Everything on a handle gets counted twice
The tang is one thickness. Everything else is a pair. Scales, liners, spacers, glue lines — each of them lands on both faces, so the number quoted on the box is half of what it does to the handle. A tenth of an inch of liner material is a fifth of an inch of handle.
Glue is the one that gets counted as zero, and it never is. Under normal clamp pressure on two surfaces that are flat but not lapped, epoxy ends up somewhere in the thousandths, and there are four of those lines on a handle with liners: scale to liner and liner to tang, twice. That is enough to take a handle you measured carefully on the bench and hand you back something noticeably fatter.
A tapered tang tapers the handle by exactly the same amount
This is the result that surprises people, and it falls straight out of the arithmetic. If the scales are parallel — the same thickness at the front and the butt — then the handle thickness is the tang thickness plus a constant. A constant added to a taper is the same taper. So a tang that goes from 0.15 down to 0.09 gives a handle that is exactly 0.060 thinner at the butt than at the front, whatever the scales are made of and however thick they are.
If you wanted the finished handle to be parallel, the scales have to carry the taper themselves, in the opposite direction: half the tang taper of extra material each side at the butt. That is shaping done before the scales go on. Trying to sand it in afterwards means sanding through the front of the scales to get the back of them down, and on anything with a liner you go through the liner first.
Every pin is a different length
| Station | What sets the pin length |
|---|---|
| Front pin | Thickest tang, so the longest pin |
| Middle pins | Interpolated along the taper |
| Butt pin | Thinnest tang, so the shortest |
| All of them | Plus the same allowance proud of each face |
Cut all the pins to one length and either the front ones are short or the back ones are wasteful, and on a peened pin being short is not recoverable. The page gives a length per station because the tang thickness at each station is different, and it adds the proud allowance at both ends of each pin rather than once.
The lanyard tube gets the same treatment. It sits at its own station and it is its own diameter, so what matters beyond its length is whether it has room next to the last pin — the clear space between the two holes, edge to edge, rather than the distance between their centres. Those differ by half of each diameter added together, which on a quarter inch tube and an eighth inch pin is exactly three-sixteenths of an inch of the gap you thought you had.
What the numbers cannot decide
Whether the handle is a good handle. Thickness is the easiest thing to measure and one of the least useful things to judge by, because how a handle feels comes out of the cross-sectional shape, where the palm swell sits and how the edges are broken — none of which is a stack-up. A handle that measures right and feels wrong is a shaping problem, and the number that fixes it is not on this page.
The same applies to whether a pin layout is strong enough. That depends on the pin material, on how well the scales bedded, on the epoxy and on what the knife is asked to do. This page adds up dimensions; it does not assess anything.
Questions people ask
Why did my handle come out thicker than I calculated?
Almost always the doubled terms. Liners are quoted per side and land twice, and glue lines get counted as zero when under clamp pressure they are a few thousandths each. A handle with liners has four glue lines in it — scale to liner and liner to tang, on both sides. Thirty thousandths of liner and five of epoxy per side add seventy thousandths to the handle before the scales are counted at all.
Does a tapered tang give a tapered handle?
Exactly as tapered, if the scales are parallel. The handle thickness is the tang thickness plus a constant, and adding a constant to a taper leaves the taper unchanged. A tang that loses sixty thousandths from the front to the butt gives a handle that loses sixty thousandths, regardless of what the scales are or how thick they are.
How do I make the handle parallel over a tapered tang?
The scales have to carry the taper the other way — half the tang taper of extra material each side at the butt. That is shaped into the scales before they are glued on. Trying to correct it afterwards by sanding means removing material from the outside of the butt end, which on anything with a liner cuts through the liner at the front before the butt is down where you wanted it.
Should all the pins be the same length?
Not on a tapered tang. Each pin passes through a different total thickness because the tang under it is a different thickness, so a pin cut for the front station is too long at the butt and one cut for the butt is short at the front. The page gives a length for each station, with the proud allowance added at both ends rather than once.
How much clearance should the pin holes have?
That is a decision about how you are fitting them rather than a number this page supplies, which is why it is a field. A press fit wants none and relies on the hole being exactly right; a glued pin wants enough for the epoxy to get around it and for the hole to line up through three or five layers that were drilled separately. What the page does is turn whatever you choose into a finished hole size and the nearest sixty-fourth to it.