Bowl Scrapers

[crokett™]

He is still active on the AAW forum

Yeah, I saw a few recent posts of his over there.

[hairy]

 They are nice and thick--a little over 3/8" --so chattering isn't much of an issue.


Gary

That's what interest me in getting it. 1 & 1/2" wide x 3/8" thick.

[imapseudonym]

Other than more thickness to absorb vibration along the shaft, I don't see what the advantage of the step down design would be.

I use sheer scrapers and negative rake scrapers extensively on bowls. When properly sharpened a negative rake scraper leaves a great finish and eliminates the oopsies I have had using a flat-top scaper tilted down near the bottom of the bowl where different portions of the arc present slightly different angles. I find a negative rake scraper held flat on the rest more controllable. I like the D-way tools ones a lot if buying new.

[Grey Mountain]

I used exclusively scrapers for many years. I had everything from a 1/4 inch to 1 1/4 inches. Some scrapers I bought; others if refashioned from skews, some I made from everything from files to other pieces of metal I had. I have ground the tips to just about every shape conceivable.

Lonnie

[Arlin Eastman]

Surprisingly hard to find good images. It also turns out that there are at least 2 different interpretations.

In both cases, the top surface of the scraper is not flat all the way to the tip.

Instead, the last of the top surface is either:
- ground at a shallow angle at the edge to form a chamfer and a negative rake scraper. or
- ground with a step-down.

The step-down is the one that Myron Curtis invented.

For scale, that is the end of a 1/4" square tool steel rod.

The negative-rake version is what they taught in our Turning 101 class.
The Glenn Lucas signature scraper is a negative rake scraper.
Here is a link to a pinterest video of making one.

Edited to correct: the Glenn Lucas negative rake scraper is made by Hamlet in Sheffield and not by Crown. Sorry.

What does a drop down scrapper do different then a top scrapper?  They both work with a burr but the drop down has less metal so I do not see that it is better so I would like to know.

[iclark]

What does a drop down scrapper do different then a top scrapper?  They both work with a burr but the drop down has less metal so I do not see that it is better so I would like to know.

Some descriptions say that the drop down moves the edge closer to the plane of the tool rest. That is said to give more control.

When cutting circles for trivets, the shorter height at the tip is helpful for cleanly cutting the smaller circles.

It is also possible to sharpen it so that you can do planing cuts with them.

There is some discussion of them in the AAW article on Myron Curtis, but I could not find a way to copy those passages. Sadly, Myron passed before I had a chance to take a lesson from him.

I have not had any time at the lathe to try things out since I realized the difference between negative-rake and drop-nose.

[Arlin Eastman]

Thanks for the info Ivan

[AHill]

One thing to note about the linked video from Robo Hippy. He's mostly cutting green wood, so he can afford to be more aggressive with his scraper compared to seasoned bowl blanks. Robo Hippy is a huge advocate of scrapers, practically doing an entire bowl from start to finish with scrapers. I remember some healthy debates on this forum between those who disagreed with Robo's methods. If you use your tools properly and safely, it doesn't much matter what method you use.

[hairy]

That's what interest me in getting it. 1 & 1/2" wide x 3/8" thick.

I went and got the big Sorby bowl scraper. Lowest price I've seen.

https://www.amazon.com/Sorby-Left-Hand-Bowl-Scraper/dp/B0036B4LQE/ref=sr_1_1?crid=3JM0M242WQ9L9&keywords=sorby+scraper&qid=1677620015&sprefix=sorby+scraper%2Caps% 2C109&sr=8-1

I want to make it negative rake. It is 80 degrees as shipped. I'm thinking 15 degrees is the right angle to do that.

Does that sound right?

[imapseudonym]

I usually use scrapers with that profile as sheer scrapers (handles dropped way down, corner of the tool on the tool rest so the sharpened edge presents about a 45* angle to the surface. Used that way, I don't normally but a negative rake grind on them.

If you do want it to be a negative rake to be used flat on the rest, the combined angles of the two bevels have to be less than 90* or it won't cut. An 80* main bevel with a 15* negative rake would be more than 90.  I think my negative rake scrapers have a combined angle somewhere between 70 and 80*, I haven't noticed much of a difference if it is the same angle on each bevel (say 40*) or if one is steeper than the other, except that if they are the same angle it is easier to flip the tool over to get the opposing profile.