Smoothing curves

[Phil Pascoe]

I did some quite vicious shaping on a turned dish - I had abrasive in rolls, so I cut some lengthways two feet long and glued it to a broomstick. Nice long even strokes, brilliant.

 

[Nelsun]

I'm surprised by the lack of support for the scraper approach, I'd have thought thats what everyone would be suggesting.

I spent some time yesterday working on a long hand carved bowl with some similar sized concave curves (under handles at either end) just yesterday. I'd shaped them using various rasps and a file then, after hand sanding the whole thing to 180 grit, I went over it with a thin card scraper. The difference between the sanding finish and that left after a light going over with the scraper was very noticeable. I'll be doing that again for sure. I do have a curved spokeshave (I need to spend more time practicing with it as it chatters more than my motormouth of a daughter) but the card worked a treat in this case for getting a nice finish.

 

[Phil Pascoe]

Scraping a fine finish and scraping n amount of waste is slightly different, though.

 

[ED65]

I'm surprised by the lack of support for the scraper approach, I'd have thought thats what everyone would be suggesting.

Scraping is a super fine-finishing technique. It's less suited to a more full-on flattening/smoothing operation, as in tackling the irregular surface left after a bandsaw cut.

Think about the stage a scraper would typically be used on a panel glue-up, it wouldn't be straight after rough surfacing with a jack, it would be after a try plane or jointer had gone over the surface at least, and possibly even after a smoothing plane was used.

 

[custard]

I'm surprised by the lack of support for the scraper approach, I'd have thought thats what everyone would be suggesting.

Scraping is a super fine-finishing technique. It's less suited to a more full-on flattening/smoothing operation, as in tackling the irregular surface left after a bandsaw cut.

With an aggressive hook you can remove yacht varnish, paint, or dried glue; so it's not really correct to say "scraping is a super fine-finishing technique".

Instead think about the geometry of scraping and the virtual absence of a sole on a card scraper. On a flat surface you could scrape away bandsaw marks providing the card scraper was skewed so that it bridged across the bandsaw tool marks; you'd spare your thumbs and be faster with a bench plane, but you could do the job with a card scraper. The critical thing is bridging the tool marks with a sole or by skewing, otherwise you'll just dig in and create a divot. On an internal curve though everything changes, if you skew the card scraper you only connect with the outer corners and therefore dub them over. In theory flexing the card scraper might compensate, in reality on a quick curve...well good luck with that! The really tricky part when using a card scraper (or indeed a spokeshave or any short soled tool) is entering and leaving the cut, and short quick curves just exacerbates that problem.

 

[Ttrees]

If you really want to go the sanding route ...
Have a look at the rolling pin sander approach, frequently used by luthiers
https://www.youtube.com/watch?v=FMXZe2B_NGE
Good luck
Tom

 

[transatlantic]

If you really want to go the sanding route ...
Have a look at the rolling pin sander approach, frequently used by luthiers
https://www.youtube.com/watch?v=FMXZe2B_NGE
Good luck
Tom

This looks like overkill, have you seen the image I posted at the beginning of the thread? ... they're quite small and tight curves

 

[Ttrees]

A tool to have for again though ...
If you don't want to cut these with an iron in some form or another.
Tom

 

[transatlantic]

A tool to have for again though ...
If you don't want to cut these with an iron in some form or another.
Tom

Oh yes, it does indeed look like a very useful tool