[tonysteve66]

I've been replacing the broken railing (stairs spindles) .. 3 of them are in very bad condition..I have remove the all of them and installed new ones.. but one of them is bit of shacking ..not fit..
May be i would cut it wrong or more then necessary.. but what can i do stop it from shacking..?

 

[Steve Neul]

Can you post a picture so we can see how the joint was done?

 

[TimPa]

much depends on the joinery type - dowel, morise and tenon? assuming that the spindle is "inside" some sort of pocket, maybe get some thin tapered wood and drive in beside the spindle, then cut it off flush. some glue will help.