Throughout the majority of cutting, designate a particular edge of the cutter, or a particular tool to the process. A slightly used cutter will have more of a tendency to tear out end grain as it cuts. This works fine during initial roughing cuts, when the overall quality of the wood's surface is not as important.

When making finishing cuts, make sure to use the sharpest portion of the tool available. Again, designate a particular edge of the cutter, or a particular tool to this process. A new, or very lightly used cutter will cut more cleanly than a used one, and can remove most tearout or unevenness in the wood's surface. If you've done a good job of roughing out your shape, you should only require a few passes with the tool to clean up the surface and prepare for sanding.

Carbide insertShape chart

Gasses have the slowest quench rate of the three main categories of quench media. Common gasses include air, nitrogen, and argon. While some parts are quenched in standing gas, it is more common to speed up the process by forcing the gas over the part.

Millinginsertspecification

There are multiple shapes made for the carbide inserts of turning tools. The most common ones are square, slightly rounded square, or round in profile. Square-shaped cutters are best for removing heavy amounts of material quickly, or from cutting flat spots. Slightly rounded square (the sides of the square are ground with a slight radius) cutters can remove material quickly, but can also be used to some degree as a finishing tool. Rounded cutters can remove material nearly as well as the squared-edge types, but are best used for final finishing cuts.

Quenching is the rapid cooling of hot metal in a liquid or gas medium to preserve certain mechanical qualities it received through previous heat treatment methods. Chemical reactions and structural changes occur within the metal during heat treatment, and quenching can be viewed as a way to lock those desirable changes in place. However, that is not the only reason to use quenching. It can increase the hardness of metals and even prevent the development of undesirable traits that may occur if the cooling of a part is not strictly regulated. It is an essential part of the overall heat treatment process.

Aqueous quenchants are chemical mixtures with water and include water-soluble polymer solutions and water by itself. They have the fastest quench rate of all three media categories and can be used to bring metals to maximum hardness, but with the possibility of cracking due to too-rapid cooling. Water quenching is used in aluminum solution heat treatment.

Quench rate refers to the speed at which a part is cooled within a quench media. The faster the quench rate, the less time there is for the internal chemical reactions caused by the heat treatment to revert. This means that parts that are quenched faster retain more of their beneficial properties. Because of this, a fast quench is typically preferred. However, slower quenches are sometimes required in order to protect the part from cracking or distorting. Exactly how fast each part should be quenched depends on a wide variety of variables and can be very complex to determine.

Insertnose radius chart

Carbide tools, regardless of shape, are still scrapers. They are designed primarily for scraping the wood's surface away, even if they will perform in other functions such as hollowing or shearing. Learning to use the correct tools (such as bowl gouges, spindle gouges and skews) will greatly improve the quality of your work straight from the tool, and reduce the amount of time that must be devoted to sanding away defects caused during cutting.

The first step when quenching a metal part is the initial heat treatment. If the part is not heated to the right temperature, it will not receive the full benefits that quenching can provide. For steels, in particular, the goal is often to heat them to a point above the austenite temperature. Holding the part at this temperature for a set amount of time (depending on the type of steel and the dimensions of the part) will cause it to transition to the martensite stage. This is typically the stage quenching is used to preserve. Other stages that are less frequently desired are ferrite, pearlite, cementite, and bainite.

Quenching is the cooling part of the heat treatment process that comes after other heat treatment has been performed on a part. By submerging hot metal into a quench media, it can be rapidly cooled and therefore retain the beneficial properties it gained through the heating process. Different quench rates and media are used for different metals, temperatures, and desired outcomes.

Latheinsertchart

Carbide insertmaterial codes

Carbide-tipped tools have replaceable carbide inserts at the tip of the tool. These small carbide cutterheads are much harder than conventional high speed steel tools, and will hold an edge for longer periods of time. This equates to less down time, as the turner can spend more time at the lathe, and less time at the grinding wheel sharpening tools.

Carbide tipped tools are designed so that they can be rotated (to a sharper section of the tool) or replaced when dull, rather than sharpened. This is a huge benefit to beginners and persons without grinding equipment.

Quench media refers to the substance in which a heat treated part is submerged to cool it down. There are three main categories of quench media, and which one you use will affect both the quench rate and potential for part warping. These three categories are gasses, oils, and aqueous solutions such as plain or salt water and water-soluble polymer solutions. Additionally, parts can either be submerged within the quench media or have the media forced over them. Forced media has a faster quench rate than stagnant quench media, and is just one more way in which the rate can be manipulated to produce the desired results. Quench speed is critical to retaining austenite in the quenched part.

Oils have a quench rate that is faster than gasses, but slower than water-based quenchants. Common oils include mineral oil, whale oil, cottonseed oil, and synthetic oils — which have recently become the most popular choice. One key benefit oils have over aqueous quenchants is that there is a reduced chance that parts quenched in them will warp.

Types ofturninginserts

Carbide tipped turning tools are becoming increasingly popular with many of today's wood turners. We'll begin this tutorial by looking at the pros and cons of these tools in comparison to standard high speed steel tools. We will then conclude with details about how you can get better results using these tools by making just a few small adjustments to your methods.

Although carbide will hold an edge for longer periods of time than high speed steel or carbon steel, it can not achieve the same degree of sharpness. A new, unused carbide insert will perform as well as a freshly sharpened steel tool, but only briefly. For fine finishing cuts before sanding, carbide tools (at least in the long term) will not perform as well as other steel tools.

Carbide insertidentification chart PDF

Once the part has achieved the desired state, it is submerged in a predetermined quenching media at a predetermined rate. The media to which the part is exposed and the rate at which it is quenched depend on the type of part, the metal it is made of, and the final properties that are desired.

L&L Special Furnace manufactures industrial quench tanks for a variety of uses and quench media, including gasses, oils, and aqueous solutions. Contact us today for more information on our quench tank specifications and help selecting which tank is right for your particular need.

However, oils also have flash points that need to be considered when making your selection. Above a certain temperature, the oil will ignite. This flash point is different for each type of oil, so will need to match your heat treatment temperature to your quenching oil. If you are heating a part to 850°C (1550°F), the oil you are using must have a flash point at a higher temperature.