Well it took awhile, but I found and fixed the cause of my problem ( cutting a taper).I have only a little knowledge of shapers , I have a hand shaper which is more of a fun toy than useful tool , The grind on the shaper tools makes a big difference to the cut force (using a handle to pull the tool through the work helps find this out) so it's worth playing with noes radius etc. maybe very small radius for roughing and a shear bit for a final pass on a flat surface with a very small depth of cut.
Stu
The table didn’t have a tight fit to the cross rail. The cross rail is a dovetail on the bottom and a box way on the top. The box way was the problem area. It was worn. I had to scrape both the cross rail and the under side of the table to get a good precise fit. The shaper is now able to stay within a half thousandth on a 4”’long cut in steel at a .020 depth cut. My thanks to all who helped.