TOPIC: NHT cam nut tool

Many seem in love with the intermediate shaft support fixture or a cutaway timing cover, as the ideal retention tool for removing the cam shaft nut.

On a recent training session for a local norton newbe, the removal of the nut seemed quite difficult. The owner is freshening up a combat that was worked on decades ago and partially reassembled by another person. A Whitworth socket and 1/2" breaker bar also needed a fork leg extension and a tremendous amount of torque to remove the nut. It is suspected it was red loctited...I have never seen one as hard to remove. Stress through the chain to restrain the cam sprocket must be immense and possibly damaging? This is my motivation for this new tool.

My new camshaft sprocket holder project started with an extensive DMM dimensioning of many timing chest component locations. I am using as the origin, the 2 dowel pins as the horizontal axis.

This project is progressing. It consists of several tasks.
Establish a "reference set" = the lower front dowel as 0, 0 for x0, y0 and the rear dowel as X1 and y0 . This is accomplished using the Heidenhain digital readout. This "reference set" establishes a standard starting point for both rectangular and polar data sets.
The rectangular data set is all that is needed for the much simpler intermediate shaft support design.
The camshaft nut tool design goes much farther to establish all the rectangular and polar data sets required for tool positioning which in the final result, is converted back into milling machine rectangular format..

FWIW the 2 dowel pins are 2 thou under 1/4". This is why they are able to be cleaned and be finger removable. Though many don't believe me
The Intermediate Shaft support needs the positions for the 2 reference dowels and 2 adjacent screw holes, Intermediate Shaft and an additional top screw hole for I S fixture attachment. This is all relatively easily measured.

The cam nut tool is a huge project in comparison.The camshaft position in relation to the I S is needed, but all are measured, and the tool attached, with reference to the 0x, 0y reference dowel. The cam position result needs to be an angle and distance which is in polar coordinates. The cam sprocket and teeth also needs to be defined in polar data. The cam position and cam sprocket teeth orientation will however need final conversion back to rectangular data for cutting metal on the tool
Attaching the cam nut tool requires an additional screwattachment point on the upper edge of the timing chest, rectangular data is necessary here also.

Just for the record, I also located the two tensioner stud holes for this twin chain engine as I intend doing another cam nut tool version for the single chain engines too
Rough draft of the tool below which is flipped over and lowered on to the sprocket and screwed down to the timing chest.


Currently brushing up on my calculator button pushing skills so progress is a bit slow getting started