8 x 8, the mandrel pairs with inserts of that same designation.

Wire thread insert inserting tool for UN 1.3/8 x 8 threads

The tool form is a threaded mandrel with a drive shank. The mandrel thread engages the coil of the V-COIL wire thread insert. Rotation is applied from the square drive end. This keeps the driving torque in line with the hole axis. Operators can work by hand with a ratchet or switch to a power tool when several holes are involved.

Mandrel and drive design

Construction combines two working ends. One end is the threaded mandrel matched to UN 1.3/8 x 8. The other end is a 1/2 inch square drive connector. The square drive is a common socket tool interface, so existing ratchets and wrenches can be used. No separate adapter is listed for this item. Each order line covers one piece.

• Tool form: threaded mandrel with drive shank
• Drive connector: 1/2 inch square drive
• Operated with a wrench, ratchet or power tool
• Product type: V-COIL inserting tool
• Package quantity: 1 piece

The single-size layout keeps selection simple. The mandrel is chosen to match the insert designation, not the outside hole diameter. Workshops that service large UN threads usually hold one mandrel per size in use.

Thread system and size coverage

The thread system is UN, with the designation UN 1.3/8 x 8. Eight threads per inch on a 1.3/8 inch nominal diameter places this item in the coarse large-diameter group. The applicable range stated by the manufacturer is UN 1.3/8 x 8. The item is declared to works standard rather than to a public dimensional standard.

• Thread system: UN
• Thread designation: UN 1.3/8 x 8
• Size range: UN 1.3/8 x 8
• Standard: works standard
• Application: UN 1.3/8 x 8 wire thread inserts

Matching the mandrel to the insert designation matters for engagement. A mismatched mandrel can deform the coil during winding. Check the marking on the insert packaging before installation, then confirm the mandrel size.

Common applications

Typical use is thread restoration in large UN tapped holes. Examples include machine housings, hydraulic blocks, flange faces and heavy equipment components where the original thread has stripped. The mandrel is also used when a new UN 1.3/8 x 8 insert is fitted into soft base material to raise load capacity. Maintenance departments, machine shops and mobile repair teams use this class of tool during on-site work. The 1/2 inch square drive suits the torque levels of large-diameter inserts.

Catalog technical data

The manufacturer listing states: one piece V-COIL inserting tool with 1/2 inch drive connector for UN 1.3/8 x 8. Technical features given are product type V-COIL inserting tool, thread system UN, thread designation UN 1.3/8 x 8, standard works standard, drive connector 1/2 inch, size range UN 1.3/8 x 8 and package quantity 1. No further dimensional values are published for this item.

For ordering, specify the thread designation together with the drive connector size. Where a full repair kit is required, the matching tap, drill and inserts are ordered separately, since this line covers the inserting tool alone.