Tool Information Guides Archives - Page 3 of 3

10 Reasons to Use Flat Bottom Tools

January 23, 2018/10 Comments/in Drilling, Drilling & Holemaking, Harvey Tool, Holemaking, Machining 101, Tool Geometry, Tool Information Guides, Tool Selection/by Harvey Performance Company

Flat bottom tools, or tools with flat bottom geometry, are useful in a variety of situations and operations that tools with typical cutting geometry are not. The standard characteristics of drills or end mills are useful for their primary functions, but make them unsuitable for certain purposes. When used correctly, the following flat bottom tools can make the difference between botched jobs and perfect parts.

Flat Bottom Drills

Flat bottom drills are perfect for tricky drilling situations or for creating flat bottom holes without secondary finishing passes. Consider using these specialized drills for the operations below.

Thin Plate Drilling

When drilling through holes in thin plates, pointed drills are likely to push some material out the exit hole and create underside burrs. Flat bottom drills are significantly less likely to experience this problem, as their flat bottom geometry generates more even downward forces.

Crosshole Drilling

When drilling a hole that crosses the path of another hole, it is important to avoid creating burrs, since they can be extremely difficult to remove in this kind of cross section. Unlike drills with points, flat bottom drills are designed to not create burrs on the other side of through holes.

Irregular/Rounded Surface Drilling

Flat bottom drills initially engage irregular surfaces with their outer edge. Compared to making first contact with a standard drill point, this makes them less susceptible to deflection or “walking” on inclined surfaces, and more capable of drilling straighter holes.

Angled Drilling

Even if the surface of a part is flat or regular, a pointed drill is susceptible to walking if it engages the part at an angle, known as angled or tilted drilling. For the same reason flat bottom drills are ideal for drilling on irregular surfaces, they are perfect for angled drilling.

Half Hole Drilling

When drilling a half hole on the edge of a part, the lack of material on either side of the drill makes the operation unstable In this situation, a pointed drill is susceptible to walking. A flat bottom drill makes contact with its entire cutting geometry, allowing for more versatility and stability when drilling half holes.

Flat Bottom Counterbores

Flat bottom counterbores are an excellent choice when a flat bottom hole is needed and a tool without flat bottom geometry was used to create it. Keep some of these tools on hand to be prepared for the operations below.

Bore & Finish Drilled Holes

Drill geometry is designed first and foremost for factors like stability, rigidity, and chip evacuation. Some holes will need secondary finishing operations. Flat bottom counterbores are often designed with a slow helix and low rake, which help them avoid part engagement and control finish.

Straighten Misaligned Holes

Even experienced machinists may drill a less-than-perfectly-straight hole or two in new and unfamiliar jobs. Fortunately, flat bottom counterbores are well-suited for straightening misaligned holes.

Spot Face & Counterbore on Irregular Surfaces

The unique geometry of flat bottom counterbores makes them effective at spotting on irregular surfaces. Standard drills and spot drills are susceptible to walking on these kinds of surfaces, which can potentially ruin an operation.

Remove Drill Points

When a standard drill creates a hole (other than a through hole) it leaves a “drill point” at the bottom due to its pointed geometry. This is fine for some holes, but holes in need of a flat bottom will need a secondary operation from a flat bottom counterbore to remove the drill point.

Remove End Mill Dish

The dish angle present on most standard end mills allows proper end cutting characteristics and reduces full diameter contact. However, these end mills will naturally leave a small dish at the bottom of a hole created by a plunging operation. As with drill points, flat bottom counterbores are perfect to even out the bottom of a hole.

4 Important Keyseat Cutter Considerations

November 15, 2017/2 Comments/in Harvey Tool, Tool Geometry, Tool Information Guides, Tool Selection/by Harvey Performance Company

Keyseat cutters, also called woodruff cutters, keyway cutters, and T-slot cutters, are a type of cutting tool used frequently by many machinists – some operations are impractical or even impossible without one. If you need one of these tools for your job, it pays to know when and how to pick the right one and how to use it correctly.

Keyseat Cutter Geometry

Selecting and utilizing the right tool is often more complicated than identifying the right diameter and dialing in the speeds and feeds. A keyseat’s strength should be considered carefully, especially in tricky applications and difficult materials.

