Hi everyone,

I have tried to contact Zenith via the web form and direct email over the last 2 weeks with no luck so will post here hoping that the community can help.

I will just copy and paste here the email sent to Zenith.  Hopefully someone knows the answers.


I have been planning on scratch building a CH650 for many years and purchased the plans quite a while ago.

I have recently purchased an abandoned 601 build with the intention of scrapping whats been done and using the remaining aluminum and rivets for my build.  I paid what I believed to be a fair price on what I was told was there.  As it turns out, the rivets were not as specified for a Zenith build.   Instead of the A4 and A5 rivers, I have been supplied the following Avex rivets

01661-00414 x 5000,

01661-00512 x 1500,

01661-00516 x 2000,

01661-00613 x 2000.

The specs for these rivets can be found here https://www.dropbox.com/s/n2u66ee6dwpjeyq/Avex_1661_mm-Jayson.pdf?dl=0

I understand that a lot of time and research went into deciding what rivets to use on Zenith Aircraft and wanted to build as per the design but was wondering if there was any chance that I could use these rivets for my build.  (I paid too much for what I purchased if these rivets are unsuitable)

If these are unsuitable could you please advise me how many A4 and A5 rivets are required to build a CH650 from scratch.

I have a very well equipt workshop and have undertaken some challenging projects in the past.

I have built a 4 x 12 foot CNC router, 2x CNC milling machines and a Magnabend Electromagnetic sheet metal folder.  Some pictures here routedstuff.com.au/photos 

Hopefully these tools will make building my aircraft somewhat easier.

I am looking forward to the challenge of scratch building a CH650 .

Thank you for your time, any assistance would be greatly appreciated.

Regards,  Jayson Wallis (Horsham, Australia)

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I will tell you what I beleive but as always this is my opinion only and you will have to do your own further research and decide what works for you. Your specs are in metric where as mine are in english so you should do the conversion and I don't see strength specifications so you should compare them to. We just had a thread here about avex rivets so you might want to take a look at that also. Zenith calls them an A4 and A5, I beleive this is there reference and not industry standard. The rivets I source have the same specifications as the Zenith supplied rivets and I beleive that (within reason) all Avex rivets are created equal. At one time I remember that Zenith stated that they ran QC tests on the rivets they supplied, but I am sure that they also source there rivets from somewhere outside of Zenith. From the information I have gathered over time I beleive you probably have rivets that are the industry standard. Your numbers appear to be proper and closly match the numbers I have. (slight difference with the addition of some zero's which I attribute to being a different manufacturer) My initial impression is that you have acceptable rivets but continue to investigate until you are satisfied. You will find strength specs in the Zenith construction standards. Bear in mind I have no qualifications to be able to give anything other than my opinion here. Dan. 

Thanks Dan,

I appreciate the reply.  I will continue to research and see what I can find.



In the 601-XL construction manual (I'm building a 650 but this is the manual Zenith sent with my plans) on page 9 you will find the shear strengths for the A4 and the A5 blind rivets.
There is a "designated" shear strength (I think this is Zenith's design shear strength) and then Zenith lists their actual shear strength.
A4 - design 110 lbs., actual 130 lbs.
A5 - design 180 lbs., actual 220 lbs.
The table you show has the shear strength in kN. Do the conversion and see if the rivets you have are acceptable.


Thanks Earnie,

0.73kN is roughly 164 lbs

1kN is roughly 224 lbs 

1.5kN is roughly 337 lbs

Theoretically these rivets are ample, however, Theory and my life on the line ...

The rivets I have, have a normal head also, not countersunk ...  too many differences resulted in my question.


I took a quick look at your photogallery. Cool to see a fellow mechmate builder here. I wish I had had the space to build 12 foot table.

Thanks Damon,

It was a great machine to build.  It does take up lots of room though.

I have had to build a second 20 x 40 foot shed as I keep running out of room.

Now I want to build my CH650...  


go to the above web site, it gives a good description of why the flush type rivets are used.

Below is a quote from that article.

"Note: It is obvious that the notch depth in the stem is directly related to the breaking load. The Avex rivets (from Textron’s Avdel division) manufactured in the state of New York and in Brazil do not have the consistency of those manufactured in the UK and should not be used on aircraft. Zenith Aircraft imports Avex rivets from England and makes a systematic test on every lot received, thus guaranteeing the correct quality. The FAA type-certificated ZENITH CH 2000 aircraft uses these same rivets."

This may or may not be true now. This article was from 2004 and Zenith may still import their rivets from the UK I have no knowledge of whether they do or do not, but a lot has changed in the last 15 years. What I do know is that now when a reputable manufacturer publishes shear and tensile strengths especially for aircraft use I am comfortable they will meet those specifications if for no other reason than liability. 

I was mistaken, This was published in 1987, more than thirty years ago and while the content is still relevant I question the accuracy of rivets not being of the same basic quality with todays manufacturing standards.

I guess if I am going to question data I should be able to have fairly definitive data to prove or disprove my beliefs if only for my own piece of mind. I have started gathering materials for a home brew test fixture for some rivet testing which will give at least a comparison of shear strength of the different sources of Avex rivets. I will order some Zenith rivets as well as the rivets I have sourced and can include any other rivets we deem fit. I will also be able to compare the rivets in there original countersunk configuration as well as the domed head we convert them to. It may also be interesting to compare the break off point of the stem of the pulled rivet.

Thanks Russell,

I have read that.  I was just hoping I could get conformation on the rivets I have purchased being acceptable.

Spending another few thousand $ on rivets just wasn't foreseen when I purchased this mess   abandoned project.


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