Friday, October 22, 2021

An Apollo Hatch

 Long before computer operated mills (CNC) all of this was done using "a meat computer"; the guy turning the handle, knew how far to turn it.

As a kid, I hung around my dads aerospace machine shop, and watched guys on old Bridgeport mills, turn blocks of metal into amazing mechanical shapes. 

The main hatch of the Apollo Command module, that took men to the moon, was a beautiful piece of mechanical art. Fabricated by guys like the ones who worked for my dad. These unassuming guys, in their plaid shirts, oil stained leather aprons, cigarette in their mouth and a cup of coffee on a nearby bench, created the millions of parts to America's Apollo Spacecraft, with no computer operated machines, just their skill and experience.

Know as the "The Unified Hatch", this was a 350 pound, quick opening "vault door". 

It was called the unified hatch, because the original design, was actually 3 separate hatches, all of which had to be opened by the astronaut, in order to exit the spacecraft. After the tragic accident of Apollo One, in which a fire developed so quickly, that opening these hatches was impossible, NASA required a new design that could be opened quicker.

The redesigned hatch could be opened in around 3 seconds, and get out of the spacecraft in less than 30 seconds. A great improvement over the 60-90 seconds for the original design. 

Utilizing 15 latches, a mechanical gearbox, a counterbalance system and a gaseous nitrogen operated piston, this was an incredible piece of engineering and machining. 

This is the hatch from Apollo 11, which is now on display in the Smithsonian's Air and Space Museum.

In early 2019, I was talking with one of my clients, who had purchased one of my replica Apollo spacesuits, about the amazing accomplishments of America's industry, in designing and creating the massive amount of technology and hardware for Mercury, Gemini and Apollo spacecraft, in only 9 years. We both were fascinated by the spacesuits the astronauts wore, but at some point in the conversation I brought upon the Command Module hatch as one of my favorite pieces from the spacecraft. He agreed and I mention how I had wanted one, just to hang on my wall, to showoff  the skill of the 1960's machinists I admired as a kid. He said it was one of his dreams as well, them paused, and asked, "do you think you could build one?" At first I thought, no way. Those guys were far more skilled at machining than I'll ever be, but then realized that much of their skill and experience is sort of "captured" in the computers that run CNC mills and lathes today. For 40 years, I have been building things for film, museums and some for aerospace clients, and I thought well you have figured out complex projects in the past, why not this.

I told my client, that I thought I could....but it would be very expensive. He asked how much. I gave him a ballpark, thinking I could wriggle out of telling him I could build this, and he said, OK, think about it and give me a formal quote.

Once I had the check in my hand, I realized there was no way of getting out of it. So, like with any project, you start by gathering images and information. Having spent 30 years building replica space hardware, I have become friends with a number of retired aerospace people, and collectors. I have built full size Lunar Modules, both interior and exterior, along with replica's of just about every spacesuit that has gone into space. But, I hadn't done anything from the Command Module before. Well I had to start somewhere, so I reached out to my usual sources. Information was slim, but I did manage to acquire some original drawings and spec sheets on the hatch, alone with some high quality images of the individual hardware elements. There was also an Apollo hatch near me in the California Science Center, which I have done work for. 

One big advantage I had (which had not occurred to me initially) was having grown up around the type of shop that built parts like this, I was recognizing machining details, edge treatments and surface finishes as I was looking at the photos.

Real Apollo hatch in
the California Science Center
Gearbox detail of the Apollo hatch in
the California Science Center

The original hatch locking system was mostly machined stainless steel, with the body of the hatch made in aluminum. Since the intent was to hang this on a wall, I wanted to reduce the weight as much as possible, while still keeping it in machined metal. I also wanted the latches to function. So I would have most of the hardware machined from aluminum, and experiment with various finishes in order to match the original hatch.
The parts where drawn in Solidworks, a complex 3D engineering software. I had had limited experience with Solidworks, and self taught, so I new this was going to seriously test my skills. I started with some of the simpler parts and 3d print test pieces. I got a email one day from a friend who is incredibly knowledgeable about the Apollo Luna Module, and he said he had been looking into a source for information on the hatch.