As with any tool, a longer reach will make this tool more prone to deflection and breakage. A tool with the shortest allowable reach should be used to ensure the strongest tool possible.

A keyseat cutter’s neck diameter greatly affects its performance. A thinner neck allows for a comparatively larger radial depth of cut (RDOC) and more clearance, but makes for a weaker tool. A thicker neck reduces the cutter’s RDOC, but greatly strengthens the tool overall. When clearances allow, a keyseat cutter with a thicker neck and larger cutter diameter should be chosen over one with a thinner neck and smaller cutter diameter (Figure 1).

Cutter width has an effect on tool strength as well. The greater a keyseat cutter’s cutter width, the more prone to deflection and breakage it is. This is due to the increased forces on the tool – a greater cutter width equates to an increased length of engagement. You should be particularly careful to use the strongest tool possible and a light RDOC when machining with a keyseat cutter with a thick cutter width.

two Harvey Tool Keyseats showcasing bottom geometry of tooling

Harvey Tool Keyseat Geometries

Radial Depth of Cut

Understanding a keyseat cutter’s radial depth of cut is critical to choosing the correct tool, but understanding how it affects your tool path is necessary for optimal results. While it may be tempting to make a cut using a keyseat cutter’s maximum RDOC, this will result in increased stress on the tool, a worse finish, and potential catastrophic tool failure. It is almost always better to use a lighter depth of cut and make multiple passes (Figure 2).

When in doubt about what RDOC is correct for your tool and application, consider consulting the tool manufacturer’s speeds and feeds. Harvey Tool’s keyseat cutter speeds and feeds take into account your tool dimensions, workpiece material, operation, and more.

Desired Slot Size

Some machinists use keyseat cutters to machine slots greater than their cutter width. This is done with multiple operations so that, for example, a keyseat cutter with a 1/4” cutter width can create a slot that is 3/8” wide. While this is possible and may save on up-front tooling costs, the results are not optimal. Ideally, a keyseat cutter should be used to machine a slot equal to its cutter width as it will result in a faster operation, fewer witness marks, and a better finish (Figure 3).

Staggered Tooth Geometry of a Keyseat Cutter

When more versatility is required from a keyseat cutter, staggered tooth versions should be considered. The front and back reliefs allow the tools to cut not only on the OD, but also on the front and back of the head. When circumstances do not allow for the use of a cutter width equal to the final slot dimensions as stated above, a staggered tooth tool can move axially in the slot to expand its width.

Machining difficult or gummy materials can be tricky, and using a staggered tooth keyseat cutter can help greatly with tool performance. The shear flutes reduce the force needed to cut, as well as leave a superior surface finish by reducing harmonics and chatter.

Having trouble finding the perfect keyseat for your job? Harvey Tool offers over 2,100 keyseat cutter options, with cutter diameters from 1/16” to 1-1/2” and cutter widths from .010” to ½”.

Optimize Roughing With Chipbreaker Tooling

October 24, 2017/8 Comments/in CNC Machining, Helical Solutions, Tool Information Guides, Tool Selection, Troubleshooting Tips/by Harvey Performance Company

Chipbreaker End Mills feature unique notch profiles, creating a serrated cutting edge. These dividers break otherwise long, stringy chips into small, easily-managed swarf that can be cleanly evacuated from the part. But why is a chipbreaker necessary for some jobs, and not others? How does the geometry of this unique tool impact its proper running parameters? In this post, we’ll answer these questions and others to discover the very real benefits of this unique cutting geometry.

How Chipbreaker Tooling Works

As a tool rotates and its cutting edge impacts a workpiece, material is sheared off from a part, creating chips. When that cutting process is interrupted, as is the case with breaks in the cutting portion of the tool, chips become smaller in length and are thus easier to evacuate. Because the chipbreakers are offset flute-to-flute, a proper, flat surface finish is achieved as each flute cleans up any excess material left behind from previously passed flutes.

