Made in Germany, so it has to be metric - right?

Surfer_kris wrote:I would guess that it is not a standard thread.
Have you measure the diameter and pitch?

Thanks Kris, It's probably pretty specific as it has a venturi screen on it. I would be quite happy with just a nut so I could get it running.

Its probably British 1/2 thread pitch ? You may have to either have one made DYS or find a better upper on the Bay for less $E$ and use it for parts .. here is a chart that's a pain to use . https://mdmetric.com/tech/tict.htm

There are many non standard thread pitch listed out there. For example the TD .020 Venturi thread pitch is one that was used on Singer sewing machines.

How about BSC? BSC is a thread system used in bicycle industry. Also known as CEI standard.

Would 5/16" / 24tpi be close? That is 7.94mm in metric, so an M8 nut would not be very loose though. But anyway, if you have a bicycle shop nearby, maybe it would be worth a visit?

https://en.m.wikipedia.org/wiki/British_Standard_Cycle

Try 7 mm fine thread.

Hi Bob, It is M7 fine indeed. That is M7 x 0,75. Below a page out of the French magazine MODEL AVIA of September-October 1968. It's part of a complete article on the Hurrikan. On top of the page, there's a table with the correct threads for each part:



It says after "écrou-filtre" 7mm diameter and 0,75 pitch. The HS standard means "high strength".

What do I win???

You win the eerou fltre - Filter nut............ if I ever find it.  

7mm fine?  Wow I swear I tried it several times.  Maybe my fumple fingers let me down..........again.  I shall go back and try some more.

Thanks Lieven and all.

The worst part is, I know that nut is under some workbench somewhere just begging to be found.

Bob

The worst part is, I know that nut is under some workbench somewhere just begging to be found. wrote:

LOL you gotta hate it when this happens Just to know your not alone i lost my 2/56 tap after just one use , found the 4-40 but the little one is missing in action

getback wrote:  LOL you gotta hate it when this happens Just to know your not alone i lost my 2/56 tap after just one use , found the 4-40 but the little one is missing in action

I always look where it isn't.

Bob's law. Look where it is and you will never find it.

Hayes Fasteners for Murphy’s Law applications.

Love the display Rene, story of my life.

But this is weird, crazy, and ridiculous.  There appears to be no 7mm 1 or .75 pitch fine nut in the universe.  

I went back to the local store and there is a 7mm course nut, but no fine.  Came back home and got on to McMaster-Carr who has everything hardware and found their metric fine nuts go between 8mm and up and 6mm fine and down, but no 7mm.  Thanks Taifun.

I got a couple of 7mm course nuts with the thought of retapping to 7mm fine, but I doubt I have a 7mm fine tap.  A better idea would be to tap out a smaller nut though.

So, guess I will have to put this engine on the scrap heap of life.

Robert.....................

Try ebay? :
https://www.ebay.com/itm/M7x0-75x2mm-Carbon-Steel-Hex-Nuts-Fastener-50pcs-for-Screws-Bolts/351762031357?epid=1174059695&hash=item51e6a6a2fd:g:5uUAAOSwVtZaR2xI

Thanks Kris, but a benefactor might have solved my problem. This forum rocks.......

Bob

If you where closer I could have made one for you.
Still possible if nothing else works out...