I bough an wooden garden chair table set from a company called vidaXL. There is one step where a half threaded metal stud needs to be screwed in the wood. The other half of the stud is smooth and cylindrical which will move through the groove to facilitate folding of the chair. But the problem is that the other part of the stud is completely smooth and cylindrical with a rounded head (resembling half of a capsule) and no screw driver or wrench works to make it turn. I haven't tried an adjustable wrench but looks like it will not be enough as there will be enough contact surface. However, is there any better tool to turn it and screw that thing firmly into the wood?
The stud gets screwed into the wood piece by using a tool that grips onto the smooth cylindrical part of the stud. That could be any of the following types of tools:
(Pictures from Irwin Tools web site. Other brands of similar tools available too).
In some cases the stud will be relatively soft steel and the tool could mar the smooth surface of the stud. In this case you can try wrapping a strip of leather around the stud and then use the tool to grip the stud through the leather. A strip of rubber can also be used but I have found the strip of leather to work better for this. The right most type of tool shown above can be adjusted so that it can firmly clamp onto the stud and then be used to turn the stud into the wood piece. The other two will gain grip while you hold the handles together.
A pipe spanner (aka. "Channellock" pliers) will work. The only concern is that they can chew up the surface of the stud. Putting cloth/something around the stud will help or just file down the damage afterwards.