Benefits of Chipbreaker Tooling

Machining Efficiency

When chips are removed from the part, they begin to pile in the machine. For extensive operations, where a great deal of material is hogged out, chip accumulation can very rapidly get in the way of the spindle or part. With larger chips, accumulation occurs much faster, leaving machinists to stop their machine regularly to remove the waste. As any machinist knows, a stopped machine equates to lost money.

small metal chips in cnc machine resulting from the use of a chipbreaker end mill

Prolonged Tool Life

Inefficient chip evacuation can lead to chip recutting, or when the the tool impacts and cuts chips left behind during the machining process. This adds stresses on the tool and accelerates rate of wear on the cutting edge. Chipbreaker tooling creates small chips that are easily evacuated from a part, thus minimizing the risk of recutting.

Accelerated Running Parameters

A Harvey Performance Company Application Engineer recently observed the power of a chipbreaker tool firsthand while visiting a customer’s shop in Minnesota. The customer was roughing a great amount of 4340 Steel. Running at the parameters below, the tool was able to run uninterrupted for two hours!

Helical Part No.	33737
Material	4340 Steel
ADOC	2.545″
RDOC	.125″
Speed	2,800 RPM
Feed	78 IPM
Material Removal Rate	24.8 Cubic In/Min

Chipbreaker Product Offering

Chipbreaker geometry is well suited for materials that leave a long chip. Materials that produce a powdery chip, such as graphite, should not be machined with a chipbreaker tool, as chip evacuation would not be a concern. Helical Solutions’ line of chipbreaker tooling includes a 3-flute option for aluminum and non-ferrous materials, and its reduced neck counterpart. Additionally, Helical offers a 4-flute rougher with chipbreaker geometry for high-temp alloys and titanium. Harvey Tool’s expansive product offering includes a composite cutting end mill with chipbreaker geometry.

helical solutions 7 flute chipbreaker end mill cutting edges — Helical Solutions 7 Flute Chipbreaker

In Summary

Chipbreaker geometry, or grooves within the cutting face of the tool, break down chips into small, manageable pieces during the machining process. This geometry can boost shop efficiency by minimizing machine downtime to clear large chips from the machining center, improve tool life by minimizing cutting forces exerted on the tool during machining, and allow for more accelerated running parameters.

The Multiple Uses of a Chamfer Mill

August 30, 2017/6 Comments/in Harvey Tool, Machining Techniques, Tool Information Guides, Tool Selection/by Harvey Performance Company

A chamfer mill, or a chamfer cutter, is one of the most common tools used by machinists daily. When creating a part, machining operations can oftentimes leave a sharp edge on a workpiece. A chamfer mill eliminates sharp edges, leaving a sloped surface, or a chamfer, instead. In doing so, the part will be stronger and more aesthetically appealing to its eventual user.

This singular tool can provide many cost-saving benefits to machinists. Aside from the namesake operation it performs on a part, a chamfer mill can be used for several machining operations including beveling, deburring, countersinking, and spotting.

Chamfer Mill for Beveling

The terms “chamfer” and “bevel” are often used interchangeably. These two features, while similar, actually have two different definitions. While a chamfer impacts a portion of the side of a workpiece – specifically the edge of a part, a bevel angles the entire side of what was a squared-off part feature. Thus, the side of a part can feature two chamfers, or only one bevel (Figure 1).

infographic of chamfer mills chamfering and beveling a part

A chamfer mill, however, can perform both operations. The two features are equivalent in both geometry, and how they are machined. A chamfer mill will create both part features in the exact same fashion; a bevel just may use a larger portion of the cutting surface, or may require multiple passes to create a large part feature.

Chamfer Mill for Deburring

Like many other versatile tools, a chamfer mill can be used to easily and swiftly deburr a part during the CNC machining process. In doing so, efficiency is maintained as manual deburring – a time exhaustive process – isn’t necessary.

A chamfer mill’s angled cutting surface, shown in the image below, makes it a great tool for deburring workpiece edges. Because a very small amount of the chamfer cutter’s cutting face will be used, a simple adjustment to running parameters will allow for simple deburring operations using a very light cut depth.

Did you know that Harvey Tool fully stocks Deburring Chamfer Cutters, that are specifically designed for deburring operations? This tool features an increased flute count, allowing for minimized cycle times.

Chamfer Mill for Spotting & Countersinking

Drilling precise, clean, and aesthetically appealing holes into a part is not a one-step process. In fact, some use up to four different tools to machine a perfect hole: spotting drill, drill, flat bottom counterbore, and countersink. However, a chamfer cutter is often used to perform two of these operations simultaneously.

