Top effort!

Nice, like the look of the seat tube brace

So the printed plastic is part of the frame yes? How much weight does it add? And do you use less carbon fibre layers this way?

great work OP! Is the the mold structural? Can it be dissolved away?

Interested to here about the 3d printer being used as a mold too.

The guy behind Carbon Wasp has a few videos up, one clearly shows him using a 3D printed external mould and presumably an internal bladder

As ever thank you for the kind comments.
So to answer a few questions, i was an apprentice tool maker for a small place ghat used to make moulds for toys, the bloke that introduced me to CNC turned Han Solo’s shoulder joints in the 70’s!
Any way i’ve always been in precision engineering untill moving to education 10 years ago. Always been making things in one form or another, never composite stuff though (Did a thread with a 28t chainring on standard crank)

The tube form will stay in the frame, semi structural and i’ll use four layers for the main tubes with local reinforcment as needed.
I’ve done this frame with pla printed parts. The next one will use abs and disolve it out using acetone.
The two tubes above weigh 600g the swing arm weighed 800g before i did some finish sanding last week.

A quick update from the weekend.

I’m fed up with smashing the mandrel out of the head tubes and had a spare hour or so in between setting up and calibrating the 5 axis machine, lunch and meetings, manage to make some tools for removing the bottom cup thing and the sleeve.

Still some bashing but eventually freed the head tube.

Looks more wonky in the photo than it really is, the inside has a good’ish finish.

That’s it till the weekend then I can start tackling the main tubes.

Far more real than steel.

Loving this. Great work – keep the pictures coming.

brilliant.

Not much of an update.
Seat tube arrived so mock up the frame on the floor.

Looking good, I presume the seat tube is an off the shelf job then?

I’ve just mocked up some frame parts on my 3D printer but its going to take 11 hours to print.

I really hope this frame comes off and rides well. Seriously impressive.

really interesting. Is the 3d print staying inside the carbon then?

Wow wow and wow not had much time working with carbon lay up but now starting to think. Please keep this thread updated dude it’s been a good read so far and loving your work.

bigdean – The tube form will stay in the frame, semi structural and i’ll use four layers for the main tubes with local reinforcment as needed.

andybrad – really interesting. Is the 3d print staying inside the carbon then?

As ever thank you for the kind comments.

As nothing to report we’ll look at the rockers which i made over a year ago!

Mark 1 version

Was never really happy with how these looked, i did play with some flexing simulation but didn’t go crazy over it.

So the mark 2 was drawn up with a bit of tweeking the points all came together. I had two designs in mind and went with these.

Looking good, I presume the seat tube is an off the shelf job then?

I’ve just mocked up some frame parts on my 3D printer but its going to take 11 hours to print.

Yep not point making a mandrel to make the tube which would be a pig to remove.

I try to avoid anything over 6hrs as you only need a slight error to scrap the whole print. Same goes for multiple parts, i do one at a time then if anything happens only one has failed.

I really hope this frame comes off and rides well

Me two but it wont be light(am aiming for around 3KG the swing arm is 800g at the min)which the haters will love.

Really loving this thread. I know how tricky it is from my considerably easier work making RC glider parts. Can’t wait to see the finished item.
Next time (!) how about printing mould halves for the frame, finishing and polishing that and then laying up inside with a bladder to compress the laminate?

This is amazing!!

Fantastic.

Wow, keep this thread going.

What else have you made besides the 28t?

Progress, kind of.

Finally got the first layers of fabric on the main tube, doing the vacuum bags is a pain and still trying to get leak free.

This weekends task is some extra reinforcement around the pivots and final layer before sticking it all together.

In true “project Binky” style we have some CAD not pretty but does the job.

Trying to follow the outline was like those magic eye things.

Machining and toolage.
So the pivot mount things are too big for the location recesses in the frame, this was intentional so i could get them round and to a size i wanted. I trial fitted the bearing only to realise that i couldn’t remove them without distorting them with usual screwdriver and hammer ignorance.

