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About Corbin DC-Dies Software

The DC-DIES program helps you calculate the breaking pressure and maximum safe pressure that can be used in a swage die of any diameter and tensile strength, and what gauge pressure this would be on a hydraulic press with any desired size of drive cylinder. It also calculates the equivalent pressure and ram thrust for any two hydraulic presses using different size drive cylinders, which is useful for press design.

There are two screens. On the first screen, you will see these entry boxes:

  1. Bore Diameter (inches)
  2. Die Diameter (inches)
  3. Tensile Strength (PSI)
  4. Drive Cylinder Diameter (inches)

Three buttons, labeled "calculate", "reset", and "quit", are provided. The "reset" button fills in the blanks with standard example sizes and values, similar to those used in the CHP-1 Hydro Press made by Corbin. The "calculate" button applies the values and brings up a set of answers. The answer boxes appear when you press "calculate" and are erased when you press "reset".

The answers are:

  1. Safe Pressure (PSI)
  2. Breaking Point (PSI)
  3. Punch Area (Sq.In)
  4. Oil Pressure (PSI)
  5. Ram Thrust (Lbs)
  6. Ram Thrust (Tons)

The "bore diameter" is the smallest diameter in your swage die that is subject to pressure. For straight hole dies, it is the bore size of the die (not necessarily the caliber of the bullet, because core swage dies have much smaller diameters than the caliber). For point forming and boattail forming dies, the smallest area subject to pressure is somewhere near the tip of the die, or across the small end of the boattail base. A .308 point forming die with a long pointed nose might have a diameter that approaches an ejection pin hole of only 0.081 inches. If you push lead up into the ejection pin hole, then the smallest diameter of bore subject to pressure is 0.081 inches, not .308. Point forming dies have the characteristic of a curved bore, so that the smallest point subject to pressure will vary with the length of bullet that you are attempting to form, and whether or not you push the bullet all the way to the tip of the die.

If you use less than the full length of the die bore to form your bullet, it means that the pressure actually is zero just ahead of the bullet tip, and rapidly increases to full pressure further back along the ogive. Generally, we use the first point of contact in the ogive as the diameter for purposes of determining normal breaking or safe pressure point, with the assumption that you will not be pushing the bullet material up against the ejection pin or into the ejection pin hole (which vastly reduces the ram thrust that can be safely applied). This is usually close to the full bore size. If you were to push a smaller diameter solid rod into the die, it would contact the ogive at the diameter of the rod, which would reduce the effective bore size for pressure calculation purposes (meaning, it would be easier to break the die since the force would all be initially applied in a smaller area and thus more highly concentrated).

As indicated by the link which appears between the two frames, the pressures and forces shown on the right for the press parameters are those for the maximum safe operating pressure. They are not the pressures and forces that are sure to break the die, but are about 75% lower, giving you a 25% safety margin under normal proper operating conditions (normal temperature, non-impact or low shock contact conditions where the ram is brought up smoothly and with reasonable slow speed until contact is made with the material).

The menu at the top of the screen has these choices:

  • Quit (ends the program)
  • Print (brings up the printer selection options and number of copies)
  • Calculate (duplicates the function of the calculate button)
  • Reset (duplicates the function of the reset button)
  • Hydraulics (brings up the second screen)
  • Help (displays and lets you print the DC-DIES.TXT help file if it is present)


Hold your mouse pointer over any grapic, box, or word on the screen to bring up additional information in a little box. It takes a few seconds for the information box to pop up. Click on the logo or the title to get other information such as web address or phone number for Corbin. Error messages will appear below the control buttons in a window, if you enter values that are too far out of range, and your entry will be replaced with something that works.
  1. Click the "RESET" button to make sure all the values are in range before starting.
  2. Put the cursor in the first box labeled "Bore Diameter". Change this number to the actual diameter for your swage die.
  3. Put the cursor on the other values that you may want to change, and edit them. You can jump to any of them and change only that one value to see how it affects the answers.
  4. When you are ready, click the "CALCULATE" button to see the answers appear.
  5. To view the HELP page or bring up the hydraulic system comparison calculator, click on the HELP or HYDRAULICS menu choices at the top of the screen. If nothing happens when you click HELP it probably means you already opened up the HELP screen and left it open when you went back to the calculator window, so that the HELP is hidden behind the current window. Look in your task bar for Windows and see if the HELP icon is there, and click it to bring it to the front.

Hydraulic Systems Calculator

The Hydraulics window has two columns, labeled Cylinder A and Cylinder B. These represent the figures for two different hydraulic designs using different size cylinders (you can enter the same size and check the answers, which should be the same for both in that case).

The items that you can enter are:

  • Diameter (inches) for system A
  • Diameter (inches) for system B
  • Pressure (PSI) applied to both

The diameter is the piston diameter (or cylinder bore). The pressure is applied to both so you can compare the thrust developed in both size hydraulic systems. The answers appear for both system A and for system B. There is also a conversion of the pressure to Kg/sq-cm.

The answers are (for each of the two systems):

  • Area (Sq-in) of the pistons
  • Thrust (Lbs) developed by the cylinder
  • Press Tonnage

Note that when you click RETURN it takes you to the first screen for die strength. If you have both screens or windows showing, and click QUIT on the first screen, it closes all the windows at once and shuts down the program. The HELP choice opens the same window for both sections of the program, but it displays different text. That is, if you click HELP on one window, and then click HELP on the other, the same HELP window stays up but the text changes to apply to the last-clicked HELP choice.

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