It turns out, Andrew Barth, and engineering student, working with Adam Savage (Myth busters fame), decided to scan the Smithsonian's hatch and build a replica. But, this replica was to be made by dozens of different artists around the US, and out of a wide range of materials. The model files were posted on the Smithsonian's site, under free license for anyone who wanted to print a copy for themselves. The files were all solid .STL files, and were not useful for machining a working replica, but like the photos and drawings I already had, they where a useful source for information to assist my Solidworks drawings. Also, since the files were intended to be 3d printed, there where many parts that grouped together multiple parts, and had cavities which could not have been machined.

In the end I did about 200 drawings in Solidworks. The parts were jobbed out to CNC machine shops and as I received them, I did some machining operations for minor corrections, and edge treatments. This is where my experience in my dad's shop came in handy. The parts needed to look like they had been machined and surface finished with 1960's aerospace conventions and standards. So I did dozens of tests and various parts in order to get the appearance of the parts correct. My client wanted an "as new", or "just flown" look, so I didn't want too much aging or surface patina.
While some parts of the real hatch are made from aluminum, the parts that needed to look like stainless steel, I had electroless Nickle plated and then tumbled to match the stainless steel look of the originals. I also sourced correct cruciform, high tolerance bolts, to match the original bolts used on the real hatch. (Some cost $25 each)

My replica of the Apollo "Unified" hatch.

I wanted the latches to function, and as an added feature, I powered them with a remote control servo, so with a press of a button, you can lock and unlock all 15 latches.


For the exterior my client wanted it to look just like the freshly return spacecraft. At first this was tricky, because the real hatch, looks a bit "Fake", with it discolored chrome "mylar" outer layer. In researching the original specifications of the lunar mission hatches, I learned they were covered in aluminized Kapton. Kapton is a plastic that has a very wide operating temperature, and is transparent amber in color. The "Gold Foil" you see on the outside of the Lunar Module, is neither, it's not gold, and it's not foil. What it is, is Kapton, that has been aluminized on one side, and because it's transparent yellow, when viewed from the other side, it appears gold. It turns out, the Kapton on the exterior of the Command Module (CM), is Kapton that has been aluminized on both sides, and the yellow discoloration on the recently reentered CM, is where the aluminum micro-thin coating has burned off.
Well, lucky me, because I just happen to have, original, double metalized Kapton film (found on eBay years ago). After coming up with ways to "burn" off the aluminum, it was nearly a perfect match to the original. 

Exterior of the replica hatch, mounted on the wall stand, with the ablated aluminized Kapton film.

The wall mount allows the replica hatch to be swung so either the inside or outside surface can be displayed.

I have made 5 of these, and have 3 still available. (as of this publish date) 

If interested, please visit, Orbital Surplus for more information. or email

Monday, March 22, 2021

Greenwich armour; Nearing the finish line.

 After nearly 4 years of decoration, the Greenwich armour project is nearly complete.

I have the burgonet, falling buff and locking gauntlet to complete, but all of the other pieces are finished.

Here are some images of the finished pieces, and some in progress shots.

Here is a little info-graphic I made to illustrate the steps I used to decorate each piece of the armour above.

Monday, June 8, 2020

Greenwich Armour- One step at a time

   My Greenwich armour project is progressing slowly, but at least it is progressing.
I have been asked many times about the process for etching and plating, which I have mostly addressed in earlier posts. This is my first time doing anything like this, and as I have progressed, I have discovered better or more accurate (to the original armour) ways to do this. I have tried to update the techniques whenever I have found something that works better.
At some point, at the end of this massive project, I will have to post a synopses of the techniques I use and see how my experience over the course of a couple of years working on it, have changed my  approach.
For now, I have a list of all the steps from getting the heat-treated piece of armour, to the final assembled piece. (For those of you who make armour, some of these steps listed are obvious)

The decoration (etching, gilding & bluing) involves 40 steps for each plate:

Greenwich armour Decoration steps (after heat treat)

