Hobson UNC Hex Bolt, 1" / 2 1/2"

The Hobson UNC hex bolt range has 55 items (Grade 8, zinc): 5/16" to 1", in lengths of 1" to 11". A hex bolt has a hexagonal head and a threaded shank, and is fitted with a nut or screwed into a tapped hole. Grade 8 is high tensile, and corresponds to metric class 10.9.

UNC means Unified National Coarse Thread and TPI means threads per inch. Spanner sizes are the width across flats (A/F), using its grade 5 and 8 column. Pack quantity is shown for each item.

Where this product is used

• Screwing into a tapped hole in a casting, plate or housing where there is no room for a nut
• Fabrication and repair work where the head can be reached with a spanner or socket
• Trailer, rack and frame builds where a replaceable bolted joint is preferred to welding
• Dry-environment assemblies where a zinc plated finish is enough protection
• Heavy-duty assemblies and machine building where a high-strength fastener is wanted
• The 55 items cover diameters from 5/16" to 1" and lengths from 1" to 11", confirm the size against your drawing before ordering

Features

• 55 items: 5/16" to 1", 1" to 11" long
• UNC thread, hex head
• Grade 8, zinc
• Minimum tensile strength for each size, shown for each size
• Zinc plated finish, for indoor and sheltered locations
• Heavy-duty Grade 8 alloy steel

Key specifications

Choosing the right option

Choose the thread form first: the bolt and its nut must match in thread form, diameter and pitch. Sizes are nominal diameters in inches; compare the threads per inch shown for each item with your nut. Length is measured from under the head to the end of the bolt, so choose size and length together. Spanner size is the width across flats of the head and nut.

These hex bolts are zinc plated, which means a thin electroplated layer of zinc over the steel. That is enough for dry, indoor or sheltered use; it is generally not recommended for external applications and is not suitable for treated pine. Keep zinc plated parts for the dry side of the job, and use hot dip galvanised or 316 stainless where moisture, weather or salt air are involved.

The thread is UNC (Unified National Coarse), the general-purpose inch thread. Use it with UNC nuts and tapped holes only. For load-critical, structural or lifting joints, confirm the fastener against the engineer's specification. Fasteners are not lifting rated unless marked.

Related bolts: Hobson UNC Hex Bolt, Grade 8, Zinc, 1/4" to 1" x 1/2" to 10", Hobson UNC Hex Bolt, Grade 8, Plain, 1/4" to 2" x 1/2" to 20" and Hobson UNC Hex Bolt, Grade 8, Zinc Plated, 1/4" to 1" x 1/2" to 14".