Gear Broaches and other art forms

[KL7AJ]

Yesterday, I was at one of our remote radar sites performing our semi-annual azimuth bullgear regreasing. The bullgear on this radar is about 6 feet in diameter, with spokes...and a true work of art. Every square inch of this monster gear is machined...it didn't have to be, since it's a low speed gear...but somehow that silly thing called craftsmanship slipped into the process...under the radar...so to speak.

I worked at Garrett Airesearch in Torrance for a year and a half in 1974-75 in the machine shop. There was an old guy who'd been running a gear broach for about 30 years. For those who don't know what a gear broach is, it's like a hacksaw, but with each tooth a bit longer. You can make a single pass of the broach through a gear blank and have a nearly perfectly formed tooth. Some gear broaches are lateral, but this particular one was vertical....looked like a big guillotine with a deep pit underneath. The stroke of this particular broach was over 20 feet. Waht an amazing machine...and it sort of grieves me that there's hardly anyone under 50 who's ever seen a broach....or any other real machine tool, for that matter.

The Germans used to require all their engineers to spend time in a machine shop before getting their degrees....regardless of what the particular discpline was.

I think it's a great idea...whether you have any ambitions to being a machinist or not....everyone needs to know how some things are made.....or the fact that they ARE made in the first place.

Eric
(Tilting at bullgears)

[AF6LJ]

As we move away from a society that makes things tools will become more and more alien.

A sad commentary on a society that once was independent.

[W4HAY]

When I went to work at Hammarlund in '62 they turned me over to an elderly German fellow who gave me a scrap of brass and told me to form it into a 1 +/-.005" cube using nothing but a hacksaw, a file, emery cloth, machinist's square and vernier caliper. Then he took me into the machine shop and, along with the machinists, showed me how to operate every piece of equipment in it, and the capabilities and limitations of each machine. I think that ranks among the most pleasant and educational two weeks in my career.

As a hobby, he made and sold filigree covers for wall switches and receptacles using a coping saw and needle files. One of his duties was making the contoured plates and frames for prototype air variable capacitors. He typically worked to accuracies of .001".

[N5PVL]

Yesterday, I was at one of our remote radar sites performing our semi-annual azimuth bullgear regreasing. The bullgear on this radar is about 6 feet in diameter, with spokes...and a true work of art. Every square inch of this monster gear is machined...it didn't have to be, since it's a low speed gear...but somehow that silly thing called craftsmanship slipped into the process...under the radar...so to speak.

I worked at Garrett Airesearch in Torrance for a year and a half in 1974-75 in the machine shop. There was an old guy who'd been running a gear broach for about 30 years. For those who don't know what a gear broach is, it's like a hacksaw, but with each tooth a bit longer. You can make a single pass of the broach through a gear blank and have a nearly perfectly formed tooth. Some gear broaches are lateral, but this particular one was vertical....looked like a big guillotine with a deep pit underneath. The stroke of this particular broach was over 20 feet. Waht an amazing machine...and it sort of grieves me that there's hardly anyone under 50 who's ever seen a broach....or any other real machine tool, for that matter.

The Germans used to require all their engineers to spend time in a machine shop before getting their degrees....regardless of what the particular discpline was.

I think it's a great idea...whether you have any ambitions to being a machinist or not....everyone needs to know how some things are made.....or the fact that they ARE made in the first place.

Eric
(Tilting at bullgears)

I set up a small machine shop here at home as an educational aid for my son Mini-Me, who is home-schooled. It set me back around 30k, but when he graduates next year at 21, he'll take a turn at running the family while I kick back for a well-earned rest.

Besides doing machine work, I would list hunting, killing, preparing and cooking your own food as an educational and uplifting experience.

The way women have degenerated in the last few decades, a fellow who likes to eat well had better know how to cook. - Another very good thing to know!

[AG3Y]

If you want to see an honest piece of craftsmanship, take a look at an old safe door. I'm talking about the kind that you can find in the lobby of some hundred year old bank building.

We have a bank building in downtown Hagerstown that has probably been around that long, and the safe door, which is about six feet in diameter, is covered with a hand-tooled swirl pattern, that is absolutely gorgeous ! Even the locks on the lock-boxes inside the vault have these features on them.

The door has an interlocked system of gears and wheels that move the pins in and out of the frame ( to lock the door shut ), and the whole thing is probably a foot or so thick! Astounding !

Getting back to ham radio, have you ever looked carefully at an old Hallicrafter's from the WWII era ? Look at this example, and tell me that the modern radios look better !

http://www.trumanlibrary.org/whistlestop/qq/dsradio.htm

73, Jim

[N5PVL]

If you want to see an honest piece of craftsmanship, take a look at an old safe door. I'm talking about the kind that you can find in the lobby of some hundred year old bank building.

