Thread: Bowl Scraper Question

Originally Posted by Backyard Shed

On the inside wall I am having trouble eliminating stepping from the starting and stopping with my gouge.

Without actually watching your technique, I'll hazard a guess that you may find it easier if you add a bit of 'twist' to the gouge as you go around the curve. Not that this works for everybody.

Either way, it's practise, practise, practise.

So essentially buying a round nose scraper and adding the grinds would be the ways to go, or am I missing something?

Pretty much. FWIW, I wouldn't prioritise the regrinding to a negative rake as a plain old round scraper should do what you need well. Down the road, once you're familiar with the finish(es) you can get with the scraper you can try regrinding for a comparison.

But unless the timber you're using really needs the negative rake to get a good finish I'd stick with the plain ol' grind simply because it simplifies sharpening sessions and means more time spent at the lathe vs time at the grinder.

I also find a LH bullnosed grind better for inside bowls than a standard round-nose; as a consequence most of my round scrapers have slowly been shaped that way with subsequent resharpens.

I would keep practising with the bowl gouge and in particular different grinds. You will find that with a bit of patience and time the finish will come. As for the scraper, I have reground many to a negative edge but in the end much prefer a more traditional grind.
The main thing to remember about scrapers is not to go to far up the wall towards the edge of the bowl unless you want a major catastrophe. Other than that they can produce a good finish.
Have a look at the YouTube videos of Richard Raffan, he is a master when it comes to the use of the scraper.

Cheers,
Peter

Well I go with Skew n Peter, as scraping is a great way to correct the gouge marks. But technique on the gouge is perhaps of more importance.
https://www.google.com/search?q=rich...t=gws-wiz-serp
And you cant go wrong with Richard Raffan

Also if you listed what town/ locality you live in someone local to you could possibly help.
Rgds,
Crocy.

To get straight to your question - no I don’t think the only difference between a bowl scraper and a round nose scraper is the grind. Bowl scrapers are mostly much heavier duty tools. The round scraper you get with most starter kits is probably something like 19 mm wide and 6 mm thick. A Heavy bowl scraper is wider and thicker. That improves performance when the tool is extended well over the tool rest, as it is when you are scraping the bottom of a bowl.
my bowl scraper is more like 30 mm by 8 or 9 mm thick. (That makes a lot of grinding to change the shape so you generally buy one the way you want it.)
I agree with those who say practice with your gouge. Aim to do a final light finishing cut in one clean cut. As your technique improves that will reduce the steps and grooves.
I don’t use scrapers a lot on the sides but do a lot of the bottom with scrapers.
Bruce

Thank you all for taking the time to share your wisdom!

I think I will spend some more time in the shed. Its makes more sense to me now that the bowl scraper is thicker hence the price difference.

Perhaps stepping back a little to understand why you are leaving the "steps" with your bowl gouge may be very helpful in reducing the amount of cleanup work you have to do.

Without getting into all the nitty gritty of the pro's and con's of flute shapes and grind profiles on bowl gouges one needs to understand that "bevel rubbing" is important in controlling the cut of the bowl gouge. In saying that the length of the bevel can work for you as a "guiding reference surface" and also against you as the heel of the bevel also acts as a fulcrum levering the cutting edge away from the wood.

For long slow curves on the inside of a wide shallow bowl the length of the bevel is an advantage, however as the bowl becomes narrower and deeper the length of the bevel works against you. To over come this, and to prevent "heel bruising," many experienced turners use a secondary bevel and grind the heel away reducing the length of the primary bevel. The first image (not my photo) offers some insight into the length and purpose of the bowl grind / profile, the 2nd is my bowl gouges on the LHS that I use on bowls in the 75mm to 150mm dia and up to 100mm deep range.

The primary aim when starting out is to not confuse yourself with all the variations. Stick with a standard conservative grind and a conservative bowl profile and concentrate on understanding how the "pitch, roll, and yaw" presentation of the tool and hence cutting edge affects tool performance and the quality of the cut. Sharp tools also reduce "problems" as forcing a dull cutting edge to "cut" introduces more issues.

Thanks for this Mobyturns.

My issue is area where the side transitions into the bottom of the bowl so I have assumed as you have described the bevel is getting in the way. More to the point, they way I am using the tool is probably causing the bevel to get in the way.

I think I understand your 'pitch, roll, yaw' reference but I am not 100% sure.

Very hard to describe in words but I will give it a go. Starting at the rim the gouge is at 3 o'clock and I go down the side at this angle. I start to roll the gouge to approx 2 o'clock as I go around the bend into the bottom. This is where I can be a little hit and miss. Stopping and starting, trying to pick up on an edge. Hence the stepping.

I am using a 3/8 bowl gouge and using your diagram as an indication I would say it is closest to a fingernail grind. No secondary bevel.

I still have another 5 or so blanks to go so I am happy to keep practicing, I thought that the scraper may give me some satisfaction of a better finish in the mean time.

An image is worth a thousand words. So if you're able, a shot of your gouge along with the angle its ground to etc. Also, where the side meets the bottom can be tricky if its not a continuous flowing curve. I like one sweeping curve top to bottom and always aim for that. But then I use hollowing tools rather than gouges for the internal work.

Originally Posted by Backyard Shed

Thanks for this Mobyturns.

My issue is area where the side transitions into the bottom of the bowl so I have assumed as you have described the bevel is getting in the way. More to the point, they way I am using the tool is probably causing the bevel to get in the way.

I think I understand your 'pitch, roll, yaw' reference but I am not 100% sure. As in aircraft terminology, pitch - handle up / down; roll - as in your 2 & 3 o'clock reference; Yaw - handle to or away from your body.

Very hard to describe in words but I will give it a go. Starting at the rim the gouge is at 3 o'clock and I go down the side at this angle. I start to roll the gouge to approx 2 o'clock as I go around the bend into the bottom. This is where I can be a little hit and miss. Stopping and starting, trying to pick up on an edge. Hence the stepping

As Hughie states photos will help immensely to tailor advice. A lot depends upon the "smoothness" of your bowl gouge grind here, how smoothly it transitions from wing to nose. It needs to be a flowing curve not faceted, or "pointy". As you roll the tool handle from 3 to 2 o'clock (opening the flute), the actual point doing the cutting moves along slightly on the length of the cutting edge. The more pronounced the movement the more it moves along. If the face is faceted or not a smooth flowing curve you are adding numerous small and complex "fulcrums" that lever the actual cutting edge away from the surface to be cut. Often the transition in bowl profile requires more than one adjustment, roll + pitch etc. As you gain experience from constant practice you will start to combine all three movements (pitch, roll, yaw) into a fluid motion. Also consider that as the cutting tip extends further away from the tool rest the geometry of the cutting edge to surface changes, the nose of the bowl gouge rises so a pitch adjustment is required, in fact it requires constant small fine tuning movement/s. The better the grind the more predictable the tool becomes.

I am using a 3/8 bowl gouge and using your diagram as an indication I would say it is closest to a fingernail grind. No secondary bevel.

I still have another 5 or so blanks to go so I am happy to keep practicing, I thought that the scraper may give me some satisfaction of a better finish in the mean time.

Rather than just "hog out" the bowls concentrate on making lots of light "finish cuts" to achieve the bowl profile. You will learn more about tool control and get more bang for your buck from your blanks.

Good luck.