Your window into Jim's life ::
Spar turning arrangement
Quick draft - will tidy up later.
Warning - anyone using these ideas is responsible for their own safety.
When I made the spars for Hookey, my John Welsford designed Truant, I spent a long time hand-sanding my mast to get it from the raw octagonal shape of the birdsmouth construction to a round spar. I used a wide floor sanding belt to start and finished with a standard fine sanding belt.
I figured there had to be a better way for the two spars which I cut from solid western red cedar. Ater a bit of research on the net I found some pointers to a method that involved mounting the spars between two points that allowed them to rotate and sanding them using a inside-out sanding belt driven by an electric-drill powered roller. (Will try to locate the original link)
The parts I used are shown
here.
I made two of the plywood brackets with the bolt through it. These were clamped onto a scaffold plank. I drilled a centre hole into each end of the spar and fitted it between the brackets with an inside-out sanding belt threaded over it. I then mounted the roller on the threaded shaft in a power drill, put the length of orange conduit over the long end to hold onto while it turned. Turn on drill, belt turns, spar becomes round.
The roller is made of disks cut from 12mm plywood with a hole saw. If doing it again I would put larger side checks on to stop the belt running off. I sliced my knuckle one time that happened and wore heavy leather gloves after that.
Here is a link to a photo on this page (scroll down) that shows a similar but somewhat larger setup than I had.
The spar is not free to rotate - the aim is not to have it rotating at the speed of the belt. I clamped it to stop it turning freely and rotated it manually at short intervals.
It needed some hand sanding to clean up some marks left by the belt.
When done I filled the holes in the spar ends and varnished them.
Warning - anyone using these ideas is responsible for their own safety.
When I made the spars for Hookey, my John Welsford designed Truant, I spent a long time hand-sanding my mast to get it from the raw octagonal shape of the birdsmouth construction to a round spar. I used a wide floor sanding belt to start and finished with a standard fine sanding belt.
I figured there had to be a better way for the two spars which I cut from solid western red cedar. Ater a bit of research on the net I found some pointers to a method that involved mounting the spars between two points that allowed them to rotate and sanding them using a inside-out sanding belt driven by an electric-drill powered roller. (Will try to locate the original link)
The parts I used are shown
Spar turning parts
I made two of the plywood brackets with the bolt through it. These were clamped onto a scaffold plank. I drilled a centre hole into each end of the spar and fitted it between the brackets with an inside-out sanding belt threaded over it. I then mounted the roller on the threaded shaft in a power drill, put the length of orange conduit over the long end to hold onto while it turned. Turn on drill, belt turns, spar becomes round.
The roller is made of disks cut from 12mm plywood with a hole saw. If doing it again I would put larger side checks on to stop the belt running off. I sliced my knuckle one time that happened and wore heavy leather gloves after that.
Here is a link to a photo on this page (scroll down) that shows a similar but somewhat larger setup than I had.
The spar is not free to rotate - the aim is not to have it rotating at the speed of the belt. I clamped it to stop it turning freely and rotated it manually at short intervals.
It needed some hand sanding to clean up some marks left by the belt.
When done I filled the holes in the spar ends and varnished them.
