Big-Sert Thread Repair Inserts

Oversized Time-Sert inserts for repairing previously failed thread repairs

When Standard Time-Sert Won't Work

Big-Sert inserts are oversized versions of Time-Sert inserts designed for situations where the hole is too large for a standard Time-Sert, such as after a failed Helicoil repair or when the original hole has been damaged beyond standard repair limits.

When you need Big-Sert

  • Failed standard sparkplug thread repairs
  • Oversized or damaged holes
  • Multiple previous repair attempts
  • Severely damaged cylinder head threads

Oversized Solution

Big-Sert provides a larger external diameter for situations where standard repairs won't work

Metric Big-Sert Sizes

Kit SizePart NoInsert Length (mm)Insert Part No
M5x0.8TS55087.60TS55081
10.00TS55083
M6x1.0TS56109.40TS56101
12.00TS56103
M8x1.25TS581211.70TS58121
16.20TS58123
18.00TS58125
M10x1.25TS501214.00TS50121
20.00TS50123
M10x1.5TS501514.00TS50151
20.00TS50153
24.50TS50155
M12x1.5TS52159.00TS52150
16.20TS52151
24.00TS42123
30.00TS52155
M12x1.75TS521712.00TS52170
16.20TS52171
24.00TS52173
30.00TS52175
M12x1.25TS52129.00TS52120
15.00TS52121
17.50TS52122
24.00TS52123
30.00TS52125

Imperial Big-Sert Sizes

Kit SizeThreadPart NoInsert Length (Inches)Insert Part No
10-32UNFTS5032S0.187TS50324
1/4"-20UNCTS54200.38TS54201
0.50TS54203
1/4"-28UNFTS54480.38TS54481
0.50TS54483
5/16"-18UNCTS55610.45TS55611
0.62TS55613
5/16"-24UNFTS55620.45TS55621
0.62TS55623
3/8"-16UNCTS53810.40TS53810
0.52TS53811
0.75TS53813
1.00TS53815
3/8"-24UNFTS53820.52TS53821
0.75TS53823
7/16"-14UNCTS57610.60TS57611
0.87TS57613
1.00TS57615
1.25TS57617
7/16"-20UNFTS57620.60TS57621
0.87TS57623
1/2"-13UNCTS51210.65TS51211
1.00TS51213
1/2"-20UNFTS51220.65TS51221
1.00TS51223

Big-Sert installation process

1

Drill oversized hole

Prepare the damaged area

2

Counterbore

Cut recess for flange

3

Tap the hole

Create new threads

4

Install insert

Thread insert into place

5

Lock insert in place

Secure permanently

Big-Sert vs Time-Sert

External diameter: Larger than standard Time-Sert for oversized or failed repairs.
Internal thread: Matches the original thread size. No special bolts needed.
Applications: Designed for oversized holes and failed standard repairs.
Installation: Uses larger drill bits and taps but follows the same basic steps.

Important Notes

  • • Big-Sert cannot be removed with screw extractors due to locking pin design
  • • If removal is necessary, drill out with the original drill bit
  • • Ensure adequate material thickness around the repair area
  • • Use cutting fluid when drilling and tapping
  • • Clean all metal chips from the work area
  • • Test fit with original bolt before final assembly

Technical Specifications

Kit Contents

  • • Oversized drill bit
  • • Special size tap for threading
  • • Counterbore tool
  • • Insert driver tool
  • • Big-Sert insert(s)
  • • Installation instructions

Material Properties

  • • High-strength steel construction
  • • Same materials as Time-Sert
  • • Corrosion-resistant finish
  • • Temperature resistant to 500°F

Applications

  • • Failed Helicoil repairs
  • • Oversized thread damage
  • • Multiple repair attempts
  • • Automotive and industrial use

Technical Specifications

View detailed engineering data including drill sizes, tap specifications, and counterbore measurements for Big-Sert products.

View Big-Sert Engineering Data

Need Help with Oversized Thread Repairs?

Our technical team can help you determine if Big-Sert is the right solution for your oversized thread repair needs. Contact us with details about your specific application.

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