5/8 Long Arm Alloy Steel Hex Key is an L-shaped alloy steel hex key for socket-drive work where the exact 5/8 in. width matters. The ASME B18.3 width band is 0.6225-0.6250 in.; the key is held just under nominal so it enters an in-tolerance socket and bears on the flats.
Assembly benches and tool cribs use loose hex keys when individual driver sizes need restocking without a full kit. Long Arm geometry adds reach and leverage; the same width in Short Arm form is the natural compact comparison.
Since 1962, Cold Headers has supplied specialty socket hardware and the hex keys that complete the working system. Review the 5/8 in. width, Long Arm format, short-leg length, and arm length before ordering. Non-catalog hex-key widths and series can be reviewed when a tool crib needs a special driver.
Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.
