Even among experienced machinists, choosing the right insert for boring a hole remains a difficult process fraught with myth and misconception.

However, it is no myth that insert selection can completely save or kill the performance on an application. We can spend all day talking about the best insert substrate/coating (or lack thereof), shape, chip breaker geometry, etc. for a job, but I feel it's important to address one of the most common problems that I come across: use of improper insert nose radius.

I've spoken to machinists who are loyal to one nose radius size or leaving a certain amount of stock on a hole simply because it worked on a job years ago and seems to work well on most other jobs. They are then dumbfounded when working on a new job and suddenly there is heavy chattering or poor surface finish.  

​The truth is, proper nose radius selection depends on the unique specifications of each job, mainly:

• How much material stock remains
• Desired feed rate or surface finish
  
  

In general, you want to minimize radial forces and maximize axial forces acting on the cutting edge. The dreaded chattering phenomenon is caused by excess radial force deflecting the tool, causing it to "bounce" rapidly on and off the wall of the bore. The typical rule of thumb is to have a radial depth of cut one-half to two-thirds of the nose radius.

For example, when using a 16 thou nose radius insert, leave a stock of 16-20 thou on diameter for your finishing pass (be careful not to confuse radial depth of cut with depth of cut on diameter). Maintaining these proper cutting forces encourages good chip formation.

Try to use a smaller nose radius as your boring jobs get longer, as this will combat the overwhelming radial forces that cause chattering. But above all, make sure you're leaving the right amount of stock for your particular inserts.

Sometimes, jobs will require a certain surface finish. Surface finish, insert nose radius and feed rate go hand-in-hand. Without getting too technical, surface finish improves as you decrease the feed rate (keeping speed the same) and increase the size of the nose radius.

These are the first two options you will want to consider. For this reason, don't forget to increase the amount of stock if you switch to a larger nose radius. Also, decreasing the feed rate too much in an attempt to get a better surface finish runs the risk of chattering because the axial depth of cut is less than the hone on the insert tip.

If all else fails, you can "cheat" by changing the shape of the nose radius itself to a wiper geometry. This makes the radial cutting edge effectively flat, which produces a surface finish 2x better than a standard insert nose radius at the same feed rate.
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Yet another factor to keep in mind is the fact that a smaller nose radius corner will be more prone to breakage than an identical-sized insert with a larger nose radius.

So, as you can see, many different factors are at play and it's easy for your head to start spinning. Hopefully, some of these tips point you in the right direction. If stubborn applications don't seem to respond to anything you do, or if you need assistance in selecting the right insert, BIG DAISHOWA's technical department is here to assist you. Please contact us 

The ARNO FAST CHANGE program is designed to meet the demanding needs of Swiss turning operations, from miniature components to larger parts up to 1-5/8" in diameter. As a leader in Swiss quick-change tooling, ARNO offers a comprehensive solution to optimize their processes, reduce downtime, and enhance overall performance.

Expansive Tooling Capabilities
The ARNO FAST CHANGE program is unparalleled in its versatility, with over 50 different gang plates in stock and nearly 200 different types of tools available. This extensive range ensures that ARNO can support a wide array of Swiss turning applications, delivering the precision and reliability that their operations demand.

Innovative Turning Solutions
Their tooling capabilities include options for turning with both positive and negative ISO standard inserts, including C, D, and V geometries. Whether traditional, neutral, or back-turning orientations are required, ARNO FAST CHANGE has the tools to accommodate specific needs, ensuring optimal performance across all turning operations.

Precision Swiss Grooving
ARNO is at the forefront of precision Swiss grooving, offering tools that deliver exceptional accuracy and surface finish. Their Swiss grooving solutions are engineered to meet the tight tolerances and intricate designs typical of Swiss turning, ensuring that every component meets the highest standards of quality.

Multi-Function Groove & Turn Tools
Their multi-function groove and turn tools provide versatility and efficiency in a single tool. With options that include full radius features, these tools enable machinists to perform multiple operations without the need for tool changes, further reducing cycle times and enhancing productivity.

ARNO has engineered the ACS (ARNO Cooling System)—a patented cooling innovation for efficient parting, grooving, and groove-turning with the SA and SE systems. It feeds coolant directly along the insert seat, into the cutting zone, effectively flushing chips away and removing swarf from beneath the insert.

