But on the convex front edge of the seat, I would reach for my flat scraper and work diligently to get a clean shape. The small contact area tends to leave "stripes" and makes a tough job even harder.
So recently I ground a flat blade with a concave edge and have been thrilled with the results.
You can see that it makes contact more fully and by slicing across the grain, I get a clean, even shape.
I actually look forward to working this area. To make the blade, I simply set my toolrest on the grind 90 degrees to the tangent of the wheel and slowly cut the shape. I'll be showing a great tip for filing and honing the edge next.
Peter,
ReplyDeleteVery interesting article - beautifully illustrated too. I wonder:
1. how you determine the radius in relation to the convex surface to be worked, and
2. how you avoid 'riding' the soft and hard parts of the pine grain. I tend to get a wavy pattern when scraping wood with distinct soft and hard rings.
Alfred
What Made you decide to grind the flat blade concave?
ReplyDeleteAlfred,
ReplyDeletehonestly, I just guessed. But the idea is that you want a curve that is more open then the shape you wish to scrape so that you can hold it at a skew while scraping, much the same way that various coves can be cut on a tablesaw by pushing wood across the blade at an angle. I will be making a video soon about scraping. The key is a sharp scraper and scraping from a variety of direction.
Chair-man,
I simply realized that I was using the wrong tool for the job!! It's obvious that you wouldn't use a flat scraper in a bowl shape, because it wouldn't fit, but because rounded shapes don't restrict the scraper type, I've always used a flat scraper, which makes too little surface contact to be much help shaping the piece. How's that for a run on sentence!