5/16" jam nut on air cylinder question

[DaveInFloweryBranchGA]

While I was ordering some stuff and asking questions about my Star Luber sizer, I was advised by their tech support guy I should get a 5/16" Fine Thread jam nut to lock the aluminum pistol (AF107 on their parts diagram) to the air pistol shaft (AF106).

I don't see this jam nut pictured in their diagram and the used setup I received doesn't have this jam nut. I'm wondering if I really need this or is it just a luxury item. I can't seem to find one locally, even checking with local machine shops. So do I need one or is this unecessary?

Thanks

[Dave Bob]

I think it would be better to have it. I have one on mine, but I didn't use magmas setup. I ordered the air cylinder online and it came with the nut. I got two parts from Magma, the aluminum piston AF107 was about $12 and the bolt to hold the hycar washer to the piston AF108 was $0.25 I think. The aluminum piston is just 1" aluminum about 1.1" long drilled and threaded to fit the air cylinders rod. I used a Harbor Freight regulator and the whole setup only cost around $50.

Dave

[The10mmKid]

Dave,
Try an auto parts store. Ford was known for between size fasteners.
I can send you a 5/16-24 if you can't source one. May not be a jam-nut (which is usually thin), but a regular grade-5 plated hex nut. I can surface grind it flatter if the cylinder rod doesn't have the room for a standard thickness nut.

Later.
'da Kid

[DaveInFloweryBranchGA]

Made a couple calls and found one at the Ace Hardware in the next town over. Problem solved. I wonder if the local outfit didn't have one, but the guy helping me just didn't know what it was.