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BAC-LOK Twin Ferrule Assembly Instructions

BAC-LOK Tube fittings are delivered completely assembled, finger tight. They are ready for immediate use. Disassembly before use can result in dirt or foreign materials getting into the fittings and causing leaks.

BAC-LOK Tube fittings are installed in two easy steps.

1. Insert the tubing into the BAC-LOK Tube fitting until it bottoms in the body.

2. Tighten the nut to finger tight and tighten as follows: Mark the nut to help count the number of turns and tighten 1 1/4 turns. (For sizes 1/8” and 3/16” only – tighten 3/4 turn.)


Re-assembly of BAC-LOK Fittings

BAC-LOK fittings can be assembled and disassembled repeatedly.

1. Fittings shown in disassembled position

2. Insert tubing with pre-set rings in position.

3. Tighten nut by hand. Then rotate nut with wrench one-quarter turn, then snug slightly with wrench.


Pre-assembly of BAC-LOK Fittings

BAC-LOK fittings can be assembled and disassembled repeatedly. Below is information on pre-assembly.

(Please note: The 4th image above shows our special pre-assembly tool.)


Tube O.D. inch UN thread Part number
1/8 5/16-20UN 2BAPAT
3/16 3/8-20UN 3BAPAT
1/4 7/16-20UNF 4BAPAT
5/16 1/2-20UNF 5BAPAT
3/8 9/16-20UNF 6BAPAT
1/2 3/4-20UNEF 8BAPAT
5/8 7/8-20UNEF 10BAPAT
3/4 1-20UNEF 12BAPAT
7/8 1.1/8-20UN 14BAPAT
1 1.5/16-20UN 16BAPAT


Tube O.D. mm UN thread Part number
4 3/8-20UN 4mBAPAT
6 7/16-20UNF 6mBAPAT
8 1/2-20UNF 8mBAPAT
10 5/8-20UNF 10mBAPAT
12 3/4-20UNEF 12mBAPAT
18 1-20UNEF 18mBAPAT
20 11/8-20UN 20mBAPAT
22 11/8-20UN 22mBAPAT
25 15/16-20UN 25mBAPAT

Assembly Instructions

It is recommended that when Bac-Lok fittings are to be Installed, a pre-assembly tool is used, pre-assembling the joint.

The joint is then broken, and assembled with, nut, ferrules & tube attached, insert into the Bac-Lok coupling body until the seating seals firmly. Tighten the nut until a rise in torque is felt, then tighten the nut a further small amount to ensure the assembly is positively sealed.

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