3D Printed bike toolbox mini project

So a few years ago I bought a J.Guillem Atalaya, this is a gravel bike which I've setup as a dual wheel set gravel/modern rando bike. The main purpose of this bike was to build something versatile, meant for long distance road touring/rando but still reasonably quick. So I built a pair of WR 65mm Light Bicycle carbon rims paired with DT 350 rear and a SON 28 dynamo front wheel with CX-Rays, 32mm GP5000 TR on top of these. The rims are super wide and fit flush with the inflated tyres which gives it a nice aero profile and low rolling resistance but still plush.

The frame has 3x bottle mounts with one on the downtube which I stuck a storage bottle on for when I used my saddle bag, this was to store spares, tube, tools etc. This generally worked fine, but not the most elegant and it was a bit awkward taking things in and out of it.

I saw this Orbea Orca Aero and was really inspired to make my own version of this for my bike or something similar...

Wow, I imagine the word machine was created for this thing
🥵🥵

I work as an architect so use a lot of 3D modelling software, also I have some experience in 3D printing from making models so I decided to model my own and give it a crack. I don't have my own printer so I would have to outsource this. However all the modelling I could do on my own.

First was deciding what I wanted it to do. Main goal was to have something a bit more integrated looking and able to carry the following

1. Spare tube (700x 32mm Butyl)
   
2. Multitool + Levers
   
3. Spare derailleur hanger
   
4. Patch kit + Tubeless plugs
   
5. Latex gloves and other sundries
   
   

Secondly, what was the design and build process. Design I would do using Rhino3D which I am very familiar with, printing process/material would likely be ABS plastic with FDM (Fused Deposit Modelling) which is reasonably cheap and widely available.

So to begin my initial step was to measure the downtube and mounting holes, this is not easy as the downtube on this bike is ovalised and transitions between two shapes along its length, so I basically cut out some cardboard and took some profiles every few cm. Sorry for the weird scan, but my scanner went a bit funny and did doubles.

This was traced into 2D and then lofted between the profiles to create a model of the downtube. You can see here with the profiles in blue and the loft/extrusion in red. It transitions from a round to a squashed/elliptical profile along its length

Next was version 1 of the toolbox. This was initially modelled so it would fit rather snug to the downtube and not obstruct the front wheel w/ mudguard. The idea is that there would be an upper piece bolted to the bike frame and the lower piece with click onto it with some bendable tabs at the back and a hooked bit at the front

I sent this to print with a provider, cost around £30 and took a week or two. However this was a bit of a fail, I had assumed it would take me at least 2 tries to get it right. I overestimated the flexibility of ABS and the back tabs snapped the first time around, Also the upper piece did not fit the frame properly because the BB stuck out too much. Also the print itself had too much faceting, this was due to my own mistake of not meshing it with enough triangles in the 3D modelling phase. Lastly there was long pieces of unsupported "wall" so the sides of the box were curved inwards from distortion, one of the limitations of this kind of 3D printing... So back to the drawing board.

So onwards with Version 2. This time I revised the attachment system as this was a complete fail. One of my first observations and lessons learnt from the first one was that the FDM print was actually quite crude and not that accurate, I've done some in the past with PLA but that was a long time ago. In any case the conclusion was that I should allow for large tolerances and make it a bit more simple. Thus I decided to use a simple silicone strap at the back with a large knob type thing to keep it secure and tightly fastened together.

Secondly I made it a bit smaller and I also added some reinforcement ribs to prevent distortion and sagging from the print. If you imagine how FDM works, it's like a tube of toothpaste being squirted out layer by layer and even with some supporting structure which is removed at the end, you have to limit your lengths of unsupported material otherwise you will get this.

I do a lot of things on the FDM machine at work, from simple homers to complex fixtures for our test machines. I find it best to design out any overhangs completely and think about how fixings are going to work according to the direction of print. What you don’t want is tall objects like your tabs printed vertically, because that’s the weakest orientation. You could print those laying flat and bond them on. Try to design things with 3D printing in mind rather than like you would with an injection moulding or a machined part.

This is great. You weren't tempted to use the space inside the frame rather than underneath?

Depending on how many iterations you'll need: if you are quite handy with stuff and fancy a new hobby, you can get started with printing ABS from around £250 (used Ender 3 printer, all metal hotend, home-made enclosure). Only if youve got a bunch of time on your hands! :)

Besides what Jonny69 mentioned above, also consider that you dont have to solve all your problems with 3d printing, you can combine it with other solutions. Strong magnets so that it snaps in place when youre putting it on, rubber fasteners connected to pieces bonded on to the surface of your 3D printed shell...etc.

