boltsfastenerfasteningthreading
I'm getting replacement for some M5 x 30mm hex bolts. The original ones are fully threaded, i.e. the whole shank length. The ones I can find have an unthreaded portion (i.e. grip) but their overall length matches the original.
I wonder if the unthreaded portion can also fit through the hole because I need the whole length inside the wedge that the bolt goes into. Or does the bolt stop where the threaded portion ends?
You are not going to find this on a shelf, you may get one from the manufacturer of the chair, if you talk nice and beg. Otherwise the chance is slim.
I would get a pan or philister head machine screw with the threaded portion about 1" longer than the screw pictured is over all. Chuck 3/4" of the threaded end in a drill and crank it down. Turn on the drill, keep it steady and run a file to grind off the threads exposed beyond the drill chuck to smooth the shank like the one in the picture. Since the screw is longer than needed and the drill damaged the end of the threads to hold it while it was spinning, cut it off and soften the corners like the original.
The drawing I referred to earlier
I would buy a bolt that includes the part you seek
OK, it might not be exactly what you thought you needed, but it is what everyone else uses to securely locate the bolt end in the frame.
If you have an electric hand drill you can easily make one of these yourself if necessary.
Best Answer
Unthreaded portions of bolts are generally just a tick under their nominal diameter. So an 8mm bolt might be 7.8mm across the shaft.
Typically, the OD of threaded areas is smaller than that, so it might be an issue. You also have the possibility of bottoming out the threads if the screw goes deep into the threaded portion.