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OT: The Mother of Invention

rj newbould

Diamond
Joined
Aug 29, 2005
Location
Hernando, FL
We’ve all heard the expression “Necessity is the Mother of Invention.” and in my case it’s true.

My very first “real” invention was due to my employer’s need for a variable grinding wheel dresser to create an involute form, which would be variable.

I was working for Alan Tool in South Amboy N.J. at the time, about 1961. They had a mold to make for an involute gear. Not knowing precisely what the shrinkage would do to the form, they wanted to be able to vary it slightly according to test results.

This was long before computer generated forms. The available dressers used gearing to generate the form, and were not easily varied. We didn’t have a Diaform available, or the means to make a master for one if we did have it.

The owners of the company and the design engineer were stumped for a solution. I asked if I could have a go at it. That night I designed an involute dresser, which used no gears, and would be infinitely variable within it’s size range.

I gave my sketch to them the next day, and the engineer’s response was “That’s a world beater.” They had me make it, and it worked perfectly.

That gave me the confidence to tackle the problem which led to the Newbould Indexer.

Fast forward to 1971. I had started my shop in 1965 in ½ of a one-car garage with $200 as my only cash. By 1971 I had two Model 242 Excello EDMs and a host of other equipment in a 3,200 sq ft loft in Kenilworth N.J..

Both EDMs had built-in rotating spindles with friction locks. If you used anything other than a round electrode, aligning it necessitated using the table travel and an indicator on the electrode in order to lock it in the desired position. Once unlocked, the whole procedure needed to be repeated, often meaning a time consuming re-positioning of the table.

I didn’t like the inconvenience and waste of time doing all that, and decided to install some sort of locking system where I could just lock the rotational position where I wanted it.

My first though was a shot-pin setup, but even with a two-pin vernier setup that was too limiting. That would be OK for going back to an original position, but I often wanted to make just a very small-predetermined angular adjustment. Yes, a sine adjustment could work, but that seemed awkward to me besides not being all that accurate.

A worm gear in such a small size would not be accurate enough for the precision I sought.

An optical ring with microscope could do it, but was very expensive and would have been tricky to install. This was back in the days before precise magnetic encoders.

A serrated-tooth indexer with multiple numbers of teeth combinations (such as made by AA Gage in Michigan) had all the accuracy and mechanical characteristics I wanted, but were not direct-reading.

By this time, a week had gone by and I had decided a differential serrated-tooth mechanism was the only way to go.

Now… How to make it easy to use? That was the question. The following week was spent hour after hour, sometimes till the wee hours in the morning, punching different combinations of teeth into my Frieden rotary calculator, looking for a combination that would be easy to use. Finally, after all that time I was sitting at my desk about 10AM, with a nice warm sun on my back, looking all those notes scattered on the desk, and decided there was no combination to be had. All combinations required a mathematical calculation to determine the final angle, and none would provide a movement of exactly one second of arc.

Damn… I said to myself. I don’t want to have wasted all that time. I’ll find another way. What if I make the second set of teeth 61 minutes to give me a one-minute differential from a 60-minute set, what happens?

That gives me 354.09836 teeth leaving a small tooth at the end of the circle, now what? OK, I’ll just clear a spot on the other disk for that odd tooth. But I can’t move it, it won’t fully engage… Well, if I take out another tooth it will. Now I have two positions with exactly one minute differential.. That’s handy, but what good are two positions? Not much, so I’ll take out another tooth. Now I have 3 positions. Damn… If I keep this up, I won’t have any teeth left on the opposing set. But wait.. If I clear 60 degrees worth of teeth, I can go back to my original start and will have moved exactly one degree. Eureka… That’s it. I can make the differential whatever is easy to read as long as I subdivide the previous set’s division in equal parts.

That thought process took about 10 minutes. I was able to find a mechanical solution to a mathematically impossible problem, by not limiting the number of teeth to an integer.

A serrated form of engaging members is about 2,000 years old. The first patent for a differential set was made in Netherlands before I was born. All those which were designed to be engaged in a variety of positions, used a whole number of teeth (integers) in the circle.

There are only 3 elements, or characteristics if you will, to the Newbould Indexer. Serrated teeth, the differential principle, and the use of an non-integer number of teeth with a corresponding open space on the engaging member. Remove any one of these three elements, and it no longer works as a direct-reading indexer. That makes it basic, and that’s why it was put in the Smithsonian.

How it came to be in the Smithsonian is another story if y’all are interested.
 
Well, I am, I love stories like this. :)
Do you have any drawings or descriptive literature about this differential serration principle? Maybe it is just late but I can't quite visualize this. :) Dave
 
Sure, RJ, keep on truckin'. This would be a good thing to blog about, now that we have that feature!

That's why it's here now. It's been in the blog for a few days, and it seems many either don't go there, or missed it. As per a suggestion from another member, I moved it here for that reason.

I'll continue in here and see what happens. :)

becksmachine... I'll put something in here. Meanwhile, if you like, you could look up patent # 3,846,912. That's it. I'll look for the link. I had it bookmarked but lost the link to the patent office portion..

WOW.. I just googled for it. patent

How neat is that..?

Notice in the patent...., there is NO application shown. There's a reason for that. (Subject for a different post.)
 
AA Gage in Detroit

In patenting procedure is a thing called “Interference”. It is a court type hearing wherein two competing applications for the same invention duke it out to see which applicant has the valid claim to the patent.
Normally speaking, (in 1971 at least) the patent examiner guidelines called for not declaring an interference if there was at least a three month separation between to applications for a SIMPLE invention, which I considered the indexer to be. In such a case, the first application was consider to be the prevailing one.

