What rasps do I need?

H

HSteier

Well-known member
I'm making some shield back chairs and am rasping the curves with Nicholson #49 and 50 rasps. I'd like to get some finer Auriou rasps to use, instead of following the Nicholson's with files and sandpaper. What grain #'s should follow the Nicholson's? Can the finer rasps get surfaces smooth enough to avoid needing to scrape or sand?

Howard Steier
 
Howard,

After ruffing with the Nicholson rasps I use metal files to smooth out the surface.  A ruff cut or second cut are medium to course while a smooth or smooth bastard are very fine.  These metal files I buy a ACE Hardware.  Just by looking at them you will be able to tell what type of surface (smoothness) each produces.  You can buy them flat on both faces and half round.  They are much cheaper than the Nicholson wood working rasps.  Buy several.

Dennis Bork
 
Howard- I'm assuming you're rasping the curves on the back legs after sawing them out. I tend to get rid of bandsaw marks with a # 50 then go to spokeshaves then scrapers, Grind some hollow scrapers for the back of the legs and another one for the molded fronts. Clean up the inside of the shield and index your scraper from that surface. Clean up any extra outside the molding after scraping.-Al
 
Thank you both.

On the topic of the molded fronts I have another issue. I have made scrapers to scrape the beads on the front of the shield and have had a heck of a time with tearout of the bead surface. The shield is curved so obviously there are large areas where I'm scraping against the grain. Any suggestions?
I am scraping both sides of the shield to create the bead, then carving/scraping the profile between the beads. That part seems to be working OK

Howard Steier
 
Howard,

When I scrape across the grain, I make a light pass just to leave a mark.  Then I use my small V-gouge to carve out some of the area to minimize tearout.  Then use the scraper to complete the bead.  The scraper I made cut one bead and half of the inside profile, then reverse it.

Dennis Bork
 
I do what Dennis does, and sometimes moistening the wood helps, and sometimes it makes it worse...You can us high speed and a light pressure to minimize tearout, and make sure the scraper is very sharp.-Al
 
Howard,

One last point if using a mill bastard file. It will leave a very smooth surface, sometimes so smooth that dyes will not stain it as dark as other areas.  Sanding the surface with fine sandpaper (I like to use 320 grit) will help to eliminate this problem.

Also, the metal files come in all lengths from 10" to 4" and some with a tapered point.  I use these small sizes a lot for smoothing out the interior curves of a splat. Some are wedge shaped which makes them great for reaching into a tight corner.

Dennis Bork
 
More helpful advice. Thank you very much.

I tried wetting first with marginal benefit. I've already tried the V-tool along the lightly scraped line (I bought a 35 degree V-tool) and it makes scraping/following the curve somewhat easier, but there' still a fair amount of tearout.
I then ground a bead scraper that had a very slightly larger diameter beaad to use to clean up the after the first scraper. The second doesn't hang up as much. This seems to help.

Howard Steier
 
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