Hi guys, yes my home "office" often doubles as my shop during the early stage of gathering parts and modeling clean stuff the other shops not so much. I actually just like having them in front of me & available at odd times (which are often when I'm concerned).
Rick the frames neck tube houses the fork steering tube and two bearing races upper & lower are pressed into the neck tube and comprise one half of the upper and lower bearing headset support, the remaining bearing support is provided by the "crown race" (lower support) & the upper by the "headset" nut or cap. The steering tube is welded to the crown support plate which supplies the only support for the steering tube of the fork assembly in most modern fork designs for bicycles. You are probably saying "ah ha" at this moment because the Simplex design is motorcycle & you're right. I'm using a Simplex triple tree design on a 1910's design motor bicycle frame not a heavy modern motorcycle. The top plate can be used for a lot of things requiring support, but my main concern is just to attach the steering. The fork plate does not support the neck head tube, the frame does that, nor is it necessary for the support of the headset bearing or the internal steering tube as the two bearing races of the headset assembly complete that task. Two critical elements are required to make this Simplex fork work on this Sportsman Flyer frame the first being the original Simplex threaded headset nut bearing race, which being a stepped design allowed me to thread it on enough (3/8" perhaps) to hold the 1" threaded steering tube centered and secure all the headset parts and of course the fork. If the original fork tube had been cut about an inch longer I could have mounted the fork like any other threaded headset assembly, but wasn't the case. The second necessary component was the "star nut" bolt and cap assembly which is used on thread less fork steering systems. As I earlier described it I'll only add photos. The design of the star nut cap is really important too as is correct installation of this innovative fastener assembly which not only centers, & secures but also compresses the bearing sets correctly .
I used it as a measure of safety only as it performs the same functions as the threaded system only from an inside the tube design rather than external threads on the outside of the steering tube. That small bolt will hold a set of mountain bike forks on through a fifty foot free fall without failing...repeatedly.
Both the threaded & thread less fork design elements were used together, just in case. I also discussed beefing up the weld at the crown plate in a previous post...which probably isn't necessary, but just in case. Hope this helps though I doubt this problem occurs frequently lol. Rick C.