With this in mind, you might be able to upcycle your first shell into a test iteration of a different solution.

Yeah so lessons learnt from version 1, version 2 came out a lot better. The rubber attachment system worked a lot better much like @kiskubai suggested I ditched trying to print everything and reverted to something simpler and using rubber to hold it on. The smaller unsupported area and additional ribbing helped to minimise any distortion, this one printed quite flat. However in the process of making it smaller, I realised only after that it was too small to fit the inner tube I needed (its a 700c x 32c which is not available in TPU or lightweight butyl...)

There really isn't much space inside the frame as this already has the brake line, dynamo wiring, brake cables etc, also the little hatch at the BB is absolutely tiny...

Points taken from @kiskubai and @Jonny69. It's been a while since I have 3D printed and I usually had one of the grads actually sort out the details of printing itself. In any case as I'm farming out the printing I have less control over the actual process. Would be fun to have my own 3D printer! but can't justify the cost or the space... My work probably will have one soon though...

Good point about the direction of printing, the first two versions appeared like the printed it vertically rather than flat. Version 3 was printed horizontally which I'll show later

One thing I did discover when mounting this which threw off the whole thing, had nothing to do with the design or production. Basically the bottle cage bolts on the downtube are off centre! By about 3-5mm which causes the whole thing to sit wonky... It's something like this in the photo

So onto version 3...
The whole thing got redesigned with the following main objectives

1. Model the actual accessories I want to carry, not sure why I didn't do this before as this was a bit of an oversight
   
2. Allow the upper piece to adjust for the off-centre holes
   
3. Make the attachment system even more robust, the V2 one worked ok, but wasn't as secure as I would like
   
   
   

First things first I revised the attachment system to make it even more simple and robust, so the upper and lower would be bound together with a Voile strap. The tension of the strap just compresses the two together which should stop any rattling and make it very robust. The upper and lower just need to get a reasonably snug alignment and does not rely on any small lips or nibs to stay put.


The whole thing was resized to match the accessories which I modelled, and likewise I added a support in the middle to prevent distortion and add strength/stiffness to the lower structure, add support to the upper. Thickness of the shell was upped to about 4mm.

The upper piece was redesigned and thickened to allow for sufficient material around the hole made for the Voile strap, this would cause the lower part to sit proud off the downtube giving it a bit of a shadow gap effect.

So sent this to print and this is straight from the printers. This was printed on its side instead and gave much better curved surfaces. next to no distortion or sagging so looks like it worked really well.

Generally this was the best result so far. Did a test fit and ride. It fits very snugly and doesn't rattle, the Voile strap keeps it very tight to the upper and it fits all the bits comfortably.

So looks like I will keep this one as the final version so I decided to do the final refinishing. Due to the printing process the surface isn't perfectly smooth so needed sanding and filling. Started at 400 then all the way to 800. This was then filled with XTC-3D which is a sort of resin based filler meant for this application. This fills in many of the small bumps and voids from the FDM process which are unavoidable.

Then I sprayed this with a few coats of high-fill primer. Followed by 3 coats of enamel matt black.

Finished pics.

It's not immediately obvious in the pictures but next time I'll probably do the primer fill a bit more as there were some imperfections which showed through. Also I've learnt quite a lot through this process through trial and error, and also found a reasonably cheap and local place which can do the prints. Anyway that's it for now!

That looks awesome, good job!

Really nice!

Suits the bike very well

Amazing <3

Cool project. Why wasn't a small bag under the top tube an option?
Shouldn't interfere with bottles and easier to grab stuff on the fly.

really smart, the end result looks great!
it's been an enjoyable project to follow. thanks for sharing!

Heya thanks! Yeah I already have a top tube bag that I use occasionally for Bikepacking/touring. The intention is that this toolbox is a permanent fixture on this bike and always occupies this space regardless of bag setup.

That makes sense. So far it looks awesome.
Really wish I could get involved in some 3d printing.

@ghettro
Question is, would you consider making them for other people? I would love a solution like this that's not the usual under the frame bottle cage and storage bottle.

Heya, I'd consider making one for a friend as a favour. Although I don't think I'd offer to make them on a forum as it's a slippery slope, I already have a full time job and enjoy my spare time!

You could upload to thingiverse and then people could download the file and print.

Although I guess there would be a high degree of customisability for different frames.

I'd have printed in a small loop to retain the end of the Voile strap.