Llewellyn's Lathe. 

New track fixie dropout project

February 2009-01-25

For some time  I have had a desire inside me to address nagging issues with the front and rear track dropouts in my builds.

Not that the dropouts that I source from the USA were at all bad, just that I wanted to tweak the design and improve the aesthetics.

A few things just were not quite right to my eye and sensibilities.

My current stock of dropouts that I use for road fixies and trackies is getting low thus I was prompted to get creative and produce my own.

I could go all funky and do lots of curves and engravings with LASER etched stuff but I do not feel that is needed for a real working bike.

Funky for Funky’s sake or complication is not my desire. The part must function in my build process.

For me it is the pursuit in the purity of my build processes in the workshop.

Before I committed to get a large pile of dropouts water jet cut I made a prototype proving set by hand to confirm all was correct and sweet to my eye.

First issue I wanted to correct was to lengthen the rear axle slots.

Not really an issue with road fixies but for track bikes it gives a wider range of gear ratios before one is forced to change the chain length.

So I added 6mm to the slot length.

Then I wanted more material on the part of the dropout that fits into the slots in the chainstay and seat stay tubes. This is the brazing joint between the dropout and the stays.

By adding more material it allows me to file nice points to the dropouts running along the stay tubes. When I select to use 18 or even 19 mm diameter seat stays for trackies I like to bottom cut the tapered length off to use more of the beefy section. So the freedom to use the larger diameter is some thing I desired. One can easily remove the excess and trim down the dropout tabs to obtain the sweet aesthetic I desire.

The previous drop outs I was using restricted this.

This extra material was also applied to the new Llewellyn design front track dropouts for the same reasons.

These ideas have been circulating around in my cranium for some time and now the time arrived to sort it!

I put pencil to paper and made some sketches, which translated to computer onto the 3D CAD program {Solidworks}

Banged the keys around, tweaked it a bit here and there.

I also did the drawings for the stainless steel wheel bite facets that I silver braze to the dropouts at the end of the build and finish file of the frame. {These are LASER cut}

These facets serve two purposes, one is to keep the paint tidy around the dropouts.

I just do not dig chewed up paint from the axle nuts on dropouts.

Secondly, when they get chewed up from constant wheel and gear changing at the track one rebrazes fresh ones in place when refurbishing/painting the frame, making the dropouts look and function like brand new. Removing those awful grooves that allows setting chain sweet tension. {trackies will know what I speak of}

Things can look nice and tidy on the frame while not sacrificing one tit bit of function if one wants to go the extra in the frame build process.  It just takes time and effort and desire

I printed off CAD drawings that I converted to 2 D to scale of the dropouts, then cut them up and used them for marking out templates.

Steel 5mm plate was marked out and cut into two pieces for the rears and two for the prototype front dropouts.

Next the embryo dropouts are bolted together and to the drill and mill they go.

A bit of time on the mill/drill and the slots are milled and cut outs drilled, a pair at each time.

Followed by some hours of elbow work with the piecing saw, linishing belt and files.

Bingo, a set of front and rear dropouts for a trackie or road fixie.

Stay tuned for March

I will show the build, braze process, finish file work and final prototypes in Darren’s new trackie.

Just to remind you of a BASIC llewellyn, and I mean that only in terms of the lack of polished lug work...

Hey Charger!

Posted by fyxomatosis on 11 February 2009

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