We have a bank building in downtown Hagerstown that has probably been around that long, and the safe door, which is about six feet in diameter, is covered with a hand-tooled swirl pattern, that is absolutely gorgeous ! Even the locks on the lock-boxes inside the vault have these features on them.

The door has an interlocked system of gears and wheels that move the pins in and out of the frame ( to lock the door shut ), and the whole thing is probably a foot or so thick! Astounding !

Getting back to ham radio, have you ever looked carefully at an old Hallicrafter's from the WWII era ? Look at this example, and tell me that the modern radios look better !

http://www.trumanlibrary.org/whistlestop/qq/dsradio.htm

73, Jim

They call that series of circular swirls "engine turning" sometimes, but "jeweling" is slowly replacing the older term.

It seems to me that the aluminum sheeting wrapped around the nose of The Spirit of Saint Louis was engine-turned. - The plane must have been outstandingly pretty when it was rolling out of the Ryan factory back then, brand new and freshly doped up in silver.

Freshly engine-turned aluminum which has not had a chance to oxidize yet displays beautiful colors in the swirls as light reflects from them. - Like thousands of tiny rainbows darting around as you change your point of view, or the angle of the light. The freshly minted Spirit of Saint Louis sported that - but today you can only see the engine-turning on the cowl, the colors have long been clouded, obscured by oxidation.

It's still pretty, don't get me wrong.

I sometimes jewel or engine turn rifle bolts and some small parts like bolt releases or safety levers on firearms. - It's basically the a case of lowering a turning brush or abrasive rod onto a piece of polished metal covered in abrasive. - Fine or medium grit valve-grinding compound works well for that. - Then, you must be able to move either the piece or the rotating brush in a very precise manner before making the next swirl so that the circular swirls overlap like fish scales. Each alternate row of these is offset from the last, which adds greatly to the effect. - It can be done on a drill-press, but I prefer to use a milling machine.

I have equipment that allows me to make more complicated patterns in the jeweling, including barber-pole striping or even lettering - but I have yet to try it out on anything as it is labor-intensive. The CNC ( computer numerically controlled ) machinists have really got a leg up on that kind of thing.

Besides being attractive, jeweling is very practical as the micro-scratches tend to collect and hold oil on the metals surface much, much better than you could expect to happen on smooth, polished steel.

High quality watch movements and cases often feature jeweling. - And though I am no expert on older radios, it seems to me that I remember seeing some jeweling on the aluminum face-plate of some old rig or another that I have seen, somewhere.

Jeweled sheet metal ( steel or aluminum ) can be mass-produced inexpensively, looking a lot pricier than it actually is.

It's always pretty, well worth the effort involved, and sometimes quite practical.

[W4HAY]

Larry Potterfield is big on jeweling.

Back in the '50s, friend and his Dad built a classic flathead Deuce rod and jeweled a sheet of stainless steel for the firewall. They took quite a few trophies home with it.

[AF6LJ]

I set up a small machine shop here at home as an educational aid for my son Mini-Me, who is home-schooled. It set me back around 30k, but when he graduates next year at 21, he'll take a turn at running the family while I kick back for a well-earned rest.

Besides doing machine work, I would list hunting, killing, preparing and cooking your own food as an educational and uplifting experience.

The way women have degenerated in the last few decades, a fellow who likes to eat well had better know how to cook. - Another very good thing to know!

You won't get any argument from here on that last part Charles.

[AG3Y]

Potterfield makes it look so easy, but you can bet that there is a lot more to getting those swirls even than just moving the thing along an eighth of an inch each time. Amount of pressure, time pressed against the part, etc. etc. will all make a difference. And then, how do you suppose they Jeweled the front of "The Spirit" for instance ? That would have taken a very large whirling tool to do that job !

http://www.google.com/imgres?imgurl=...9QEwBg&dur=814

73, Jim

[N5PVL]

The way women have degenerated in the last few decades, a fellow who likes to eat well had better know how to cook. - Another very good thing to know!

You won't get any argument from here on that last part Charles.

Not to pick exclusively on the ladies, I will note that the last few decades worth of "men", the casterati had dern well better know how to cook when their wife gets home from the office, tired and ready for a relaxed, civilized meal. I mean, what else is he supposed to be good for - besides babysitting, running the vacuum-cleaner every once in a while, fooling around on the internet, and playing video games all day?

I keep my machinery de-energized ( Can't be turned on normally ) when I am not using it, just in case somebody like that walks through the shop while I am gone.