Hi' what makes these things popular with most people is that if you have a guard around the PTO shaft, is that its not so easy to put in the locking pin generally a bolt through the hole in the adapter through the PTO shaft, lining up the holes with the guard in place can be frustrating , then there is the safety aspect you cant see if the locking pin is still in place broken or coming off, if you have dexterity problems with your hands quick couplers are great, It would be difficult for me at least to use a standard type, not impossible but not without pain.
The other thing is the pin hole sizes in the simple standard type adapters are not all the same even if the splines match if they are the same size as the hole in the PTO shaft then there is a shear load on the pin or bolt which will fail due to radial back lash or ware on the splines, the holes in your adapter should be slightly bigger than the hole in the PTO shaft, The pins job is only to keep the adapter from coming off, nothing else, these can and do break.
Just another point I never hook up a PTO drive unless its in neutral with the motor stopped.
The other thing is the pin hole sizes in the simple standard type adapters are not all the same even if the splines match if they are the same size as the hole in the PTO shaft then there is a shear load on the pin or bolt which will fail due to radial back lash or ware on the splines, the holes in your adapter should be slightly bigger than the hole in the PTO shaft, The pins job is only to keep the adapter from coming off, nothing else, these can and do break.
Just another point I never hook up a PTO drive unless its in neutral with the motor stopped.