Parker "51" Aerometric Breather Tube

[smbaugh]

Quoting Richard Binder:

The breather tube in the first aerometric pens was clear plastic; Parker changed the material to sterling silver for the Flighter, and that is the design depicted here. Later, Parker returned to plastic.

 

I just took apart my first aerometric "51" and it has a metal tube with pits and a hole about 1/2 inch aft of the end of the feed. I assume this hole is corrosion and not part of the design? Are replacement tubes available somewhere (I have no donors).

 

Thanks in advance,

 

Steve

[Gerry]

Doubt that was original - perhaps an aftermarket replacement.

 

I'm not aware of a commercial supply (please post if you know where correct replacements can be obtained), but have heard of a number of possibilities for make-do replacements - from the small plastic stirring sticks to tubes from aerosol spray cans (like WD-40) and others. If the tube is used - I'd clean it thoroughly (prefer to use new ones myself).

 

Other suggestions?

 

Gerry

[Dillo]

Hi,

 

There is supposed to be hole in the tube. Be sure to drill the hole with a fine wire bit that comes with the Dremel drill bit set. You will need a Dremel to use it.

 

Dillon

[Ron Z]

Dillo has it right. It's not a replacement tube. That hole is what makes the aerometric 51 aerometric. Without that hole, the pen will flood in flight - or maybe while you carry it around in your pocket on the ground!

 

A proper repair for these pens is replacement of the tube, usually done today with stainless steel. Not plastic.

 

Parker went back to the short plastic breather tube in later versions of the pen.

 

The hole BTW is made with a #77 drill.

[smbaugh]

Thanks gents. Very helpful. Here's a pic with the hole marked. It's 6mm from the end of the feed and seems to be glued in. I think I'll just fix up the current tube and leave it in there.... Do you have a source for stainless tubes for future reference?

 

The pen, by the way, is marked with "8," so first year aero....

 

All the best,

 

Steve

[Richard]

My statement that the earliest aeros were plastic is in error, and I will fix it. Sterling was the original material; I've verified this on several '48 aeros. My apologies for the oopsie.

[smbaugh]

My statement that the earliest aeros were plastic is in error, and I will fix it. Sterling was the original material; I've verified this on several '48 aeros. My apologies for the oopsie.

Richard,

 

I certainly was not quoting you to point out an error--no apologies needed! Simply registering surprise and wondering if this was a replacement tube and defective with the hole. I can't tell if this tube is sterling. As you can see, most of it's covered with what I took initially to be paint, but it's probably just old ink. The feed and tube were soaked in water overnight and run through the ultrasonic twice, so it's really on there!

 

So have *you* been making replacement aero tubes? (I searched old posts before making this one. )

 

Steve

[smbaugh]

That hole is what makes the aerometric 51 aerometric. Without that hole, the pen will flood in flight - or maybe while you carry it around in your pocket on the ground!

 

The hole BTW is made with a #77 drill.

I finally get it! I read about the design of these pens, but it's not until I open it up and see for myself and figure out what's going on that it starts to make sense. Very cool!

 

P.S. I've had a set of jewelers drills and other useful stuff for years inherited from my father in law. Now I have use for them!

 

Steve

[Richard]

I certainly was not quoting you to point out an error--no apologies needed

On the contrary, I do need to apologize for leading you, and probably others, astray. I've fixed the error -- it was in my "51" anatomy page. I always appreciate having mistakes pointed out so that I can correct them.

 

So have *you* been making replacement aero tubes?

Well, now that you mention it, yes. I had Daniel Kirchheimer build me a fixture so that I could drill the No. 77 hole without going through all the contority and derundment that attend attempting to drill a tiny hole on the side of an only very slightly larger tube of rather hard metal. The next issue of the PENnant will have an article that Daniel and I wrote together, explaining exactly how the aerometric system works and illustrating the making of the fixture.

Edited June 15, 2006 by Richard

[smbaugh]

I'll look forward to that issue of PENnant! And I looked at my drill bits--WAY too big for that hole, and I can understand the need for a special mechanism to drill that tiny thing. Cool!

 

Steve

[kirchh]

So have *you* been making replacement aero tubes?

