How to Jewel a Rifle Bolt
Since the turn of the century, gunsmiths and firearm enthusiasts have been jeweling (or engine turning) different metal parts on their rifles and pistols to add a distinct look to their weapons. No bolt jeweling work is the same, as each craftsman has his own preferred and unique way to do it.
The reason behind firearm jeweling was initially only practical. Namely, it was done to create small pockets or tiny grooves that would retain oil better than a polished metal surface which would provide a smother action. The practice evolved into an aesthetic feature over time, and nowadays, the purpose of putting jewels on a gun is primarily decorative and the aim is to create a design that will separate a pistol or a rifle from all other pistols and rifles out there. And if done by a master gunsmith, jeweling could add immense value to an otherwise plain firearm.
In case you’ve never jeweled before, we advise that you start with jeweling flat surfaces first (find a piece of scrap metal and jewel away!). You’ll need to get a sense of pressure and distance between the swirls, and you’ll need to learn about patience and focus and keeping your hand steady. After you master flat surfaces, you can practice on a hardened metal rod a few times before jeweling the real thing. Jeweling round surfaces is a whole lot trickier. Usual difficulties that you can encounter are the swirls not coming out as even circles, but ovals with longer flat sides, or centers of the swirls that don’t get polished, but remain untouched by the jeweling tool. Crooked and miss spaced lines and step-overs, heavy or light swirls will all prevent your bolt to look pretty.
First, you’ll need to figure out what looks good, and then how to work the surface at points where it changes from flat to round. Many gunsmiths feel that larger swirls are both more difficult and more unappealing, and that together with coarse spacing, you’ll bolt might look a bit cheap.
The recommendation would be to start with the 50% of swirl diameter overlapping. Pay attention to the pressure and the contact time.
But hey – it’s not as horrible as it sounds. One positive thing about jeweling is that a quick polishing job can erase your mistakes and you can start over. Once you start getting a grip, you’ll lose more time and be more efficient. Pretty soon you’ll jewel other parts, such as hammer sides and even internal parts.
So, how do you jewel a bolt? Like jeweling any metal, it’s quite easy once you get the hang of it and you won’t need a whole lot of tools to do it. It all depends on how you’re equipped, and there are a lot of tool combinations that can be quite sufficient. You’ll need to polish the bolt to a high shine, so you’ll need some high-quality polishing tool (check out Chapter 1), you’ll need a jig or a vice to hold the bolt, a drill press and a jeweling tool. These are basic tools. Of course, in case you have a drill press with a moveable table, mill drill or a mill, your job just became a whole lot easier.
While just about any cheap drill can be used for jeweling, the bolt jeweling jig that holds the workpiece is the thing that is really important. It can be a custom, homemade bolt jig made from wood or metal scraps and all you’ll need to make it is a little bit of imagination. The point is to create a mechanism that will allow consistent axial and lineal movement. You can also purchase a bolt jeweling fixture at various gunsmithing stores or at online gunsmithing tools retailer. Holding the workpiece depends on the kind of machine and tooling you have.
What would make your bolt jeweling process a whole lot easier is coming up with an indexing system for horizontal and rotational adjustments. There are a lot of ways to do this and you’ll need a spin indexer and tail center. However, in case you don’t have a spin indexer, just get a couple of clamps and a v-block.
In case you’re using a cross-slide vise and an old-school machine such the Unimat, one indexing strategy is to tape a piece of aluminum can on the vise as a pointer, and to tape a ruler printout around the bolt to indicate rotation.
The markings on the ruler will be used to get a uniform jeweling pattern by rotating the rifle bolt. The distance between each separate row should be the same and there should be sufficient overlap in the pattern. For the horizontal index you’ll use the Unimat’s moving carriage. The wheels should be turned for the same number of times between each successive mark to achieve sufficient overlap in the desired pattern. Last step would be to clamp the cross-slide vise to the Unimat’s carriage while making sure the vise is aligned properly to the lathe bed.
Next would be to apply a coating of an abrasive compound (e.g. silicon carbide 320 or 240) on the surface part, especially if you’re using a wire brush, as the wire brush alone won’t provide the desired look. In case you are using rubberized stick an abrasive compound is not essential. You’ll need a holder for the stick to chuck it which you can purchase online. Simply place the jeweling rod in the drill chuck with about 1″ sticking out and you’re ready to go. Of course, you CAN use a lapping compound, we’ve seen that different gunsmiths have different preferences when it comes to the depth and overall look of the patterns. The main difference between a wire brush and abrasive stick is that stick gives a softer look to your swirls than the wire or some hard abrasive. Since it doesn’t require an abrasive compound, it provides a much better visibility of the contact area and the way the tool is working the metal.
Now it’s time to turn on the drill press. Start on the outside of the area that you plan to jewel. A good idea is to slowly lower the bid first, just to get an idea about where the jeweling bid will contact the bolt before applying the actual contact. After you make sure everything is set the way it’s supposed to be, start applying consistent, light to moderate pressureon each swirl to create a jewel. Rubberized stick requires just a light pressure for about 8-15 seconds, so in case it squashes out, that’s a sign that you applied too much pressure. You can go with 300-400 rpms in case you don’t use any abrasive compound or go even to 1000-1500 in case you a mixture of water and oil as coolant. As for the grit, we recommend coarse or medium.
Move the carriage horizontally after each jewel to achieve the desired overlap. Repeat until you have completed a horizontal line of swirls that run lengthwise down the bolt.
After you’re finished with one row, rotate the bolt and begin creating the next row of swirls by overlapping it with the previous row. Also adjust the carriage horizontally to either stagger or offset the rows, so that there are no gaps between them.
NOTE: We already pointed out that each craftsman has his own way of putting on the decorative pattern on his or her firearm. As for overlapping, 50% is a rule of thumb, but you can overlap more or less; you can create straight lines or create swirls at an angle, you can use different compound, pressure, pressure duration, etc. Since there are no wrong or right ways to do it, we just described one of the possible ways.
After you’re done, it is time to rinse off the abrasive compound if any. In case you are using a water-based lapping compound, you can simply run the piece under water until it is clean. In case you are using an oil-based compound, rinse the piece with an appropriate solvent. Either way, just make sure you never wipe the compound off the piece as that can scratch the surface and cause hazing.
And there you have it! A cool rifle bolt with a unique and custom look.