Toolbox Catch Removal

[AWJD]

I need to remove the Dzus fastener from my A10 toolbox lid before I can re-paint it. It doesn't have an obvious retaining circlip as found on other BSA catches and I'm struggling to work out how the fastener is held in place. There seems to be a bush pressed into the hole in the toolbox lid inside which the fastener is a loose fit but it's not clear what is stopping me from pushing it out the other side of the bush.

There must be a retaining circlip but does anyone know how to dismantle the fastener since I need to re-plate it?

[RichardL]

I believe it is swedged in. See detail 3 on page 417  (or 4 of 14).

http://www.southco.com/static/Literature/D4.en.pdf

Richard L.

[beezermacc]

The aluminium collar has to be lifted up with a screwdriver all around the fastener on the inside of the tool box lid, then the whole thing will press out. Unfortunately this damages the collar but you can get away with it once or twice if you're lucky. Replacements are available.

[RichardL]

If you are plating, I think you will have to replace the collar. I don't believe you can have the dissimilar metals in the plating bath.

Bill, I believe it is a Dzus fastener, as they go back to the '30s.   

"Invented and patented by an American engineer of Ukrainian descent William Dzus (Volodymyr Dzhus) in the early 1930s."

Richard L.

[AWJD]

I believe it is swedged in. See detail 3 on page 417  (or 4 of 14).

http://www.southco.com/static/Literature/D4.en.pdf

Richard L.

Hi Richard.

Many thanks for that - it looks like Detail 4.

beezermacc.

I'll check if the interior collar is Aluminium and, if so, will try to lever it off or I might grind it off. I'm sure that if I can get the steel Dzus stud out I can always hold it back in place with a circlip if necessary. Will try tomorrow.

Many thanks Guys for your help.

 

[TimK]

I had a similar problem when I wanted to repaint the toolbox on my GF, after scouring the internet I found the following item (http://bullantperformance.com.au/dzus-fasteners-2/#!/5-16-Steel-Undercut-Oval-Head-Dzus-Fastener/p/58142558/category=15356077) this dzuz fastener  comes with a plastic retaining washer, as the washer only retains the fastener when it is undone it should last a reasonable time and bullant also sell spare retaining washers.

cheers

Tim

[RichardL]

...it looks like Detail 4.

Yes, I stopped one step too soon in the four-step process.

I like the plastic retainer idea.

Richard L.

[Billybream]

I used a cam lock with key as complete replacement

[AWJD]

Again, many thanks for the helpful suggestions. Later today, I'll try to remove the current fastener. I'm hoping the retainer is made of Aluminium (Aluminum) which should make it easier to remove. I'll post a few pics afterwards to show how I got on.

[AWJD]

The Dzus retainer was made of Aluminium and effectively provides a bush for the stud with a bobbin shaped structure either side of the hole in the toolbox lid to keep it in place. It's not at all clear how the fastener was assembled. My best guess is that the retainer was first pushed on to the stud and then effectively crimped into the retaining recess in the stud. The whole assembly was then inserted into the hole in the toolbox lid and the inside end of the retainer expanded via some compression process to keep it in place.

Problem now is that I will need to machine up a top hat shaped bush to insert into the toolbox hole from the outside. To retain the bush, I might machine a groove in it to take a circlip - the alternative might be to bond it in place. I will then need to machine a groove in the Dzus stud to take another circlip to hold that in place.

So, although this looks like a simple toolbox catch, it's not a very simple job to replace it!

[trevinoz]

I just use nylon washers slightly smaller in I.D., one each side of the lid. A bit difficult to get on but the fastener will never be lost.

[AWJD]

I've now re-engineered the Dzus fastener as shown. I decided to make up a top hat shaped bush machined from Aluminium which is a tight push fit in the hole in the toolbox. The diameter of the rim of the bush is the same as that of the Dzus fastener and therefore effectively provides a washer on the outside of the toolbox similar to the original Dzus retainer. The new bush projects about 2 mm into the toolbox. Without the bush, the Dzus stud would be very loose in the toolbox hole because that is where the original groove in the stud is.

I finished off by machining a new groove in the Dzus stud approximately 3 mm from its head which takes a external circlip to keep it in place. The level of engineering wasn't quite what I originally planned but seems adequate for its purpose. 

[RichardL]

Looks good to me.

[AWJD]

I'm going to try to find a snap ring to replace the circlip which will make it slightly more elegant - not that anyone will see the difference once the lid is shut!