Australian Tube Products Stem Cap Project

[QuangVuong]

According to old steel bikes, the ATP bars are 19mm internal diameter with a 21.75mm outer diameter. Other bars from the era had an I.D. of 19.5mm, but the same O.D. of ~21.75mm. So to make these plugs suit all types of bars, I've made the plugs slightly tapered, from 19mm to 19.6mm. It should end up a snug fit in the larger diameter bars, but still be able to be pressed tightly into the smaller diameter ATP bars. But happy to get more measurements of other bars from the era.


The ATP stem with a 3D printed stem cap and bar plug in unknown bars.


Don't mind the slight discoloration in the red cap. That was due to a dirty buffing wheel.


Shape is very accurate.


For anyone interested, each pair of bar plugs in red will be $7.50, or $10 for custom colours. Stem caps can still be printed too in red for $7.50, or $10 for custom colours.

Also, I have moved the files onto Thingiverse. The 3D model can be viewed direct from the site if you click on Thingiview of the last image/file. The STL files as well as the Solidworks part file can be downloaded for printing and editing.
ATP Stem Cap
ATP Bar Plugs

[ian theobald]

I have a very old bike which would like to restore and fit original components back on it.
It originaly had this type of handle bar and stem but were replaced with alloy back in the early 80s
Would any one have a set complete or could help out with the rest of bike components
My frame is called a Century and has intricate clover leaf lugs and arrow carvings. Having one of these stems suggests was made in the 50s
it took a while to identify what type of stem was fitted so if any body has some would gladly purchase.thanks ian

[QuangVuong]

Looks like the 3D print stem cap has made it big. Spotted on a stem made by Geoff Duke which was on display at the Handmade Bicycle Show Australia last weekend.

[old steel Bikes]

Quang not sure if anyone had noticed but the bar end plugs in the Hetchins are the ATP ones you produced in gold for me.

IMG_4925 by Danny Brooks, on Flickr

[Tmuir]

On Friday I was contacted by a fellow collector asking me if I knew anyone that could do 3D printing.
I asked him why and he said he had some stems from Australian bikes that had a red cap that pushed into the end of the tube and one of them had shattered and he needed to get a replacement made. This triggered a memory of a post I had read on this forum, so I went back and did some searching and found this thread again by QuangVuong.

A quick look on Thingaverse and I found QuangVuong's STL filed , so downloaded them and printed them on Friday night.
I then gave them an acetone vapor bath and dropped them off at the person's house today.
He was frilled that I had been able to make them and sort it in a couple of days for him when he was expecting it to take months to get sorted.

So just wanted to say a big thank you to QuangVuong for sharing the STL files and share some photos of the process and the end result.

[Imwit]

Nice work Tmuir. No wonder your friend was happy. The chrome on those stems is much better than mine. They look great.

[Tmuir]

I'm pretty sure he said he had rechromed the stems, but it is a amazing what a fresh lot of chrome does for an old tired part.
I must say I was pretty pleased with how the parts looked after their acetone vapor bath as that was the first time I had done that as everything else I have printed being to the correct dimensions was more important than how shiny the part looked.