Spar making plane

[David Bewick]

OK chaps I want to pick your brains.  I while ago I picked up an old wooden plane for a few quid at a boat jumble.  I intended to turn it into a concave plane for spar making.  I came across it in the workshop today and it got me thinking about exactly how to do it.  The key decision is what radius to make it. Clearly, it cannot be a perfect fit for every spar but a bit of curve will a lot better than a plane with a flat sole.  Has anyone ever done this and can offer any advice?  I guess a typical mast has a diameter in the 50 - 75 mm range and other round spars, a bit less.  There is no easy way to make a convex sole and blade as tight as this but what do you think would be a good radius to go for?  I have made a concave wooden plane before and that is a whole lot easier.  Answers on a postcard, please. Many thanks and best regards,

David

[inwe]

Hi David
Sorry to be the bringer of bad tidings but to try and re-model the throat of a wooden plane by that sort of amount is not easy and will probably fail. The big problem is that the gap within the throat must stay even. you will probably have to add an insert on the sole. To plane a spar usually only needs an ordinary plane, you just move yourself around. I say ordinary plane either a try-plane or a jointer. I used a try- plane for mine followed by the careful application of a smoothing plane . You could get away with a Jack plane to start with or even an electric plane  to quickly remove the rough bulk. It just isn't worth the effort of trying to alter the sole of a wooden plane. Even re-grinding the blade is not easy. Also you would have to regrind both the Back iron and Cap iron. Sorry.

Richard

[David Bewick]

Richard, thanks for your comments.  I have made several spars with flat planes and I am just looking for something to help the transition from multi-faceted to round without too much sanding.  I think I got my convexes and concaves a bit mixed up in my original post but you clearly got the gist. I think even a gentle curve would help a lot.  I would expect to make a curved wood former with the sole radius and to cover this with abrasive to finish making the body and to grind and hone the blade. I know this is not easy but there are lots of wooden moulding planes made in this way.  It might be easier to start from scratch, though.  I will continue to ponder. Regards, David

[momist]

Hi David.  For rounding off after sixteen siding with a flat plane, why not use a home-made scratch stock.  Have a look at this link to Paul Sellers chair devil, all you need is a slightly bigger version:
https://woodworkingmasterclasses.com/2014/08/making-chair-devils/
BTW, the technique with these is to angle the stock to adapt the radius to that of the finished piece, so you make one with a bigger radius than the largest part of the spar, and then angle it more as the spar tapers.

[Timmo]

I've had success making convex soled planes from wooden planes acquired at car boot sales for pennies. Both longitudinally curved (like for planing the outside of a wheel rim) and laterally curved (for planing wide grooves.) Also tried one curved both ways for planing out the spoon shape on oars. It does work but a tool I was given specifically designed for carving out seats works better.

Never made a laterally concave version, but entirely see where your coming from Dave. If it can be made to work it could be a useful addition to the tool kit.

Also understand the real problem Richard is highlighting. Maintaining the right throat dimensions will be difficult 

Shaping the blade and cap iron and then sharpening the curved blade will be extremely tedious but fractionally less problematic than the throat diension issue. Would be easier if you can source (or create) a curved face grinding wheel.

With the fancy woodwork needed to sort the throat issue and the labour/expense of the the grinding process it looks like it might be a hobby piece rather than a cost effective route to round spars. But the idea still appeals.

Now I'm thinking about it I'm wondering whether something along the lines of a scraper plane might be worth considering. They work with the blade almost vertical, throat width a. not an issue, and b. easier to manage anyway. Not good for main shaping, but could do the job of knocking back those final edges to get a real curve before sanding. Not sure starting with an old wooden block plane is the easiest route to that sort of device though.

Let me know if you do try Dave, happy to learn lessons from your experiments. 

On 7 Nov 2015, at 11:23, David Bewick [via UK HBBR Forum] <[hidden email]> wrote:

Richard, thanks for your comments.  I have made several spars with flat planes and I am just looking for something to help the transition from multi-faceted to round without too much sanding.  I think I got my convexes and concaves a bit mixed up in my original post but you clearly got the gist. I think even a gentle curve would help a lot.  I would expect to make a curved wood former with the sole radius and to cover this with abrasive to finish making the body and to grind and hone the blade. I know this is not easy but there are lots of wooden moulding planes made in this way.  It might be easier to start from scratch, though.  I will continue to ponder. Regards, David

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[David Bewick]

Guys, Many thanks for your ideas.  I am familiar with the fancy Veritas chair devil tools but I had not thought about a DIY version.  I think this could well be the answer but I surprised I have never seen one mentioned in the context of spar making. Now, where did I put that old saw blade that I kept for making.scrapers?

Best regards,

David