Omega R8 End Mill Holders – Weldon Side-Lock, 10–32 mm

Give your milling cutters a positive hold with Omega R8 End Mill Holders. Designed for straight-shank tools with a Weldon flat, these holders combine side-lock clamping with an R8 spindle connection and a choice of six metric bore sizes.

Which end mill holder do I need for a Bridgeport milling machine? For a machine with an R8 spindle and 7/16″ UNF drawbar, choose an Omega R8 End Mill Holder with a bore that matches your cutter’s shank diameter. Its side-lock design clamps against the Weldon flat, giving the cutter positive mechanical retention for milling work.

• Keep your cutter securely held: The clamping screw engages the Weldon flat to help resist tool rotation and axial movement under cutting load.
• Get the right fit for your tooling: Choose from 10, 12, 16, 20, 25 and 32 mm bores to match the cutters you use for everyday machining.
• Keep regular cutters ready for the next job: Dedicated holders allow frequently used cutters to remain mounted, reducing repeated clamping when changing between tools.
• Choose a holder with specified balance quality: Omega balances this range to G6.3 at 12,000 rpm, providing a documented balance specification for your tooling setup.

Choose your bore size and order from PMI, or send us your cutter’s shank diameter, spindle type and drawbar details for help selecting the correct holder.

Specification	Details
Brand	Omega
Product type	R8 end mill holder
Spindle interface	R8 — Bridgeport type
Drawbar thread	7/16″ UNF
Tool shank compatibility	Straight shank with a Weldon flat
Clamping method	Side-lock screw acting on the tool’s flat
Available bore sizes	10, 12, 16, 20, 25 and 32 mm
Stated balance specification	G6.3 at 12,000 rpm
Sale quantity	One holder in the selected bore size

Compatibility, installation requirements and what is included

• Machine compatibility: For Bridgeport and other milling machines fitted with an R8 spindle and a compatible 7/16″ UNF drawbar.
• Cutter compatibility: Select a holder bore matching the cutter’s shank diameter. The tool must have a suitable Weldon flat positioned for engagement by the clamping screw.
• Correct size selection: Order by the tool’s shank diameter, which may differ from its cutting diameter.
• Installation: Clean the spindle taper, holder bore and cutter shank before assembly. Secure the holder with the drawbar and tighten the clamping screw against the flat using the appropriate instructions and tightening requirements.
• Operating speed: G6.3 at 12,000 rpm is the stated balance specification. Follow the operating limits of the machine, holder and cutting tool.
• Product supplied: One Omega R8 end mill holder in the selected bore size.