Bobsled Building Plans
Bobsled Building Plans
by Lynn R. Miller
This material appears as a side-bar in Lynn Miller’s Art of Working Horses. It appears here by permission of the author.
Here are two old-style, heavy-duty, bobsled building plans of the sort you might find in New England and the Maritime Provinces of Canada. These are designed to haul cord wood on the sled frame. Loggers and woodcutters from the north woods have long known snow and ice to be a friend to heavy skidding, as this old photo will attest. The sled under this massive (and dangerous) load is of the same basic design as the two plans shown below, except for the fact that it is designed, with curved log bunks, to received full logs lengthwise .
Notice in the plans below (top one for eight food wood, bottom one for four foot wood) that these sled set-ups employ two autonomous “bobs” which are connected with a length of suitable chain running from the front of each rear runner, criss-srossing, on to the main-frame ends of the front bob. This allows for a simple articulation on curves so that the bobs “round” the corners instead of dragging across. When the front bob turns left, the cross-chain tightens and turns the back bob slightly right (in a following action). This bobsled design is particularly elegant in that it features, on both front and back bobs, a swiveling cross yoke. On the front this means the tongue swivels up and down easily over rough terrain. On the back, the cross yoke ends have axle pins which fasten by plate to the ends of the reach chain which allows that there is no binding when running up and down over cross ridges in the skid. With the top design the top bed-frame is anchored by two heavy bolsters which each pin into the sled frames. These bolsters allow the bob to pivot ‘neath them is same fashion as a traditional wagon running gear. This sled will receive eight foot logs either lengthwise, in two bunk loads, or crosswise for the entire length. The runners are lined on the bottom with steel.
The plan below, for four foot, cross-ways, wood, is designed for a single horse and narrow skid trails. It features shafts instead of tongue and has a lower profile. In this variation the front bob is affixed to the rack and the back bob, cross-chained, is allowed to pivot under the frame on turns. The same “following” aspect occurs here.