Planning and Dimensional
Information

4 Ft. - 6 In. Diameter, Three Quarter Turn Series, Spiral Stair

Stock Number: USS46-10-3QT
Stair Diameter: 4' - 6" (137.16cm)
Minimum Opening: 58" x 58" (142.24cm x 142.24cm)
Outside Radius: 27" (68.58cm)
Inside Radius: 5" (12.7cm)
Stringer Width, Outer: 9 - 3/4' (24.8cm)
Stringer Width, Inner: 5" (12.7cm)
Stringer Thickness: 1 - 1/2" (38.1 mm)
Tread Width at Outer Stringer: 12 -1/2" (31.75cm)
Tread Width at Inner Stringer: 4-1/2" (11.43cm)
Tread Thickness: 1 - 1/2" (31.75mm)
Tread Passageway: 19" (48.26cm)
Handrail Width: 2 -1/2" (6.35cm) - Opt. 3 - 1/2" (8.09cm) or 1- 1/2" (3.81cm)
Handrail Thickness: 1 - 1/2" (38.1 mm)
Baluster Spacing: Approx. 6" (15.24cm), Opt. 4' (10.16cm), or alternating 2", 3",2"
Turn per Inch of Rise: 2.857 Degrees
Rise per Degree of Turn: 0.35" (8.89mm)
Floor to Floor   Risers Degrees of Turn
74" to 82" (187.96cm to 208.28cm) 9 188 to 208 Degrees
>82" to 90" (208.28cm to 228.60cm) 10 208 to 231 Degrees
>90" to 98" (228.60cm to 248.92cm) 11 231 to 255 Degrees
>98" to 106" (248.92cm to 269.24cm) 12 255 to 278 Degrees
>106" to 114" (269.24cm to 289.56cm) 13 278 to 301 Degrees
>114" to 122" (289.56cm to 309.88cm) 14 301 to 324 Degrees
>122" to 130" (309.88cm to 330.20cm) 15 324 to 347 Degrees
Tread Capacity
lbs. / kgs.
1051 / 477 Stair Capacity
lbs. / kgs.
@ 114" Ht.
1752 / 795

Specifications for heights up to 190" (4.83m) are available upon request.