ORBO Le Klunker de Acatène

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Twente, the Netherlands
1000041497.jpg


So I decided to enter the ORBO competition this year.
I already started on the frame a while ago. Its my learning project: Learning to: Braze, Mitre/Notch, Use my alignment jig, Roll tubes and Bend tubes.

The project is standing still due to lack of a base for the bending machine or tool.

I ordered a 'post' or stand to work in my shack and with a good working height, so I won't hurt my back and the tubes have good clearance for swinging.
The first post I got from a shop was terrible. Very thin wall thickness and couldn't handle the torque + force.
I sent that one back and I designed one myself.
1000041491.jpg

Long story short: When this post is done and ready to anchor to the floor, I can start bending the CrMoly chainstays and seatstays.


The bike's general direction:

20240915_161501.jpg

First sketch!

20241212_150016.jpg

Headtube, bottom bracket, seat tube brazed together and the shaft is temporarily assembled.

20250105_111230.jpg

Current state. Top tube nearly ready to braze. I want to braze the top tube and chain/seatstays in one go.

Lots of work to do!

I'm planning on 26" wheels. Tires won't be super fat due to the shaft limiting tire clearance.
Ratio 2:1 (like a 44t - 22t regular chain driven bicycle).
A nexus 3 hub will work fine or a single speed.


Link to original topic on Ratrodbikes forum

Name inspiration historic bicycle link

Translation of Acatene:

Adjective​

acatène (plural acatènes)

  1. chainless
 
Last edited:
View attachment 286592

So I decided to enter the ORBO competition this year.
I already started on the frame a while ago. Its my learning project: Learning to: Braze, Mitre/Notch, Use my alignment jig, Roll tubes and Bend tubes.

The project is standing still due to lack of a base for the bending machine or tool.

I ordered a 'post' or stand to work in my shack and with a good working height, so I won't hurt my back and the tubes have good clearance for swinging.
The first post I got from a shop was terrible. Very thin wall thickness and couldn't handle the torque + force.
I sent that one back and I designed one myself.
View attachment 286593
Long story short: When this post is done and ready to anchor to the floor, I can start bending the CrMoly chainstays and seatstays.


The bike's general direction:

View attachment 286594
First sketch!

View attachment 286595
Headtube, bottom bracket, seat tube brazed together and the shaft is temporarily assembled.

View attachment 286596
Current state. Top tube nearly ready to braze. I want to braze the top tube and chain/seatstays in one go.

Lots of work to do!

I'm planning on 26" wheels. Tires won't be super fat due to the shaft limiting tire clearance.
Ratio 2:1 (like a 44t - 22t regular chain driven bicycle).
A nexus 3 hub will work fine or a single speed.


Link to original topic on Ratrodbikes forum
Loving the looks of that. And a unique shat drive to boot. So awesome 👌.

Curious who you bought the frame tooling from. That is a great setup.
 
Loving the looks of that. And a unique shat drive to boot. So awesome 👌.

Curious who you bought the frame tooling from. That is a great setup.

Thanks guys!

@metalchewy in the 'build from scratch' section, I have a topic dedicated to my tooling. Topic "Build a welding JIG first" :thumbsup:

In regards to the tooling:

Almost ready to weld the bending tool 'post' or 'base'. After that I can bend the chainstays and seatstays.

1000041546.jpg

10mm S355 plate. Tube is 102mm round.

1000041549.jpg

Extra rigidity.

1000041551.jpg

Top plate with the 8mm holes for the bending tool.

1000041552.jpg

I could add more strength to the base.
I can also add a handle somewhere on the top.

I can always change things up later.

Currently I have exactly the same tool as the youtube video below. Next best tool according to my market research is 8x more expensive. This seems to do the job for me.
That guy said he is bending 25mm diameter, 1.65mm thick stainless steel. The forces are pretty immense!

 
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I still need to catch up on that thread, very good stuff. I'm going to build my own someday but at this rate it might not be until I retire. 🤣
When you have a jig, you want the rest too (tube notcher, benders etcetera) :thumbsup:
In my workspace of 2 meters by 3 meters, I have to be smart with the space and machines.

I finished the post or base for the bender today! I drilled some holes in the ground for female threaded anchors.

20250117_101053.jpg

I hope that, with large diameter tubing, the large stones will stay put!