By using a pointed chamfer cutter with a diameter larger than that of the hole being drilled, a machinist can spot and countersink the hole in one operation prior to its creation. Tipped-off Chamfer Cutters are unable to perform a spotting operation because they are non-center cutting. By spotting a hole, the drill has a clear starting point. This works to alleviate walking during the drilling process, which in turn drastically reduces the chance of misaligned holes. By countersinking a hole, the screw sits flush with the part, which is often a requirement for many parts in the aerospace industry.

One consideration to keep in mind is that a carbide spot drill should always have an angle larger than that of the drill following it. However, many countersinks have angles that are smaller than most drill points. This creates a dilemma in choosing a chamfer tool for both spotting and countersinking, as they can reduce the number of tools needed, but do not see the full benefit of a spot drill with a proper angle.

three helical solutions chamfer mills of different end profiles — Helical Solutions Chamfer Mills

Key Takeaways

A chamfer mill, also known as a chamfer cutter, is a tool that can perform several machining operations including chamfering, beveling, deburring, spotting, and countersinking. Due to this versatility, chamfer mills are an essential part of every machinist’s arsenal. All that’s needed to run them is these various operations is a slight change to running parameters and depth of cut.

Undercutting End Mills: Well-Rounded Tools That Offer Maximum Versatility

August 16, 2017/0 Comments/in Harvey Tool, Machining Techniques, Specialty Tools, Tool Information Guides, Tool Selection, Tools In Action/by Harvey Performance Company

Undercutting end mills, also known as lollipop cutters or spherical ball end mills, are a common choice for machining undercuts. An undercut is a common part feature characterized by one part of a workpiece “hanging” over another. Undercuts are typically difficult, or even impossible, to machine with a standard tool, especially on 3-axis machines. In many cases, a specialty tool is needed to tackle this feature. Although they are frequently associated with a singular use, undercutters are actually very versatile tools that are worth keeping on hand for a variety of operations.

Undercutting

Unsurprisingly, these tools are very well suited to undercutting operations. Creating an undercut on a part can be tricky and time consuming, especially when forced to rotate the workpiece. Fortunately, this can be greatly simplified with an undercutter.

Exactly what tool to use depends on the geometry of the feature and the part. These tools are available with a range of wrap angles like 220°, 270°, and 300°. Greater wrap angles are the result of a thinner neck and create a more spherical cutting end. This style offers more clearance at the cost of rigidity. Likewise, undercutting end mills with lower wrap angles sacrifice clearance for greater rigidity.

Deburring & Edgebreaking

Since undercuts have a wrap angle that is greater than 180°, they are very well-suited to deburring or edgebreaking anywhere on your workpiece, including the underside. Deburring your parts by hand can be inefficient for your shop – using an undercutting end mill instead will save you time and money. Edgebreaking operations are often a critical final step to create a part that looks and feels like a finished product and that is safe to handle.

All undercutting end mills can be used to deburr and edgebreak, which makes them a useful tool to have on hand in any shop. Some manufacturers also offer specialized deburring tools that are designed with a right and left hand flute orientation, giving them “teeth” that make them particularly useful for deburring complex shapes. Using a deburring tool in a 5-axis machine often makes it possible to deburr or edgebreak an entire workpiece in one shot.

Slotting

Most machinists might not think of undercutting end mills for slotting, but they are fully capable of this operation. An equivalent slot can be machined with a regular ball end mill, but doing so might not be feasible due to clearance issues – an undercutter has a reduced neck, unlike a standard ball end mill. Additionally, using an undercutter to slot can save time switching to an equivalent ball end mill.

Harvey Tool Stocks a Wide Variety of Undercutting End Mills Perfect for Your Next Machining Job

Since only 180° of the cutting end can be used to slot, undercutting end mills with lower wrap angles and thicker necks are best suited to slotting. However, high helix undercutting tools may be ideal if improved finish and increased chip removal are important to the operation.

Contouring & Profiling

contouring and profiling illustration with lollipop end mill

With their wrap angle and increased clearance, undercutting end mills are very useful for both simple and complicated contouring and profiling operations. Their versatility means that it is sometimes possible to accomplish the entire operation with a single tool, rather than several, especially when 5-axis milling.

