Shear scraping with skew

[Tiger]

The first book I ever bought on turning pens was the book by Kip C and Rex B. A great book with good ideas and projects. In the book they talk about shear scraping with the skew chisel but I don't think it's all that well explained. I have shear scraped on bowls with gouges and it works well, does anyone here use shear scraping with the skew chisel? My experience when I attempt to use it is that sometimes for no apparent reason the skew will bite. Other times it works well. It could be the angle I'm presenting the tool, it could be timber, I don't know. The tool is sharp so we can rule that out. Any help on this would be appreciated.

 

[Jim Burr]

A bowl gougle with a fingernail or sweep grind is much more suited to a shear cut than a skew...IMHO.

 

[Tiger]

A bowl gougle with a fingernail or sweep grind is much more suited to a shear cut than a skew...IMHO.

You may well be right but as I've already got the skew in my hands it's mighty convenient if it can pull off a very light shear cut and save me some sandpapering.

 

[low_48]

There is scraping and there is shear scraping. Scraping would be done with the skew laying flat on the rest, end of the handle slightly higher than the cutting edge. Shear scraping would be done with the skew up on an edge corner, included angle between the blank and the skew at less than 90 degrees, and pulled along the blank. Look at John Jordan page on his shear scraper. Different tool of course, put position and cutting angle would be the same with your skew. Shear Scraper

 

[Tiger]

Thanks Low, looks like a dicey sort of cut on a pen. Don't have anything to back up that statement but I guess if not much of the cutting edge is hitting the wood it should be "safe"?

 

[low_48]

Very safe IF you keep the angle between the skew and the wood less than 90 degrees. Go over that, and it will self feed or catch.

 

[KenV]

There is a neat shear scraper sold by John Jordan (and can be made from a rectangular bar of High Speed Steel) that does a nice job -- It an be used from the tool rest AND it can be used without the tool rest -- . Malcolm Tibbitts shows it being used free hand on one of his videos.

http://www.johnjordanwoodturning.com/John_Jordan_Woodturning/Shear_Scraper.html

You can do the same with a skew, but if the handle is long it is much more awkward.

This is an excellent approach when a CA finish goes rough and ridged -- light shear scrape to level and go back to work.

Rich Kleinhenz shows shear scrape in his book and some of his articles using a skew.

 

[Tiger]

Very safe IF you keep the angle between the skew and the wood less than 90 degrees. Go over that, and it will self feed or catch.

I was referring to the Jordan picture where the tool is actually rotated so that it hits the wood at 45 degrees, i assume you're talking about scraping with the skew lying flat on the toolrest? You can guarantee that angle by just raising the toolrest so that it's a bit higher than the workpiece.

 

[low_48]

I'm too confused know. With the skew flat on the rest, it will never be shear scraping. There are two angles to consider in shear scraping. The amount of rotation in the handle and how perpendicular the handle is to the wood. Perpendicular to the wood is not good. You have to have the handle leaned in the direction of the cut. That is the less than 90 degrees I was talking about.

 

[Tiger]

I'm too confused know. With the skew flat on the rest, it will never be shear scraping. There are two angles to consider in shear scraping. The amount of rotation in the handle and how perpendicular the handle is to the wood. Perpendicular to the wood is not good. You have to have the handle leaned in the direction of the cut. That is the less than 90 degrees I was talking about.

Ok thanks for clearing that up.