Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 42390 found under Cutting Attachment Pipe And Rod by Ridge Tool Company. The National Stock Number assigned to this part is 3419002297952, and the Federal Supply Class is 3419 Miscellaneous Machine Tools. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 42390.