So a bit of measuring, scribbling a drawing (which forgot to take a picture of), machining and filing we have this handy little bugger.

This shows how it works, slide in just enough then is located on opposite bearing. tap with a mallet and out they come.

So after that distraction got to make a mandrel for the pivot thingies.

Made sure it was running true.

Before

After

The yellow is some kevlar chucked in for good measure.

So waiting for one set of resin to go off so i can do it all again tomorrow.

Saturdays used to be for riding bikes…

Hmmm, can someone tell me why this page breaks the internet? nearly all browsers crash when i open it.

Finished the rockers and mocked up all the bits that join together. They fit! just a fettle of an edge needed.

Also mocked up nearly all the parts, getting excited now just go to double check everything before the final joining of tube bits.

Ace work.

Can’t wait for the eventual ride report!

Great work.

Have you been following the MTBR framebuilding forum? – there have been some nice carbon frames on there recently.

Hmmm, can someone tell me why this page breaks the internet? nearly all browsers crash when i open it.

I’d imagine it is the pictures – are they some stupidly large resolution?

awesome!

cant wait to see this finished and read the ride report!!

This page is slow to load but does not crash Chrome

I wonder of your image host isn’t that fast serving all the pictures

And the story goes on..

You know the saying measure twice… well faffed for two days checking the jig.

During which i re calibrated the 3d printer to about 0.1mm in x&y so i could print some jig parts as didn’t have time to machine them.

No pictures on the jig was a sticky mess stressing to pack any gaps with the resin/ fiber mush i mixed together.

After a day drying on the jig in front of a warm heater i managed to remove the front triangle.

First thing was to weigh it, now i was never going to be comparable to a carbon frame you can buy but the same as an ali one would be good.

The highly accurate kitchen scales show about 1.5 kg for front.

The rear with rockers and shock is about the same.

so looking at just over 3kg for the frame including shock, bit disappointed wanted it to be under 3kg.

Anyway dispite not being finish i couldn’t resist this.

To give you some scale that’s a 23″ seat tube! i need to take a bit off.
I recon you could build it up and ride around on it just glued together, not going to happen mind.

Rear triangle is a it close so new rockers to be made, checking the CAD sketch slackens everything about 0.5 degrees and makes a 445 rear triangle, plus the chain only grows 10mm in the first 40mm of travel so that should be ok.
I was bored at work and did some quick and dirty FEA on solidworks just to see if they would bend, i’ll post some pics soon. Plus i might make them pretty..

Oh and why has nobody made a millennium falcon seat clamp?

Love this thread, keep it up OP.

A combination of impatience, snagging and excitement.

To say it’s big is an understatement.

23″ seatube that you plan to cut down ain’t that big….some of us have seat tubes that long anyhow…

Wow, top work OP.

I’m liking it very much, what are you doing about the joints? I assume that you’ll be wrapping them? How many wraps do you think it’ll need?

What forces would you expect at the shock mount? How many wraps have you given it?

Looking good by the way! 😀

What forces would you expect at the shock mount? How many wraps have you given it?

A lot and enough? there should be next to none laterally but the shock has so much pressure it’s got to push against something.

The shock mount has had 4 layer of carbon per side at this stage.

Some reinforcement around the head tube.

And some more this time wrapping round top tube to top tube etc..

Brilliant thread that never disappoints! Top work.

So to the rear brake, the rear swing arm may have clearance issues so no need to be pretty.

A superstar brake adapter bolted to the caliper, the caliper was lined up on the rotor.

A high tech solution to fixing the caliper in place.

The wheel was then rotated till the adapter was touching the swing arm.

Then using a cable tie and some epoxy & chopped carbon “tacked” in place.

After this set the cable tie was cut off and the other hole cleared, then strands of carbon were threaded through the hole and around the adapter with more epoxy chopped carbon to keep it secure.

A quick sand and it will look fine.