The purpose of a die holder is for it to grip round dies and hold them in a lathe tailstock during a threading operation. This makes it much easier to cut threads on a piece of metal if you want to make a screw or a threaded stud using the lathe. It is worth noting that this is a potentially dangerous procedure and requires prior experience with all of the listed tools to safely perform their operations.

Supplies

-1.5 inch diameter piece of cold-rolled steel, 4 inches long

-Hardinge HLV-H EM 9 inch lathe

-5C square collet block

-AR 6 C5 carbide cutting tool

-Servo II CNC Bridgeport Model 2J milling machine

-CAD software

-Deburring Tool

-Work Gloves

-Bluing Solution

Step 1: Dimension Your Design

To begin, it is important to design your threading die holder on a CAD software to visualize your part. Creating this design will make it easier to organize the dimensions of the part and keep track of how everything needs to be measured. The software used for this demonstration was Fusion360.

Step 2: Drill the Initial Hole Diameter

Take the 1.5 inch diameter piece of cold-rolled steel, which in this case is 4 inches long, and place it into a 5 inch lathe chuck in a Hardinge HLV-H EM 9 inch lathe. The first step is to drill and ream a ⅜ inch diameter hole through the length of the stock. This step requires an experienced operator for the Hardinge Lathe, as it is a dangerous piece of machinery and can cause bodily harm if not used properly.

Step 3: Boring Your Hole

You must bore a 1 inch diameter hole, ⅜ inch deep into one end of the stock using a boring bar mounted in a 0.5 inch capacity chuck. The boring bar needs to be located directly above the area that is being bored, and centered properly so that the machine bores into the middle of the part.

Step 4: Remove Excess Material

Break the sharp edges of the bored hole on the outside diameter with a deburring tool. The stock is then removed from the lathe chuck and turned around and a lathe parting tool is used to cut off the excess material to reduce the length of the part to 3 inches. This step requires the use of gloves due to the risk of receiving cuts from the sharp edges. In addition to the gloves, it is very important that caution is exercised when using the deburring tool.

Step 5: Fitting the Part for the Tool

Reduce the diameter of the back of the part to 0.5 inches so that it will fit in a 0.5 inch drill chuck during use. This machining is done with an AR 6 C5 carbide cutting tool. Place the part into the cutting tool as seen in the image provided. Safety is a concern in this next step as well, as gloves are recommended during this procedure to reduce the risk of injury while using the carbide cutting tool.

Step 6: Machining Set Screw Holes

Using a Servo II CNC Bridgeport Model 2J milling machine, place the part into a 5C square collet block for machining of the set screw holes. The machining of the 10-24 set screw holes consists of center drilling the hole 0.1875 inches from the end of the part. Experience with a Bridgeport Mill is required for this step as well, due to being a potentially dangerous piece of equipment that can cause injury if not used properly.

Step 7: Drilling Deeper

A #30 hole is drilled followed by a #22 drill, followed by a #20 reamer, which should be 0.161 inches in diameter. The hole drilled must be done in this order to allow for the excess material to be removed easily, and allows for the tool to operate more quickly with less material waste in the way. The image above serves as a visualization for the holes drilled and how they should look on the part.

Step 8: Threading the Holes

The hole needs to be threaded with a 10-24 taper tap while using the Bridgeport spindle as a tapping guide. Experience using the 10-24 taper tap is required to properly thread the holes needed for this part, and gloves for safety precautions are recommended as well for this operation.

Step 9: Coating the Part

The threading die holder needs to be coated in a bluing solution to keep it from rusting. This can be completed with any form of bluing solution and requires gentle coating that does not create too thick of a layer on top of the part. The bluing solution will increase the longevity of the part and will allow for long-time use. The image above provides an idea of what the threading die holder should look like after being coated.

Step 10: Testing the Part

Before using the threading die holder, it is recommended that part is placed in the tailstock end of the lathe while the lathe is functioning to see how it operates without the threading die. The part needs to prove to fit and function properly before being used since this will prevent any dangers of causing harm to the operator if the part does not serve its function. After this step, if the threading die holder safely fits into the machine, it is safe for operation.