Some regulators available don't supply a threaded port to add a pressure gauge so you may view what the pressure rating to the valve is running at. Though not imperative, it's still a nice convenience to know relatively what pressure your marker is running at. In this article I will show you how to strategically add a 1/8" NPT port to the newer style vertical adapter of your Spyder so you may install a gauge.

Vertical Adapters

There are a couple of different stock Spyder VA designs that are available. There are some aftermarket VA's available as well. Modifying an older style VA or Bob Long type VA are pretty much straight forward. This type has an extended area in the front that houses the threads and seal of the low pressure chamber(LPC) or volumizer. You can simply drill and tap a 1/8" NPT(national pipe thread) thread in the center of the VA and plug a gauge in. When performing this mod you will not have to worry about drifting into the threaded or sealing surface area of the LPC.

On the other hand, the newer style VA as shown in the photograph above is a bit more of a challenge because the LPC threads have been pushed into the front portion of the VA. If you do not strategically find a spot to drill and tap, you will run into the flat sealing area for the LPC o-ring. A leak will most assuredly ensue, not to mention the LPC will not screw completely into the VA. I will try to help you find this VA gauge sweet spot to avoid any leaks or rendering the VA  completely useless.

Materials And Tools

The materials and tools needed to perform this mod would be: a vertical adapter, gauge and LPC of course, vice, 1/8" - NPT - 27 tap and tap handle, .3390" drill bit(around 5/16"), 2 slightly smaller drill bits, center punch, small round file(s), sandpaper, drill(variable if possible), masking tape, teflon tape,  2 small pieces of corrugated cardboard and a small measuring tool or a caliper preferably.

Modifying the Vertical Adapter

Rather than scribing measurement lines into the anodizing of the VA, you can simply apply a piece of masking tape across the side you choose to install the gauge on. Use a pen or pencil to mark the lines with.

Install the LPC and see exactly where it stops at the face of the VA. Using either a scribe, marking pen or a piece of tape, make a mark on the LPC at that point. Remove the LPC and find the measurement from the marked point to the o-ring end of the LPC. Use that measurement from the face of the VA to make a vertical line across the masking tape on the VA. You want to make sure that the hole you drill does not go forward of that point. Now find the center point of the LPC threaded hole in the VA and make a horizontal line across the masking tape at that measurement. You now have the horizontal centerline point that you will drill into and the vertical point that will prevent you from drilling into the LPC sealing area.

You may now find the vertical center point that you will use to drill through the VA at. Calculate half the distance of the drill bit size that you're using. Add about 1/64" to1/32" to that measurement. You need to add this measurement in case the drill bit drifts towards the LPC sealing area. Starting from the vertical line you made earlier, use this combined measurement and make another vertical line across the horizontal centerline you made earlier towards the o-ring end of the VA. You now have the center point that you will use to drill the hole in.

Using the center punch, indent a starting point for the hole. If you do not, chances are the drill bit will drift somewhere that you don't want it to. Clamp the VA in the jaws of the vice using a couple of small pieces of corrugated cardboard to prevent the anodizing from being scratched up. If you have a variable speed drill, drill the holes at a slower speed as it will make the holes you drill more accurate and aluminum is a soft metal and drills much better at lower speeds. As insurance, it's best to drill what is called a 'pilot hole' so the element of drill bit drift is less likely. I made 2 pilot holes before making the final hole to be tapped. I used a 9/64" and 17/64" bit for the pilot holes. You do not need to use those exact same drill bit sizes but what you are doing is progressively making the hole larger before making the final hole for the tap. I cheated a little and used a 21/64" bit for the final hole which is slightly smaller than the correct .3390" bit but it worked out just fine. You should actually use the correct drill bit for the best results in tapping. You only want to drill these holes to a depth of about 1/4" to 5/16" into the VA wall. Wrap a small piece of masking tape around the drill bit at this measurement so you will know at what point to stop drilling at. Once you've drilled completely through the side wall of the VA you will actually be drilling around 1/8" to 3/16" into the vertical back inner wall of the LPC area. Be sure that you are drilling as close to 90* as possible while drilling all holes otherwise when screwing the gauge in it will be at the improper angle that you drilled at. After drilling, clean up any jagged edges of metal on the inner and outer portion of the hole with a round type file and sandpaper before tapping.

Now that the hole is drilled to the proper size, depth and angle, it's time to tap the hole. Using a 1/8" - NPT - 27 tap, tap the hole that you just drilled until you can see the threads of the tap from the front of the VA LPC hole. For the best results, turn the tap 1 full turn then turn it back a half turn if you feel it binding then continue. Dip the tap into some tapping oil before turning it into the VA hole as well. After the tapping has been completed, clean the VA of all metal particles with hot soapy water and an old toothbrush.

All that's left to do now is screw the gauge into the freshly tapped hole. Using either the yellow or white teflon tape, wrap about 3 - 4 layers of tape around the gauge threads. You need only hand tighten the gauge into the newly threaded port. Cut any excess tape from the end of the gauge before turning it into the threaded hole. If there is a leak from this area after gassing your marker up, you'll need to remove all of the teflon tape from the gauge and VA threads and wrap the gauge threads again but a couple more times than you did previously so there'll be a solid seal.

Gauges

There are a ton of aftermarket gauges available but which do you choose for your particular marker? The mini or micro gauge as shown in the photograph above is best suited for paintball marker applications. If you are running an LP Spyder setup, use a 0 - 600psi or 0 - 750psi gauge. If running a HP setup, use a 0 - 1200psi or 0 - 1500psi gauge. There are other aftermarket gauges available that may either run from 0 - 300psi or in excess of 3000psi. The lower psi gauges are for electro-pneumatic markers or others that run at extremely low pressures of 100 - 200psi. The higher denomination gauges are for HPA tanks and are not applicable for paintball markers at all.

Technical Information