The enhanced ACS2 version adds a second coolant channel that cools the tool flank from underneath, delivering up to a 300% increase in tool life, along with higher cutting speeds and exceptional process reliability. This precision-guided coolant delivery requires no manual adjustment—eliminating setup errors and making the SA and SE systems true productivity powerhouses.

If you’ve ever wrestled with trying to squeeze multiple setups onto your CNC table or struggled to get full access to a part without running into your vise, you’re not alone. Traditional vises have their place—but when you’re machining complex parts, working in tight spaces, or just trying to run more parts per cycle, they can start to feel like a limitation.

That’s where the OK-Vise® from Jergens steps in.

What Is the OK-Vise?
The OK-Vise is a low-profile clamping system that’s built for modern 3-axis and 5-axis machining. Instead of a bulky vise body that hogs up table real estate, OK-Vise uses a compact wedge-style clamp to lock parts in place—tight. Once it’s set, it’s not going anywhere. You get rock-solid holding power in a footprint that makes traditional vises look oversized and outdated.

Why It Works Better
With OK-Vise, you’re clamping from the side, not the top. That gives you full access to the top and most sides of the workpiece, which is a huge win for anyone doing multi-face machining. Think of the time you’ll save by not having to reset the part or switch fixtures between operations.

And because of the compact design, you can mount multiple parts closer together, maximizing the use of your fixture plate or tombstone. That means more parts per cycle—and more spindle time before you need to open the doors.

Extend Your Cycle Time, Not Your Setup Time
Let’s be honest—nobody wants to babysit a machine. OK-Vise gives you the ability to load more parts at once, which stretches out your unattended run time. That’s great whether you’re lights-out machining or just trying to keep things moving while you prep the next job.

There’s more than one way to skin a cat, just as there’s more than one way to finish a hole. The most effective option will depend on the number of parts, acceptable cycle time and tolerance callouts. One of the most effective options is boring.

Boring, in its most basic sense, is internal turning. The first and foremost goal, like any other finishing process, is to enlarge a drilled hole to final diameter, which will usually have a precise tolerance.

​A capable boring tool will also clean up after the drill and produce a nice surface finish. Finish boring can be a delicate operation. After all, it takes only one oversized hole to scrap an entire part. So, oftentimes the drilled hole needs to be further prepped in order to improve the odds of success of the final cut-to-size. This is where the use of “rough” boring tool becomes a necessity.

The question is, when is it appropriate to use a rough boring tool versus a finish boring tool? Or should you use both?

Casting processes dominate the metalworking process in many industries and will continue to dominate for the foreseeable future, despite advancements in additive manufacturing. They make possible the fabrication of otherwise difficult-to-machine parts, at relatively low cost and production time. But one thing casting is not known for is tight geometric tolerances.

Fresh out of the mold, a hole diameter can potentially be tens of thou away from a nominal value, which is why they’re typically cast well undersize. But equally as concerning (when it comes to boring) is the fact that the hole will also almost always be slightly curved or ovular to some degree. A rough boring tool is required to correct these issues before a finish boring tool can be used.

Another common cause of crooked holes is a wandering drill. This occurs when a drill “walks” off center very slightly when creating the initial hole, which mostly happens if the drill is slender, fed too hard or has a damaged tip. While the drilled hole might certainly appear straight to the naked eye, oftentimes using precise measuring equipment will reveal quite the opposite.

Why is a finish boring tool so sensitive to curved/out-of-round holes? Mainly because it’s one-insert effective, so it will only really experience radial force acting from one side. A finish boring tool is more likely to bend from radial cutting forces because it isn’t supported by an insert on both sides (as with a rough boring head) and taking off very little stock.

What this means is that feeding one of these tools into a crooked hole will encourage it to follow whatever path is set before it. The longer the hole, the easier it is for a boring tool to bend when cutting.

This is also a problem encountered with reaming. So, it’s good practice to be extra cautious and make sure a long hole is already “true” before doing your finish pass. In contrast to a finisher, a rough boring tool does not really care about how straight the initial hole is, it will pretty much bore true regardless because most of the forces are axial.
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Though it probably goes without saying, it also comes down to surface finish. Typically, a rough boring pass surface finish isn’t terrible, but some applications will specify a finish that isn’t practically attainable by a rough boring head.

