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The entering angle, KAPR (or lead angle, PISR), is the angle between the cutting edge and the feed direction. It is important to choose the correct entering/lead angle for a successful turning operation. The entering/lead angle influences:

There are many parameters to consider when choosing turning insert. Carefully select insert geometry, insert grade, insert shape (nose angle), insert size, nose radius and entering (lead) angle, to achieve good chip control and machining performance.

The -WMX wiper geometry is first choice, and is a good starting point for most applications. When conditions change, there is always a productive alternative. Choose a positive wiper geometry to lower forces and maintain productivity in case of vibration problems. Choose wiper geometry as follows: -WL:For improved chip control when moving to a lowerfn/ap. -WF:Improves chip control at a lowerfn/ap. Also for lower cutting forces when vibrations occur. -WMX:Always first choice within the wide chip application area. Provides maximum productivity, versatility and the best results. -WR:When a stronger edge line is needed, for example, for interrupted cuts.

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Select insert size depending on the application demands and the space for the cutting tool in the application. With a larger insert size, the stability is better. For heavy machining, the insert size is normally above IC 25 mm (1 inch). When finishing, the size can in many cases be reduced. How to choose insert size

Zhuzhou Sieeso Cemented Carbide Tools Co.,Ltd. Is a Chinese company that started operations in the year 2019, located in Zhuzhou City Hunan Province where is famous in the world for its tungsten carbide industry.

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​The insert shape should be selected relative to the entering angle accessibility required of the tool. The largest possible nose angle should be selected to provide insert strength and reliability. However, this has to be balanced against the variation of cuts that need to be performed.

But for the home user, the Opus will more than get the job done. Unless you’re an aspiring barista or a diehard plastic hater, a lighter machine with fewer controls is just easier to use. That’s probably what you actually want after you’ve just woken up pre-coffee, no matter what the snobs might say. All around, the Opus might be the best conical burr grinder we’ve ever tested.

The Opus also wants to make your coffee experience as tasty and hassle-free as possible. It features anti-static technology so you won’t have grounds flying around and sticking to things. The grinder is timed to auto-stop at 30-second intervals so you won’t accidentally over-grind your beans when you’re sleepy or distracted. Plus its low-hopper size means you’re only grinding what you’re going to use, which is a good habit to get into for the freshest, tastiest coffee.

The insert geometry and insert grade complement each other. For example, the toughness of ​a grade can compensate for lack of strength in an insert geometry.

Until I tried Fellow’s new grinder, the Opus. I thought having a quiet burr grinder was basically impossible: Pulverizing coffee beans between toothy metal disks requires a powerful (noisy) motor, and then there’s the din of high-velocity coffee bean shrapnel. But this one is so quiet, I can grind coffee with the bedroom doors open and still not wake anyone up.

A large nose angle is strong, but requires more machine power and has a higher tendency for vibration. A small nose angle is weaker and has a small cutting edge engagement, both of which can make it more sensitive to the effects of heat.

Use wiper inserts for improved surface finish with standard cutting data, or, maintained surface finish at substantially higher feed rate.

Price is one of the Opus’ greatest selling points, but, at just $195, I was initially dubious that it could be anything but mid. A good burr grinder will be at least $100. You can find a few rare standouts below that price, but if you want something you won’t have to replace every few years, $100 is the minimum. That’s why the Opus is so impressive: It’s a $195 grinder that grinds like a $500 grinder.

​Turning geometries can be divided into three basic styles that are optimized for finishing, medium and roughing operations. The diagram shows the working area for each geometry, based on acceptable chip breaking, in relation to feed and depth of cut.

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There are some pro-grade features you get at those higher prices, like a grind time display, a built-in scale, or adjustable dosing control, and the Opus’ body is more plasticky than I typically expect from Fellow products. The cord is a bit short too. At 3 feet, you'll need to be conscious about placing it right next to an outlet.

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For a grinder that seems simple on the outside, the Opus is an infinitely fine-tunable machine. It has 41 grind settings and an internal ring for even further adjustment. For example, if you’re using it solely for espresso but find that one click toward coarse feels like it makes things too coarse, and one click toward fine makes things too fine, you can use the inner ring to make an even tinier adjustment. (Fellow has a video that shows how this works.) It's not too dissimilar to what you'll find on grinders like the Baratza Encore ESP.

For a beverage most people enjoy in the early morning, coffee can be a noisy endeavor. Even if you manage to avoid the espresso machine pumping out shots of coffee and the steam wand screaming into a whirlpool of milk, there’s still the earsplitting shriek-crunch of the grinder. On most mornings, I have to wait until my partner wakes up to brew my first cup.

If there’s one thing you can do to bring more flavor out of your coffee, it’s to grind with a burr grinder. That’s step one in bringing the cafe experience to your home kitchen, and no matter what you brew with—even if it’s a humble Mr. Coffee drip machine—using burr-ground coffee is going to add more smoothness and more dimensions of flavor to every single cup. This is the burr grinder you should do it with.

The Opus is also the jack of all trades of grinders. It’s powerful enough to grind beans super-fine for espresso, but it can still make a coarse grind for a French press. It has a relatively small footprint, looks cute on the countertop, and is fairly inexpensive for its quality. All of this, combined with its astounding quietness, has made it a morning routine game-changer.

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The internal ring feature will also come in handy as the grinder ages. I’ve been using the Opus as my daily driver for about six months and it still produces grounds as fine as the day I unboxed it. But as you use any grinder over the years, the burrs will wear down a bit, which can make your super-fine settings feel only kinda fine. The internal ring lets you adjust the grinder to bring things back to true, like honing a knife after it’s started to feel a little dull. Basically what you’re doing is bringing the burrs closer together to compensate for their wear and tear.

The nose radius, RE, is a key factor in turning operations. Inserts are available in several sizes of nose radius. The selection depends on depth of cut and feed, and influences the surface finish, chip breaking and insert strength.