Reduced shank tools offer the most versatility in complex contouring and profiling operations. The ability to chuck these tools at any depth means that they are capable of maximum clearance.

Choosing An Undercutting End Mill

While most undercutting end mills are conceptually similar, there are a few key differences that must be considered when picking the right tool for your job. Harvey Tool offers the following styles as stock standard tools.

selection undercutting end mills sizes and styles

Selecting the Right Plastic Cutting End Mill

April 7, 2017/7 Comments/in CNC Machining, Harvey Tool, Material Specific, Plastics, Tool Information Guides, Tool Selection, Troubleshooting Tips/by Harvey Performance Company

Many challenges can arise when machining different types of plastics. In the ever changing plastics industry, considerations for workholding, the melting point of your material, and any burrs that may potentially be created on the piece need to be examined prior to selecting a tool. Choosing the correct tool for your job and material is pivotal to avoid wasting time and money. Harvey Tool offers One, Two, and Three Flute Plastic Cutting End Mills with Upcut and Downcut Geometries. The following guide is intended to aid in the tool selection process to avoid common plastic cutting mistakes.

three Harvey tool plastic cutting end mills

Choose Workholding Method

When it comes to workholding, not all plastic parts can be secured by clamps or vices. Depending on the material’s properties, these workholding options may damage or deform the part. To circumnavigate this, vacuum tables or other weaker holding forces, such as double sided tape, are frequently used. Since these workholdings do not secure the part as tightly, lifting can become a problem if the wrong tool is used.

Downcut Plastic Cutting End Mills — tools with a left hand spiral, right hand cut — have downward axial forces that push chips down, preventing lifting and delamination. If an Upcut Plastic Cutting End Mill is required, then a tool with minimal upward forces should be chosen. The slower the cutter’s helix, the less upward forces it will generate on the workpiece.

Chart of workholding parameters and their preferred selection to upcut or downcut as a result

Determine Heat Tolerance

The amount of heat generated should always be considered prior to any machining processes, but this is especially the case while working in plastics. While machining plastics, heat must be removed from the contact area between the tool and the workpiece quickly and efficiently to avoid melting and chip welding.

If your plastic has a low melting point, a Single Flute Plastic Cutting End Mill is a good option. This tool has a larger flute valley than its two flute counterpart which allows for bigger chips. With a larger chip, more heat can be transferred away from the material without it melting.

For plastics with a higher heat tolerance, a Two or Three Flute Plastic Cutting End Mill can be utilized. Because it has more cutting edges and allows for higher removal rates, its tool life is extended.

Chart of end mill flute count and their respective workpiece heat tolerance levels

Consider Finish Quality & Deburring

The polymer arrangement in plastics can cause many burrs if the proper tool is not selected. Parts that require hand-deburring offline after the machining process can drain shop resources. A sharp cutting edge is needed to ensure that the plastic is sheared cleanly, reducing the occurrence of burrs. Three Flute Plastic Cutting End Mills can reduce or eliminate the need to hand-deburr a part. These tools employ an improved cutting action and rigidity due to the higher flute count. Their specialized end geometry reduces the circular end marks that are left behind from traditional metal cutting end mills, leaving a cleaner finish with minimal burrs.

Shop Harvey Tool Plastic Cutting End Mills Today

Flute Count Case Study

2 FLUTE PLASTIC CUTTER: A facing operation was performed in acrylic with a standard 2 Flute Plastic Cutting End Mill. The high rake, high relief design of the 2 flute tool increased chip removal rate, but also left distinct swirling patterns on the top of the workpiece.

3 FLUTE PLASTIC FINISHER: A facing operation was performed on a separate acrylic piece with a specialized 3 Flute Plastic Finisher End Mill. The specialized cutting end left minimal swirling marks and resulted in a smoother finish.

Image of facing operation patterns from a standard 2 flute plastic cutter beside another image from a specialized 3 flute plastic finisher

Identifying the potential problems of cutting a specific plastic is an important first step when choosing an appropriate plastic cutter. Deciding on the right tool can mean the difference between an excellent final product and a scrapped job. Harvey Tool’s team of technical engineers is available to help answer any questions you might have about selecting the appropriate Plastic Cutting End Mill.