Thread: Tutorial on Shear scraping.

SHEAR SCRAPING with a BOWL GOUGE.

Photo 1: Vic Wood doing a shear scraping cut with a bowl gouge.
Attachment 130882

The gouge has two cutting edges, the top edge (which you can see) and the bottom edge (that you cannot see).
The cutting edges must be razor sharp and slightly convex.
All of the cutting is carried out by the lower cutting edge, the angle of presentation of this edge to the work is critical in shear scraping.
The bottom cutting edge should be presented to the work, between 10 and 45 degrees from vertical. This is controlled by holding the handle of the gouge low on your body.
The gouge should be rolled over so that the top cutting edge is almost touching the work.

Photo 2: shows the position of the cutting edges and the handle of the gouge.
A 5 cent piece was placed under the top cutting edge to show how close this edge is to the work. If the gouge is rolled over too far and both the top and bottom cutting edges touch, the gouge will stop cutting (but never catch).
Attachment 130883

Photo 3: close up of tip of gouge (with coin spacer).
Attachment 130884

Photo 4: Vic uses a slightly flatter presentation angle than me and makes a wider cut, which is shown by the wider black marks. This wider cut will leave a smoother surface finish than my more vertical cut.
Attachment 130885

Photo 5: I normally work on hard woods that tear very easily, and I tend to make smaller pieces with limited access, therefore I shear scrape at an angle closer to vertical. The smaller area of cut is shown by closer black marks.
This steeper angle of cut will give you the best chance of eliminating tear out, however it will leave some surface lines, these lines are very shallow and remove easily with sand paper.
Attachment 130886

Photo 6: Vic shear scraping using a spindle gouge.
Attachment 130887

Photo 7: Shear scraping produces fine hair like shavings.
Attachment 130888

SHEAR SCRAPING with a ROUND NOSE SCRAPER.

Photo 8: Vic shear scraping with a round nose scraper. I sharpen my scrapers to 50 degrees, you will notice in the photo Vic uses a much more agressive angle. Both Vic and I polish the top of our scrapers and remove the burr.

The scraper, like the bowl gouge, is presented to the work at an angle, between 10 and 45 degrees from vertical. The scraper must be moved so that the lower edge that is sitting on the tool rest cuts the wood first. In the photo the cut is being made from the center of the bowl towards the outside (with the grain).

Attachment 130889

It is almost impossibe to have a catch with a bowl gouge when shear scraping, the same can't be said for a scraper.
The scraper MUST be presented to the work at less than 90 degrees or it will catch (the angle formed between the top surface of the tool with respect to the face of the work).

Photo 9: Shows the scraper being presented at the correct angle, less than 90 degrees, and is therefore SAFE.

Attachment 130890

Photo 10: Shows the scraper being presented at the incorrect angle, greater than 90 degrees, and is therefore UNSAFE.

Attachment 130891

Thanks to Tealady for the photos.

Thanks to Ken for the captions and Vic Wood for checking it.

Thanks for teaching me too.

To be continued..........

Thanks , Vic, Ken, Jim, Tea Lady. This tutorial explains why I, at times, have some trouble with the round-nose scraper. Presenting it at the wrong angle. I await the next instalment.

Good God, anyone would think these guys know what they are talking about.....

Lesson no. 245 and all for free.

Thanks for the tute

I have used the bowl gauges before for shear scraping, but don't use the scraper, probably because the first time I did I obviously used it the wrong way you indicated and it caught .

I would also like to argue that the bowl gauge cant catch when you roll too far, I can make anything catch

I would like to add my thanks to the chorus!!!!

good one, guys

This is excellent. Thank you. Thought I was the only one doing scraping and shear scraping with the bowl gouge. Am scared of regular scrapers; have one and never use it. Very encouraging to learn that I have been doing it somewhere near right all this time.

Thanks gentlemen (& TL)

What's the plus in a long bevel on a scraper?

Great stuff, many thanks


Phil.

Thanks guys - like i said in the other thread before - clear as mud

Also as i proved myself - easier to explain then actually do

Cheers

Thanks , Vic, Ken, Jim and Anne-Maria. Great tutorial

I think I get it now. Gotta go practice some

Cheers,
Dave