Hobson KBC88GCM060020 M6 x 20mm Cup Head Bolt & Nut, Class 8.8, Hot Dip Galvanised

The Hobson cup head bolt & nut on this page is a domed-head bolt supplied with its nut, in class 8.8 with a hot dip galvanised finish. It lists 54 items, from M6 x 20mm to M24 x 230mm, each sold as a box or pack of the quantity shown in the table.

A cup head bolt has a smooth domed head with no drive, so it is tightened from the nut end. Cup head bolts are normally made with a square section under the head that holds the bolt in place while the nut turns.

Hobson lists class 8.8 as high tensile, and its class and grade chart pairs class 8.8 with imperial grade 5 (manufacturer-stated).

The table gives the minimum tensile strength for each size from the Hobson guide, which is a head-marking table, so treat it as the class or grade minimum and not a test result for the item (manufacturer-stated).

The product name for this range refers to AS 1390 (manufacturer-stated). No certificate or test result is published on this page.

The pitch shown for each size is the coarse pitch given in the Hobson thread table (manufacturer-stated).

Pack quantity changes with size and length and is shown for each item. Head diameter, neck size and thread length are not stated in the supplier data used for this page, so check them if they matter for your joint.

Where this product is used

• Fixing parts together through a drilled hole, with the nut tightened on the side away from the head
• Joints where a smooth domed head is wanted on the visible face
• Replacing a cup head bolt of the same thread, length and finish

Features

• 54 items: M6 x 20mm to M24 x 230mm
• Domed cup head, supplied with nut
• Class 8.8 strength level
• Hot dip galvanised finish
• Minimum tensile strength for each size from the Hobson guide, shown in the table (manufacturer-stated)
• Pitch shown for each size, from the Hobson thread table (manufacturer-stated)

Common specifications

Key specifications

Selecting the right option

Choose the thread size first, then the length: the bolt has to pass through all the parts, any washer and the nut. The length in the table is the length the supplier gives; for a cup head bolt it is normally measured from under the head to the end of the bolt. Metric sizes are the nominal diameter in millimetres; compare the pitch in the table with your nut. Strength figures are the class or grade minimums in the Hobson guide, not a test result for the item (manufacturer-stated).

Related products

Related cup head bolts: Hobson Cup Head Bolt & Nut, Class 4.6 UTS, Hot Dip Galvanised, M6 to M24, Long Lengths, Hobson Cup Head Bolt & Nut, Class 10.9, Zinc Plated, M10, 40 to 65mm and Hobson Metric Cup Head Bolt & Nut, Grade 4.6, Mild Steel, Galvanised, M6 to M20.