Star Tooling

From PyroGuide

Star tooling is simply the tool used to make pyrotechnics stars. The tools come in a wide variety, including star pumps, cavity pumps, crossette pumps, and comet pumps, just to name a few. If you're just a hobbyist, and you're looking at buying one, I bid you wait; please read this article. It's much easier than you think.

[edit] Materials

It's relatively easy to make your own star tooling if you have access to some standard shop tools.

- A ruler
- A Vise
- A Drillpress
- Drill Bits
- Tap and Die set
- Assortment of steel files, both round and flat (even those used for sharpening chainsaws)
- Some Brass, Aluminum, or other soft metal

Metal
You must be asking yourself where to find pre-machined aluminum or brass. The best source I know of is a website called speedymetals.com. They sell brass, aluminum, steel, and many other metals, either round, square, or flat, and they pre-cut them to the 1/16 of an inch. The shipping can be a little bit high, but it's pretty much a flat rate no matter how much you buy. So if you're planning on making more than one star tool at a time, make sure you buy everything you need in one order. The sizes or the metal we'll get to later in the tutorial.

Drill Press
You'll need a drill press for this. It doesn't have to be big, only big enough to be a little taller than the vise you're using, as it will need to be underneath the drill.

Vise
A workshop clamping vise will need to be implemented for stability reasons. Usually the device that comes on the drill press is good for holding flat and rather large items. What we're doing is not the case.

Drill Bits
Drill bits probably need to be high speed oxide bits, or cobalt, for cleaner drilling. And of course, they need to be the appropriate size for the tooling you're making. i.e. if you're making 1/2" pressed stars, you'll need 1/2", 3/16" and 5/32" drill bits. (I'll explain why later on)

Tap and Die Set
A tap and Die set will be used in this example to attach the handle to the star tools to the press part. Very little prior experience is needed to use these tools. Again, the size of such will be discussed later on.

Files
Flat and round files will be needed not only to clean the metal up after drilling, but to flatten ends and, in some cases, even shape the tooling itself.

[edit] Picking Your Tool

First things first- you'll need to know the type of tool you're looking for. Star pumps are easily made in about an hour, whereas crossette pumps can take up to four or five hours. This tutorial will show how to make three different types of pumps.

[edit] Basic Star Pump

I personally choose to use brass for my star pumps because of its easy workability and resistance to corosion. Easy cleanup also plays a part in its ease of use. The star pump I'll show you how to make here will be a 1/2" star pump, with a star length of 1".
First of all, the exact materials list for this pump and their approximate prices:
- 3/4" Daimeter round brass, 2" long; about $1.33 an inch
- 3/16" diameter brass, 3" long; about $.09 an inch
- 1/2" diameter brass, 3/4" long; about $.59 an inch
- 1/2" drill bit; about $3.00
- 3/16" drill bit; about $1.25
- 5/32" drill bit; about $1.25
- 3/16" tap and 3/16" die set; about $5.00 purchased sparately - make sure the thread counts match!!!
(Alternatively, a long 3/16" machine screw could be used in place of the 3/16" brass, but the tap used must match the threads per inch [tpi] of the screw.) All together, the price of this is less than half of a professionally machined pump, and will last you just as long.

[edit] Procedure

You'll need to fix your vise to your drill press, or to the same surface your drill press is fixed to. In doing this, make sure that your vise will be able to be moved directly underneath your drill. Use a file to flatten one end of the 3/4" brass until it shines. Next, you will need to take your ruler and, with a sharpened pencil, find the exact center of the diameter of brass. This will be 3/8" from each edge. Mark it. If you want, take a small punch and lightly tap a small indent at that spot. However, this is not needed, it will only make things a little easier.

Place your piece of brass into your vise, marked side up, and position it under your press. Now, the tedious part. The drill bit (now chucked into the press) must hit that marked spot on the brass dead on, or else your pump might not look like a pump. In the meantime, your metal needs to be clamped in plumb to the drill bit to avoid drilling out the side. Take your time in doing all of this. I have a rig set up just for doing this, and it still takes me about 5-10 minutes to get everything right. The first time, I think I started drilling after about a half hour.

Once positioned, drilling needs to commence. Not too fast, though; let the drill bit do it's work. The hole needs to be drilled 1-3/4" deep into the metal. Stop frequently and stick something into the hole to verify depth. (Mark it and hold it to your ruler to verify.) Make sure you do not go any deeper than 1-7/8" or you risk breaking out of the bottom of your 2" brass. Once finished, you'll need to remove the 1/2" drill bit from the chuck, and replace it with the 3/16" drill bit. Repositioning the metal back under the press this time should be easier because of the "V" shaped bottom of the previous drill bit. Just find the spot where the drill bit fits the best, and clamp it down. Drill the 3/16" hole in the center of the metal all the way through this time. (The 1/8"-1/4" remaining). All that is left is drilling a air escape hole in the side, which we'll do later. Next, prepare the 1/2" brass.

