Secret weapon #1 against tearout --- a skwaper.

[Dan Forman]

This is something I cooked up after getting interested in negative rake scrapers, mainly for cleaning up tearout or tool marks on the inside of bowls. 219672219673219674 The bowl in the pic is a roughout that I mounted up as a prop just to show the shearing cut (mentioned below), so don't look for a smooth surface, there isn't one. At times I have used a curved skew as a scraper, but always had to worry about the point at the end the curve, and would often have to come uncomfortably close to that point when negotiating the curve of the bowl. I basically just eliminated any points, and have a varied curve, any part of which can be used for scraping, depending on what is needed. The nose can be used to take the tiniest cuts near the rim, where greater contact would cause chatter, or the more gradual portions can smooth out ridges if there is enough thickness to support the longer edge contact. It can be used at a variety of angles, without risk of a catch, as long as it is flat on the tool rest, and due to the negative rake, there is no need to hold it in a downward orientation, nor angled so that the edge is contacting the tool rest, as in a shear scrape with a normal scraper. One can obtain more of a shearing cut by orienting as in the photo, which I'm guessing is at a good 35* to 40* angle to the bed of the lathe. This would be disastrous with a regular scraper, but I haven't been able to actually cause a catch so far with this tool flat on the rest. By dressing both sides each time you sharpen, you merely have to flip the tool over to gain a fresh edge, so there is less time running back and forth to the grinder. You just have to remember which side of the tool to sharpen to get the burr on the desired side, left or right, depending on whether you are using it on the inside or outside of a bowl. It also works well with spindles. After making this from a parting tool that came with my first turning tool set (from Harbor Freight), I saw something roughly similar that Cindy Drozda sells, but hers is more of a round nose scraper that still has points on either side of the curve. I've never seen anything exactly like this, where there are no points at all to worry about - not to say that someone else hasn't done the same thing, just that I haven't seen one. I'm sure that I could patent this and make millions of dollars selling them on TV infomercials :), but out of the goodness of my heart, I'll just put it up here for free, and let y'all make your own. This one is 5/8" wide. I have found it very useful indeed. Dan

[John Keeton]

Dan, that is neat! I have a couple of skews on a shelf because of their infrequent (perhaps never!) use, and I have intended on making negative rake scrapers of them anyway. I will now use your contoured profile! Thanks!

[Ken Whitney]

Thanks Dan. I've been using a couple of oval-profile skews as negative rake scrapers, but I like the roundness and lack of corners on your version.

Off to the grinder...

[Jack Mincey]

Dan, I'm always looking to improve my final cut on the inside of my open bowls. I have one round nose scraper ground like this already that I use on plastic pen blanks and will have to try it on the next bowl I return know.
Thanks for the tip,
Jack

[Hayes Rutherford]

Looks good Dan. Now I'm thinking a huge one like from 1-1/2 x 3/8.

[Sid Matheny]

If it works, it's a great idea! May have to make one myself. Thanks Dan for caring more for us than your wallet.:rolleyes:

Sid

[Greg Just]

Thanks Dan. This might just what I need as I struggle at times with tear out and tool marks on bowls.

[Nate Davey]

Great idea Dan, consider this idea copied.

[Allan Ferguson]

That looks pretty good Dan. May regrind one of my cheap scrapers and give it a try.

[Peter Blair]

Great idea Dan. Still can't get my head around a 'negative rake" but I too have several tools that sit unused that could easily be converted to this application. Do you suppose you could let me know what angle you grind each side? I'm assuming that you use it right from the grinder without any honing, correct?

[Bernie Weishapl]

Dan looks good. I bought a cheap scraper from PSI and made a negative rake scraper and it does work nicely for tear out and tool marks. Mine isn't ground as far back as yours.

[David E Keller]

Neat idea. My only suggestion would be to call it a 'screw' rather than a 'skewaper'... My autocorrect doesn't like the latter term. Plus, it's your go-to tools when your screwed with all the others in the arsenal!

[David DeCristoforo]

Great idea. As to the name, I would take out the "e" and just go with "Skwaper" (think Elmer Fudd). Keller's spul chucker probably won't like it any better though...

[Reed Gray]

I may have to experiment some more with NR scrapers. I just get a better cut with a high shear angle, and my go to tools for that are a Thompson fluteless gouge, or a gouge that is more round nosed. Any scraper tends to leave some tear out when used flat on the tool rest. Just the nature of the tool, though on end grain orientation, it does a lot better. I have used the NR scrapers with honed burrs, grinder burrs (CBN wheel burrs are superior), and lightly honed burrs. They all work, with the honed burr being the weakest, and the burnished burr being a tiny bit more durable than the grinder burr. Note here, when burnishing, I use a burnishing tool, not the vertical one from Lee Valley. The rod needs to be only a few degrees off parallel with the bevel, so bevel at 45 degrees, burnisher at 50 or so, not 90 like the LV one.

robo hippy

[Bill Wyko]

Finally, something I can do with that Crown 1/4" parting tool. That'll come in real handy this weekend. Thanks Dan.

