A turnbuckle takes up slack and applies tension. The body has a right hand thread at one end and a left hand thread at the other, so turning it draws both end fittings in together — or pushes them apart, depending which way you turn. That gives controlled, measurable adjustment in a rigging run, which is what guy wires, bracing, tie rods and stays all need.
**Jaw and jaw** is the most versatile configuration: a clevis jaw at each end connects directly to shackles, eyes, plates and other fittings without an intermediate component. The **jaw and eye** version, TBJE, has a jaw at one end and a closed eye at the other, which suits a permanent connection at one end and an adjustable clevis at the other.
Two details worth noting. Every item is available **with lock nuts**, which prevent the body unwinding under vibration and should be considered standard on anything left in service. And the securing method changes with size: **up to 5/8" a safety bolt is fitted, 3/4" and above use cotter pins**.
Key Features
- Opposed threads: Right hand one end, left hand the other, so turning the body adjusts both ends simultaneously. Marked L/R for identification.
- Jaw both ends: Connects directly to shackles, plates, eyes and fittings without an intermediate component.
- Proof load tested to 2.5 x W.L.L.: Individually proof tested, not merely rated.
- 5:1 minimum breaking load.
- Lock nuts available on all items: Prevent the body unwinding under vibration. Worth specifying on anything left in service.
- Size-dependent securing: Safety bolt up to 5/8", cotter pins from 3/4" upwards.
- Hot dipped galvanised: Full corrosion protection, since turnbuckles are typically installed outdoors and left there.
- CE and UKCA marked with W.L.L., manufacturer's ID, size, traceability code and thread direction.
Technical Specifications
| Product Code |
Size (inches) |
Take Up (inches) |
W.L.L. (t) |
A (mm) |
B (mm) |
D (mm) |
E (mm) |
F (mm) |
C (mm) |
O (mm) |
Weight (kgs) |
| TBJJ6X4 |
1/4 |
4 |
0.23 |
120 |
102 |
11.5 |
15.75 |
7.5 |
200 |
302 |
0.16 |
| TBJJ8X4.5 |
5/16 |
4 1/2 |
0.36 |
138 |
114 |
12.7 |
21.2 |
7.6 |
244 |
358 |
0.24 |
| TBJJ10X6 |
3/8 |
6 |
0.54 |
180 |
152 |
13.7 |
21.5 |
9 |
290 |
442 |
0.71 |
| TBJJ12X6 |
1/2 |
6 |
1 |
190 |
152 |
16 |
26.5 |
11 |
330 |
482 |
0.37 |
| TBJJ12X9 |
1/2 |
9 |
1 |
267 |
229 |
16 |
26.5 |
11 |
406 |
635 |
0.79 |
| TBJJ12X12 |
1/2 |
12 |
1 |
343 |
305 |
16 |
26.5 |
11 |
480 |
785 |
1.09 |
| TBJJ16X6 |
5/8 |
6 |
1.59 |
203 |
152 |
21 |
33 |
14 |
378 |
530 |
1.35 |
| TBJJ16X9 |
5/8 |
9 |
1.59 |
279 |
229 |
21 |
33 |
14 |
454 |
683 |
1.53 |
| TBJJ16X12 |
5/8 |
12 |
1.59 |
355 |
305 |
21 |
33 |
14 |
530 |
835 |
1.79 |
| TBJJ19X6 |
3/4 |
6 |
2.36 |
213 |
152 |
26 |
37.25 |
17.5 |
422 |
574 |
1.99 |
| TBJJ19X9 |
3/4 |
9 |
2.36 |
289 |
229 |
26 |
37.25 |
17.5 |
498 |
727 |
2.48 |
| TBJJ19X12 |
3/4 |
12 |
2.36 |
365 |
305 |
26 |
37.25 |
17.5 |
574 |
879 |
2.68 |
| TBJJ19X18 |
3/4 |
18 |
2.36 |
517 |
451 |
26 |
37.25 |
17.5 |
726 |
1183 |
3.32 |
| TBJJ22X6 |
7/8 |
6 |
3.27 |
222 |
152 |
31 |
42.75 |
20.5 |
466 |
618 |
3.15 |
| TBJJ22X12 |
