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Tiny Tools …  Part 2


This is a continuation of Part 1. This section describes a V-cutter, skew, parting tools, a long-bevel tool with a very fine point, and others. Toward the end are two bad designs – tools that didn’t quite work out.



V-Cutter with a Curved Shank   


This is a versatile tool for small turnings because it has the ability to cut either toward the left or toward the right along a line more or less parallel to one of the bevels. Cutters of this shape are frequently used as hollowing tools. What it cannot do is cut straight ahead, cutting with both edges at the same time. It will quickly bog down in a wide cut if presented to the wood this way.


I used a 3 1/2” section of a 5mm diameter chainsaw file for this project.


The first step is to soften the section to be used so it will be easier to work. Then, while it is still full length, remove the teeth of the file or at least smooth them a bit.

It is convenient to shape the rough form of the cutting edge at this stage. Form a bevel on each side of the blank. Note that the blank is held nearly horizontal at the appropriate angle to the plane of the grinding wheel.

Next, form the bevel at the end of the tool directly under the tip. Also, grind a flat surface on the top.

In anticipation of making the bend, note carefully where it should be, allowing for the section that will be inserted into the handle. Also pay attention to the direction if you have already roughed out the cutting edge.


What worked for me was to heat the blank at the point of the bend and then stick it between the jaws of a vise. The part near the tang remained cool enough to grasp, and the length gave sufficient leverage to make the bend easily. The extra length was then removed.

The next step is to reharden the blank; that is, heat it to a high temperature and then quench in water.  


After hardening, the metal must be tempered. This involves heating it to about 450° F, using the oxidation colors as a guide to the temperature, and then quenching in water. The following photo shows the top surface of the cutter as it appeared when quenched. It is combined with the image of the masonry nail we saw above.


Tempering is the last of the heat-treatment steps so you can now fit the tool in a handle. Because of the bent shaft, you will not be able to drive the tool into the hole. Therefore, size the hole for a sliding fit and then secure the tool with epoxy.


Smooth the top surface and the bevels with a diamond hone. Remove the burr that may appear at the cutting edge, and then form the keeper burr. The tool should then be ready to use.



Three-Point or Pyramid Tool


This tool is a variation of the V-cutter, or maybe it’s the other way around. It differs from the V-cutter in that the top surface near the tip is angled downward relative to the axis of the tool, and the three bevels form a three-sided pyramid.

Because this tool is straight, no heat treatment will be needed provided you are careful not to overheat it during the grinding phase. You can install it in the handle early on to make the tool easier to hold.


However, once installed in the handle, heat treatment is no longer an option. An alternative is to use a Jacobs chuck as a holder and postpone installing it permanently until after all the grinding is done.


Grinding the tool is straightforward. Form the top bevel first and then the side bevels. Follow the grinding with honing to form the final cutting edge.


Avoid rounding the very tip of the tool; be sure the planes of the bevels extend all the way to the tip. To do this, first hone the top dead flat and then hone the sides, being careful to keep the hone flat against the bevel at all times.



A Tiny Skew  


Many pen turners favor a small skew for shaping the body of a pen. Others use the long point for shaping fine detail on a finial. It is a versatile tool. However, a tiny skew has direct competition from its larger counterparts; you can do considerable fine detail work with a full-size 3/4” skew if it is ground with a long bevel.


Therefore, for a tiny skew to be worth the effort, it should be capable of reaching where the larger version cannot. This means it must have a long bevel.


A skew is one of the more difficult tools to sharpen. Various jigs are available to aid the process but it is unlikely that a tiny skew would fit any jig that’s available for purchase. Therefore, we must improvise.


The first thing to do is mount the blank in a handle so you can hold it more easily. The specifics of your blank will dictate the details, but this amounts to using epoxy to secure the blank in a hole in the handle.


If you are using a flat masonry nail with a tapered shank, drill holes of different diameters to match the taper. Only about 1” of the shank needs to be inserted in the handle. An alternative method is to drill an oversize hole and then fill around the shank with epoxy mixed with a filler such as sawdust or coffee grounds.


Once the blank is mounted in a handle, you can begin to shape the cutting edge. These instructions are based on what I did. You may be able to improve on this or modify it to suit your needs.


Grind the head until it is flush on all sides. Reduce the width of the blank near the cutting edge if you wish to do so.


Begin forming the bevels. Hold the tool horizontally. Place its axis at an angle to the plane of the grinding wheel in order to set the angle (and length) of the bevel. Then roll the blank against the wheel so that contact is made first with the lower edge of the blank and then progresses upward as you roll the tool. The idea is to form the bevel using dozens of light passes rather than one heavy cut.

The natural tendency of this method is to from a bevel that is straight along its length but curved across the width. Make a conscious effort to avoid this by making only very light contact with the wheel at the beginning and end of each pass.


If a curve starts to develop, you can correct it by placing the bevel flat against the side of the wheel for just an instant.


A bevel length equal to twice the thickness of the blank gives an included angle of 29°. This is smaller than what is found on typical skews but is good for a skew which must reach into very tight spaces. You may wish to make the angle even smaller.


Stop just short of having the bevels intersect at the tip of the tool.


Form the angle at the end.  The angle is usually 20° but you can make it larger for a longer long point if you wish. Be gentle at the grinder because the metal is thin and will overheat quickly.  

Note that the end where the cutting edge will be is no longer of uniform thickness. The next task is to grind the bevels at an incline until the uniformity is restored. This requires grinding more near one edge of the blank than the other.