[Mike Campbell KS]

cool tool there Dan. I have the same 3 point thingy that came from HF, and I have never found a use for. I'll be making one this weekend.

[Dan Forman]

Thanks for all the comments. I'll be curious to hear what your results are with this grind, so please do post them.

I was happy to have my 80 grit CBN wheel when grinding, took quite a while, and left a big black pile of dust, but was nice not having to stop all the time and wait for the tool to cool down.

When cleaning up thinner bowl rims, I usually need to dampen vibration with my hand on the outside of the bowl, but it's nice to know that I don't have to worry about a catch.

Peter --- I measured the angle at 37* relative to the flat of the tool. This is just how it ended up when I thought it looked about right, nothing magic about the number as far as I know. It seems a good compromise between sharpness and durability, though obviously more blunt than a skew. You are correct in that it is used straight from the grinder with the burr intact.

David D --- Skwaper does roll off the tongue a little easier, doesn't it?

David K --- You might just have to teach your spell checker this new term.

Reed --- I haven't used this on green wood yet, but in dry, it really is different than a regular scraper, especially when presented well above center as in the pic. It doesn't leave a glassy smooth surface on end grain, but does pretty darned good, nothing I would call frank tearout, just not glassy like side grain. If you try it, I would like to hear what you think of it. I use more traditional negative rake scrapers on the outside of bowls, and consider them tearout free in most wood. I did have one particularly troublesome bowl of black locust that defeated all of my tools with tearout, but it succumbed to my second, near secret weapon, which I will reveal in another thread.

Hayes --- I did finally put a negative rake on all 3 of my big scrapers, but much more subtle than this - for one thing, too darned much steel to remove. :) This one is really my finesse tool, light in the hand and easier to control than the big scrapers, and used for smaller trouble spots. Bring a dry roughout with you on Monday and give this and secret weapon #2 a try.

Dan

[Jim Burr]

Guess I caught this late Dan...could you cover the pic's more? Is the first what you use and is came out of the second pic? Great idea, but I'm old and slow with need of "hand-holding" in these area's. Nice work and keep it up!

[Bill Wyko]

Well I decided to do a little search on negative rake scrapers and low and behold, Glaser is already on it. Check this out I was surprised to find the coincidence here. More fun for all.
http://www.negativerakescraper.com/

[Dan Forman]

Jim --- Both are pics of the new tool, just different views, one showing the shape, the other showing the angles involved.

Bill ---Negative rake scraping in not new, just not widely known. Several companies are now marketing NR scrapers, but I've never seen this particular shape done before. Also, most have a long primary bevel with a very short negative bevel, rather than two bevels of nearly equal lengths, and the bevels tend to be much steeper.

Dan

[Bill Wyko]

I'll be modifying my parting tool to a grind like you've done there. I use the mini parting tool now so I have no use for the crown. Now it'll have a new chance at life. Thanks for the post, it'll be very useful.

[David E Keller]

I looked at the Glaser site you listed, Bill... Not entirely accurate. The article I read there indicated that bkackwood couldn't be scraped with a regular scraper. I know this isn't true because I just finished doing 'the impossible'. I only mention it in case someone else here chose to read the article... I'm sure they make a great scraper.

[Peter Blair]

Hey Dan. With nothing but time on my hands you inspired me to re-grind several bowl scrapers that I no longer use.
Here are a few shots of my Skewaper.
219801
219802
219803
Worked slick on the inside outer edge, not as good as my regular scraper across the bottom.
Thanks again for the idea!!!
How do you sharpen yours? As you can see I just ground it using my Wolverine, gives quite a different profile than your shows.

[Jim Burr]

Ok Dan...many other famous turners can figure this out...I'm happy to say I'm stupid. With the pic's you show in the original post...the grind can't be done. It is either a round neg rake or an angle grind and have a great day. Understanding your faith, I don't mean to beat up a dead horse...but the pic's in the original post can't be the same tool without adjustment. I saved the pic's so I have a reference. Again...not sure how you can make a curve all around with a picture of a flair wedge on the bottom and no illusion adjustment for the curve on the top. And again...I love the idea...just can't see the proof on film.

[Dan Forman]

Pete --- I find it most useful for the upper two thirds of the bowl as well. To reach the very bottom of a bowl, you would have to use the nose, which I find a little too narrow. For the very bottom, I use a 1 1/2" wide round nose NR scraper. I sharpen using just the platform, no jig. It gets a little iffy near the end of the curves on either side. See first tow pics below.

