Properly identifying a leaf chain is essential. Leaf chains operate in critical lifting applications using anchors and rollers; improperly identifying a leaf chain can mean that the chain won't fit within the existing anchors and rollers or be properly rated for the application resulting in catastrophic failure. There are four different series of leaf chains, AL, BL, LL, and LH.
- AL – Lighter duty, has a smaller pin diameter, and thinner side plates.
- BL – Heavy-Duty uses a larger pin diameter. More specifically, the pin diameter will always be oversized to the next ANSI chain size up.
- LL – Metric, medium-duty dimensions can come close to AL and sometimes BL series leaf chains dimensionally.
- LH – Directly interchanges with BL series leaf chains; contact us for properly interchanging this series.
Step 1 - Lacing:
The first step is to identify the lacing of the leaf chain. There are seven primary lacing styles; 2X2, 2X3, 3X4, 4X4, 4X6, 6X6, and 8X8 and seven non-standard lacing configurations; 4X5, 5X6, 6X7, 7X8, 8X9, 10X10, and 10X11. If you have a non-standard lacing configuration, there is a high probability that you have a custom leaf chain.
See the below illustrations of the different standard leaf chain lacings:
2X2 Lacing - 
2X3 Lacing - 
3X4 Lacing - 
4X4 Lacing - 
4X6 Lacing - 
6X6 Lacing - 
8X8 Lacing - 
Note: The lacing type is designated by the number of female (pin link) plates X the number of male (interior link) plates.
Step 2 - Measurements:
Next, we need to take down the chain measurements; the illustration below shows the key measurements needed to verify the leaf chain size.
P = Pitch (this is the measurement from the center of one pin to the next)
A = Pin Diameter (this is the diameter of the pin)
B = Plate Thickness (this is the thickness of one singular plate)
C = Plate Height (this is the height of the plate)
D = Pin Length (this is the overall length of the pin when taking this measurement, please make sure it is a chain pin and not a connecting link or anchor pin)
Step 3 - Identification:
After the lacing is figured out and the measurements are taken, it's time to identify the chain and produce a part number accurately. Sometimes, the manufacturer will put what series the chain is on the side plates, greatly simplifying the processes.
Example: AL8 means this is an AL series leaf chain with a 1.00" pitch; then, we need to identify the lacing. If the lacing is 4X4 based on the above illustrations, the part number would be AL844.
When there is no stamping on the side plate, we have to really utilize all of the measurements gathered. The first measurement we'll use is the pitch (P). Refer to the below chart to see the different leaf chain series and their pitch measurement.
Leaf Chain Pitch Chart
|
AL4
|
AL5
|
AL6
|
AL8
|
AL10
|
AL12
|
AL14
|
AL16
|
AL20
|
|
0.500"
|
0.625"
|
0.750"
|
1.000"
|
1.250"
|
1.500"
|
1.750"
|
2.000"
|
2.500"
|
|
BL4
|
BL5
|
BL6
|
BL8
|
BL10
|
BL12
|
BL14
|
BL16
|
BL20
|
|
0.500"
|
0.625"
|
0.750"
|
1.000"
|
1.250"
|
1.500"
|
1.750"
|
2.000"
|
2.500"
|
|
LL08
|
LL10
|
LL12
|
LL16
|
LL20
|
LL24
|
LL28
|
LL32
|
LL40
|
|
12.70mm
|
15.875mm
|
19.05mm
|
25.40mm
|
31.75mm
|
38.10mm
|
44.45mm
|
50.80mm
|
63.50mm
|
|
LH08
|
LH10
|
LH12
|
LH16
|
LH20
|
LH24
|
LH28
|
LH32
|
LH40
|
|
12.70mm
|
15.875mm
|
19.05mm
|
25.40mm
|
31.75mm
|
38.10mm
|
44.45mm
|
50.80mm
|
63.50mm
|
After this, the pitch should narrow the series to one of three selections since BL & LH leaf chains are dimensionally equivalent. Next, we need to identify the pin diameter (A). Refer to the below chart to see the pin diameter of each leaf chain series.