7/8 |
12 |
3.27 |
374 |
304 |
31 |
42.75 |
20.5 |
618 |
922 |
3.96 |
| TBJJ22X18 |
7/8 |
18 |
3.27 |
527 |
457 |
31 |
42.75 |
20.5 |
770 |
1227 |
5.09 |
| TBJJ25X6 |
1 |
6 |
4.54 |
233 |
152 |
33 |
52 |
24 |
510 |
662 |
4.44 |
| TBJJ25X12 |
1 |
12 |
4.54 |
385 |
305 |
33 |
52 |
24 |
662 |
967 |
5.69 |
| TBJJ25X18 |
1 |
18 |
4.54 |
537 |
457 |
33 |
52 |
24 |
814 |
1271 |
6.74 |
| TBJJ25X24 |
1 |
24 |
4.54 |
690 |
610 |
33 |
52 |
24 |
966 |
1576 |
8.03 |
| TBJJ32X6 |
1 1/4 |
6 |
6.89 |
236 |
152 |
47 |
70.5 |
31 |
598 |
598 |
8.55 |
| TBJJ32X12 |
1 1/4 |
12 |
6.89 |
388 |
305 |
47 |
70.5 |
31 |
750 |
1055 |
10.27 |
| TBJJ32X18 |
1 1/4 |
18 |
6.89 |
541 |
457 |
47 |
70.5 |
31 |
902 |
1359 |
11.99 |
| TBJJ32X24 |
1 1/4 |
24 |
6.89 |
693 |
610 |
47 |
70.5 |
31 |
1054 |
1664 |
13.69 |
| TBJJ38X12 |
1 1/2 |
12 |
9.71 |
403 |
305 |
57 |
70.5 |
37 |
800 |
1105 |
13.56 |
| TBJJ38X18 |
1 1/2 |
18 |
9.71 |
555 |
457 |
57 |
70.5 |
37 |
952 |
1409 |
16.2 |
| TBJJ38X24 |
1 1/2 |
24 |
9.71 |
708 |
610 |
57 |
70.5 |
37 |
1104 |
1714 |
18.88 |
| TBJJ44X18 |
1 3/4 |
18 |
12.7 |
571 |
457 |
66 |
85 |
44 |
1046 |
1503 |
25.15 |
| TBJJ44X24 |
1 3/4 |
24 |
12.7 |
724 |
610 |
66 |
85 |
44 |
1198 |
1808 |
28.06 |
| TBJJ50X24 |
2 |
24 |
16.8 |
740 |
610 |
66.3 |
92 |
54 |
1340 |
1950 |
43.71 |
| TBJJ63X24 |
2 1/2 |
24 |
27.2 |
795 |
610 |
78 |
110.8 |
60.5 |
1478 |
2088 |
81.8 |
| TBJJ70X24 |
2 3/4 |
24 |
34 |
795 |
610 |
93.5 |
104.5 |
73 |
1562 |
2172 |
95.14 |
The jaw/eye TBJE range runs from 3/8" × 6" at £3.78 to £904.49. Working Load Limits by size are in the user information sheet. Note both ranges use UNC threads and imperial sizing.
ASTM F1145-92 | Proof Tested 2.5 x W.L.L. | MBL 5 x W.L.L. | -20 °C to +200 °C
Drop forged high tensile steel, SAE 1035 or SAE 1045, meeting the performance requirements of ASTM F1145-92 (formerly US Fed. Spec. FF-T-791b). Every unit proof load tested to 2.5 times the Working Load Limit; minimum breaking load is five times the W.L.L. UNC threads. Marked with CE, UKCA, W.L.L., manufacturer's identification, size, traceability code and thread direction. Under LOLER 1998, thorough examination by a competent person at intervals not exceeding 12 months where used as a lifting accessory.
Suitable Applications
Turnbuckles are used wherever a rigging run needs tensioning or adjustment: guy wires on masts and towers, structural bracing and tie rods, fencing and barrier tensioning, marine rigging and mooring, tent and marquee structures, and machinery alignment. The jaw/jaw configuration suits runs where both ends connect to shackles or plates; jaw/eye where one end takes a permanent connection. The -20 °C rating extends their use into winter outdoor work, which matters since most turnbuckles live outside.
More About This Product
A turnbuckle is one of the few rigging components whose failure is usually caused by adjustment rather than by load. Overloaded turnbuckles are rare; turnbuckles wound out until almost nothing is threaded into the body are common, and they fail at a fraction of their rating without anyone having exceeded the marked capacity.