 

 

Well, now that you mention it, yes. I had Daniel Kirchheimer build me a fixture so that I could drill the No. 77 hole without going through all the contority and derundment that attend attempting to drill a tiny hole on the side of an only very slightly larger tube of rather hard metal.

 

My ears were burning, and now I know why! Here's a picture of the beast in question:

 

http://home.comcast.net/~kirchh/Misc/Parker_51_Breather_Tube_Drill_Jig_Checking_Alignment.jpg

 

The next issue of the PENnant will not only have an article about the fabrication of this tool, but there will also be an exploration of the sealing and venting of the Parker "51" over the years.

 

--Daniel

[smbaugh]

So, the real question is when are you gents going to go into production of whole new 51s??

 

Seriously, that looks like a real labor of love. I commend you both!

 

All the best,

Steve

[kirchh]

Parker went back to the short plastic breather tube in later versions of the pen.

 

Interesting...are you certain of this (as opposed to the possibility of seeing some incorrect replacement breathe tubes)? A short tube would prevent the pen from filling very much, though it would be safer than a long tube without the side vent.

 

--Daniel

[Vintagepens]

Richard is correct here. You still get a good bladderful of ink with the shorter breather tube, since the squeeze system is quite efficient when it comes to expelling air (unlike, say, the Vacumatic or Ink-Vue).

[Gerry]

The tool is impressive Daniel. Really impressive. I was wondering though - was there a reason you didn't try a cross drilled block to be used as a guide? Although it would have wear issues perhaps, it would be pretty simple to make I would think. And using a stopped hole for the breather tube would guarantee that the vent hole is located exactly where it should be...

 

One nice advantage of your tool is that drilling the vent hole is a visible process...

 

Question: Does the vent hole go through both sides of the breather tube?

 

Gerry

[Ron Z]

Question: Does the vent hole go through both sides of the breather tube?

No, the hole is on one side only.

[kirchh]

I was wondering though - was there a reason you didn't try a cross drilled block to be used as a guide? Although it would have wear issues perhaps, it would be pretty simple to make I would think. And using a stopped hole for the breather tube would guarantee that the vent hole is located exactly where it should be...

 

I actually discuss the design considerations in some detail in the forthcoming PENnant article, but I'm happy to review the matter here.

 

To immobilize an object by placing it into contact with another object, the energy curve along the possible displacement path should have a cusp. That is, when the part is in the registered position, there should be a non-zero threshhold force needed to dislodge it. A cylindrical object resting in a V-shaped groove has this property; it is immobilized until sufficient lateral force is applied to overcome the pressure from one of the two walls of the 'V'.

 

On the other hand, a cylindrical object in a hole that is necessiarily of slightly larger diameter has an energy curve without a cusp at the indexed position, so the tube can be easily displaced laterally (though the amount of force needed increases with increased lateral displacement). That is one of the reasons that, for example, vise jaws have a V-shaped groove for holding round objects.

 

Also, from a machining standpoint, creating two perpendicularly-intersecting holes of extremely small diameter, with a tolerance at the intersection measured in ten-thousandths of an inch, is not trivial.

 

I do have a simpler design; that's shown in the PENnant article.

 

One nice advantage of your tool is that drilling the vent hole is a visible process...

 

Good observation, and one I discuss in the critique of the project. I haven't used the tool extensively, but I suspect that this is a nice attribute.

 

Question: Does the vent hole go through both sides of the breather tube?

 

Nope! It goes through one wall only. The collar with the set screw that you see on the shank of the drill is a depth stop to ensure this.

 

--Daniel

[Dillo]

Hi,

 

May I ask what the tool is made of?

 

Is that tool more complicated to make than my tools?

 

 

Looks like a nice tool.

 

Intreresting!

 

Dillon

[kirchh]

May I ask what the tool is made of?

 

The rectangular blocks are 6061 aluminum. The posts are stainless steel, as are the post screws. The drill bushing is tungsten carbide, as is the drill bit itself. The clamping screw is steel with a black oxide coating. The depth stop collar is stainless steel, I believe. And the little feet that were added later are rubber with brass screws.

 

Is that tool more complicated to make than my tools?

 

Somewhat, but not dramatically. Your tools are completed, by the way; after you receive them, I'll post a picture here. You want the pleasure of seeing them for the first time in person! But here's an in-progress shot.

 

--Daniel

Edited June 17, 2006 by kirchh