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OPINION

Filing is fun

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Filing by hand is one of the joys of frame building… or it should be if you want to enjoy building frames

I once asked a mate why he hadn’t stuck with bicycle frame building when he tried it out prior to the start of a long and more-or-less successful career in cycling journalism. ‘Filing’, he said; ‘I couldn’t stand spending ages filing tubes.’

Maybe it’s as well he found out sooner rather than later that not every facet of frame building is glamorous, for most of them aren’t. For every minute spend playing a carefully-adjusted oxy-fuel flame over tubes and lugs fluxed and ready for the brazing rod, hours must be invested in the more mundane processes of measuring, marking out, rubbing down and, yes, filing.

And yet filing is, alongside brazing and silver brazing, one of the cornerstones of the frame builder’s craft. It is not easy to do well and, if done badly, lets the whole frame down, whether visible or not. Using a file properly is about more than simply removing metal with a few well- (or ill-) chosen strokes. The great Henry Royce was reputed to be able to file a perfect hexagon freehand and, while this degree of toolmaker’s virtuosity may not be required when building bicycle frames, it is indicative of the results that may be obtained when using what looks like a simple tool.

Getting good results needs, not surprisingly, correct technique (get instruction if you wish to master it) and sharp tools. Hand files are made in a wide variety of shapes, from the good old flat file to the frame builder’s friend, the half-round. They also come in various lengths and in degrees of coarseness: bastard, second and smooth cuts being the most commonly found. Coarseness is relative to the length of the blade, so that a smooth cut six inch is finer than a smooth cut 10 inch. My personal favourite for shaping mitres is an eight inch half-round second cut…

A file previously used on aluminium is next to useless on steel and files for use on steel and stainless steel should be kept separate. In fact, it is no bad idea to have a vast selection of files, each suited to some specific task, and to have them mounted on a wall board for easy access. Happily, this allows owning and working with hand files to satisfy the most demanding of OCD urges.

What, then, is frame building’s most enjoyable filing exercise? Some builders will doubtless enjoy carving the intricacies of baroque lug work, while others might find joy in shaping a perfect shoreline (the edge of a lug) or crafting a perfect transition from rear stay or fork blade to dropout, but nothing, surely, beats the satisfaction to be had from filing the perfect tube mitre. It’s a job often done by clamping the tube to a lathe or mill and passing it over a tube cutter of the required diameter set at the precise angle. This is a great way to save labour where numerous tubes must be cut to the same angle, but not necessarily in small-scale manufacture as a competent worker can mitre a tube by hand in the time it takes to clamp the work in the machine. It’s possible to achieve as close a fit by hand as by machine – and a lot more satisfying. 

If there’s a downside to this rewarding activity, it is surely the process of ‘cleaning up’ excess brass or, worse because a lot more expensive, silver solder left, perhaps, around the shoreline of a lug or in a blob clinging to the side of a tube. Removing the excess is time-consuming and doing it without damaging the thin sidewall of the tube a task that requires a rock-steady hand, which is where neat brazing technique comes in handy…

halletthandbuiltcycles.com

Winner: Bespoked 2015 Best Touring Bicycle

Richard spends most of his time making bikes, writing about bikes and riding bikes in the hills of west Wales, while imagining how much more of the above he’d be able to do if he only had more time…

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7 comments

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3wheelsgood | 8 years ago
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Filophilia is a much neglected aspect of the dark side of those inclined towards a velocipedal tendency; most refreshing to see such an elegant and informative discourse exposing the true nature of the beast. We must all pray for tolerance and understanding of this debilitating condition from those of narrow minds.

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Jimbomitch replied to 3wheelsgood | 8 years ago
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3wheelsgood wrote:

Filophilia is a much neglected aspect of the dark side of those inclined towards a velocipedal tendency; most refreshing to see such an elegant and informative discourse exposing the true nature of the beast. We must all pray for tolerance and understanding of this debilitating condition from those of narrow minds.

Filophilia does sound like doing unspeakable things to flaky pastry.........

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Richard Hallett | 8 years ago
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Plenty of pics online of contemporary work if you search 'thinned lugs'. I lightly feather the edges of the fork crown and other parts with a shoreline. Maybe I'll go a bit further with my next lugged frame

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SouthCraven | 8 years ago
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Great article Richard. But in all your mention of filing you missed out thining the lugs and finish filing the lugs.

Mitering the tubes and finding the stay ends are fairly quick jobs in comparison to thinking the lugs and finish filing the lugs.

I think it's a bit of a dying art because not many framebuilders now thin the lugs down. Possibly because they don't feel the need with cast lugs having a reasonably even finish.

But when I see beautifully thinned lugs I think it's the real hallmark of a craftsman.

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Richard Hallett replied to SouthCraven | 8 years ago
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Doubtless true about modern cast lugs, which are often impressively thin. I guess the modern equivalent is filing the surface of stainless steel lugs to remove dimples and other imperfections prior to prep for polishing.

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SouthCraven replied to Richard Hallett | 8 years ago
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I'd say modern cast lugs are uniform and require much less work, but I wouldn't say they are thin.

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harman_mogul replied to SouthCraven | 8 years ago
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SouthCraven wrote:

Great article Richard. But in all your mention of filing you missed out thining the lugs and finish filing the lugs.

But when I see beautifully thinned lugs I think it's the real hallmark of a craftsman.

Agree 100% with this! The only full-custom frame I have is by Tom Board. Seeing my new frame in bare metal, I asked Tom if he might not thin the spearpoint lugs a little more, in the style of the pre-war Carpenter I had previously owned. He was only too happy to accept the challenge...and what a lovely frame it is!

Great article Richard. Let's have more of this!

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