Rounding a small spar

[Bob Thomson]

I'm making the mast for a 9 1/2' Nutshell using the solid spar method: tapered square to 8-sided to 16-sided, then working to round. I've seen some rounding techniques in WB magazine, including the inside-out sanding belt on a drum chucked into a drill, and the shop-built spar lathe. Any thoughts on the best approach to this task?

Thanks

[Thorne]

I think there have been some recent threads showing various spar holders.

Personally I just use a hand-sander and roll 'em back and forth on a long table or three sawhorses, but that's not the pro or trad method for sure.

[Gary Bergman]

I sorta with Thorne, altho I favor my power planer, then the sander..just finished another mast 'on the run', but it ain't pretty yet, just functional...

[Thorne]

Well, I was assuming the spar was already 16-sided. From scratch I use a spar gage, power planer, then belt sander, then palm sander. The result is round-ish....

(grin)

[Captain Blight]

So.... What's wrong with leaving it 16-sided? On a small spar, that extra material can't be more than a pound or two... Is it worth the clouds of sawdust and the power drain and the blisters?

[Jim Ledger]

For a spar the size of a Nutshell mast, already sixteen-sided, I would simply cut a heavy, cloth, 36 grit sanding belt into a square piece sized to fit the palm of your hand. Sanding fore and aft, the radius of the cloth can be adjusted to the spar by squeezing your hand. It'll make quick work of those ridges, followed by increasingly finer grits to suit.

[Michael Beckman]

I made a small spar a few months ago. I planed to 8 sides, then by eye to 16 then 32. Then finished off with sandpaper. I would have preferred to just take it round with a plane, but it wasn't very sharp nor in great shape. Really, its much more enjoyable to work with the grain and peel off wood then take a power-whatever to it and create a ton of dust.

[Dennis Rioux]

For what it's worth, I used the inside-out sander belts by hand on sixteen sided blanks on the six spars for my yawl-rigged MacGregor canoe. With the spar supported by a couple sawhorses, I started with a 60 grit belt and "shoe-shined" the spar which made short work of the edges on my douglas fir blanks, then an 80 belt, then a 100 belt. After a bit of sanding with finer regular paper it leaves some scratches that I couldn't/didn't get out that can't be seen from seven feet away which is okay by me. Good rhythm practice -- I can use all the help I can get -- and it did not take too long. But, yes, some clouds were also created.

Dennis

[dstreck]

I've had good results with the power plane down to 16 sides, handplane down to 32, then the Bud McIntosh drill-driven spar rounder (P. 206 of How to Build a Wooden Boat) to round.

[Brian Palmer]

I've glued some sandpaper to the inside of a half-pipe of PVC, and that works well to remove the corners without scratching across the grain. Use the smallest diameter of PVC that will still fit over the spar.

Brian

[Thermo]

I cut my mast to 8-sided with a saw and used a small block plane to round the rest and taper it. Only took an hour or so. Then again, the mast is only 10 feet long.

[Bill Perkins]

With small spars I've had good luck 8 siding the spar on the table saw , then working in the taper with planes (both electric and people powered ) , then 16 siding with planes and rounding with a setup like dstreck . No spar gage required .

[drift montana]

For my Melonseed, I used the table saw to 8 sides, then hand planed down to 16 sides. Finished off with the belt sander trick. Worked great! Here's a YouTuble link I put together for my folks with the sanding.

http://www.youtube.com/watch?v=vWnK7AbFY_U

-Tony

[Eric Hvalsoe]

From 16 facets (on a small mast), begin block planing with a slightly diagonal, but level sweep across the mast. Set up a pair of notched holders on a pair of sawhorses for the spar. It is quite easy to slowly rotate the mast with one hand while block planing with the other. Again the motion is diagonal but level across the mast as you slowly rotate with the other hand. This motion will take the ridges off and fair the surface. After block plane work sand lenghwise with rough grit, big soft pad that takes some mast shape, work down to your desired finish grit.

[cs]

I guess I can echo what others have said.

I've always taken down to 8 with a table saw and go straight from there to rounding with a hand plane and from there a belt sander. Finish up either with sanding by hand or with a R/O sander. No spar gauge or nothing fancy, just some good quality time with a hand plane. BTW if your hand plane is not sharp enough to do the job, sharpen it.

This will get you "roundish" as mentioned above. Any better than that I can't help you with it.

Chad

BTW I've always wanted to try to saw it down to 16 sides, just never have. It would probably reduce the amount of quality time that you would get to spend with your hand plane. Now that I have a power planer I may try to use it on my next spar.

[David W Pratt]

Post # 10 is my method. Hate the deep scratches you can get with across the grain sanding.
Good luck.

[Eric Hvalsoe]

This is a tapered spar, what use is a tablesaw for any part of the process - unless you are freehanding the initial 4 sided taper? I usually use the bandsaw for this, then nicely smooth the four sides. After that it is a spar gauge and a draw knife, after that snap lines and draw knife, then the block plane work. Am I missing some clever guide system for a (very) long taper?

[andrewe]

I´ve heard that it is very easy to gouge the spar using the inside out belt/power drum system. The V-block sharp plane eyeball works for me, getting out the cross scratches from belts is more work than I need.
Andrew

[Bob Smalser]

Sanding is the hard way.



Making Spar Planes Inexpensively

[Bob Thomson]

Thanks for all the ideas. I tried Brian Palmer's suggestion of a PVC-pipe sanding block and it works great. If my first attempt at posting a picture works, it looks like this: (Note one of several semi-circle templates I used to guide planing and then sanding of various diameters of the taper. Bob Smalser is right, though, sanding is the hard way. Some day I'll graduate to planes. But, for my first attempt at a spar, it's coming out OK.)

[StevenBauer]

Here is the spar sander Stonington Boatworks uses:




Steven

[Bill Perkins]

The sanding blocks shown are really interesting . I've got to try one or both of those "next time". This would be after belt sanding though , that contraption works well .