QUESTIONwhen we talk about nut and bolts, galvanised or stainless steel. tell me grade2 and grade 5 nut and bolt difference, also it says 13 UNC and 18UNF, what is this, hahaha, i am doing hardware on substation. as we have to give each and every nut bolt washer for the transformer installation.if u know tell me.otherwise its okANSWER

Stainless steel is the material from which the nuts and bolts are manufactured. It is an expensive material Galvanizing is the process that is done on cheap material in order to save cost and where too much expensive materials are not required. Basically there are three grades for hexagonal or square nuts and bolts. Grade 2

Grade 5

Grade 8

The diameter range of all the nuts and bolts for these grades is 0.25 inch to 1.5 inch.

However if more than this dia. Would be required then grade will be changed.

Grade of both nuts and bolts should be the same or if not available then Nut grade should be higher than bolt.

Identification of Grade 2, 5 & 8 Nuts:Grade 2 nuts are not marked

However there are three ways to mark Grade 5 and Grade 8 nuts

Grade 5: With a dot on the face of nut and radial or circumferential mark at 120 degrees. Counterclockwise from the dot A dot at one corner of the nut and radial line at 120 degrees clockwise from the nut. One notch each of the six corners of nutGrade 8: Dot on the face of the nut with a radial of circumferential mark at 60 degrees clockwise from the nut. Dot at one corner of the nut an d a radial line at 60 degrees clockwise from nut Two notches at each of the six cornersNote: As you have inquired about Grade 2 and Grade 5 nuts and bolts only so do not consider grade 8 nuts and bolts as I have written them just for your knowledge. UNC stands for unified coarse

UNF stands for unified fine

These are the categories of threads that are present in nuts or bolts.

Threads may be of any type depending upon their feasibility.

13 UNC or 18 UNF are nothing as alone, there should also be written the class of threads like 2A or 2B along with 13 UNC or 18 UNF