Matt Assenmacher and I share a similar history. We are both frame builders in Michigan that learned in Yorkshire England. Although his shop in the eastern part is more than 200 miles from mine in the south west. Our marketing areas don't really overlap. He went (as already noted) to Bob Jackson in Leeds about 1973. His college degree is from Central Michigan University in Mt Pleasant. That is in the upper middle part of the lower peninsula and where he began making and painting his frames under the trade name "Mathews" (his 1st name). In 1977 he moved his operation further east to Swartz Creek, MI not too far from Flint. Flint was a car manufacturing town until it wasn't. It was famous a few years ago for its water problems. He then started using his last name to brand his frames. He also ran a full service bike store so that limited his frame painting and building. He recently moved his bike shop again and no longer offering painting services.
I went to Ellis Briggs in Shipley West Yorkshire in 1975 after I got my teaching degrees and had taught high school for a few years. Shipley is in the same metropolitan area as Leeds. The 2 shops were only 17 miles apart although it seemed a lot longer because to get from one to the other required driving on winding city roads with lots of stop lights. I build and paint frames in Niles on the southwest corner of Michigan just north of Notre Dame University and South Bend, Indiana.
Matt and I have always had a friendly relationship. Both Ellis Briggs and Bob Jackson offered painting services. That knowledge has served us both very well once we started our own businesses in the Michigan. He taught me something really important about painting. Dust nibs in paint is much more likely to come through the airline than through the air. Once I put a nearly $1000 filter in the airline just before it goes into the spray booth, I greatly decreased that problem. I've passed this information on to my colleagues too (including Joe Bell - who was surprised like I was at the news).
Someone needs to interview Matt about his experiences living and learning to build frames in Leeds. Just for reference Bob Jackson's is where Kevin Sayles (now at Woodrup's in Leeds) got his start. They may have been at Jackson's at the same time but maybe Matt had left before Kevin got started there.