Counterbore Adapters


  • Convert a Counterbored Clearance Hole into a Tapped Hole
  • Convert a 1/4" (M6) Clearance Hole into a #8 (M4) Clearance Hole

CBA25E

CBA8E

SD1

Cross Section of RC2 Rail Carrier with Included SD1 Counterbore Adapter Ring

Related Items


Please Wait

Counterbore adapters are used to mate two parts that support different thread standards. The counterbore insert or adapter ring has an outer diameter that matches the standard counterbore diameters used by Thorlabs. The counterbore inserts have a threaded inner bore while the adapter ring has a clearance hole for an #8-32 (M4) screw.


Posted Comments:
No Comments Posted
Back to Top

Threaded Counterbore Adapters

  • Converts a Counterbored Clearance Hole into a Tapped Hole
  • Slotted Edge for Tightening
  • Designed for Slip Fit with Thorlabs' Counterbores

Threaded counterbore adapters are used to convert a counterbore into a threaded hole. A part such as the KM100 Kinematic Mirror Mount features a counterbore that provides imperial and metric compatibility; a cap screw is typically used to fasten the mount to a post. In some instances, it may be necessary to attach the mount to a post with a fixed threaded stud. The counterbore adapter facilitates this mounting option. These adapters feature a slotted edge that enables tightening or removal.

Item # Thread A
(Internal)
Outer Diameter B Use in C-Bore
CBA8E 8-32 0.28" (7.0 mm) #8
CBA25E 1/4"-20 0.40" (10.2 mm) 1/4"
CBA4M M4 x 0.7 0.28" (7.0 mm) M4
CBA6M M6 x 1.0 0.40" (10.2 mm) M6
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
CBA8E Support Documentation
CBA8E8-32 Tapped Counterbore Adapter
$8.74
Lead Time
CBA25E Support Documentation
CBA25E1/4"-20 Tapped Counterbore Adapter
$8.74
Today
+1 Qty Docs Part Number - Metric Price Available
CBA4M Support Documentation
CBA4MM4 x 0.7 Threaded Counterbore Adapter
$8.74
Today
CBA6M Support Documentation
CBA6MM6 x 1.0 Threaded Counterbore Adapter
$8.74
Today
Back to Top

Counterbore Adapter for Cap Screws

SD1 Adapter Ring in RC1 Rail Carrier
 Cross Section of RC2 Rail Carrier with Included SD1 Counterbore Adapter Ring
  • Use an 8-32 or M4 Cap Screw in a 1/4" or M6 Counterbore
  • Package of 10 Adapters

The SD1 stainless steel adapter ring allows an 8-32 or M4 cap screw to be used within the 1/4" or M6 counterbores found on many optomechanical components.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
SD1 Support Documentation
SD11/4" (M6) to #8 (M4) Counterbore Adapter Ring, 10 Pack
$9.21
Today