AutoTight® by Commins
Manufacturing, Inc.
The Continuous Rod Holdown System

Table 1a: AutoTight® Holdown System
Allowable Rod Load Capacities¹, 2003 IBC
Nominal   Rod  2,3,
Diameter     Allowable Load Per
(inches) Model Dia. & Thread5 IBC 20034 1997 UBC6 1/8" Defl.7
ASTM A307 Grade A Steel Rod2  
 3/8 R3 3/8"- 18 NC 2,209 2,945 1/8" defl
 1/2 R4 1/2"-13 NC 3,928 5,237 Limit
 5/8 R5 5/8"-11 NC 6,130 8,173 not 
 3/4 R6 3/4"-10 NC 8,836 11,781 limiting
 7/8 R7 7/8"-9 NC 12,026 16,035  
1    R8 1" - 8 NC 15,708 20,944 Use 
1 1/8 R9 1-1/8" -7 NC 19,880 26,507 IBC, CBC
1 1/4 R10  1-1/4" -7 NC 24,540 32,720 or UBC 
1 3/8 R11 1-3/8" - 6 NC 29,698 39,597  
1 1/2 R12  1-1/2" - 6 NC 35,343 47,124 Capacity
1 3/4 R14 1-3/4"-5 NC 48,106 64,141  
ASTM A197 B7 (125ksi) High Strength Rod3  
 3/4 R6HS 3/4"-10 NC 18,408 24,544 17,677
 7/8 R7HS 7/8"-9 NC 25,054 33,405 24,106
1    R8HS 1" - 8 NC 32,725 43,633 31,739
1 1/8 R9HS 1-1/8" -7 NC 41,417 55,223 40,176
1 1/4 R10HS 1-1/4" -7 NC 51,125 68,167 49,594
1 3/8 R11HS 1-3/8" - 6 NC 61,871 82,495 60,117
1 1/2 R12HS 1-1/2" - 6 NC 73,631 98,175 71,425
1 3/4 R14HS 1-3/4"-5 NC 100,221 133,628 97,219


1. Allowable Load Capacitates are in Pounds force (lbf). For SI: 1 inch = 25.4mm., 1 lbf = 4.45N., 1 psi = 6.89 kPa.
2. Standard Strength Rod, with the Prefix "R" conforms to ASTM A307 Grade A Steel, Fu = 60,000 psi. Ft = 20,000 psi
3. High strength rod, denoted by the letter prefix "R" and suffix "HS", conforms to ASTM A193-B7. Fu = 125,000 PSI
4. IBC Rod Tensile value (Allowable Load) calculated from area (Nom. Diameter) X Ft, Ft = 1/3 Fu (AISC 4-3, 9th Ed.)
5. Fastener Standards, Industrial Fasteners Institute, Sixth Edition, Page A30
6. Per 1997 UBC-1612.3.2, Includes 1/3 seismic increase. Also 2001 CBC.
7. Deflection limit of 1/8" of 10' - 0" Rod. When Applicable.


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AutoTight® Rod Holdown Systems and components are covered by one or more of the following U.S. Patents 6,390,747; 6,585,469; 6,625,945, other patents both foreign and domestic are pending.