The second cause is vibration. A turnbuckle carrying a guy wire on a mast, or bracing on a structure with plant running nearby, will unwind itself over weeks. The tension goes, the brace stops working, and nothing about the installation looks different from the ground.
Thread Engagement, Locking and Reading the Body
Thread engagement is the specification that matters and the one nobody records. Both end fittings must remain substantially threaded into the body — the manufacturer states the minimum, and a turnbuckle wound out towards its limit is carrying its load on a few threads at each end rather than along the full engagement.
The practical rule is that if you need more take-up than the turnbuckle comfortably provides, you need a longer turnbuckle, not a more optimistic reading of this one. Open body straining screws have a genuine advantage here: you can see the engagement, which on a closed body you cannot.
Locking matters on anything left in service. Lock nuts on both ends, tightened against the body, are the standard answer. Wire locking is used where vibration is severe. An unsecured turnbuckle on a vibrating structure is a maintenance item that will need attention long before anyone plans for it.
Reading the body at inspection tells you what has happened to it. A bent body means side loading — the turnbuckle has been used at an angle rather than in straight-line tension, and it is scrap. Distorted jaws or elongated pin holes mean overload. Both are visible if you look, and both are easy to walk past on a structure with fifty turnbuckles on it.
How to Use the Turnbuckle
- Check thread engagement: Both end fittings must remain adequately threaded into the body. Winding a turnbuckle out towards its limit leaves too little thread engaged and is a common cause of failure.
- Fit lock nuts on anything left in service: Vibration unwinds turnbuckles. Lock nuts are available on all items and should be treated as standard for permanent installations.
- Tension progressively: Turn the body steadily rather than forcing it, and check the run as tension comes on.
- Do not use as a lifting accessory unless rated for it: Turnbuckles are primarily rigging and tensioning components. Check the W.L.L. and the application.
- Fit the securing device: Safety bolt up to 5/8", cotter pins from 3/4". These retain the jaw pins.
- Do not modify: Never weld, heat, machine or drill.
Warning: Winding a turnbuckle out too far leaves insufficient thread engaged and is a common cause of failure. Both ends must remain adequately threaded into the body. Fit lock nuts on any installation left in service, since vibration will unwind an unsecured turnbuckle.
Safety Information
- Never exceed the marked Working Load Limit.
- Maintain adequate thread engagement at both ends.
- Fit lock nuts on permanent and semi-permanent installations.
- Fit the correct securing device: safety bolt up to 5/8", cotter pin from 3/4".
- Do not apply side or angular load to the body.
- Withdraw any turnbuckle showing thread damage, jaw distortion, body bending or cracks.
- Never weld, heat treat, machine or repaint.
- Operating range -20 °C to +200 °C.
- Where used as a lifting accessory, thorough examination by a competent person at intervals not exceeding 12 months under LOLER 1998.
Inspection and Maintenance
Check thread engagement first, since that is the most common problem and the easiest to see: both end fittings should be well into the body, not wound out to their limit. Inspect the threads themselves for damage, stretching and corrosion, and the body for bending, which indicates side loading. Examine both jaws for opening and wear at the pin holes, and confirm the pins and their securing devices are present and correct. On galvanised turnbuckles left outdoors for years, check for corrosion where the galvanising has broken down, particularly in the threads where it matters most.
Downloads
Frequently Asked Questions
Q: Jaw/jaw or jaw/eye?
Jaw/jaw connects to shackles, plates and fittings at both ends and is the more versatile. Jaw/eye has a closed eye at one end, which suits a permanent connection there — through a thimbled wire rope eye, for instance — with the adjustable clevis at the other.
Q: Do I need lock nuts?
On anything left in service, yes. Vibration unwinds turnbuckles, and a guy wire or brace that has slackened is doing nothing useful. They are available on all items and cost very little relative to the consequence.
Q: How far can I wind it out?
Not to the limit. Both end fittings must remain adequately threaded into the body, and winding out towards the end of the travel leaves too little engaged. If you need more take-up, use a longer turnbuckle rather than extending this one to its limit.
Q: Why do the securing devices change with size?
Up to 5/8" a safety bolt is used; 3/4" and above take cotter pins. It reflects the pin sizes involved. Worth knowing when ordering spares, since the two are not interchangeable.
Q: Are the threads metric?
No, UNC, and the sizing is imperial throughout: 1/4" through 2". Worth noting if the rest of your rigging is metric.