File down and find the center of the 1/2" brass the same way you did the 3/4" piece. Next, place the 1/2" piece of brass in the vise and chuck in the 5/32" drill bit. Make sure it is in the center, and drill that piece about 3/8" deep. Do not exceed 1/2" depth when drilling this piece.

Clamp down the 3/16" brass in the vise, but not under the drill press. Use your 3/16" die to cut a thread into the brass that is 3/8"-1/2" long. (Extra here will not hurt.) You must, however, make sure the threads are cut level into the piece though. you'll actually have 2 chances at this- if you mess up one end, you can do the other as well. Once completed, clamp in the 1/2" brass again, hole side up. Use your 3/16" tap to add threads to the inside of the hole. This is much easier than the die you just used. The tap will follow the hold you drilled if you just let it do the work- don't force it. Tap until you hit the bottom (the tap won't go any further), and remove the tap. Now thread the pieces together.

If you're machine work was good, the handle of the plunger should go into the mouth of the 3/4" piece you drilled first, and the plunger should slide all the way into the shell. IF your plunger does not go all the way in, it might have to be shaved with the files you have. make sure you shave the bottom portion of the head of the plunger, but leave the topmost portion (the part that pressed the star) it's original diameter.

Once cleaned up and working properly, you'll need to drill an air escape hole right above where the plunger sits inside it. Take a small stick or nail and put into the mouth of the pump with the plunger retracted. mark the length to the end of the pump and measure it. Now mark the outside of the pump (from the mouth end) the same distance. Drill (with your press or hand drill; doesn't matter really) a small hole ABOVE that mark (closer to the mouth) through just the one side of the pump. Clean the hole up inside with a round file, and your star pump is done.

[edit] Cavity Pump

Cavity pumps are used to leave a generous cavity at one end of your pumped star. This effect is sometimes described as a colored star leaving behind a different color or effect tail. The cavity pump is very similar to a basic pump except for one detail- the cavity it leaves in the star. So to conserve space, I am going to work off of the basic pump procedure above. (I'm guessing you read that.) The materials list will be the same except for the piece of 1/2" brass. Instead of being 3/4" long, it will need to be 1-1/4" long.
The same procedure will be followed to drill the sleeve, drill and tap the plunger, and to die the handle. What you will end up with is an elongated plunger head. This is where the files I asked you to have come in handy. What you will have to do to achieve the cavity is file down the last 1/2" of the plunger to, instead of 1/2" diameter, to 3/8" diameter or 1/4" diameter, or anywhere in between. It's really your decision depending on how much effect you want your star to have. Once completed, your pump will be ready to use.

[edit] Crossette Pump

Crossette pumps are used to create stars that emit their color for a short period of time, then burst into 4 symmetrical pieces in different directions. This effect usually looks like the stars form an outmoving "X" in the sky. The procedure differs quite a bit from basic and cavity pumps, so I'll include a summary of those with the details needed to make crossettes.

First of all, the material list for this star changes. Here's what you'll need:
- 3/4" diameter brass, 2" long
- 1/2" diameter brass, 3" long
- 5/16" diameter brass, 5/8" long
- 1/8" diameter brass, 2" long
- a machine screw, preferrably a 6-32 at least 2" long (That's #6 with 32 tpi)
- a 6-32 tap - 1/2", 1/8", and #36 wire gauge drill bit - assorted flat and round files

[edit] Procedure

You'll need to set up your vise and drill press the same as in the basic pump. File down and mark the center of the 3/4" brass and place it in the vise. You can also use a punch to make an indent at the center to make it easier to drill. Drill a 1/2" hole in the brass, althouth this time, you'll be drilling all the way through. Be careful coming out the other side that your drill bit does not bind up. To prevent this, go extremely slow breaking through. When finished, remove this piece from the vise.

Next, file down and find the center of the 1/2" brass. You'll need to clamp in the 1/2" piece and chuck the #36 drill bit. Drill a hole in it about 3/8" deep. While still in the vise, use your 6-32 tap to tap threads into the piece. make sure the tap hits the bottom of the hole.

Remove the 1/2" brass and place the 5/16" brass in. Mark the center of the 5/16 piece with a pencil. Using the same #36 drill bit, drill completely through. Once again, use the tap to tap threads all the way through the brass. Check that the 6-32 machine screw you have threads into and through the pieces you tapped. The most tedoius part of making a crossette pump is the "X" shaped piece construction. This will be filed down from the last brass piece you threaded. Using round files, four round indents need to be cut into the brass equally. (See pictures)