Adjustable Rake Fork – mitering the fork legs for the dropouts

I’ve started to build a unicrown adjustable rake fork.  I’m using Hooded/Wright/Breezer style singlespeed dropouts from Paragon and will drill and tap on of their slider bolt sets into them so I can evenly space the axle.  I tried to figure out a way to use sliders but it just didn’t look like it would work right.  So, it’ll have to use cantilever brakes on it since when you adjust the wheel forward, the disc needs to go with it.

I set up the unicrown legs in my 1-1/4″ tubing-blocks fixture thingy and made sure, to the best of my ability without an inspection table, that the legs were evenly spaced and level to each other using a universal height gauge first, and then the Anvil fork fixture with the steerer unit removed.

Coping the fork legs for these dropouts turned out to be harder than I thought because the dropouts are not a constant radius.  I wanted to make a 5-piece fork for this one, but the dropout hoods wouldn’t fit a non-tapered 1″ tube – the True Temper fork blades aren’t long enough to work on a 29er.  The dropouts are about a 1.125″ radius that goes more or less flat.  Just like when these dropouts are installed on a singlespeed, they need to be horizontal to the ground so that when you adjust the axle front or back, the headtube angle stays the same, as much as possible at least.

 

photo stolen from Paragon Machine Work's website

To get the right miter, I first used an 8″ half-round bastard file to get the pattern started, and then I mostly used a 10″ half-round bastard (the radius of the 10″ half-round is 1.125″, something I didn’t realize until just recently), and finished up with a 12″ 2nd cut to smooth out the edges and make it fit the horizontal part better.  With the fork legs turned upside down in the vise, I could file both legs at once with the 10″ and 12″ files making everything in phase and quicker than doing each leg at a time.  The trick was switching sides so that I didn’t overdo one side since even though I thought I was filing perfectly straight across the fork blades, my right hand was putting more pressure down and forward than my left making an uneven miter.

It took me probably 3 hours total.  Had I done a better job at estimating the actual fork leg length for the rough cut, it’d have taken less time.  I never could’ve done this as quickly as I did without the tubing block fixture thingy and the new Wilton Tradesman 5-1/2″ vise.  The jaw width is perfect and the sweet copper soft-jaws are amazing.  I never knew how much a good vise made a difference in time and energy.  That thing is solid.  Highly recommended.

Reading Frameforum, you get the impression that if you don’t file all your tubes, you’re not a real framebuilder, or at least not someone making a true “handmade” frame.  I repect that point of view (after all, I’m a young retrogrouch in some people’s minds) but I don’t fully agree with it.  Filing does give you more of a sense of the intricacies of the tubes and their junctions with eachother I suppose, it’s all human-powered (except for how the tools were made of course), but I don’t believe it’s more ‘pure’…just like a singlespeed is not more pure of a bicycle than a geared mtb.  But to each their own…there are no shortage of opinions out there when it comes to framebuilding.  Filing certainly takes ten times as long.  Anyways, the point is, while well into my second hour of filing, checking, filing, checking…i realized that I was having fun.  I’m usually not a hugely detail oriented person (you should see my carpentry skills, or lack thereof), but framebuilding has changed that and brought out something I always have struggled with – patience.  I love ‘sculpting’ the bike and seeing it come together.  I love seeing a bunch of tubes lying on the workbench and knowing that some day soon they will be a functional utilitarian vehicle that will bring lots of joy to me or someone else for years to come.  That, my friends, is pretty cool.

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