Stelpipe Bolts (Groutable Rockbolts)

Nominal 5/8" and 3/4" sizes

Dimensions3/4" (19 mm) Stelpipe1" (25 mm) Stelpipe
Body Diameter E0.68" (17.3 mm)0.92" (23.4 mm)
Grout Hole Diameter F0.34" (8.6 mm)0.40" (10.2 mm)
Thread Size (left & right) I3/4" - 10 UNC1" - 8 UNC
Roll Threading 
Thread Size / Type
Pitch DiameterMajor Diameter
3/4" - 10 UNC0.6773" to 0.6832"
(17.20 mm to 17.35 mm)
0.7353" to 0.7482"
(18.68 mm to 19.00 mm)
1" - 8 UNC0.9100" to 0.9168"
(32.11 mm to 23.29 mm)
0.9830" to 0.9980"
(24.97 mm to 25.35 mm)

Standard UNC 2A Values
Left Hand (LH) & Right Hand (RH) threads available

 

Technical Data3/4" (19 mm) Stelpipe1" (25 mm) Stelpipe
Steel Grade1022M
Minimum Tensile Strength27,000 lbs
(120 kN)
50,000 lbs
(222 kN)
Recommended Hole Diameter1-1/4" to 1-3/8"
(31.8 mm to 35 mm)
1-3/4"
(44.5 mm)
Recommended Expansion ShellFrazer & Jones Model
3/4" x F 1/4" with bail center hole
Frazer & Jones Model
1" x F9F with bail center hole
Ultimate Axial Strain15% typical

Specification for the tube bolt steel is selected by Stelpipe's metallurgical department