Knurled or just reg bolts?

[TEX-CTD]

so this is the hitch that they guy gave me when i bought the rv, been sitting in the garage with hardware in a bag.

fixing to put in the frame brackets (reese 10 bolt rails) on the new truck (08 F-250) and noticed that i have all except:

2 of the 10 1/2" carriage bolts
2- spacers,may not need these IDK
4- 1/2" nuts
10- 1/2" lock washers
2- tube spacers, may not need
8-1/2" knurled bolts

question is do i have to use the knurled type bolts or can i just use some reg grade 5 or 8 bolts to put the L brackets to the frame of the truck?

thanks

[349]

When I installed my rails I just used Grade 8 1/2" bolts. Its been 5 years and no loosening of the bolts or rails

[TEX-CTD]

thanks thats what i figured but better ask

[Ray,IN]

The knurling is to lock the bolt into the frame and eliminate any clearance, making a solid connection. Reese (any hitch mfgr) must have a good reason to design such a bolt.

[RVhauler]

Grade 8 bolts with lock washers and locktited nuts. 2nd dually done this way. BTW a professional hitch shop did both trucks.

[frankdamp]

In the aeropace business, bolt holes are specifically reamed to give the closest possible contact between the bolt and the thing it's being used to fasten. This minimises the risk of fretting and therefore the chance of fatigue caused bu work hardening.

Also, aerospace inastallations are designed so there's no thread in the hole. They use a washer under the nut to provide the clamping force and to keep the thread outside the hole.

It's probable that the knurled bolt is intended to do the same - make intimate contact with the item it's pushed through.