How do you hold and work on a Garratt locomotive engine unit ? There aren't many flat areas it can sit on - and you don't want to bend those delicate waggly bits yet you still need to be able to get at the thing from lots of angles. With both hands.
Solution - stuff the motor down the central tube of the reel of solder. It's heavy enough to stay put and the motor/tube interface (as they say in management apparently) is good enough to ensure it remains stable while hot irons, pliers and bad language are brought to bear.