DIY Rifle Stock – Part 2
by Tom Gaylord
Writing as B.B. Pelletier
Today’s report is a continuation of reader Vana’s excellent report on stock making.
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And now, over to you, Hank.
This is my original 55 year old Slavia 618 in its new “firewood” stock. I made this one in a “camo” style, using cherry and maple blocks in a random arrangement of the pieces.
This report covers:
- Stock Layout
- Let’s get started!
- Putting pencil to paper
- Two approaches to stock making
- Which way to go — subtractive or additive?
- Before we start, tune your tablesaw!
- The forend block
- Machining the receiver mounting points
- Bedding the receiver
- Cutting out the spacer
- About gluing…
- The “spring retention cap” retainer
- Cutting the forend profile
This is the layout for a new Slavia 618 stock with all the important details drawn in.
I will be using datum points and datum planes to work from. These are the reference points and reference surfaces used to measure from, to locate features on our template and our material. All dimensions are taken from the datums. The stock mounting holes are ideal datum points and I will use the top edge of the original stock for my datum plane. In this instance we will use them to relate the features on the receiver to the stock.
Let’s get started!
There are two considerations in laying out the stock — the parts of the stock that contacts the shooter and the interface between stock and the receiver. Good fit for both are important. I’ll be using the original stock as a reference to make a Try-Gun stock. Because it is adjustable I don’t have to worry about getting things “perfect” as the whole benefit of this approach is that it can be made to fit later.
Putting pencil to paper
The outline is not critical but I try to be as accurate as I can while penciling around the perimeter. Then I go over the pencil lines with a straight-edge and felt markers. To keep things clear, I use different colors for the receiver, the original stock and for the new portions of the stock. In the image above, I have added (in the green dotted line) the changes I will be making for the new stock. I prefer ballpoint pens for marking fine accurate lines on the template and on the wood.
To locate the mounting surfaces, clearance cutouts and other features on the stock I’ll take all critical dimensions from the datum point and datum plane on the stock and add them to the cardboard layout. The datum plane (usually the flat top edge of the stock) will be used as a reference for measuring the position of the butt and the height of the cheek-piece as well as the depth of various features to be carved out for the receiver.
Two approaches to stock making
Most commercial stocks are routed out of a specially prepared (laminated or natural) block of wood with a computer controlled router. This machining approach, where all the material that doesn’t look like a stock is removed is often referred to as “hogging it out of solid”.
Which way to go — subtractive or additive?
The subtractive approach — carving a stock from a single block of wood — is possible with hand tools but it is a challenging way to do it, and one little OOPS can ruin the whole show. It’s best to get some experience before going this way. Making a Try-Gun stock and a rough stock out of spruce will give you a good idea if you are ready to use the subtractive approach.
I will be using an additive approach and make the Try-Gun forearm, grip, cheek piece and butt as separate pieces. Working with smaller pieces is easier to do with hand tools and if something doesn’t work out it is quick to make another one. The firewood stock is slightly different, as the blocks are added as the work progresses rather than making the pieces and joining them at the end.
Before we start, tune your tablesaw!
For tight-fitting joints it is important to have a tuned tablesaw. I clean and lubricate the saw blade support structure, wax the table to be sure that everything operates smoothly. The blade-to-table clearance insert needs to be flush and solid, if it is not level, or if it moves around, the accuracy of the cuts will be compromised. Like the pre-flight walk-around on an aircraft, I start every session by confirming that the blade is sharp and undamaged, the fence is parallel to the blade, the blade is perpendicular to the table and all hardware is tightened… don’t like nasty surprises.
The forend block
The forend is the most challenging part of the stock because this is the part that needs to fit the metal receiver closely. Lacking the sophisticated routers that commercial stock makers use I do most of my shaping with my 10 inch table saw. Because I will be using both sides, the top and the bottom of the block to control my cuts I need to take special care that all the faces are square.
Preparing the forend block… The top image shows the four pieces cut to size and below, shows the block assembled and dressed square.
Because this stock has a slot for the cocking-bar on a breakbarrel I’ll make the forend from four pieces of wood screwed together (they will be glued later). Two thin strips of wood are used as spacers that will create the channel for the cocking-bar and clearance for the trigger. To provide a wide, flat working surface the assembled forend block is a lot wider than necessary – it will be cut to width just before the profile is cut out.
For stress distribution reasons, I’ll match up the boards with the grain orientated “face to face” (like samples #4 & #5 as shown in the “Selecting the wood” section in Part 1) and label them so I can keep track of where they are in the block.
To prepare the wood I’ll dress both sides of the lumber (remove a bit of wood with the tablesaw) to make them flat and smooth.
