11-12-2019, 07:51 PM
  • ChiefBroom
  • Chief of Dark Holler
  • North Central Colorado, USA
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This installment introduces Frank and Lynn McInroy and the two-person, family business they created together. It also provides some history with regard to the lathe and its evolution over the past 540 years. The latter section is probably too long and might fairly be criticized as smacking of pedantry, but it’s there to drive an important point.

The terms CAD-CAM and CNC are occasionally employed with a purpose to conjure images of robot machines that dehumanize manufacturing work and their output. By way of example, one self-styled master wood-turner refers to the slew of artisan brush makers out there, most [of whom] use simple manual wood or metal lathes, while some utilize computer controlled machines capable of creating hundreds of identical brush handles in a fraction of the time needed to do similar work by hand. That characterization may be factually true as far as it goes, but it also, in my opinion, peddles a bit of BS. Although pursuit of efficiency and productive capacity has driven a large part of innovation in machining technology, so has a quest for improved control and resulting precision. The stereotyped notion that operation of a CNC lathe intrinsically involves less skill, craftsmanship, mindful care, investment of soul, sweat, blood, time and/or labor, than work performed by someone who turns objects manually is simply wrong. Not all artisans employing computer-controlled machines gain efficiency or achieve relative scale by their use. And no matter what level of skill might be applied to turning a brush handle manually, hand-turners simply can’t match the repeatable fidelity of execution that CAD, CAM, and CNC enable.

There may a slew of artisan brush-makers out there, but there was only one FrankLynn Technology. And what Lee Sabini accomplished in resurrecting Rooney shaving brushes and establishing Morris & Forndran as a brand depended heavily on the background, skills, and capabilities Frank and Lynn McInroy were uniquely positioned to contribute.

Frank McInroy and the making of an artisan-machinist

Frank McInroy is 76 years old. He grew up in Aberdeenshire, Scotland, and attended Skene School. His father was a gamekeeper on the Castle Fraser estate. Frank has been actively engaged in engineering for over 60 years. What follows in italics are Frank’s own words with very minor editing.

The school leaving age in my day was fifteen, and the minimum legal age to get an apprenticeship was sixteen. Back then it was all about getting you ready for the workplace and hopefully an apprenticeship.  I was lucky, because the secondary school I attended offered three years of one day a week that consisted of Woodworking, Metalwork, and Technical Drawing. 

If an apprenticeship was your goal, after leaving school you had to find suitable part time work or go to college for extra training. There were a limited number of technical colleges around then, and unlike today, you had either to pay or sit the entrance exam and gain a bursary. Fortunately, I passed the entrance exam and obtained a bursary, so I was able to lay on extra technical training until my sixteenth birthday, when I acquired an apprenticeship.

An apprenticeship was a real prize. This was where you trained and gained experience in your chosen trade. After five years, you’d would be known as a journeyman and could then go on and get a job in your chosen profession as a skilled person.

By the time I completed my apprenticeship I had attained a good grasp of technical drawing. Long before CAD (Computer Aided Design) engineers always worked to a drawing, and if you didn’t have one, you had to make one that was precise and included all the dimensions and related information necessary for anyone else anywhere to reproduce the same component. You would always have a sort of three-dimensional image in your head. That’s how things were made. If you were very good at it, you most likely became a draughtsman and would end up in design. But if you also had good hands-on skills with tools and machinery, the foremen of the day would never let you go to design. You’d be considered too skilled for that and be regarded as an artisan of your craft.

Frank turned 16 in 1959, completed his apprenticeship five years later in 1964, and came to be regarded as an artisan of his craft almost four decades before being approached by Lee Sabini to assist in the resurrection of Rooney shaving brushes. Frank was not, however, the type of artisan who previously would have been employed to turn Rooney or Simpson shaving-brush handles on a manually operated lathe (whether powered by water or electricity). He was precision engineer, and very importantly to Lee at that time, Frank was a precision engineer who had mastered the use of CNC lathes to turn modern plastics into elegantly refined shapes embodying complex geometries. As such, Frank was enabled by technologies, methods, and skills developed over the course of five centuries by engineers whose pursuit of excellence required progressive departure from handwork.  

Lathes, precision machining, NC, CNC, CAD and CAM

A 1963 Scientific American article entitled “The Origins of the Lathe” by Robert S. Woodbury begins:

Machine tools lie at the heart of the industrial production, and the acknowledged queen of machine tools is the lathe. Yet because the lathe originated in antiquity and has no single inventor it receives short shrift in most histories, which often describe the Industrial Revolution as if it had been evoked solely by the steam engine, the power loom and the cotton gin. Without major developments in the lathe between 1750 and 1830 the Industrial Revolution could not have taken place. [And, it might be added, without those developments and their enablement of the Industrial Revolution, the motor-driven lathes almost all hand-turners use today (most of which are made in China) would not exist.]

Archeological artifacts suggest the lathe was invented nearly 3,000 years ago. The earliest known graphic representation of a lathe is carved on the wall of a third century B.C.E. Egyptian grave. Advances from that time until the late 15th century related for the most part to methods of spindle rotation. But in about 1480 a drawing was included in the Mittelalterliche Hausbuch showing a lathe in which the cutting tool was placed in a mechanical device (now called a slide rest) rather than held in the hands of the turner. The cutting tool was fed into the work by means of a screw mechanism much like modern cross-feed devices. Moreover, the toolholder was held fixed in the lateral direction, while the workpiece was moved past it by means of what is now known as a lead screw, turned by a crank. From that point forward, evolution of machines of the type Frank McInroy would eventually operate diverged substantially from lathes fed by hand.  