1. Polish with 400grit greaseless compound
2. Polish with white “stainless” compound
3. Pattern sunken areas for artwork with masking tape
4. Scan masking tape patterns
5. Draw or modify decoration artwork (on computer) for unique areas of the plate to be masked.
6. Cut vinyl decoration masks
7. Weed vinyl & add peel cover
8. Clean steel with acetone
9. Apply vinyl’s to steel plates. (Figure 8, wavy and vine patterns)
10. Adjust vinyl, trim overlaps
11. Clean surface with alcohol & window cleaner
12. Add dots and any missing artwork (averages 100 dots per inch of decoration)
13. Let dry 10-15 hours
14. Mix paste batch let sit for 3 hours, remix
15. Apply 1st paste batch- let sit for 2 hours
16. Remove paste
17. Apply 2nd paste batch- let sit for 2 hours (fix dots as needed)
18. Remove paste - rinse with water & dry
19. Apply 3rd paste batch- let sit for 2 hours (fix dots as needed)
20. Remove paste - rinse with water & dry
21. Apply 4th paste batch- let sit for 2 hours (fix dots)
22. Remove paste - rinse with water
23. Clean off vinyl decoration masks and dots (very hot water and soft metal scraper)
24. Dry part and remove large area masking
25. Assemble part to check artwork alignment
26. Power wire wheel etched areas (from all four directions)
27. Thoroughly clean with acetone, window cleaner and alcohol
28. Paint black paint (Rustoleum high temp black) onto specified areas (let dry for 12 hours)
29. Wet sand etched areas with 2000 grit paper removing over-paint
30. Mask areas not to be plated, with nail polish (dots and edges)
31. Electro clean surface to be plated (Heated to 160 degrees F.)
32. Rinse with distilled water
33. Nickle plate
34. Rise with distilled water
35. Gold plate
36. Strip nail polish masking with acetone
37. Tape off plated areas with masking tape
38. Re-polish areas to be blued
39. Put in oven at 290 Celsius until correct blue color is achieved then remove
40. Spray with surface protectant.

Part is ready for straps, linings & assembly

This requires
1. Cut buff leather strap (first find true "buff leather")
2. Split it to to half thickness
3. Cover with antique French burgundy velvet ribbon and sew in place
4. Make strap ends in brass
5. Solder brass 10mm caps on rivets
6. Scothbrite then wire brush surfaces of all (buckles, strap ends, rivets)
7. Rinse with distilled water
8. Nickle plate
9. Rise with distilled water
10. Gold plate
11. Rivet buckles and straps in
12. Rivet armour plates together (Also add articulation leathers)

Here is the size of the dots needed. (and the ones shown here are a touch larger than the original)
These are added one at a time with a needle bottle with a 27 gauge needle. (McMaster-Carr PN-1902T341)

I was using nail polish, but recently, I have switched to a marine paint made by Duralux (purchased - Home Depot-online)
The paint seems to be more durable (against the salt paste) and flows better with the needle bottle than the nail polish.

Here is the right arm complete. (The left is waiting for it's last 3 rivets, I can fit the mounting pin for the jousting Passguard)
I have added elbow straps, even though there seems to be evidence they did not originally, but since I am unsure of this, I added them. If they prove useless, I can cut them out at a later date.

Next, the Pauldrons....

Wednesday, December 11, 2019

Heat treating armour - A modern way

Many amourers and knife makers heat treat their own stuff, and while I have heat treated my own things before, I'm going to a professional company for this project. Having grown up around aerospace manufacturing, I learned years ago that there is more to heat treating than just making it hot and quenching it, and making it hot again. Modern heat treating has come a long way, and because of the complexity of this project, and the other advantages I'll address here in a bit,  I am using Certified Steel Treating (CST) Corporation in Los Angeles Ca.

Without going into too many technical details of what heat treating is, let me outline the process for those unfamiliar with what's involved in heat treating steel. However, first off, I am not an expert in heat treating, so forgive me if I get some technical bits wrong here.

The basics of Heat Treating steel.

