Some time ago I mentioned that I was attempting to make a version of my favourite Norris, the 50. Ray and Josh provided the blade and I nearly completed the cast iron base and did actually complete the cap iron. Then progress halted. Other projects came and went but the guilt of having this unfinished project remained.
Last weekend I commenced work on the adjuster's banjo. I had pondered over the various alternatives to Norris' original left and right hand threaded version and ended up thinking the original was probably the easiest to make. And I did have a ball turner I had made a couple of years ago specifically for this task. Some 3/4" 1020 bar would have been a less wasteful alternative to turning down some 40mm stock but it would have allowed more procrastination. The 40 was all I had.
Norris' use of a 32 TPI right hand thread and a 40 TPI left hand thread results in a total travel of .057" or 1.447mm per revoltion of the adjuster's thumbwheel. I had borrowed fellow forum member Greg Q's 51 Norris and found that to be pretty coarse adjustment of the blade. I'm thinking of something a touch finer....
A 5/16" x 18 BSW and a 7/32" x 32 ME combination, both right hand threads, provide a travel of about .024" or .60mm. Substituting a 40 TPI thread for the 32 would result in about 20 thou per thumbwheel revolution.
Now, I know the general concensus is to abandon the adjuster in favour of a hammer but in the case of my pretend plane, I'm sticking with the adjuster.
I'm obviously optimistic asking this question but has anyone had a go a making their own adjuster utilising two right hand threads and if so, what combination and more importantly, were they happy with the results?
Bob.
Last weekend I commenced work on the adjuster's banjo. I had pondered over the various alternatives to Norris' original left and right hand threaded version and ended up thinking the original was probably the easiest to make. And I did have a ball turner I had made a couple of years ago specifically for this task. Some 3/4" 1020 bar would have been a less wasteful alternative to turning down some 40mm stock but it would have allowed more procrastination. The 40 was all I had.
Norris' use of a 32 TPI right hand thread and a 40 TPI left hand thread results in a total travel of .057" or 1.447mm per revoltion of the adjuster's thumbwheel. I had borrowed fellow forum member Greg Q's 51 Norris and found that to be pretty coarse adjustment of the blade. I'm thinking of something a touch finer....
A 5/16" x 18 BSW and a 7/32" x 32 ME combination, both right hand threads, provide a travel of about .024" or .60mm. Substituting a 40 TPI thread for the 32 would result in about 20 thou per thumbwheel revolution.
Now, I know the general concensus is to abandon the adjuster in favour of a hammer but in the case of my pretend plane, I'm sticking with the adjuster.
I'm obviously optimistic asking this question but has anyone had a go a making their own adjuster utilising two right hand threads and if so, what combination and more importantly, were they happy with the results?
Bob.
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