Set of D nut fittings with m8 (8mm) threads
 
D nuts can be used in D.I.Y & upholstery for fitting m8 (8mm) threaded legs to sofas, footstools, armchairs & beds etc.  
 
D nuts do the same job as t nuts with the added benefit of screw holes so the fitting can be screwed into wooden frames to ensure they do not come loose.  Where access to the inside of the furniture frame is not possible, d nuts can be fitted to the underside of the frame providing they are fitted flat and held in securely using 20mm or longer wood screws. The ideal fitting method however is on the opposite side of the frame to where the leg is in contact with, please see pics 3 and 4 of examples. 
 
Please note that d nuts must be fitted securely by the user or tradesperson to function perfectly. It is the responsibility of the buyer to ensure they are fitted properly.