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T-SM100RR - M100.75 x 0.5 Retaining Ring for Ø100 mm Mounts

Fosco Connect Part No.: T-SM100RR

  • $ 32.00 or

T-SM100RR - M100.75 x 0.5 Retaining Ring for Ø100 mm Mounts

Product Drawing

  • Standard Retaining Rings for Optics Ranging from Ø75 mm to Ø4"
  • Thread M100.75 x 0.5
  • Thickness 0.16" (4.1 mm)
  • Clear Aperture Ø3.80" (Ø96.4 mm)

Our Standard Retaining Rings are manufactured from anodized aluminum and are offered in sizes to match our optic mounts and lens tubes, are designed to maximize the clear aperture while providing sufficient holding force.

Securing an optic using a retaining ring is a stable method for holding the optic since the optic is retained along its entire edge instead of just at a few points. Each retaining ring is machined with two slots for compatibility with our selection of spanner wrenches.

T-M100.75 x 0.5 Threading
Internal Thread External Thread
Min Major Diameter 100.750 mm Max Major Diameter 100.730 mm
Min Pitch Diameter 100.425 mm Min Major Diameter 100.621 mm
Max Pitch Diameter 100.568 mm Max Pitch Diameter 100.405 mm
Min Minor Diameter
(and 83.3% of Thread)
100.209 mm Min Pitch Diameter 100.297 mm
Max Minor Diameter
(and 64.9% of Thread)
100.344 mm Max Minor Diameter 100.188 mm


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