diff --git a/common/coords.go b/common/coords.go
index bd0d613..2657d8e 100644
--- a/common/coords.go
+++ b/common/coords.go
@@ -107,11 +107,11 @@ func DecodeFromBigEndian(key []byte) (int64, error) {
 
 func CoordToInterleaved(c Coord) (result int64) {
 	const end = 1 << (numBitsPerComponent + 1)
-	x := uint16(c.X - minValue)
-	y := uint16(c.Y - minValue)
-	z := uint16(c.Z - minValue)
+	x := c.X - minValue
+	y := c.Y - minValue
+	z := c.Z - minValue
 	setmask := int64(1)
-	for mask := uint16(1); mask != end; mask <<= 1 {
+	for mask := int16(1); mask != end; mask <<= 1 {
 		if x&mask != 0 {
 			result |= setmask
 		}