Smoothing Large Radius Curves?

Re: Smoothing Large Radius Curves?

Moses Yoder in White Pigeon, MI

>You would never regret getting a radius plane; a cheap rusty old #113 works pretty good for me, a #20 would probably be a bit better, Really great planes for that inside radius. I would suggest trimming the grocery budget and maybe skipping a few meals over the next couple months and getting the radius plane; not much help, am I ;) You could always re-sell it the day before you starve to death and get some food.

Re: Smoothing Large Radius Curves?

Eric Hedberg

>I personally haven't tried this method. A friend of mine would cut a pattern on MDF with a router attached to a board/rod swing arm to establish the radius. He would then attach the pattern to the rough cut piece and use a flush trim bit following the pattern to clean the edge on the work. Eric

Re: Smoothing Large Radius Curves?

Ed Mulligan, Cape Cod

>Derek -

Ditto the radius plane or pattern routing recommendations. If neither is an option, make a sanding block out of softwood with slightly tighter radius than your desk surface. Size the sanding block to use belt sander belts. Wedges can be used to secure the belts. A couple of fat dowels for handles will give you good purchase.

Ed

Re: Smoothing Large Radius Curves?

Derek

>I've done that for smaller things, but to do it with a 10' - 13 1/2' radius requires an extremely stiff trammel arm for the router - I have not gotten that to work for me.

Re: Smoothing Large Radius Curves?

Darrell in Oakville

>Derek,

I've had pretty good luck using card scrapers to smooth curves. You need to be careful to prevent 'waves'. I used a bowsaw, rasp, and scrapers to form the curves on the posts of my son's sleighbed. Not to mention the 42 inch wide coopered panels. That was a *lot* of scraping to work the facets out of the panels and produce a fair curve.

Darrell

Wood Hoarder, Blade Sharpener, and Occasional Tool User

Re: Smoothing Large Radius Curves?

Derek

>I've never even seen one except on line. I need to finish this thing this week.

Re: Smoothing Large Radius Curves?

Ernie Miller Topeka

>I agree with Moses I have managed to pick up both at garage sales and paid less than $20 for them both. If you lived close enough I would loan you one.

Re: Smoothing Large Radius Curves?

William R. Duffield, on the Cohansey

>I use the same methods that work for you, Darrell. When the scraper starts making waves, I turn in at an angle, or several various angles, to the direction I'm scraping. That way, the edge just scrapes off the crests of the waves., without diving into the troughs and digging them deeper. Between the rasp (I prefer a #50) and the scraper, I like to use an 8" half round bastard file and a 6" second cut file. I think the sequence of smaller teeth works a little quicker than jumping from the rasp directly to the scraper.

Derek, you should use your finger tips to determine when you've achieved a fair curve. They will tell you things about small inconsistencies, and remove them, that you wouldn't be able to see until after you've put the finish on. Nobody will ever take a compass to the edge to see if you've followed some particular radius, so the precision of a router on a monster trammel is unnecessary.

Re: Smoothing Large Radius Curves?

Derek

>Thanks William. I do use my finger tips all the time - for the reason you mentioed.

I don't have a rasp. Maybe I can find a quality one locally.

Re: Smoothing Large Radius Curves?

Jack from Maine

>look for nicholson patternmakers rasps. #49 or #50. woodcraft sells them among other places.---Jack

Re: Smoothing Large Radius Curves?

William R. Duffield, on the Cohansey

>If you can't find a #49 or #50, you might be better off starting with the spokeshave. Other rasps aren't nearly as civilized, and can require a lot of work with a file to repair their insults.

Re: Smoothing Large Radius Curves?

George D. Huron

>Make a compass sander. Glue 80 or 100 grit sandpaper to a 1/4 inch thick piece of masonite and glue two wooden blocks to the side opposite the sand paper (for handles). Then sand away the high spots to fair the curve. Doesn't take long.