Set Up C.D. Weld Pins


To get work done quickly and reliably is really important on today’s jobs. At Midwest Fasteners, we know that easy to use portable stud welding can be helpful to install all types of fasteners in a fast and practical way. And we know that Midwest Fasteners can help.

Weld Pins, sometimes called “Weld Nails”, can be welded using Capacitor Discharge stud welding, a process that is often called “CD” welding for short.

This is a portable welding process which uses readily-available electric power from an everyday, one-hundred-and-ten-volt power outlet.

In addition to being portable, CD Welding Systems have:

  • simple components
  • work quickly
  • and can be used on sheet metal thickness material to apply a variety of Welded Fasteners using capacitor discharge welding

Using the CD process for Pin welding offers a strong weld quickly and reliably to impale insulating materials. It can be used with Stainless & Mild Steel, even coated and Galvanized materials, plus Aluminum; with no burn-through of the metal, and no special welding setup.

The process of Capacitor Discharge welding occurs in a series of 4 fast steps:

  • Contact
  • Ignition
  • Placement of the Pin and
  • “Completion” of the Weld

The standard, portable CD system consists of:

  • The Controller [ or Power Unit] which is plugged into the one-hundred-and-ten-volt outlet.
  • The CD Gun with Cables is used to command the power unit and deliver weld current, with the Gun also serving as the Pin holder to properly place the pin during welding.
  • Then, on the other side of “the circuit” a ground cable and clamping connection is attached to the work-surface to complete our Capacitor Discharge connections.
  • And finally, special Accessories are used to hold the Pin in the Gun.

These parts make up the CD weld system.

It is critical to set the gun up properly to allow these steps and components to go into action, and to allow pins to weld reliably. There are several ways to set up for Pin-welding with the MIDWEST CD portable pin welder.

First, the simple part called the “Bullet” Collet .

This type Collet requires no additional parts and can be used on Pins up to 4” long.

To install this accessory, prepare the C.D. Gun, by loosening the screws at the end of the gun shaft to accept the Collet. At the same time, loosen the set screw on each gun leg.

Before installing the Collet, make sure the Collet is the proper size for the pin and diameter to be welded.

Insert the Bullet-collet into the Gun until it “seats” and stops fully.

Next, tighten the set screws (in this case 2 of them) and check to see that the Gun is free and clear to operate smoothly during the weld.

With the Collet installed, insert a Weld pin fully into the Collet until it stops. Slide the Leg and Foot Assembly until you have only an eighth-of-an-inch of pin sticking out past the foot. This is called “proper protrusion” and is critical to allow the Welder, Pin and Capacitor Discharge Welding Process to perform properly.

Once the eighth-inch is set, tighten both set screws to keep the foot steady.

If your job requires different length pins to be used, make this adjustment to each pin length to be welded, always ending with the critical eighth-inch of protrusion.

That completes set up of The Bullet Collet and you are ready to weld. Just:

  • Load
  • Contact
  • and Apply

Use of the standard “B” Collet and “B” Stop are similar and can be used for lots of applications as another accessory option. Installation of these accessories occurs as before, as does the final C.D. Gun set up.

Prepare the C.D. Gun the same way, by loosening the screws at the end of the gun shaft, and also on the underside of the gun faceplate.

Remember again, to make sure your accessories are the proper size for the pin and diameter to be welded.

This time, first insert a proper length “Stop” Into the Collet. Then put this assembly into the Gun until it “seats” and stops fully.

Next, tighten the set screws and check to see that the Gun is free and clear to operate.

Now, with the Collet & Stop installed, insert a pin into the Collet, again fully, until it stops. Slide the Legs and Foot until you have the eighth-of-an-inch of pin sticking out assuring proper protrusion and weld timing. Once the eighth-inch is set, tighten both set screws to keep the foot firm during welding.

Again, if your job requires different length pins to be used make this adjustment to each pin length to be welded—always ending with the proper eighth-inch of protrusion.

Welding is simple:

  • load
  • contact
  • and Weld

For an easy setup that requires fewer Collets in the long run, many users prefer a “Collet Protector”. This option gives longer Collet life and allows many length pins to be welded from the same setup; it also prevents “TOO MUCH” pin stick-out, a condition that can cause problems on pin jobs requiring lengths of 6 inches and longer.

Installing accessory parts in this way is also simple. With the gun prepared for accessories, install a Collet (properly sized for pin and diameter) into the gun shaft and tighten it down.

[NOTE: we are using NO stop or other accessory inside the Collet or C.D. Gun]

Next, install a Collet Protector Assembly “over” the Collet. The Collet Protector should also be properly sized to your pin diameter. Tighten it down by the set screws which are part of the Collet Protector Body.

With these parts in place, make the protrusion adjustment until one-eighth inch of pin shows past the “Foot” again, and tighten down the leg screws.

If there is NO change in the pin diameter, then no change needs to be made in your Gun or Accessory setup. With the Collet Protector in use, any length pin is now exposed with proper protrusion at the weld end.

Also Collet life is prolonged versus use of the standard B Collet because it is “protected” from the weld, as well as protected from damage in pull-away or in use.

The design of the MIDWEST C.D. gun allows long pins to protrude through the gun as far as needed, thus preserving the timing-tip exposure which we have set at the weld head of the Pin. Loading and welding goes smoothly, even with different length pins.

And finally, where placement requires Pin-welding to operate in a recess, or where extra “stick out” is needed to get the fastener “TO” the work surface; the MIDWEST C.D. gun and it’s special design, can accept another set of accessories to set-up these jobs with what is called an “Internal Stop”.

Removing the rear-cap from the MIDWEST C.D. Gun exposes the back side of the gun shaft. Made with internal threading, this shaft will accept a “stop-holder” and a “stop”.

Size the stop to accommodate the long pin to be used. (For extra assistance consult the MIDWEST Equipment manuals, accessory parts lists, or your MIDWEST Distributor.)

With the stop mounted in the “Holder”, install this assembly into the shaft and replace the Gun’s Main Spring & Rear Cap.

Now install a “B” Collet just like before, with NO stop; allowing the pin to pass down-into the gun.

The fastener will be stopped at a set point by the internal stop and set-up can proceed with adjustment of the foot-and-legs, one-eighth inch protrusion and welding.

With any MIDWEST Gun accessories shown you can get fast welded results with the C.D. stud welding process.

Midwest Fasteners’ Capacitor Discharge stud welders can cycle for 15-20 welds per minute, and material can be installed quickly and cleanly, using only one-hundred-and-ten-volt power, with reliably welded fasteners, one-after-another,and all with good holding-power to support materials of all types.

For more information on Pin Welding and CD Stud Welding, please visit our website at