 First: Heat the metal to the correct temperature, this varies with the type and alloy of metal being hardened, but with steel you are in 1500-1650 f / 815-870 c temp range. In addition; The amount of time at that specific temperature is important.
 Second: Rapidly cooling the piece, by quickly submersing it in a "quench" of water or oil or molten salt (see below)
 Third: Reheating the piece to a much lower temperature, in this case 500-750f / 260 - 400c to "temper" it so it is not brittle like a piece of glass.  This is where you can control how hard or flexible the piece can be. Either hard like a file, or flexible like a spring. The choice of metal alloy you use is a big factor of these properties.

For my Greenwich armour one of the factors in deciding to use a commercial heat treating company was I'm using a "modern" steel, in this case 1050, and they will know exactly how to process it to the desired hardness. If it's too hard, it will crack when struck, too soft and it will dent easily. 1050 is a close modern equivalent to what the medieval or renaissance armorer was using. This alloy of steel has just enough carbon (.50%) so it can be hardened, but is not an exotic modern alloy with lots of other types metals mixed in.

The big advantage to a commercial company, is the use of modern vacuum or atmospherically controlled furnaces, which eliminates oxygen around the heated part. This keeps the surface from oxidizing or "burning" while it's glowing orange, resulting in a "scale" on the surface.
This way, your piece can be surface finished to bright or polished, and the surface will be undamaged by the heat treating process. It will turn blue, but bringing it back to "white" is pretty easy.
Another advantage, is salt quenching. The advantage here is lowering the thermal shock to the piece being hardened. Going from 1500f to 80f  of your oil or water quench tank, is a severe drop and can cause a lot of distortion in the work. In order to harden the steel however, you do not need to drop the temperature by 1400 degrees, you only need a drop of  800 or so. One way to do this, is to heat salt to 600 degrees and quench the piece in that. The only down side to a salt quench is you can't have any plates riveted together or other places the salt can get trapped. Because after quenching, they will thoroughly clean the parts, and any place they can't get to, that traps the salt, will corrode.

Since this process is done on a lot of material in a commercial heat treating facility, it's pretty reasonable cost wise. A batch of around 20 ponds of material will cost in the neighborhood of $200 (This is a bit of a guess from memory, but when I get this next batch back, I'll update the cost)

I-Beam clamp from McMaster-Carr (PN-29915T81)
In order to keep the pieces from warping or distorting, you want to brace the parts with a fixture that is more rigid than the part, so it will hold the part in place. There are a number of ways to do this, but I like to clamp or pin the pieces, then weld a frame to these clamp points.
On the most recent pieces, in this case the pauldrons, fauld, and arms, I found some "beam clamps" which are used for securing things to metal I-beams. These can be bought on Amazon for around $1 each, but the only ones I found are galvanized, which would have to be stripped off before using them. Another source is the company McMaster-Carr, they have unplated ones for $2.30, so I used those.  These clamps come with a 3/8"-16 bolt and nut, so once clamped the nut can be used as a jam nut to lock the bolt in place. These are threaded on both sides, so another bolt can be threaded in from the other side giving you the option to pinch the part between the bolts.

The resulting clamp arrangement means you can now just "Connect the dots" with some steel bar, or in this case square tubing. The clamps can be pivoted to facilitate using a straight piece of tubing to connect multiple clamps like seen above on the fauld lames. Here is the finished bracing.

I try to leave a flat stable surface on one or more sides so the parts can sit nicely in the furnace. Anywhere there are rivet holes between plates, #5 screws are used to secure the plates to each other. While a #5 is an odd size, it is almost exactly an 1/8 inch in diameter, which fits perfectly in the rivet holes. Once the pieces come back from the heat treater, I'll cut the clamps off the frames, so I can reuse them. This also is a great way to use up the short scraps of steel tube our shop seems to generate.
The arms and pauldrons are braced in a similar manner.

For the cuirass, I used a technique I used before, where I make tabs from 1/8" strap stock with holes, that secure to the armour through rivet holes with the #5 screws, and then I connect these tabs with steel tube. In addition, I drill holes in the steel tube and weld nuts over the holes and thread a bolt through and pin the armour. In the case of the cuirass, this requires a frame on the outside as well. I try to design it so I don't have to cut any of the tubes to remove the armour.
 In addition, I have added tabs on the front and back of the bottom skirt to trap it against the inner steel frame.
Once these come back, I'll clean the surface back to white (shiny silver) and start the etching.