For this I used the belt sander setup that I use to sharpen my regular skews. It is less aggressive than the grinder and it also has a rest that makes it easier to grind consistently. However, you can do it by grinding on the side of the grinding wheel if you work carefully.

        

Returning the end to a uniform thickness sets the angles of the bevels. Once this is achieved, continue grinding to reduce the thickness until the bevels intersect at the cutting edge. It’s at this point that the first signs of sharpness will appear.

Use a course hone to refine the bevels and the cutting edge. Try to get the bevels perfectly flat and be careful not to round the heel or long point.


Do the final sharpening with a 1200-mesh hone. This will produce a keen edge. If you want to go for a razor edge, strop or polish the bevels using a fine polishing compound. The tiny skew should then be ready to use.


After testing my tiny skew, I concluded that it was wider and thicker than what it needed to be. I backtracked to the grinding phase to reduce both the thickness and width so it would reach into tighter spaces. The following photo shows the final result.



Tiny Parting Tools    


These are detailing tools used more for making square cuts than for actually separating components. They can be made from files, flat countersink bits, and so forth. No heat treatment is required.


When working with a long slender file, the challenge lies in holding and orienting it precisely while grinding. I think it’s worthwhile to install a temporary handle at each end to make it easier to control.


Grind the bevel under the cutting edge with the handle horizontal in the same manner suggested for forming the cutting edge of the round nose scraper near the beginning of this article. Do not point the blank directly at the wheel.


A different parting tool is made from a flat countersink bit and is actually easier to do. All that’s required is some simple grinding. One convenience is that the shank is round so it’s easy to install in a handle.



A Long-bevel Cutting Tool   


This tool is capable of making a cut in very close quarters. It is used like a spindle gouge, up on its side and with the bevel rubbing. It can also be used as a keen-edge scraper if it is placed flat on the rest.


It has a flat bevel on the top and a rounded bevel on the bottom. The included angle at the tip is very small, about 30° or even less.


My version is made from a chainsaw file. After softening the metal, I roughed out the two bevels at the grinder and then switched to my upside-down belt sander for the fine tuning. Then, after rehardening, I honed the bevels to get a sharp cutting edge.



A Tiny Scraper with a Keen Edge    


This is a smaller version of the scraper described in Part 3 of the article on scrapers on this site. It has an included angle of about 30° and is sharpened to nearly razor sharp. It is good for creating or smoothing concave areas that occur in tight spaces.


It is made from 5/32” music wire. It is very simple to make because no bending or heat treatment is required.

  


A Not-So-Tiny Recess Maker


I made this tool for one specific task, namely to shape the wall of a dovetailed recess on a workpiece jam chucked against a flat surface. The tailstock gets in the way of regular turning tools.


It is made from a 5/16” Allen wrench. The first step was to increase the bend slightly and soften the steel. The shape of the cutting edge was formed by cutting the blank with a hacksaw and was then refined with the grinder. After hardening and tempering, the cutting edge was sharpened with a hone.



A Backwards Scraper  


Another specialty tool in my collection is a scraper with a bend to the right instead of to the left. Sometimes, but not often, I’ll have a bowl chucked up with the foot towards the headstock while I’m fiddling with the details of an out-flowing rim.


In this situation, it is not easy to reach under the rim on the outside in order to reduce the wall thickness or refine a curve. This scraper makes it easy and I don’t have to reverse the bowl to do it.



Bad Designs    


Hate to say, but some of my designs have had . . . shortcomings. This photo shows two examples of tools I made for hollowing globe-type Christmas ornaments. The larger is made from a 1/4” Allen wrench; the smaller, 3/16”.


The swan-neck bend allows for reaching into the cavity of the globe while at the same time keeping the cutting edge in line with the axis of the handle. This minimizes any twisting tendencies, but the extra length is the source of the problem.


To be effective in reducing the twisting tendency, the tool must be supported by the tool rest at a point closer to the handle than the first bend. This means, of course, that the remainder of the tool is hanging out over the rest.


For these tools, the overhang is 2” and 2 1/2” and that is too much for the relatively small diameters. They vibrate badly even in the lightest of cuts, and therein lies the failure. They are useless, but I hate to just throw them away.


Here’s another poor design, but less dramatic. I solved the vibration problem by using a bigger Allen wrench but stumbled into a trap by having excessive sideways extension of the cutting edge.


The tool is intended for use in a cavity whose diameter is only slightly greater than the overall width of the tool. In the small space, the twisting tendency of the offset cutting edge tends to rotate it into the wood, into a deeper cut instead of outward into thin air. This makes the tool grabby and hard to control. I don’t use it on the globes for fear of having it catch and destroy the piece.


Here is my go-to tool for hollowing just inside the opening. Note the small amount of offset. The twisting effect is minimal and it tends to rotate out of the wood which makes it stable in the cut. For the rest of the cavity I have similar tools with different angles, but all have small offsets and fairly large shank diameters.



And finally . . .


Here’s a quick glance at four more tiny tools. The first has an offset point and a small angle at the tip. Made from a triangular file.


A hollowing tool used with a captured hollowing system for making ornaments. The twisting effect is not an issue even though this tool has a fairly large offset. Made from an Allen wrench.





This funny-looking tool is used to cut a 1/8” square groove on the inside wall of a part for a kaleidoscope. Made from a saw blade.





A pair of tools used to form captive rings. One cuts to the left; the other to the right. Made from a masonry nail and a flat countersink bit.





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