Big Ugly Tool and Negative Rake Scraper questions

[Gregg Carrier]

Hello turners!

I have become interested in trying out a few new to me tools in my shop - negative rake scrapers, and the "Big Ugly" tools the Oregon folks use to such great effect. My goals are to get cleaner bowl interiors with less tearout (NR scraper), and to be able to rough like Robo Hippy (Big Ugly tool). A few questions:

- Does anyone make "Big Ugly" tools for sale? I have some welder buddies, and it looks like a cool project to make one, but worth knowing if there are commercial versions

- Do any versions of the "Big Ugly" have a "negative rake" profile? Apologies if I missed it, but I haven't seen it. The top angle would need to be shallow enough to keep the cutting edge on the Tantung layer, but seems doable?

- Would a negative rake profile help/harm/change the utility of the Big Ugly as a roughing tool? Improve it as a finishing tool?

- Looking at the D-Way negative rake scraper profiles, I am torn between a round nose profile, and the profile with a curve on one side. My goal is to get cleaner cuts inside bowls at the transition, and to minimize tearout. Any suggestions on which profile to start with? Was thinking the long and strong or the round nose?

- Can Big Ugly/Tantung be sharpened on a Tormek, or does it really want a CBD wheel to get the burr right? I inherited a full Tormek setup, so I'd rather not buy a second sharpening system, but you know...if I really *have* to buy more toys, I guess I could...

- Does anyone use a Tormek successfully to sharped the factory profiles of the D-Way negative rake scrapers?

 

[Bill Boehme]

Well, the big ugly tantung scraper is meant for hogging and a negative rake scraper is for the final touches on the surface. Combining them might be in the same league as a microwave crockpot.

 

[robo hippy]

The myrtle wood shops, it is actually California Bay Laurel, but I guess that is marketing.... those shops would finish turn the myrtle with the Big Ugly tools. They also turned at 5000 rpm. As far as I am concerned, I don't use scrapers for a finish cut, but I do use a shear scrape, with the cutting edge held to about 45 or higher degree angles. I prefer a burnished burr for that cut. A scraper will do a pretty good job if you are just sweeping across the bottom of the bowl. Once you start to come up the sides, you will get tear out. With a feather light touch, in scraping mode/flat on the tool rest, you might be able to get a fairly good surface, but that depends more on the wood than the tool. This happens because you are cutting uphill/against the grain for 1/4 turn, and downhill/with the grain for 1/4 turn, then repeat. When cutting uphill, you are cutting into unsupported fiber, and will always get tear out, and again, how much you get depends on the wood. You can get glass smooth surfaces when cutting end grain, like boxes.

That leaves the NRS/negative rake scraper. This tool has been around a long time. It is still a scraper, and cuts with a burr, which means in bowl turning orientation, you will still get tear out. Since the top bevel reduces the cutting ability of the NRS, you generally won't get as much tear out as you will when using a standard scraper. Like a standard scraper, they do a better job when sweeping across the bottom of the bowl than they do when going through the transition and up the walls. Again, I prefer the shear scrape for a cleaner surface it leaves when compared to the NRS. The tantung works great for a NRS, and I have several small ones that I use on boxes, and have plans to make more specialized ones.

For sharpening the Big Ugly tool, any grinding wheel will work. If you are sharpening on a Tormek, then it will work, but will be slower than a standard grinding wheel. I sharpen mine on CBN wheels, but keep the heel of the bar stock the tantung is silver soldered on ground down almost to the tantung. The softer metal of the bar stock can slightly load up the CBN wheels, but the tantung seems to peel that off.

Do you need a Big Ugly tool? Well, it is my go to tool for heavy roughing. I can do the exact same things with standard scrapers, which for me are 1 inch wide from D Way or Thompson. In my video 'Scary Scrapers' I don't think you need big heavy scrapers. The advantage of the Big Ugly is that the burr on it lasts a long time. I can rough out multiple bowls without needing to hit the grinder. With my other scrapers, I can rough out a bowl or two, then need to hit the grinder again. The burr on my tantung NRSs seems to last far longer than the grinder burrs on standard NRSs. I still prefer a burnished burr for a shear scrape. The tantung does take a nice burnished burr, but always seem to leave a slightly more coarse surface than the burr on an M42 or V10 scraper. I do prefer a 60/30 or 45/45 angles for my NRSs.

Grinding a Big Ugly tool to a NRS shape will, for sure, reduce its efficiency as a roughing tool, same as when compared to a standard grinder. With a burnished burr, that will cut finer and longer than a grinder burr, but still a standard scraper will still cut much more efficiently than a NRS.

For profiles, I prefer a straight across nose because that flat surface is better for smoothing out a flat bottom of a bowl or platter. The straight across area is also excellent for going down the outside of a bowl blank. I rough the outside first, finish turn it, then reverse. If I try to take a straight pass down the outside of a bowl with a round nose scraper, then that rounded profile tends to kick the scraper out of the path I want to take. Then I like a 1/4 round swept back design which is better for roughing out the transition and walls of a bowl.

I really wish some one would make them. I got out of making them because having the tools made and selling them just took up too much of my play time....

robo hippy

 

[Gregg Carrier]

Super helpful - thank you, Reed! I imagine it's no surprise that your videos are what got me interested in the "Big Ugly" as a roughing tool. It sounds amazing to be able to rough out multiple bowls with one sharpening. The big advantage of the Big Ugly seems to be in the nature of the Tantung and its ability to hold a useful burr - is that fair to say? If so, I imagine that durability could be beneficial on other tools and profiles too (one of your videos showed a bunch of profiles and some AMAZING detailed spindle work).

Again, appreciate your taking the time to respond. Cheers -
Gregg

 

[robo hippy]

The tantung works great, and so does stellite, a very similar metal. There is nothing that holds an edge like these two, except for carbide, and carbide is not as easy to sharpen. Oh, stellite is what Woodcut uses on their coring tools.

robo hippy

 

[Mark Jundanian]

So let me ask the obvious question. Why are there no tantung or stellite gouges?

 

[robo hippy]

Not sure about the stellite since it is not a cast metal like the tantung. Tantung needs to be 'supported' under the cutting edge or it will shatter/chip. I don't think stellite is as brittle as the tantung. Then there is price. A 3 by 1 by 1/8 inch piece of tantung, purchasing 50 pieces, was about 30 bucks 15 years ago. No clue as to how much it would cost now. Probably for the same reason that there are no carbide gouges. That stuff is brittle and won't take the stresses that the high speed steel will.

robo hippy

 

[Bill Blasic]

The hardest steel I know of being used for gouges is 15V (the big brother to 10V). While theory says that it should stay sharper longer (which to my trials it does) it can be chippy. Doug Thompson has made some gouges in 15V and I believe the Glaser black handle gouges were 15V.