Jim --- Don't know what to tell you, I have no idea what a flair wedge or illusion adjustment is, though wish I had one of the latter connected to my brain.:) Suffice it to say it is quite possible to grind this on a platform, just as you would a normal curved skew, except that you swing it all the way from one side to the other, then turn it over and do the same thing for the flip side. One view (of the original pics) is from the top looking down, the other is dead on from the side. What might be confusing you is the triangle which is the side of the tool where it meets the top and bottom bevels. If you look carefully at the view from the top, you can see a bit of that triangle on the lower edge.

On the other hand, doing the impossible might be just the thing to get me a gig on the demo circuit. :D

Here a few more pics which hopefully will clear things up.

Grinding left extreme and right extreme... and two angle views. Sorry about the lighting, it's late and I didn't take the time to mess with white balance.

219855219856219857219858

[Rick Markham]

Dan you're wicked smart my friend! But I'm deducting two points from your score... as this was all a big ploy to show off your CBN wheels to rub it in to "us less fortunate folks" who only have Tormeks... and broken spul chuckers.

I like this, it's clever thinking, and I will be making me one of these Schwappers

[Peter Blair]

Thanks Dan. looks like I ground mine a little too round. Not a problem, next time I tune it up I'll change that a little.
ps. What wheels do you have on your grinder?

[Reed Gray]

The particular NR scraper shown here is more pointy than I would use. I find the more bull nosed type to be more useful. You could always have two, one for the outside. which would be swept back on the right side, and one for the inside, which would be swept back on the left side.

As much as I preach about using scrapers, I don't use them for finish cuts, unless I am shear cutting, with the blade at a high angle rather than flat. I use gouges for the finish cut inside and outside the bowl. It is a more difficult and practiced cut to get smooth/bump free. The shear angle bevel rubbing cut does leave a cleaner surface.

robo hippy

[Dan Forman]

Reed --- The shape was mostly determined by the extra parting tool I had lying about, I wanted a choice between relatively pointy and more gradual curve (parabolic), useful for different purposes. I use the sides a lot more than the point. It is also basically a cleanup and repair tool, to get me by until I can get those clean inside cuts going. Without something like this, I wouldn't actually complete many bowls, as I always seem to have some kind of a mishap right at the end that would be too difficult to sand out. The skwaper allows me to clean up those mishaps, and salvage the bowl. You would have to try it to appreciate the difference between it and a regular scraper. For me, flat on the rest, it works better than a sheer scrape with a standard scraper. I use it mostly on the sides of a bowl, especially near the rim, which is where I most often have trouble, or transition areas if I'm taking a bowl down in stages rather than one long cut from rim to bottom. I'm hoping to need it less and less, but until then...

I just got a Thompson 5/8 fluteless gouge, but am having a hard time trying to figure out how to use it. I try to rub the bevel, but get frequent catches, and it always seems unstable, much more so than with a bowl gouge. Any hints?

Dan

[Reed Gray]

On my 'to do' list is a short You Tube video on using that tool. If you are getting catches, you are coming off the bevel. You can use it like a shear scraper on the outside of a bowl where it the handle is rotated/pulled far enough away form the cut so you are off the bevel. If you just barely come off the bevel, it can dig in like a skew. You need to cut on the lower 1/3 of the tool, not at center, which is the temptation. Best if you drop the handle a bit. Also, it is extremely difficult to make an entry cut on the rim with it. You use it at a high shear angle, 45 plus degrees. It does have a short bevel, and is close to 60 degrees, so perfect for the transition and bottom of bowls. It does cut well with a burr, or with the burr honed off, or even a burnished burr. It is not a good scraper because of the rounded profile.

Wish we lived closer together. You live way out east. My joke for here is 'back east' means Bend, OR. For when I did shows in Seattle, 'back east' there meant Spokane.

robo hippy

[Dan Forman]

Reed --- wish we lived closer too. Back east for me is Fargo. :) . Would love to see a youtube vid. I need to do some more roughouts again, that would be a good way to practice, less chance of doing irreparable damage.

Dan

[Jim Burr]

Duh...now I get it. Thanks for the extra pic's and helping the really slow!

[Reed Gray]

Not slow, not fast, just half fast. From a sigh in the Brownsville tavern years ago. If you don't get it, say the last part fast a few times.

robo hippy

[Jamie Donaldson]

Dan- you can forget about the patent idea, because I've been using a very similar NR scraper since the late 1990's when I saw Stuart Batty use such a tool in a demo. It is best applied for hardwoods or figured woods that suffer tearout, and now that I have mastered the bowl219987 gouges I seldom have any use for this user friendly salvage tool. I don't know that any of the turning tool makers now makes such a tool, but mine was a 1/4" T x 1" W heavy half round scraper in it's earlier life.

[Dan Forman]

Dang, and I already quit my day job! Wait, did you or Stuart patent it yet? :D

I am looking forward to the day that it's use is no longer required.

Dan