A clamp type coupling has an axial slot partially cutting the coupling in
half. Two hardened bolts clamp the shaft between these halves by
compressing the slot. Contact between the shaft and coupling is over a wide
area.
With the common setscrew coupling, a relatively small cup-tipped setscrew
bites into a small dimple in the side of the shaft. The area of engagement
is small, and the stress on the screw and the dimple high. Not a very
secure arrangement. hence the common advise to add a hose clamp on the
shaft just forward of the stuffing box to prevent the shaft departing the
boat if the setscrew comes adrift.
Mark Richter, M.E., M/V Winnie the Pooh
P.S. I haven't been very active on the list lately due to starting a new
job. I'm the engineer/estimator for a new commercial construction company
here in Ortona. We do mostly flood control structures for the South Florida
Water Management District. But I told the boss that I need the summer off
for crusing, so don't worry that I may be swallowing the anchor!
A clamp type coupling has an axial slot partially cutting the coupling in
half. Two hardened bolts clamp the shaft between these halves by
compressing the slot. Contact between the shaft and coupling is over a wide
area.
With the common setscrew coupling, a relatively small cup-tipped setscrew
bites into a small dimple in the side of the shaft. The area of engagement
is small, and the stress on the screw and the dimple high. Not a very
secure arrangement. hence the common advise to add a hose clamp on the
shaft just forward of the stuffing box to prevent the shaft departing the
boat if the setscrew comes adrift.
Mark Richter, M.E., M/V Winnie the Pooh
P.S. I haven't been very active on the list lately due to starting a new
job. I'm the engineer/estimator for a new commercial construction company
here in Ortona. We do mostly flood control structures for the South Florida
Water Management District. But I told the boss that I need the summer off
for crusing, so don't worry that I may be swallowing the anchor!
