Anvil 034: Mauser 71/84 horked up barrel band repair

Published on July 14, 2021
Duration: 31:50

This video details the complex process of repairing a damaged barrel band screw on a Mauser 71/84 rifle. The instructor demonstrates how to draw temper, drill, tap, and fabricate a new head for a broken screw, then re-integrates it into the barrel band assembly. The repair involves specialized gunsmithing techniques to restore the clamping function of the barrel band, emphasizing precision and careful material handling.

Quick Summary

Repairing a damaged barrel band screw on a Mauser 71/84 involves drawing temper, drilling, tapping, and fabricating a new head. The specific thread pitch is 255x27 TPI. The band tightens by backing out the screw, which pushes against a stud to clamp the band.

Chapters

  1. 00:05Identifying the Problem: Loose Barrel Band
  2. 00:42Force Diagram Explanation
  3. 01:13How the Barrel Band Screw Works
  4. 03:06Captured Screw Design
  5. 03:42Disassembly for Access
  6. 05:38Accessing the Barrel Band
  7. 06:21The Broken Screw Issue
  8. 07:32Thread Pitch Identification (255x27)
  9. 07:54Repair Strategy: Draw Temper & Re-thread
  10. 08:10Drawing Temper from the Screw
  11. 10:23Drilling the Pilot Hole
  12. 11:40Why Not Use a Lathe?
  13. 13:44Deciding on Replacement Screw Size
  14. 14:25Fabricating a New Screw Head
  15. 16:10Preparing the Hole for Tapping
  16. 17:18Drilling to Tap Drill Size
  17. 20:00Tapping the Hole
  18. 22:40Test Fitting the Repaired Screw
  19. 24:14Troubleshooting Thread Alignment
  20. 26:25Clamping and Squeezing the Assembly
  21. 28:17Forming the New Button Head
  22. 30:16Final Assembly and Tightening
  23. 31:20Maintenance vs. Glamour Work

Frequently Asked Questions

What is the common problem with Mauser 71/84 barrel bands?

The most common issue with Mauser 71/84 barrel bands is a damaged or missing screw head that provides the clamping force. This screw is designed to be captured, preventing loss, but its failure leaves the barrel band loose and non-functional.

How can a broken barrel band screw on a Mauser 71/84 be repaired?

Repair involves drawing the temper from the broken screw, drilling a pilot hole, deepening it, and then tapping a new thread. A new screw head is fabricated by heating and hammering the screw, then cleaning it up on a lathe. Red Loctite is used for permanent reassembly.

What is the thread pitch for the Mauser 71/84 barrel band screw?

The specific thread pitch for the Mauser 71/84 barrel band screw is 255x27 TPI (Threads Per Inch). This is a non-metric thread size that requires specialized tooling for accurate repair or replacement.

How does the Mauser 71/84 barrel band tightening mechanism work?

The mechanism is counter-intuitive: backing out the screw causes the barrel band to tighten. This is because the screw head pushes against a stud, drawing the band together. Pushing the screw in loosens the band.

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