20250117_141933.jpg

Lets weld thiss.

1000041616.jpg

Cleaned and preheated all parts.

20250117_142729.jpg

20250117_144357.jpg

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Hello!

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Bender base and shaft fit perfectly!

A lot of work for something that looks so simple.
I can start bending this weekend, nice!
 

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I have the bender. I have some Swag diamond rollers and some swag extenders.

The jig I tried to make didn't turn out as well as I liked. Will look into making a jig similar to yours as soon as I get the chance todo so.

Such cool and impressive work!!!
Thank you metalchewy!
I bought aluminium extrusion profiles from aluxl.nl (Dutch website) and lasercut + milled the rest.
I can email you the dxf-files on email if you are interested. Feel free to decline or send a pm :thumbsup:


In the meantime the bender is fully set up!
I tried my first bends on 15x1.5mm CrMoly steel.

It was cold and misty, so I warmed the tubes and tooling a bit first.

1000041698.jpg

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Marked the tubing!

20250119_113658.jpg

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Pretty large loop.

1000041712.jpg

The large loop doesn't look too bad.

1000041715.jpg

Marking and measuring the next bends.

1000041717.jpg

Both ends will be notched and attached to the seat tube.

20250119_120353.jpg

I did lift the tile (60cm x 40cm x 4cm large) a bit and my wife had to stand on one end. She's not heavy, but it worked!


What do you think about the large loop?
I got to think about the other side and the dropout. It does not look nice if the dropout (shaft to tube connection) is too far apart. Picture sketch below:
1000041734.jpg
 
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Thank you metalchewy!
I bought aluminium extrusion profiles from aluxl.nl (Dutch website) and lasercut + milled the rest.
I can email you the dxf-files on email if you are interested. Feel free to decline or send a pm :thumbsup:


In the meantime the bender is fully set up!
I tried my first bends on 15x1.5mm CrMoly steel.

It was cold and misty, so I warmed the tubes and tooling a bit first.

View attachment 286962
View attachment 286963
View attachment 286964
View attachment 286961
View attachment 286965
View attachment 286966
Marked the tubing!

View attachment 286967
View attachment 286968
View attachment 286969
Pretty large loop.

View attachment 286970
The large loop doesn't look too bad.

View attachment 286971
Marking and measuring the next bends.

View attachment 286972
Both ends will be notched and attached to the seat tube.

View attachment 286973
I did lift the tile (60cm x 40cm x 4cm large) a bit and my wife had to stand on one end. She's not heavy, but it worked!


What do you think about the large loop?
I got to think about the other side and the dropout. It does not look nice if the dropout (shaft to tube connection) is too far apart. Picture sketch below:
View attachment 286974
I love the big loops on the loop tail. Engineering the dropouts to be strong enuff for offroading may be a challenge. Can't wait to see what you do with them.

It'll be Fun and interesting to test them out for sure.
 
Last edited:
Thank you metalchewy!
I bought aluminium extrusion profiles from aluxl.nl (Dutch website) and lasercut + milled the rest.
I can email you the dxf-files on email if you are interested. Feel free to decline or send a pm :thumbsup:


In the meantime the bender is fully set up!
I tried my first bends on 15x1.5mm CrMoly steel.

It was cold and misty, so I warmed the tubes and tooling a bit first.

View attachment 286962
View attachment 286963
View attachment 286964
View attachment 286961
View attachment 286965
View attachment 286966
Marked the tubing!

View attachment 286967
View attachment 286968
View attachment 286969
Pretty large loop.

View attachment 286970
The large loop doesn't look too bad.

View attachment 286971
Marking and measuring the next bends.

View attachment 286972
Both ends will be notched and attached to the seat tube.

View attachment 286973
I did lift the tile (60cm x 40cm x 4cm large) a bit and my wife had to stand on one end. She's not heavy, but it worked!


What do you think about the large loop?
I got to think about the other side and the dropout. It does not look nice if the dropout (shaft to tube connection) is too far apart. Picture sketch below:
View attachment 286974
Hmmmmmmm

My first impression is it may benefit from a smaller loop. Visually I’m looking for balance front to rear

IMG_4556.jpeg
 
I like the looptail. A little smaller might be visually more balanced, but the overall look is great. Maybe consider attaching the seat stays to the top tube making a wishbone around the seat tube, that would look trick. I'm loving this one!
 

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