Thread inserts for parallel pipe threads
A stripped pipe thread in a housing costs more than one in a bracket: the part is usually a cast iron or aluminium body that is not easily replaced. A wire thread insert restores the thread. VÖLKEL carries V-COIL thread inserts of type S, free running, in 1.5 D length, from G 1/8 x 28 to G 1" x 11.
Why the thread holds afterwards
The insert is a coil of stainless wire with a diamond-shaped cross-section. It spreads the load more evenly over the engagement length than a thread cut directly into the soft base material could, and it does not wear the way aluminium or cast iron does with repeated assembly.
What 1.5 D means
Insert length is given as a multiple of the nominal diameter. 1.5 D is the standard length and covers most applications; shorter where the part is shallow, longer in soft materials under high load. The article length of thread inserts: what 1.5 D means works through examples.
Free running, type S
Free running means without a locking coil. The insert adds no extra friction torque on the screw and is the right choice when the aim is to repair or reinforce rather than to lock.
Sequence and packaging
Drill out, cut the receiving thread with the STI tap, wind in the insert with the installation tool, break off the tang. Sizes up to G 1/2 come in packs of 50, the larger ones in packs of 5, and there are refill packs of 5 for existing kits. Complete kits are under thread repair kits, all insert types under wire thread inserts.
All sizes at a glance
12 articles in 2 series. The article number links straight to the tool.
V-COIL Wire thread insert Free running type S
| Threadnominal size | Tapping drillØ in mm | 1.5 D |
|---|---|---|
| G (BSP) 1/8 x 28 | 10 | 0838050 pcs. |
| G (BSP) 1/4 x 19 | 13.6 | 0838150 pcs. |
| G (BSP) 3/8 x 19 | 17.1 | 0838250 pcs. |
| G (BSP) 1/2 x 14 | 21.5 | 0838350 pcs. |
| G (BSP) 5/8 x 14 | 23.4 | 083845 pcs. |
| G (BSP) 3/4 x 14 | 27 | 083855 pcs. |
| G (BSP) 7/8 x 14 | 30.6 | 083865 pcs. |
| G (BSP) 1" x 11 | 33.7 | 083875 pcs. |
V-COIL Wire thread inserts Refill pack Free running type S
| Threadnominal size | Tapping drillØ in mm | 1.5 D |
|---|---|---|
| G (BSP) 1/8 x 28 | 10 | 443805 pcs. |
| G (BSP) 1/4 x 19 | 13.6 | 443815 pcs. |
| G (BSP) 3/8 x 19 | 17.1 | 443825 pcs. |
| G (BSP) 1/2 x 14 | 21.5 | 443835 pcs. |
Tapping drill: drill diameter recommended by VÖLKEL (Technical Information “Tapping drill sizes V-COIL”).
