Once the shaft is cut to length it is placed in this machine to cut the taper, or tapers, if it is a double taper shaft.
Keyway is Cut Into Shaft
This is the machine used for cutting the key ways.
Spotting The Shaft
After the coupling has been fitted to the shaft the set screw hole needs to be "spotted" into the shaft. The drill press is spotting the shaft in this picture.
Spotting is the creation of a small dimple in the shaft for the head of the set screw to recess into. If your shaft is not spotted for the set screw/screws you have an poorly machined shaft. Some unscrupulous vendors cut this corner.
Here is a prime example of the unscrupulous or sloppy machining. This shaft literally fell out of the coupling and the boat took on water. The coupling was clearly never "fit" correctly to the shaft then the set screws were never spotted to act as a back up. Don't let this happen to you. Insist on a light interference fit and properly spotted set screws.
Properly Spotted Shaft
This is what set screw spotting looks like. You should have dimples in your shaft to accept the set screws..
Facing The Coupling
Now that the shaft and coupling have been "fitted", including the set screw spotting, the flange is mounted to the shaft and placed in the lathe.
When using a split coupling it is very, very important to properly and evenly torque the clamping screws. Not doing this evenly and properly can result in the face being out of round with the shaft. When facing the shaft coupling the machinist will properly torque the clamping nuts so you get a perfect facing with no run out.
Fit & Faced
Just like a brake rotor lathe the face of the coupling is made to rotate perfectly with the shafting.
If you get a new shaft and the face of the coupling does not look, and had not been freshly cut, you've been cheated of a proper machining job. It would be EXTREMELY rare that a coupling would not need to be faced. They need to install it in the lathe head to check it for run out anyway so the 60 seconds it takes to actually cut the face could be a prime indicator the shop never even checked the facing run out.
Help Support This Site
Like what you saw or read in this article? Was it helpful? Could the information save you some money? Would you like to see more articles like this?
If so feel free to donate, support the site, and keep it growing. Please DO NOT feel obligated at all. If you like it and want to make a donation, please do. Your donations help keep the content coming and also help keep it FREE.
Click the DONATE button below if you would like to make a donation via PayPal.