Sunday, September 29, 2019

Greenwich Armour: The work to get to this point.

As I stated in an earlier post, this armour was started by Robert MacPherson (Talents I have seen) and after an injury, Mac was unable to continue with the armour. Mainly because the work left to be done was all of the "heavy" work, the thicker jousting pieces and sinking all of the surfaces than needed etching & gilding.
Jeffery Wasson took up the challenge of completing this massive project. Massive, in that, not only was this a complex, advanced late period armour, but it was also a complete garniture. That being an armour with multiple separate components to allow the armour to be configured in multiple ways for different specific uses. In particularly, jousting.
For jousting, the Greenwich armours had additional heavy reinforcing plates that mounted over the main armour in order to improve the safety of  riding head to head with another jouster, who was trying to hit you with a metal tipped heavy wooden lance.
Imagine riding on the freeway in the back of a pickup truck and leaping out into a street sign and hitting the sign post. The impact is tremendous. So to help keep the guys from getting injured (or killed) heavy plates were affixed over the base armour, which helped tie loose appendages together to keep your arm from being dislocated or your neck broken.
Just like modern sports, jousting evolved over time with changes in rules and improvements to safety, usually motivated by serious injury or death. So by the late 16th century, jousting armour was pretty sophisticated and substantial. To the best of my knowledge, this is the first  replica of a complete Greenwich garniture built in at least the last 100 years (I'm not sure if any replicas were built during the Victorian period) So there is a lot to learn by trial and error in recreating these parts and making sure they interact with each other in the correct manner.
Here are some images of this process (work by Jeff Wasson):

Examining the original arm armour at the
Wallace Collection. The burgonet and
falling buff are in the foreground
(Thanks to Dr. Tobias Capwell)
The fitting of the close helm visor. (one of two)
The garniture has two helmets and 4 visor options. The burgonet has a bar grill and a falling buff and the close helm has a tilting visor and a field visor. The close helm locks onto the gorget, via a rolled top edge on the gorget and the ridge you can see on the bottom of the close helm. When properly made, the rotation is effortless.

The burgonet with it's falling buff. The bar grill
fits beneath this. The black pen lines, show
where the decoration areas need to be sunk.
The close helm with the tilting visor.
 Again, the lines indicate areas to be sunk.
The close helm being fit the gorget or "collar"

The burgonet with it's sunken boarders.

The rough ground breast with its sunken boarders.
 Sinking the boarder moves the whole piece
often requiring the piece to be reworked
in order to refit it to its mating pieces.

The breastplate being heated in order to sink
the decoration areas. Heat is required
because the breast is about 2 mm thick

If all this isn't difficult enough, an optional  second
"reinforcing" breastplate is also fit over the main one.
The reinforcing BP is 3 to 4mm thick and is intended
to be proof against heavy rifle rounds.

The reinforcing BP also needs sunken boarders.
Once the decoration areas are sunk,
the reinforcing BP needs to be refit to
the main breastplate. Areas that should not
touch are marked with soapstone and corrected.

In addition to sunken areas, the more traditional
rolled edges need to be added to many
of the plates.

The backplate is considerably thinner, but still needs
sunken areas for decoration. The rolled edges also
get grooves hammered in, called "roping".

An earlier test fit of all these pieces.

Pauldrons (Shoulder defences) are particularly tricky.
Not only do these need to fit perfectly, they also need to be
the correct proportion for the period of armour.

Roping being added to the rolled edge
of the couter (elbow)

Here we have the gorget, burgonet, falling buff, spurs
arms and tassets all ready for heat treat and decoration.

In addition to all that, the jousting plate known a
grandguard is patterned over the breastplate
and pauldrons.

Here is the formed grandguard, now, continuing
up over the left side of the helmet, again with the
to be sunken areas indicated with soapstone lines.
All of the specialized tilting pieces.
All the pieces for the torso defense.