Lolly Pop

Held in the indexer for milling and drilling

The flats milled with a half-inch pilot hole drilled in the center

An excellent 1 inch hole

Kingpin sitting in one of the tapered bearing hub caps

Axel partially pressed into kingpin

This is the kingpin center of the hub center steering assembly. This is the pin on which the hub pivots. On a conventional motorcycle you have the steering stem which is the axis of rotation of the front steering assembly and the forks. On this bike, this is the center of the steering assembly likewise the rake and trail figures are determined by the angle at which this is positioned by front axle or more specifically through a measurement taken perpendicular from the ground. This was a piece I turned out of 4130 steel in the CNC lathe, as you can see in a previous post. Here I finish it by locating and boring the one-inch hole through the center on the Bridgeport.  I bought a new one-inch high speed steel end mill on eBay and after milling the flats on either side and drilling a pilot hole all I had to do was plunge the end mill through and center and I got a perfect one-inch hole. The fit is as good as if it had been reamed. The axle is a piece of 4130 tube with a.1875 wall and it is a nice light press fit into the kingpin as you can see in the last picture. The kingpin will also get welded to the axle and the angle of the kingpin will be determined by how the axle is clamped into the front swing arm. This is a very easy way to adjust the rake and likewise the trail figures to optimize the stability and handling once I am actually able to ride the bike and do some testing.

Axel partially pressed into kingpin 2