After waiting more than three months from my application, I decided to test if any of my potential competition had something I was not aware of. I didn’t want to spend time and money if someone already had it.

AA Gage at this time had been making differential serrated tooth indexing table for over 15 years. They employed 70 engineers in the company. I had phoned them a few times to see if they could make a table for me that would increment exactly one arc second. Each time they said no, we can give you about 5/8 second, or about 1-1/8 seconds, but not exactly one second. With their tables was furnished a very large manual listing all the combinations and their angular equivalents.

I now had my little clear plastic prototype (now in the Smithsonian) and drove to Detroit to visit them. I wanted to beard the lion in his den. If ANYONE had what I had, they would be the ones.

Upon arriving, I was ushered in to the office of the chief engineer, Wes Grizzel (or Grizzle). I again asked for a one second table, and was again told it couldn’t be done.

I reached into my briefcase, pulled out my plastic prototype and set it on his desk and said, “How about if you do it like this?”.

After explaining it to him, he leaned back in his chair with a roaring laugh, sat back up and said, “How much do you want?”

I replied, it’s not for sale. (My first mistake.)

We had a great visit complete with plant tour, after which I drove back to N.J. in a wonderfully high mood.
 
RJ,

I have admired your products (actually only as images on my computer screen), and have appreciated the thought put into your postings here on the PM. To have more of your story presented is a delight, thanks! I look forward to reading more.

--Larry
 
RJ,

I have admired your products (actually only as images on my computer screen), and have appreciated the thought put into your postings here on the PM. To have more of your story presented is a delight, thanks! I look forward to reading more.

--Larry

Thank you Larry. I hope some day you can get to use some of my stuff.

One of the greatest intangible results of this invention is that it has satiated my ego. Since the mid 70s, I have no longer felt the need to "prove myself" to anyone.
 
One of the greatest intangible results of this invention is that it has satiated my ego. Since the mid 70s, I have no longer felt the need to "prove myself" to anyone.

Amen to that. Seems to me that to be good at what one does and content with one's skills are a couple of the cornerstones of a peaceful life.

Thank you Larry. I hope some day you can get to use some of my stuff.

Ah yes, but my small hobby shop might be a bit of an insult to the capabilities of your tools! Perhaps an example will cross my path someday though.

--Larry
 
Ah yes, but my small hobby shop might be a bit of an insult to the capabilities of your tools! Perhaps an example will cross my path someday though.

--Larry

Nah... Nothing can insult the capabilities of my tools. :)

Actually, I have quite a few one man shop customers, and at least one dealer/gunsmith user. I swapped a 202 for some guns and other stuff.
 
Moore Special Tool

After visiting AA Gage, and bearding the lion, I felt confident that no one else had an indexer like mine. I was ready to tool up and go into production.

The first order of business was to get some way of indexing the teeth on a mold for the indexer. I had gone through the process of what to make the indexer from, and decided that plastic would be the way to start.

I needed a master indexer, or good rotary table. Moore advertised both. A 2 arc second rotary table, and a 1/10 arc second serrated tooth indexer called the 1440. I thought if I mounted the 1440 on a sine base, that would be the cat’s meow.

I went into the Moore office in Bridgeport, and asked to see the 1440. Their sales engineer took me into the room where they finish ground and lapped the tables. Neat setup. They had modified a shaper to grind the teeth with automatic indexing, and had an automated lapping setup which would take about a week or so to lap the teeth with progressively finer lapping compound, finishing with kerosene.

He asked me why I needed an accurate indexer, so I dragged out my little plastic prototype and showed it to him. I was not prepared for his reaction. I thought his eyes would pop out. He said Wayne and his dad Richard were in the middle of a meeting with their reps and dealers from all over the world, and were quite busy, but would he mind if Wayne looked at my indexer. No problem from me of course. He gets Wayne on the phone and said to him, “Wayne, I think you should come down here and look at this.”.

In a few minutes, Wayne comes into the room and I showed him the indexer. Wow.. He got pretty excited and told me he wanted his dad Richard to see it, but he was busy with the reps/dealers. Would I go to lunch with them?

Are you kidding? He needed to ask?

I sat with Wayne during lunch, while Richard was at another table. Wayne had introduced me and briefed his dad about what was going on. They asked if I would hang around until after the meeting so we could talk.

He needed to ask?

All through the afternoon Wayne took me through the whole shop and showed me their operation. Super cool. Several stories, with lots of wood floors. I felt right at home coz my second story shop had wood floors too. Just not all that neat stuff like them.. :)


After the reps left, the three of us sat in Richard’s office and discussed the indexer, and how to apply it in different situations, and how did I plan to deal with concentricity issues between the different pitch centers of the teeth? I had some ideas about dealing with that, but had not progressed the whole way in design to be firm with it. At one point, Richard started to bring forth an idea, and out of the corner of my eye, I saw Wayne signal him to hush. At that point, I realized that they were evaluating me, but were not gonna do much to help. That was OK with me.

They had licensed the serrated tooth setup from AA Gage, and I don’t think they wanted to help possible future competition.

At the end of the day, Wayne gave me a copy of his book “Foundations of Mechanical Accuracy” and autographed it for me.

All in all, it was a very exciting day for me. May 16, 1972

The 1440 was too expensive for me, so I ended up buying one of their 2 arc second special rotary tables, and that’s what was used to grind the teeth on the molds.



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RJ, did you eventually wind up with a building on or just off Michigan Blvd? It's been many years but I seem to recall a building thereabouts with your name on it.
 








 
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