Suggested Methods of Mounting
Free-Flex® Pivots

For most applications, Riverhawk recommends orientation of the pivot to operate with a Vc
load condition. Vc load is defined as a pure radial load located 90° from the clearance slots,
which will tend to place the flexures in compression. Additional details regarding the effect ofvarious kinds of loading on the performance of the pivot may be obtained from Riverhawk, but
are outlined in our Flexural Pivot Engineering Data brochure.
The attached pages will show various methods of pivot mounting. The first seven methods areapplicable to the standard Free-Flex® pivots available from stock.
The remaining methods of mounting shown are not applicable to stock pivots, but can beaccommodated through special order pivots upon request. Contact Riverhawk Company or
your nearest Riverhawk Company Free-Flex® Pivot distributor for a review of your special
mounting needs.

Page 1

Screw Clamp
Hole Diameter is to be 0.0005 to 0.0015 inch larger than the pivot
diameter.
When vibration is anticipated, standard-locking methods should be
used on the clamping screw.
Clamp stresses may be reduced by drilling and slotting as shown by
dotted outline.

Spring Clamp
Suitable for low torque requirements.
Optimum diameter of the hole is a function of the material used andthe pivot torsional spring rate. Clamping force must be just highenough to prevent rotational slippage of the pivot without distorting
the pivot.
Clamp slot must be spread for pivot insertion. Caution must be used
to prevent permanent deformation of the clamp during spreading

Set Screw
Hole diameter to be 0.0005 to 0.0015 inch larger than the pivot
diameter.
Cup point set screws are recommended.
Use caution when tightening set screw to not crush or distort pivot
When vibrations are anticipated, standard screw locking methods
should be used on the set screw.

Page 2

Radial Pin

Axial Pin

Drill Depth
Not to Exceed 75%of Pivot Section
Length L

L

Hole diameter to be 0.0005 to 0.0015 inch larger than pivot diameter.
Recommend pin hole be drilled at assembly using drill guide bushing
Centerline of pin hole should not break through to pivot I.D. or cut into any
portion of the springs. This can be accomplished by locating holes 45° fromflexures in the heavy wall of the pivot as shown.

Page 3

Shrink or Press Fit
Mounting Hole
Retainer Cup

No Pressing
Force on ThisEndPress

Split Cups

American Standard shrink fit tolerances may be used.
Pivot can be soaked in dry ice without damage.
Mating part should be quenched rapidly after assembly to avoid
overheating of pivot.
Pivot temperature should not exceed 800°F at any time duringassembly
For press fit installations, special tools are required to avoid
shearing off of outer sleeve or damaging flexures.

Dowel Pin
Hole diameter to be 0.0005 to 0.0015 inch larger than pivot
diameter.
Drill and ream dowel pin hole at time of assembly
Insure the pin, drill and reamer do not touch flexures at any time.

Page 4

Non-Standard Pivot Installations

Tapped Hole
Mounting Hole to be 0.001 to 0.003 inch larger than pivot diameter.
The larger clearances are applicable to the larger pivot sizes.
The screw length must be controlled to prevent interference with theflexures.

Drill Point
Hole diameter to be 0.0005 to 0.0015 inch larger than pivot
diameter.
The drill point should be standard 120° included angle
Use caution when tightening set screw to prevent distortion orcollapse of the pivot

Page 5

Non-Standard Pivot Installations (con’t)
Key Way
Hole diameter to be 0.0005 to 0.0015 inch larger than pivot
diameter.
Recommended key slot dimensions will be supplied when complete
details of requirement are identified.

Flats
Hole diameter to be 0.0005 to 0.0015 inch larger than pivot
diameter.
Cup point set screws are recommended.
Use caution when tightening set screw to prevent distortion orcollapse of the pivot.
When vibrations are anticipated, standard screw locking methods
should be used on the set screw.

Page 6