[f-AA] Dzus question

['Botijo G' via aeronca]

How do you install the collar that protects the holes when you install a Dzus fastener?
Tks
Rafael
Sent from an NDB

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[Mark Peterson]

There’s a tool, but if you search online there is a hack to use two different bolts,and a proper size socket. From the British Triumph car group. I used it but the results are hardly the quality that your project deserves!


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> On Apr 25, 2026, at 4:19 PM, 'Botijo G' via aeronca <aer...@westmont.edu> wrote:
>
> How do you install the collar that protects the holes when you install a Dzus fastener?

['Botijo G' via aeronca]

Thanks Mark ! Have lots of scraps to practice with
Sent from an NDB

> On Apr 25, 2026, at 6:04 PM, Mark Peterson <mrpet...@msn.com> wrote:
>
> There’s a tool, but if you search online there is a hack to use two different bolts,and a proper size socket. From the British Triumph car group. I used it but the results are hardly the quality that your project deserves!

[Don Harvie]

Rafael,

I didn't use the collars on the Auster when I replaced the Dzus fasteners because after 70 years the holes were quite wallowed out, and the Dzus heads/slots had been butchered by people using a too small screwdriver head. My RH side cowl had already been modified to use what I'm led to believe were Dehavilland Mosquito cowling fasteners, they are stamped with Air Ministry part numbers - so it seems likely they are at least from the WW2 era if not actually from a Mozzie. When it came time to redo my LH cowl Dzus Fasteners, I copied the wartime ones and reproduced them out of (if memory serves) 0.020" stainless.

Photos here:

https://www.austerj4.com/gallery2/main.php/v/Don/Flying/VH-CRR/cowling-dzus/

I made an appropriate tool out of mild steel bar stock I got from Dad. To do this I copied the drawing from what looks like scanned pages out of the Aircraft Spruce Catalog. I've attached the images I have here. (Do Harbour freight sell Lathes & can you try before buy ;-) still?)

For his Chief Dad had fibreglass cowlings that came with the project which are split into top and bottom halves. For the sides along the horizontal split, Dad used the winged quarter-turn fasteners from a Stinson 108 and used Dzus fasteners around the boot cowl/firewall on the top half. These aren't captive as they  need to be completely removed from the holes to lift the top cowl off the engine.

 

HTH,

Don H,

Sydney, Aus

['Botijo G' via aeronca]

Great info! Thank you Sir!

Sent from an NDB

On Apr 25, 2026, at 8:49 PM, Don Harvie <donh...@gmail.com> wrote:



<Dzus tool.jpg>

<Dzus tool1.jpg>

<DzusFastenersDataSheet-D4.en.pdf>

['Botijo G' via aeronca]

It’s only has 8 but want to do them right

Sent from an NDB

On Apr 25, 2026, at 8:49 PM, Don Harvie <donh...@gmail.com> wrote:



<Dzus tool.jpg>

<Dzus tool1.jpg>

<DzusFastenersDataSheet-D4.en.pdf>

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