How To Regrind And Sharpen Bowlturning Tools

Sharpening Scraper Lathe
W SPINDLE GOUGE

Before getting to the tools used to turn the Fruit Bowl, I'd like to mention a couple of things about the lathe itself. 1 used a standard 36" Sears lathe to turn the fruit bowl. The Sears lathe itself is more than adequate to do the job. However, the point I'd like to make is that a lot of the light metal benches sold for Sears (and other) lathes are not adequate for this kind of project.

An 11" bowl spinning out-of-round on the lathe, creates an unbelievable amount of vibration. Unless the lathe bench is weighed down enough to dampen this effect, it will be almost impossible to turn the bowl because of the vibration.

THE GOUGE

As for the tools used: a V-i' spindle gouge did the majority of work on the fruit bowl. However, 1 reground the bevel of the gouge for use on faceplate turnings.

There are a couple of reasons for regrinding. First of all, the bevel on a spindle gouge is usually ground to about 30°. But if it's used for faceplate turning with the 30° bevel, the handle would hit the top of the bench as it's being used.

In order to keep the bevel rubbing on the wood and still allow clearance, I hollow-ground the bevel to about 45°.

In addition to changing the bevel, I also changed the shape of the tip. The standard shape on the tip of a spindle gouge is that of a fingernail. For turning on the faceplate, the fingernail shape is retained, but it's less pronounced.

NOTE: All of this grinding was done on a Sears grinder with a Norton 60-grit stone. See Woodsmit.li No. 20 for more on this sharpening equipment.

SHARPENING GOUGES

No matter what bevel angle or what shape you use for the gouge, the cutting edge must be sharp. I use slip stones to sharpen the gouge after it's been reground.

Slip stones have a long wedge shape with a crowned edge — an ideal shape for honing turning tools. (Some books show

HEAVY DOMED SCRAPER

turning tools being honed on a bench stone, hutforthelifeofme, I can't do it that way.)

SHOP NOTE: Because honing a gouge will hollow out the surface of any sharpening stone, I mark one side of the stone with a small notch to designate that this side is for gouges only. The side without the notch is used for only the flat tools (skews).

To obtain a truely sharp edge, I use a series of three slip stones: a medium India, a fine India, and a soft Arkansas.

HONING. After the gouge is removed from the grinder, the first step is to remove the bun* on the inside of the "U".

Place the slip inside the "U" and hone the entire edge from comer to corner by sliding the crowned edge of the slip back and forth in the "U".

Always keep the majority of the slip well back in the "U" to prevent any chance of it teetering and rounding over the cutting edge. If the "U"side of the gouge becomes rounded over at the cutting edge, it will have to be reground until it's flat again.

After the burr is removed from inside of the "U", hone the bevel side of the gouge. (Honing the inside of the "U" usually just bends the burr over to the bevel edge.)

Honing the bevel edge is also done with a slip — but this time the face (fiat side) of the slip is used. I sit on a stool at the workbench with the handle's butt nestled in my Lap and the steel shank of the gouge pressed against the front edge of the workbench. This way the too! is stationary, yet it can be rolled as it's sharpened.

As the gouge is honed, I slide the slip in a back-and-forth motion (in line with the cutting edge) along a small section of the bevel, keeping it pressed against both the tip and heel of the bevel.

One way I've found to be sure that the cutting edge is being honed (and not just the bevel) is to see if oil is rolling over the cutting edge and down the inside of the "U". If it is, I know the stone is in contact with the very tip of the edge.

To continue honing around the cutting edge, I roll the gouge in my right hand as 1

Vj" LIGHT SCRAPER

hone with the slip in my left hand.

Hone the bevel until the burr is removed, then repeat the honing on the inside of the "U", When the burr is removed from both sides, use the next finer slip and repeat the process.

THE DOMED SCRAPER

The heavy domed scraper I used to clean up the surface after the gouge is made by Sorby of England. We purchased a complete set of Sorby scrapers from Woodcra ft Supply Corp., but I've found that the domed scraper is the only one I use enough to justify the cost (§23.60).

The Sorby domed scraper is forged from Ys" thick steel. This extra-thick blade helps dampen the vibration, and when it's used with alight touch, it can really help smooth out troublesome end grain.

The bevel on any scraper is ground to a very steep angle (15° to 20°). This steep angle allows the thickness of the tool absorb some of the punishment.

When the scraper is used, it can be taken directly from the grinder to the lathe, without any honing. The burr left by the grinder is what actually does the cutting.

If the scraper produces nothing but dust, the buiT has been worn off, and a new burr must be formed. Lightly pass the scraper over the grinding wheel a couple of times to form a new burr. The burr put on the scraper usually doesn't last very long, so resharpening is done quite often.

LIGHT SCRAPER

The W light scrapers provided in standard starter sets are, in a nut shell, too light to do much besides forming special shapes. But for this kind of special application work, alight scraper is ideal to do the job. I reground a light scraper to form the lip on the outside wall of the bowl.

For this application, the tip of the V4" scraper is ground to a more rounded profile than was on it originally. This really helped eliminate any chance of the corner of the scraper eatching the fruit bowl's lip.

Talking Shop

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