Obviously, a rough boring head isn’t as precise as a fine boring head, so this will show up in the surface finish, among other places. Surface finish only depends on feed and nose radius (by definition), but if it’s specifically called out in a bore, this is usually a good sign that you will want to use a single-insert finisher regardless of how you’re cutting.

Tile Your Way to Comfort
You can mix and match tile colors to designate work zones or walkways, and with the patented Response surface design, these tiles offer industry-leading comfort and shock absorption. The locking system is rock-solid, so you don’t get that curling and creeping you see with cheap mats.
If you’ve been piecing together rubber mats from the big box stores or just dealing with cold concrete, it might be time for an upgrade.

Ready to give your shop floor a serious upgrade?
Ergo Advantage Safe-Flex™ Anti-Fatigue Tiles are built to keep machinists moving and feeling better—shift after shift.

Contact us to learn more!

Workholding Solutions
Recently, Jack Burley, the President and COO of BIG DAISHOWA, discussed innovative workholding solutions that are effective in combating vibration, with particular emphasis on the ROC® mineral cast solutions. These advanced solutions play a crucial role in increasing capacity and throughput by reducing burden and transport weights.

Much like a skyscraper, ROC® constructs a steel substructure for stability, precision machined and filled with ground positioning components and fasteners. The assembly is then encapsulated with a composite structure of mineral particles and epoxy resin, creating a working platform that is lightweight, yet stable and superbly dampened.

Mineral particles constitute about 90% of the added weight in these solutions, with the remainder being resin and curing agents. This composition results in an excellent density-to-weight ratio of 2.3 kg/dm^3.

The entire composite structure is produced without the application of heat, which preserves the integrity of the precision machined surfaces and clamping components. Furthermore, the low thermal conductivity and excellent resistance to corrosion of ROC® mineral cast enhance the durability and performance of the workholding solutions.

A key advantage of ROC® mineral cast is its exceptional attenuation rates, which are 6 to 10 times better than those of traditional grey cast iron, thus potentially increasing cell output significantly. ROC® mineral cast components are designed to resist impacts without disturbing the steel positioning and clamping components, due to their low tensile and impact strength.

Customizable to client specifications, ROC® also offers standard columns for horizontal machining center applications with options like integrated Unilock zero-point chucks or grid patterns.

Burley highlighted the ergonomic benefits and how ROC® mineral cast solutions facilitate machine capacity management in manufacturing settings.

Many of these solutions are about 50% lighter than their alternatives, making them highly advantageous for companies looking to standardize operator interfaces and streamline production processes.

By adopting ROC® mineral cast workholding solutions, manufacturers can significantly enhance their machining quality and operational efficiency.

Anyone who has ever machined the superalloy titanium knows that it can be a real diva, requiring special care and attention. Chips that won’t break, heat that won’t dissipate, and built-up edges are some of the common ways in which titanium puts up a fight during machining.

However, titanium’s remarkable properties make it a favorite in aviation, motorsport, and medical technology, so it is worth learning how to machine it properly. You never know when a renowned sports car manufacturer will need to place an order for titanium screws.

Whether or not the chemist Martin Heinrich Klapproth named the titanium element after the deities from Greek mythology because of its god-like properties is unclear. But the fact is that its properties make it a superalloy. Extremely tension-proof, very light, and outstandingly resistant to corrosion, titanium offers something other materials and alloys don’t.

Titanium is antimagnetic, biocompatible, and resistant to even the most aggressive media. This expensive material is becoming popular in more fields and applications. It’s no secret to the engineers at Bugatti, who use many titanium parts in their work.

Machining titanium is an investment, as it costs about three to five times more than tool steel. So logically, you want to avoid waste. The careful selection of a suitable cutting tool is only the first step. Manufacturing precision turned parts made of titanium, which are frequently needed in aviation and spaceflight, the chemical industry, vehicle construction, and medical technology, requires tools that are suited to machining this particular material, allowing for the most stubborn titanium alloys to be machined as needed.

