Monday, November 25, 2013

Finding and Making Hardware

Much of the hardware on the Hornet had been bunged up or replaced with coarse thread UNC nuts and bolts. Anything that was still in original form was heavily rusted. I set out to find replacement hardware with minimal success.  I had some luck on the internet by discovering “British Tools and Fasteners”.  They stock a substantial inventory of Whitworth fasteners. In 1967 BSA’s had mostly dome headed bolts which I could not seem to find. I was also not able to locate a source for new Pozi-drive screws I needed for the engine cases. I have used Allen head bolts in the past as replacements but do not like the look of them. I found a few odds and ends on eBay and one person who had a coffee can full of used Pozi-drive screws left over from his dealer days. He sent me ones that were good enough to clean up and re-plate. I was also not able to locate the correct diameter flat washers, although I was able to find British style lock washers and star washers.

Sorting hardware with a spares manual to figure out what I had.

With no place to purchase dome head bolts I decided to make them. I purchased grade 5 fine thread UNF bolts and put a dome on them in a lathe with a form tool. Next I put them in a drill chuck and polished them with emery cloth and a rubber block. Original bolts were used as a pattern for shape and size. Standard bolt lengths did not support all of my needs either. Longer ones were re-sized on a lathe. 

Turning the dome on a lathe. 

Finished and polished.

The original nuts were crowned on one side and flat on the bottom. This was due to the manufacturing process. They were cut off from hex bar stock to length and the bottoms were left flat. Today’s hardware is stamped providing chamfers on both sides. I replicated the originals by turning off the back of the stamped nuts I had purchased. They turned out well and starting with UNF hardware was cheaper than using Whitworth hardware. Although they are not a perfect match for the originals it is hard to tell the difference. Pictures of my methods and fixtures are below. After modifications all of the hardware threads were cleaned up using a die set I purchase from India via eBay. There was also a lot of hand filing and stoning needed to clean up burrs from turning. This was a slow tedious process but I think the results are worth the effort.

Nut held on a fixture and ready to remove the radius on one side. 

Fixtures, the form tool, and the rubber polishing block. These were used for turning flats on nuts, cutting bolts to length, and for creating the correct diameter washers. 

Cleaning out threads after turning flats on the nuts. 


The kickstand fasteners were also turned to resemble the original unit. 

One thing I learned in my quest for hardware is that Pozi-drive screws require the use of Pozi-drive screw bits. I was not aware of this and have probably boogered up hardware from not using them in the past. I purchased a set of bits from “British Tools and Fasteners” and they do grip the screws significantly better then Phillips bits. Lesson learned – after 30 years. 

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