Interlocked-Blade Dasher Churn: Each Blade's Round Shank Is Bored Through by the Next, So They Key Each Other in the Hub

"Another radial hole is then bored for the next adjacent blade, the boring tool passing through or cutting off the end of the first shank. The second blade with the same preparation as the first one is then driven in or united, its shank fitting against and overlapping the first driven one, so as to answer as a key to it, to prevent it from turning or becoming loose."

Glue up hardwood for a box A 300 x 300 mm inside and 420 deep, sides 22 mm, joints sealed with silicone sealant. Rout a seat round the top for a 22 mm lid B. Cut an opening in the lid 120 mm wide running from 30 mm behind its centre to 140 mm in front; fit a cover I to it with a 22 mm hole at the centre for the shaft c and a slot from that hole to the cover's back edge, so it can be lifted off past the shaft. Turn two hardwood buttons a on screws at the lid's edge to hold it down.

Turn a hardwood staff 40 mm across and 375 mm long, with a hub H 76 mm across for its bottom 80 mm, and the top 15 mm turned to 28 mm for the cap. Turn a groove near the hub's foot and press on a ring cut from a stainless tube as the band, so the hub cannot split when it dries. Bore a 10.2 mm hole up the middle of the hub from below, 50 mm deep, for the spindle f.

Carve six lower blades J from hardwood 8 mm thick: 26 mm wide at the neck widening to 100 mm at the tip, reaching 135 mm from the staff's centre, slightly hollowed on top, each on a round shank 20 mm across and 52 mm long, so it reaches the centre, with a small shoulder i, the blade's twist running out along the neck into the shank as the spiral lines h. Carve six upper blades K the same way, 16 to 60 mm wide, reaching 125 mm, on 14 mm shanks 34 mm long.

Bore a 20 mm radial hole level into the hub, 40 mm above its foot, to just past the centre. Coat the first J shank near its shoulder with food-safe silicone sealant (the patent used white lead or other cement) and drive it in with the blade sloped 30 degrees. Bore the next hole 60 degrees round, cutting off the end of the first shank, and drive the next blade so its shank overlaps the first. Go on round all six, each keying the last, every blade sloped the same way. Drive a 10 mm stainless rod 60 mm long up the centre hole through the shanks as the spindle f, leaving 14 mm below the hub.

Bore three 14 mm radial holes 120 degrees apart into the staff 180 mm above the hub's foot and three more 210 mm up, turned 60 degrees, so the upper blades break spaces with each other and with the lower. Set the K blades in them with sealant, sloped the same way as the J blades.

Screw two hardwood posts 40 x 40 mm, 200 mm tall, to the lid either side of the opening, 160 mm apart over their inside faces; join them with a cross brace b 60 mm up and a top bar at the top, both bored 16.6 mm over the staff. Cut a 16 mm stainless shaft c 283 mm long, file its foot 12 mm square for 14 mm, and run it down through the bar and brace with the pinion d pinned on it above the bar. Screw two hardwood blocks 50 x 25 x 100 mm on the bar either side of the pinion as the sleeve E, bored 16.6 mm across 75 mm above the bar; run a 16 mm stainless crank shaft 180 mm long through them with the crown wheel G pinned on it meshing d, a shaft collar, and a crank F of mild steel flat bar, 100 mm throw, with a hardwood handle.

Pour about 20 litres of heavy cream at about 15 °C, checked with the thermometer, into the box. Tilt the dasher in through the opening, set its spindle in the step, swing the staff upright under shaft c so the square enters the cap, and put on the cover and lid. Turn the crank briskly so the blades press the cream down, timing it. When the butter comes, turn on the same way but much slower, so the blades roll it into masses. Take off the cover, lift the dasher slowly while turning it backwards by hand so it slips out through the butter. Gather the butter, pour the buttermilk into a bowl, wash the butter in cold water until it runs clear, salt and weigh it. Scald, wash and air-dry the dasher.

**Salem T. Lamb** of New Washington, Clark County, Indiana, US 30,411, 16 October 1860, "Fastening Blades of Churn-Dashers". He claimed the "interlocking or overlapping of the shanks of the blades J, so that they shall serve to hold each other firmly in the staff". He set the shanks in white lead or other cement; we use food-safe silicone, as white lead is a lead compound. His hub band was molten metal run into a groove and his gears a cast bracket with bevel wheels; ours are a pressed stainless ring, wooden posts and printed crown gears. The patent gives no sizes; every size here is ours.