Leaf Chain Series Pin Diameter Chart
|
AL4
|
AL5
|
AL6
|
AL8
|
AL10
|
AL12
|
AL14
|
AL16
|
AL20
|
|
0.156"
|
0.200"
|
0.234"
|
0.312"
|
0.375"
|
0.437"
|
0.498"
|
0.559"
|
0.781"
|
|
BL4
|
BL5
|
BL6
|
BL8
|
BL10
|
BL12
|
BL14
|
BL16
|
BL20
|
|
0.200"
|
0.234"
|
0.312"
|
0.375"
|
0.437"
|
0.500"
|
0.562"
|
0.687"
|
0.938"
|
|
LL08
|
LL10
|
LL12
|
LL16
|
LL20
|
LL24
|
LL28
|
LL32
|
LL40
|
|
4.45mm
|
5.08mm
|
5.72mm
|
8.28mm
|
10.19mm
|
14.63mm
|
15.81mm
|
17.81mm
|
22.89mm
|
|
LH08
|
LH10
|
LH12
|
LH16
|
LH20
|
LH24
|
LH28
|
LH32
|
LH40
|
|
5.08mm
|
5.945mm
|
7.925mm
|
9.525mm
|
11.10mm
|
12.7mm
|
14.275mm
|
17.45mm
|
23.83mm
|
By identifying the pin diameter, there is a clearly distinguishable difference between AL, BL, and LL series leaf chains. For additional confirmation, the plate thickness (B) can be measured and matched to the below chart.
Leaf Chain Series Plate Thickness Chart
|
AL4
|
AL5
|
AL6
|
AL8
|
AL10
|
AL12
|
AL14
|
AL16
|
AL20
|
|
0.059"
|
0.080"
|
0.095"
|
0.128"
|
0.157"
|
0.189"
|
0.220"
|
0.252"
|
0.315"
|
|
BL4
|
BL5
|
BL6
|
BL8
|
BL10
|
BL12
|
BL14
|
BL16
|
BL20
|
|
0.080"
|
0.094"
|
0.125"
|
0.156"
|
0.187"
|
0.219"
|
0.250"
|
0.281"
|
0.391"
|
|
LL08
|
LL10
|
LL12
|
LL16
|
LL20
|
LL24
|
LL28
|
LL32
|
LL40
|
|
1.43mm
|
1.59mm
|
1.79mm
|
3.10mm
|
3.50mm
|
5.10mm
|
6.35mm
|
6.27mm
|
8.25mm
|
|
LH08
|
LH10
|
LH12
|
LH16
|
LH20
|
LH24
|
LH28
|
LH32
|
LH40
|
|
2.032mm
|
2.388mm
|
3.175mm
|
3.962mm
|
4.75mm
|
5.563mm
|
6.35mm
|
7.137mm
|
9.931mm
|
At this point, the leaf chain should be fairly well-defined. An example of using the above charts for identifying a leaf chain through processes of elimination using dimensions is explained below:
- Leaf chain XXXXX needs to be identified and has no letters or numbers on the chain.
- Based on the diagrams above, we identify that the chain has a lacing of 6X6 (six inner plates and six outer plates).
- Using step one, we discover that the chain has a pitch of 1". Knowing this narrows it down to an AL8, BL8/ LH16, or LL16 series according to the pitch chart.
- Next, we measure the pin diameter and get 0.375" or 9.525mm. According to the pin diameter chart, this dimension matches a BL8/ LH16 leaf chain.
- Finally, we measured the plate thickness to confirm our suspicions of it being a BL866 leaf chain. It comes out to 0.156" or 3.962mm, which matches perfectly. We now know that the chain part number is BL866!
Leaf Chain Part Number Defined:
|
|
|
