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HELI-COIL Screw Thread Insert STI Tap: Straight Fute, 1 1/4"-7 UNC, H4 / 3B, 4 Flute - General Purpose STI Taps
HELI-COILGeneral Purpose STI Taps

HELI-COIL Screw Thread Insert STI Tap: Straight Fute, 1 1/4"-7 UNC, H4 / 3B, 4 Flute

The HELI-COIL Screw Thread Insert STI Tap is a general-purpose tap with a straight flute design, specified as 1 1/4"-7 UNC, H4 / 3B tolerance, 4 flutes, and a plug chamfer (MPN 8187-20). This tool is engineered for…

SKU 3G-OTH-262032

Also listed as: 818720 · 8187 20

Brand
HELI-COIL
Item
Screw Thread Insert STI Tap: Straight Fute, 1 1/4"-7 UNC, H4 / 3B, 4 Flute
Category
General Purpose STI Taps
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Local availability & support

Delivery
Worldwide DHL shipping from Singapore; 7–14 business days door-to-door for most destinations.
Payment
Invoicing in USD. Bank transfer (SWIFT) and corporate PO accepted.

Technical Specifications

HELI-COIL
Manufacturer Part Number
8187-20
Type
H4 / 3B, Plug Chamfer
Flute
4
UNC
1 1/4"-7

Technical Documents

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HELI-COIL Products
3G Electric (S) Pte. Ltd. — Singapore

Product Description

The HELI-COIL Screw Thread Insert STI Tap is a general-purpose tap with a straight flute design, specified as 1 1/4"-7 UNC, H4 / 3B tolerance, 4 flutes, and a plug chamfer (MPN 8187-20). This tool is engineered for installing HELI-COIL screw thread inserts, ensuring accurate thread formation in industrial applications.

Frequently Asked Questions

What is a HELI-COIL STI tap used for?

A HELI-COIL STI tap cuts threads for installing screw thread inserts in metal parts. It is used in automotive, aerospace, and industrial maintenance to repair stripped threads or add durable threads in softer materials like aluminum.

What are the specifications of the HELI-COIL STI tap 8187-20?

This HELI-COIL STI tap has a 1 1/4"-7 UNC thread, H4 / 3B tolerance, 4 flutes, and a plug chamfer. It is a general-purpose tap designed for straight-flute thread cutting before inserting HELI-COIL inserts.

Where to buy HELI-COIL STI taps worldwide?

3G Electric supplies HELI-COIL STI taps worldwide. We handle full logistics and customs clearance to deliver this 8187-20 tap to your facility. Contact us for pricing and lead time on this and other industrial tooling.

How to select the correct STI tap for a thread repair?

Match the STI tap to the insert size and thread class. For a 1 1/4"-7 UNC insert, use a tap with H4 / 3B tolerance and plug chamfer. Always verify the tap matches the insert manufacturer's recommendations for proper thread engagement.

Used in

Common applications for HELI-COIL
Aerospace engine repair — HELI-COIL STI taps for M12x1.75 metric threads in aluminum alloy components
Automotive transmission rebuild — HELI-COIL STI taps for 7/16-14 UNC threads in cast iron housings
Industrial pump maintenance — HELI-COIL STI taps for #10-32 UNF threads in stainless steel pump bodies
Hydraulic cylinder repair — HELI-COIL STI taps for M6x1 metric threads in steel cylinder heads
General manufacturing — HELI-COIL STI taps for 9/16-18 UNF threads in machinery base plates

HELI-COIL Products

3G Electric supplies HELI-COIL general purpose sti taps. We supply genuine products with in-stock availability on common SKUs, technical documentation, commissioning support, and warranty service — worldwide.

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Cross-referenced by specification & description
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