Originally Posted by
Dave Kirk
That said I'd try something like this - I'd get an old suspension fork that has slip in blades that get pinched in place with side bolts on the crown. Pull the suspension blades out and toss them and make/have made new blades that you can slip into the MTB crown that have differing rakes to test. this way you can slip one pair out, slide another pair in, put the front wheel in place and tighten to align the blades and then tighten them in the crown. The advantage of this is that you can control span for a given rake and keep the variables down to one.
Old RockShox Mag 21 crown (very similar to switchblade crown I think) would be good donor for this approach. The Mag21 crown fit 1" diameter stanchion tubes that would be easy to replace with de-ovalized 25.4mm fork blades or else just use 1" tubing. The mag 21 crown is cast with the blades angled forward for around 40mm of rake, no need to bend all the rake into the legs. The crown leg width is setup to have the dropout positioned right in the middle of the tube for an axel OLD width of 100mm so you could use really simple plate metal fork ends slotted into the center of the tube. Because the fork ends are symetriclly centered, if you could make legs with the axle located +5mm forward for 45mm rake you can also turn the legs around in the crown and use same leg as -5mm for 35mm rake.
As logn as you are expirimenting with fork adjustability, the RS fork would also allow you to easily alter the axel-to-crown measurement, no lip at top of the crown pinch hole for the legs.