Deep Heels
SETUP
The following settings and measurements are the same for ALL samples below:
72 cylinder - 12 stitches left in work.
Gauge: 8 sts/in & 11 rows/in
Same yarn (Opal 4-ply) and machine settings for all heels.
Circumference of sock tube 9". (72 stitches ÷ 8 sts/in = 9 in)
Heel spring was used for heels only. The heel spring makes for a tighter gauge when it is in use. This can also affect the diagonal measurements around the heel as the heel and the top instep will have a different gauge. All of that has been taken into account for the calculations and samples below.
Round heel (Same as round toes. Raise and lower one double set of needles at the heel "corner")
Heel Diagonal Circumference (measured from the instep to the tip of the heel.) Note the line of blue yarn to indicate that measurement.
The Samples
NOTE: the number of needles needed to raise, in order to get similar measurements changes with different tension settings/gauge.
Sock A
12 stitches raised and lowered for a standard heel.
Heel Diagonal Circumference measures 10.37"
Sock B
14 stitches raised and lowered (+2 needles each side for a deep heel)
Heel Diagonal Circumference measures 10.67"
Sock C
16 stitches raised and lowered (+4 needles each side for a deep heel)
Heel Diagonal Circumference measures 10.97"
Sock D
18 stitches raised and lowered (+6 needles each side for a deep heel)
Heel Diagonal Circumference measures 11.27"
This specific cylinder and gauge setting would be for a 10" length foot.
10% negative ease would require a 9" circumference sock.
The heel diagonal for this foot should be 30-40% of the foot length. Using 35% (10 × 35% = 3.5")
10" + 3.5" = 13.5" heel diagonal.
Ideally one would want 10% negative ease for the heel diagonal: 13.5 × 10% = 1.35"
Therefore...13.5 - 1.35 = 12.15"
The IDEAL diagonal measurement circumference should be 12.15". Even with a +6 needle, very deep heel, the instep is still not deep enough for a 10" foot.
The Math
Conclusion
A 72 cylinder is usually appropriate for a 10" foot. Gauge is calculated using 10% negative ease and +4 needles for a deep heel. Using this formula and +4 deep heel will produce a sock with 19% negative ease along the diagonal. Therefore, the diagonal of a heel can withstand approximately 20% negative ease for most people. It’s important to consider that people with very deep heel/diagonal or thick/swollen ankles, this could be problematic and result in a sock that it too tight across the heel diagonal.
As sock makers, we should consider making much deeper heels then the old manuals suggest.
Note: the deeper heels are longer than regular heels. The foot length needs to be shortened accordingly when adding more needles for a deeper heel. (Reduce 2 foot rows for every 1 side needle added to a deep heel.)