But this diva of the materials world can do a number on your cutting tools due to:

• High heat resistance (see diagram)
• Chips not breaking
• Titanium’s distinct tendency to stick to cutting tools
• A low elastic modulus
  (Ti6Al4V = 110 kN/mm2, steel Ck45 = 210 kN/mm2)

Let’s instead take a look at the manufacture of a threaded and grooved shaft made of the standard titanium alloy Ti6Al4V Grade 5/23, as is frequently used in medical technology. With a tensile strength of Rm = 990 N/mm2, yield strength of Re = 880 N/mm2, a hardness of between 330 and 380 on the Vickers hardness scale, and elongation at fracture A5d of approximately 18%, this titanium alloy is typically used for medical implants as well as aviation applications (3.7164) and industrial applications (3.7165). With six percent aluminum and four percent vanadium, and extra-low interstitial elements (ELIs), this alloy is highly biocompatible, inducing virtually no known allergic reactions.

This requires a high-quality surface finish, reliable process safety, and controlled chip removal, all while keeping process times short despite potentially high rates of chip removal. You might assume that most of the heat generated in the turning process is evacuated via the chips, but this isn’t so. Since titanium is a poor thermal conductor, the heat cannot be alleviated from the cutting zone via the chips.

And at temperatures of 1200°C and higher in the cutting zone, the cutting tool can quickly sustain heat-related damage. The easiest things you can do to prevent too much heat from building up are to feed coolant directly to the cutting zone, reduce the cutting force by using a sharp cutting edge, and adjust the cutting speed to suit the process at hand.

Real improvements are made by selecting the correct cutting tool. Since the heat must be evacuated via the cutting edge and the coolant, not via the chips, as is the case with steel, a small portion of the cutting edge must withstand extremely high thermal and mechanical stress. The cutting pressure is reduced by using ground, high-positive indexable inserts with polished flutes, if necessary, with the appropriate coating, minimizing friction in the chip removal process.

These three parameters help prevent heat from being produced in machining. If only a little bit of the heat is reduced further through optimal coolant flow, the cutting edge will have a longer service life. Or the cutting speed (Vc) can be increased again to improve productivity.

So far, so good. But since this diva’s chips don’t like to break, you may face other difficulties. An endless chip could wind itself around the workpiece, your tool, or the machine chuck and pose a hazard to the machine or your safety. It could help to change the direction of rotation and turn the cutting edge around if the machine’s design allows it. If the cutting edge is pointing downward, chips will fall freely to the ground and no longer pose a danger.

However, when working with demanding roughing applications and less-than-stable machinery, you will have to check whether the cutting action allows the chips to be directed towards the machine bed. Once the chips have left the work zone, they can no longer disrupt the process.

If you want to make sure that you choose the right tool for titanium machining, turn to a manufacturer. Some go above and beyond, offering advice based on specific application experience in addition to supplying the cutting tool itself.

ARNO USA is a tool manufacturer that has been around since 1941. In addition to manufacturing one of the largest selections of high-positive indexable inserts, it employs many experienced application consultants who would be happy to share their knowledge to ensure that customers’ manufacturing processes run smoothly.

Its high-positive indexable inserts are sharp enough to keep cutting force to a minimum, and their optional rounded edges ensure excellent stability. Expedient high-tech coatings make them well-equipped against the poor thermal conductivity of this tricky material.

Negative indexable inserts with EX, NFT, NMT, and NMT1 geometries provide an affordable, reliable solution for more basic machining and roughing.

Arno’s positive indexable inserts with geometries PSF and PMT1 are ideal for machining superalloys.

All of these inserts are highly resistant to notch wear and heat when machining tough material. Unique geometries ensure exceptional chip control and process safety. Dedicated titanium machining experts and ARNO customers are well prepared.

For all BIG KAISER fine boring heads type AW, EW, EWN, EWD, EWE, EWB and EWB-UP, the frequency for lubrication depends on use.

If used daily, the recommendation is to oil the boring head every two to three months.

​The best procedure is to range the cartridge to the maximum diameter. Using a lubrication gun, pump oil in the unit until it stops accepting oil and then range cartridge to minimum setting. Excess oil will come out around the dial face (this is normal). If oil is excessively dirty, repeat the process.  

Recommended oils are Mobil Vactra No. 2, BP Energol HLP-D32, Kluber Isoflex PDP 94, or a similar light machine oil.