I donated, sat down with a cup of tea then fainted - fortunately putting the cup down beforehand.
"This is the only time I fainted and I'm lucky to have been queasy only two or three times."
The service was operated by Red Cross, and he recalled his father talking about Red Cross and St John being saviours when he was in a German POW camp, so he saw it as a way of giving back, even at a young age.
Another 'attraction' of being a donor is that is completely egalitarian.
"All of us, conscious of others can donate and each donation is treated as equal, no matter our financial or social status," he says.
This started a habit that has lasted another 398 donations - and counting.
"I understand the advantage of relaxing as the needle is inserted and removed," says Mr Davies.
"I have no recollection of ever feeling uneasy about insertion of the needle and watch it going in so I know when to fully relax.
"Perhaps the biggest pain is completing the exhaustive form each time before donating."
Mr Davies continued to make a handful of donations in Australia, and even once in Toronto in 1975.
"At that time Canada really spoiled their donors with special reclining chairs and great food," he says.
"However, we've certainly caught up, maybe leaped ahead with comfortable chairs to semi recline, a nice choice of drinks and biscuits and recognition of donors milestones.
"I've made donations in various centres throughout the North Island and once soon after the quakes, in Christchurch."
From 2000 most donations have been at the Hamilton Blood Donor Centre. He says it is a great place to donate, perhaps the best in the country, with a friendly, prompt and caring team.
"Donors are made to feel special," he says.
In the last 11 years Mr Davies has been a plasma donor, attending every fortnight when health permits and giving about 300 times.
He doesn't expect to get to 500 donations - but says 'who knows'.
Mr Davies has the most common O+ blood group, which is also the most in demand.
To keep on top of his fortnightly schedule, he uses the new NZ Blood Service phone app which contains his donor ID, future appointments and past donations back to 2004.
It is also how he books future appointments.
"My blood pressure is generally somewhat lower than normal, especially at 8.30am - my normal donation time," he says.
"I understand this relates to my habit of early morning exercise from 6-7am and it is a common, known phenomena for our blood pressure to drop in the two hours following robust exercise.
"My blood pressure drops to a point at which the NZ Blood staff are uncomfortable, so on a couple of occasions I took a brisk walk to bring it back up to an acceptable level.
"We also had the charge doctor note on my records that systolic pressure of 90 is normal."
His philosophy for donating blood is to serve others, and by donating plasma he can maximise this service by donating every two weeks.
Mr Davies believes there are also benefits to himself, such as donating seems likely to improve his body's response to losing blood.
However, he points out, this remains an unproven theory.
"Conversely there is no evidence donating has done me any harm."
Blood Waikato recruitment team leader Steve Dalgety says Mr Davies is an inspiration.
"It is an incredible number of donations - a completely selfless act," he says.
There is no substitute for donated blood and the New Zealand Blood Service has a constant need to recruit new donors.
In the Waikato, more than 500 donors per week are required to keep up with the current demand. Blood only lasts 35 days, so a steady stream of blood donors is needed.
Each whole blood donation helps save the life of up to three people, but the real push is for plasma donors which can be used in many more ways - and donors can give more often.
Hamilton needs 155 plasma donations each week, but during winter that can be hard to achieve.
To become a plasma or platelet donor, you must first become a whole blood donor to check your eligibility.
NZ Blood Service would like you to consider becoming a donor, and if you have not donated in sometime, would appreciate your returned support.
If you are over 18 years of age you can make a difference in your community by helping others and ensuring adequate supplies of blood are available for you as well as your family and others.
For more information on how to help, check www.nzblood.co.nz or phone 0800 GIVE BLOOD.