Spring gun tuning: Part 1
by B.B. Pelletier
Before we begin, let me announce that the last of the British-made Webley airguns are now in! Pyramyd Air bought the entire remaining stock of guns, so look through the Webley pages now. When these are gone, there won’t be any more!
I’m going to show you the fundamental steps to tune a spring gun. Although I won’t show every kind of gun, I will talk about how underlevers and sidelevers differ from breakbarrels. If you’re clever enough to do this kind of work, you’ll be able to figure out the particulars for yourself. I’m just going to show you the important points to get you started.
We’ll begin by looking at the tools and supplies needed to work on spring guns. I assume you have a standard set of tools and all the screwdrivers and Allen wrenches you need for any job. If you don’t have them all now, get them as you need them. Never try to make one tool do the job of another – that’s how accidents happen and mistakes are made.
You need a good set of these, because there are hundreds of uses for them when working on spring guns. We will use them from the beginning, so get a small set of punches right away. Airgunsmiths need small punches, because most of the pins encountered are small. I bought my set at Sears, and it has four punches – 1/16″, 3/32″, 1/8″, 5/32″, plus a 5/32″ alignment tool.
Plastic and rubber-headed hammer
This is also a general tool that’s used all the time. Get one that’s small and handy to use. This kind of hammer is essential. You can buy one at Sears or Home Depot; if you like shopping on internet, try Boston Industrial. They have one for $2.10.
A hammer with rubber and plastic heads is an essential tool for the airgunsmith.
Vices are not as useful as you might think. Spring gun tuners have very little need for vices, save one. A fine, inexpensive mainspring compressor can be made with the right kind of vice. I will give you the plans for how to build a compressor, and I’ll also tell you where to buy one if you don’t want to build it.
Dowel rods and rubber bands
Get at least one half-inch hardwood dowel. You’ll use it to lubricate the mainspring cylinder. If you have a screwdriver with an 18″ long blade, it can take the place of the dowel. Also, get a supply of thin rubber bands, to use with the dowel. I will explain what to do when we get there. A dowel 36″ long is more than enough. All you need for most jobs is about 18″.
Lubricants are a major part of a spring-piston tuner’s bag of tricks. Ten years ago, the market had the products you needed and they were easy to find. For example, Beeman sold M-2-M moly paste that was wonderful stuff. Well, they don’t sell it anymore, so you now have to buy your lubricants elsewhere. I want you to at least get black tar and moly paste. I’m sending you to Air Rifle Headquarters for these things. They are also an excellent source for replacement mainsprings, piston seals, spring guides and other important parts you will need to tune a gun. They have already created drop-in tuning kits for many popular spring rifles like the Benjamin Legacy and the FWB 124/127. So, this is a place you aspiring tuners need to bookmark.
Next time we’ll look at mainspring compressors, and I’ll show you how to make one for less than $20.