Dome nuts

Figure 12.5. Types of nut (a) wing (b) dome or acorn (c) rivet bush or nut(d) blind (e) flat spring steel fastener and (f) J type fastener...

Standard hexagon nuts are used with bolts to fasten parts together. Where parts require to be removed frequently and hand tightness is sufficient, wing nuts are used. Fig. 13.5(a). If a decorative appearance is required, a dome or acorn nut can be fitted, Fig. 13.5(b). 

Early resin-tensioned bolt systems used a fast-setting resin to provide the tension anchor. The bolter would insert the resin and holt, spin to mix the resin, wait for the resin to cure, and then apply torque to the bolt. The resistance provided by the resin causes the dome on the nut to break allowing the nut to tighten, compressing the strata between the plate and the bottom of the resin gntut. (T-45)... 

---