ROEMHELD Bore Clamps without Centering – Top Flange, B1.4842 (7.8 to 17.7mm Bores)

ROEMHELD Power Workholding,ID & Bore Clamps

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Product Information

ROEMHELD Bore Clamps without Centering – Top Flange, B1.4842 (7.8 to 17.7mm Bores) Part # CLR-4318-221L Carr Lane Mfg.®

3600 psi max

Double Acting

Bore Clamps without Centering provide internal clamping and supporting in one unit, exerting force both radially and downward against a hardened support surface. Unlike Self-Centering Bore Clamps, these clamps do not perform a locating function and will not resist excessive side loads during loading or machining, so supplemental locators are required. The top-flange version shown here allows a low-profile installation using manifold mounting with O-ring ports.

Bore Clamps are particularly suitable for clamping workpieces with small bored or cast holes and a support surface square to the hole axis. This compact design uses an expanding four-segment Clamping Bushing with teeth that penetrate slightly to exert high downward clamping force. These clamps have a pneumatic connection which can be used for continuous positive air-pressure protection in excessive chip conditions.

Bore Clamps without Centering are available in two body sizes, each with a choice of several different Clamping Bushings to cover their range of bore sizes:

Size 1 7.8 to 11.2mm

Size 2 11.3 to 17.7mm

One Clamping Bushing is included with each Mini Bore Clamp and additional sizes or replacements can be ordered separately as a Clamping Set (Clamping Bushing with matching Clamping Bolt and wiper).

Documents

B1.4842

Data Sheet

Clamping Action

Mini Bore Clamps are a combination of a double-acting pull-type cylinder and a four-segment bushing which is pulled by a tapered clamping bolt. This causes the bushing to expand radially by spring force to the bore diameter of the workpiece. The simultaneous axial movement forces the workpiece downward onto the hardened support surface of the housing. Downward clamping force is proportional to operating pressure, while radial force is not dependent on operating pressure.

Design Considerations

These clamps do not perform a locating function and will not resist side loads except by the static-frictional force between the workpiece and support surface, so supplemental locators are required (hole-position accuracy must be within +/-.008"). Clamping force depends on the Clamping Bushing's teeth penetrating slightly and penetration depth will vary depending on the material. Heat treated or hard-coated materials cannot be effectively clamped. The hole to be clamped should not be tapered more than 3°, especially with harder materials (if in doubt, we recommend a clamping test). For best results, air-blast clean the support surface and clamping bushing before every load cycle. In excessive chip conditions, the continous positive air-pressure feature should be used. Clamping Bushings should be replaced after 10,000 clamping cycles.

Mounting & Fluid Supply

Fasten clamp with four socket-head cap screws. A dowel-pin hole is provided on the bottom side of the clamp for accurate location (+/-.002"). For manifold mounting, the mounting surface must be ground flat to ensure proper O-ring sealing.

Two 1/4" BSPP ports, S for clamping, E for unclamping. For optional manifold mounting, use the S and E manifold ports underneath the clamp by unscrewing the sealing plugs and installing two CLR-3000-342-SW O-rings (Size 1) or CLR-3000-343-SW O-rings (size 2). Also install two CLR-810-F Port Plugs in the 1/4" BSPP ports. These clamps also have two 1/8" BSPP ports for air connection – one marked A for using the pneumatic seat check, and another marked L for continuous positive air-pressure protection against chips. Do not use NPT fittings.

Material

Click here for detailed material and finish specifications.

California residents click here for Prop 65 information.

ITEM	MATERIAL	HEAT TREAT	FINISH
Body	Steel	-	-
Piston, workpiece support, clamping bushing and clamping bolt	Steel	Case Hardened	-