I can't loosen or tighten again my double slotted locking nut, what do you recommend?

Question

Dear sir 

I only have a question if you could help I have an oxygen compressor whose suction and delivery valves use the double slotted nut

and to refurbish them I need to loosen and tight the nut which is always has a problem and i can't done it as it stuck in the middle and can't loosen it or tight it again 

note that the bolt is made of Martensitic stainless steel 

so the question is :- 

is this nut can be reused or it is used only for one time?

is there a procedure to loosen it and tight it again?

is there a special tool for it?

thanks in advance

Best Regards  

Answer:

First of all: auto-lok nuts are made to be re-used minimum 15 times and keep as much their initial torque, which makes them very appropiate to be re-used a lot of times.

there is no specific tool required to tighten or loosen an auto-lok nut.  although out of experience, the fixture might sit tight and you really need to use some force.
however if you tried this an you simply can't get any movement into the thing, there might be different causes:

The Auto-lok nut was wrongly specified by the company using the item.
1) wrong choice of material:

when you have a bolt and nut, the nut should always have a weaker class, otherways it will cut into the male threads after a while, which makes the fastener sit fixed

2) no use of wax:

if the stainless steel nut was a blank one without the special threatment against anti-seizing (anti-grip) then people might forget when putting the nut back on to use wax.  after a while the stainless steel nut will remain fixed on the stainless steel bolt.

3) the bolt has been bended:

off course then you'll have the issue of the nut starting to cut into the male material and after a while it remains fixed.

hope above answers help you

but I think it's topic 2

read also: https://anemo.eu/why-auto-lok-nuts-used-fasten-compressor-valves