In the early 1700s clock and instrument makers began making important contributions to lathe design with a primary focus on improving precision. The first fully documented, all metal, slide-lathe was invented by Jacques de Vaucanson (1709–1782) in 1751. Vaucanson was a genius French engineer who is also credited with creating the world's first true robots, as well as the first programmable power loom (which utilized punch cards). The first truly modern screw-cutting lathe was likely constructed by Jesse Ramsden in 1775. His device included a leadscrew, slide rest, and change gear mechanism. Ramsden employed that lathe to make even more accurate lathes, by use of which he made an exceptionally accurate dividing engine, and with that, some of the finest astronomical, surveying, and navigational instruments of the 18th century.  

At some point, lathes that evolved along the lines of those made by Vaucanson and Ramsden came to be most commonly referred to as metal lathes. Their development continued through innovation, synthesis, and refinement throughout the 19th century and up to the present. One innovation that bears mention here is the duplicating (or copy) lathe invented by Thomas Blanchard in 1818. Originally adopted mainly for woodworking applications, this type of lathe was able to create shapes identical to a standard pattern. Crossover eventually occurred, and by the 1960s duplicating attachments for metal lathes were being used in the UK motor industry. Frank gained extensive experience fitting hydraulic units to Colchester production lathes and mastering the challenges of their use, which resulted in significant advantage when FrankLynn Tech undertook to reproduce shapes with CNC lathes. In Frank’s words: The shape of the stylus was very important. I used to make mine almost like the tips I used for CNC machining brush handles, so I already had ideas about how to turn beads. Having that three-dimensional image fixed in mind stood me in good stead, and when Lynn was able to get on top of the CAD and CNC programming, we made a good team.

The immediate predecessors of CNC machines were constructed by modifying manually operated machines in order to effect slide motion via precise numeric control (NC) of attached motors (in lieu of hand-turned cranks). Positioning instructions, referred to as G-codes, were fed into NC machines on punched tape. The first such machines were developed in the late 1940s for the purpose of producing aircraft parts with intricate geometries.

A serious limitation of NC machines was that their logic elements were hardwired, which made it impossible to change the pre-set parameters. This was remedied by the development of CNC, which harnessed advancing computer technology to enable more adaptive programming. Evolution of CNC accelerated with the development of CAD and CAM software applications in the 1970s. (In the early days of CAD and CAM, those abbreviations were often used and understood to stand for Computer Aided Drafting and Computer Aided Machining. As software functionality broadened, however, Computer Aided Design and Manufacturing largely displaced the former usage.) By 1989, CNC machines had become the industry standard.

Lynn McInroy and FrankLynn Technology

When Frank McInroy acquired a pair of bench-top CNC lathes in 1998 and a CNC mill a year later, he had a powerful advantage above and beyond the thirty-plus years he’d worked as an artisan machinist; he had a wife, named Lynn, who complemented him almost perfectly in relation to the task at hand, i.e., mastering CAD-CAM in combination with CNC and putting those machines to productive use.

Growing up in London, Lynn had educational opportunities that weren’t available to Frank. She attended an excellent girl’s grammar school from the ages of 11 to 18, and then went on to study Math at Southampton University. After college she went into the engineering industry. Most of her employed life was spent in Aircraft Simulation, where she analyzed aircraft data and programmed the analysis. She learned ALGOL (Algorithmic Language) as part of her university course, and used BASIC, octal machine code, assembly language, and Fortran during her employed life, serving as Project Systems Engineer on six projects.

Lynn left work when her and Frank’s first child was born. After that she did intermittent sub-contract work, before teaming up with Frank in FrankLynn Technology. There, Lynn handled all the paperwork (of course!), putting it on a computer. When FrankLynn Tech acquired CNC machines, she learned CAD, which enabled her to produce all the drawings that were needed, and she did the major part of programming the machines (which she also frequently ran, along with doing occasional small jobs on manual machines). Lynn also performed assembly work from time to time and learned a lot about production engineering from Frank, who for his part acknowledges Lynn as having been an indispensable asset in adding CAD-CAM and CNC to the FrankLynn Tech arsenal.

When the CNC lathes were placed into productive service, FrankLynn Tech had a variety of customers and used the machines to turn wide range of materials, including stainless steel, alloys, polypropylene, and acetal. Frank soon discovered, however, that the lathes were especially well suited to machining decorative polyesters and acrylics, which could be sourced from nearby GPS Agencies.

In fairly short time, GPS began feeding leads to FrankLynn Tech by reason of the fact many GPS customers had no idea how to machine or polish the materials (polyesters and acrylics) GPS supplied. In turn, FrankLynn Tech’s mastery of CAD in combination with CNC machining brought about requests to create and execute bespoke designs. Increasing demand for their services led Frank and Lynn to add vibratory polishing capabilities (in addition to continued hand-polishing) in order to keep up with the work. All of this combined to position FrankLynn Tech as the best partner for Lee Sabini when he assumed the role of Managing Director of R.A. Rooney & Sons in 2003 without any significant background related to the production of shaving brushes.

[Part 3 is in the works.]


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 11-12-2019, 08:18 PM
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 11-12-2019, 08:25 PM
  • NJDJ
  • Senior Member
  • California
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Another great read!

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