The next step is to align the four pieces of wood, clamp them together and add screws around the margins to make up the forend block. Some care has to be taken to locate the screws so they don’t interfere with where the holes will be drilled, and low enough to clear the channel to be cut for the receiver. With that done it’s time to redress the edges and ends so that the all faces are aligned, parallel and square.
Machining the receiver mounting points
Here the stock mounting holes and clearances have been marked and drilled in the forend block.
Now that the forend block set to go I can start transferring some information from the template to the work piece. I have located the datum plane that represents the top edge of the stock 1/8 inch below the edge of the wood (black line) to allow material for final fitting and cleanup. I add the more important lines (with a red ball-point pen) all around the block and sketched in the stock for reference.
On this rifle the receiver is mounted with three screws. The first step is to locate and machine the areas for the mounting surfaces and drill the mounting holes. With the drawing done, the clearances for the receiver mounting hardware are drilled out with spade bits and the holes for the mounting screws drilled. In order to avoid tolerance conflicts on mounting surfaces, I find it easiest to drill a little deeper than required and fill any gaps with epoxy (thickened with a bit of sawdust) later.
Bedding the receiver
Here the channel for the receiver has been cut on a table saw and sanded smooth.
Here the channel for the receiver has been rough cut on a table saw. I started with the shallow cuts and worked towards the center, adjusting the depth of cut to follow the radius as I went. Because the channel is symmetrical about the center of the block, the cut location and depth can be set for one side of the arc and then flipped around to cut the other half. In spruce, the saw cuts can be over lapped by half a kerf (saw tooth width) and still be easy to sand out. In hardwood it is better to space the cuts closer together.
I use a dowel wrapped with medium grit sandpaper to start bedding the receiver. The dowel is a couple of inches longer than the width of the sandpaper so it guides the stroke and keeps it straight and level. I use a light stroke and clear the sawdust frequently, watching the saw kerf steps to be sure that I am removing the wood evenly. It helps to flip the block around so that the sanding is done from both directions.
Cutting out the spacer
Spacer detail: In the upper image, the hatched areas will be part of the forend, green and yellow areas are cut away and the remaining area with two screw holes will keep everything aligned for gluing. The lower image shows the cut-out spacer (the yellow area is part of the block and will be cut away later).
To save a lot complex chiseling and filing I create the slot for the cocking arm, the channel for the trigger and form the tenon to attach the grip with a spacer made with two thin pieces of wood. Using two pieces has the advantage of creating a “center line” that helps guide the spade bit.
I labeled all the pieces (1 through 4) to keep track of them. In the top image you can see the spacer, pieces 2 & 3 glued together — I used pieces 1 & 4 (protected with some plastic) to clamp everything in alignment. The stock was traced in (using the mounting holes for reference), the cocking arm and trigger drawn (carefully) to show where the clearance is required to allow for full movement. The yellow and green areas of wood will be removed; the hatched area is the actual spacer and the area below the hatched area (with the two remaining holes — “green circles”) is needed to position the spacer when gluing the forend block together.
The lower image shows the spacer cut to shape and ready to be glued in-between pieces 1 & 4. The yellow area is part of the waste that will be removed when the forearm is cut free of the block.
All the coloring is for the sake of my explanations – I usually keep the wood clean and natural.
When gluing two pieces together it is important that the joint is tight, clean, and that all is ready so that it can be quickly clamped and left to set without being disturbed. A glue bond takes place at a molecular level so very little is needed. Glue doesn’t compress, so using too much will result in a poor joint. After the initial bonding, a joint will need adequate time to cure before it is stressed. Made like this the joint will be stronger than the wood and almost invisible.
The “spring retention cap” retainer
Here is the rifle “spring retention cap” dowel being glued in and trimmed. The slot below the dowel is for the tendon used to attach the grip.
The Slavia 618 has a “spring retention cap” at the end of the receiver that requires a dowel to help keep it in place. Here I have added a dowel for that purpose and trimmed the forend to length.
Cutting the forend profile
The rough finished forend. In these images, you can see the clearance for the cocking arm and trigger, the mounting surfaces for the receiver (red) and the spacer (blue) that created the slot.
To finish up the forend I trimmed it down to the correct height (removing the extra 1/8 inch of wood and the top of the dowel), cut it to the width needed and cut the shape to the profile I wanted. The last step was to counter-bore the mounting hole.
For durability, the mounting holes and counter-bore surfaces are saturated with cyanoacrylate adhesive (“CA” or Super Glue). To avoid blotches in the stock finish, take care not to get any CA on the surface of the stock.
In this part we have discussed laying out the stock and the steps to make the most challenging parts of the forend. While the forend is the interface to the receiver, the grip is the prime interface to the shooter. We will get to that in the next part.