By John Zaya, Product Specialist, BIG DAISHOWA—Americas
As the title implies adjusting screws, also known as back-up screws, stop screws and preset screws, are not just a simple set screw. They are a screw with a purpose--three actually.
The first is to provide a fixed stop for a cutting tool to rest against during tool changes. This allows an operator to save time as they do not have to pull out a ruler, setting jig, etc. to reassemble the cutter into a holder.
A secondary purpose of the adjusting screw is to assist the tool holder in keeping the cutter from being pushed up into the holder if the cutting loads increase to the point where the tool may slip up into the holder.
The third is to offer sealing for coolant-through tools.
1. Expected repeatability of cutting tool length
When an old cutter is swapped out and a new one put in its place, the repeatability of this process will vary based on a few parameters such as cleanliness and the OEM cutting tool overall length tolerances.
Cleaning the clamping bore or collet of a holder provides better runout repeatability which should be old news to everyone, but if old coolant and contaminants are not removed, they would get jammed between the end face of the shank and the adjusting screw, affecting the length setting.
Cutting tool overall length tolerances may also vary from one OEM to another. We have seen them range from ±.3mm to ±.5mm (±.012” to ±.019”). Others may be tighter or looser.
Most modern machining centers come with tool length offset measurement systems which will provide the final precise gage length of a tool assembly. With the rough position provided by the adjusting screw, the machine operator can continue working and does not need to worry about tool clearances and stick outs.
2. Forms of adjusting screws
The clamping mechanism of the holder also affects the length repeatability. Both hydraulic chucks and milling chucks are radial clamping systems, whereas a tapered collet is drawn down into a taper by a threaded nut. This draw down causes the cutter to be drawn down as well.
For this we have two types of adjusting screws: HMA/HDA solid type and NBA rubberized type. The solid type is a one-piece steel construction part, whereas the rubberized type has a rubber padded conical pocket that absorbs the axial travel of the cutter shank as the collet is clamped.
3. Option for adjustable reduction sleeves for MEGA DS/HMC
Milling chucks also have a second type of adjustment screw option that can be built into the back end of a reduction sleeve. As cutting tool diameters get smaller, the length of the shank also gets shorter.
As such, the end face of the shank may not reach the HMA adjusting screw when installed it the body of the holder. The AC Type Collet adjuster screws into the back end of the reduction sleeve where the shank the tool can easily be reached.
4. Warning on holders that cannot support adjusting screws
It is always recommended to consult the tool holder catalog or technical documentation to ensure that a holder can support an adjusting screw. Some holders are very short or have very deep internal features that may not allow for the use of any adjusting screw. In those cases, a depth setting ring or collar on the shank of the cutting tool may be an acceptable alternative.
Caution should be used on shrink-fit holders. Thermal expansion/contraction occurs in all three axes, so as the body of a shrink-fit holder cools down it will draw the cutter down jamming onto the adjusting screw. This could lead to damage to the screw, the holder or the cutter.
John Zaya, Product Specialist, explains the concepts behind the UNILOCK Zero-Point workholding system.
He also discusses base pallets and options for 5-axis machines.
0:13 Basic Concepts
0:52 Features of the UNILOCK Clamping Knob
1:50 UNILOCK 5-Axis Program
BIG DAISHOWA is a different kind of tooling partner. Our mission is to find the best of the best and deliver it to our customers with a personal commitment to helping them install truly efficient solutions. We have exceptionally high standards for the products we represent. The result is an all-star line-up of products that deliver true and measurable performance advantages. Products that are engineered to exacting standards and then manufactured with materials and craftsmanship that enable superior performance.
A human hair is about .0040” thick. Martindale Gaylee solid carbide saws can be manufactured as thin as .0020” which is half the thickness of a human hair. This extreme miniaturization is made possible through their numerous years of experience.
At the other end of the spectrum, solid carbide saws can also be made as thick as 1.000” with O.D.’s typically ranging from .250” to 7.500” (6.35mm to 190mm) and tighter than standard tolerances are also available.
Keep in mind that all solid carbide saws 2” diameter and larger are manufactured with a standard hub and round key.
Martindale Gaylee has a dedicated team of saw-makers unparalleled the world over. From saws to cutting knives to slitters, slotters and cutters...we’re prepared to work with you on your specific application.
The miniature saw shown on the left above has an O.D. of 3⁄4” with 18 precision teeth. The saw shown on the right has an O.D. of 1⁄2” with 14 precision teeth. Gaylee takes pride in producing precision saws unsurpassed by any other manufacturer for your application.
Get in touch with us with any questions about solid carbide saws!
Jergen's 5-Axis ER Collet Fixtures Provide Simple Clamping of Cylindrical Parts in a CNC MIll
Looking for a simple and low profile solution for clamping cylindrical workpieces and round bars? Do you ever need to hold a round shank workpiece and machine it in a CNC Mill?
The ER Collet Fixtures provide a simple and low profile solution for clamping cylindrical workpieces using the same technology you are already familiar with in your rotary toolholders.
It’s been estimated that a tool with a run-out of 50% of the tool’s chip load will reduce its tool-life by 40%.
That means that a 1/8” tool with a 0.00019” chip load per tooth will lose 40% of its tool-life with a run-out of less than 0.0001”.
Excessive and inconsistent run-out from a properly setup ER collet chuck assembly typically occurs due to friction build-up between the 30° face of the collet and the collet nut.
Other Parlec P3 collet advantages:
Don’t throw away you ER collet chucks to improve accuracy
Try Parlec P3 collets and supercharge your ER collet system.
Put simply, the manufacturing process of boring is enlarging a hole in a piece of metal. There are quite a few different pieces of machinery or approaches that can be used to make holes from lathes and mills to line boring or interpolation. We wanted to do a quick break down of the different kinds of boring tools available to bore holes and/or secondary boring operations.
Boring deep holes can involve extreme length-to-diameter ratios, or overhang, when it comes to tooling assemblies. Since it can be difficult to maintain accuracy and stability in these scenarios, we need boring bars to extend tooling assemblies and while maintaining the rigidity to make perfect circles with on-spec finishes.
Solid boring bars
Typically made of carbide for finishing or heavy metal for roughing, solid boring bars have dense structures that make for a more stable cut as axial force is applied.
When cutting speeds are compromised, or surface finishes show chatter in a long-reach boring operation, damping bars are an option. They have integrated damping systems. Our version, the Smart Damper, works as both a counter damper and friction damper so that chatter is essentially absorbed.
Boring heads are specifically designed to enlarge an existing hole. They hold cutters in position so they can rotate and gradually remove material until the hole is at the desired diameter.
Rough boring heads
Once a bore is started with a drill or by another method, rough boring heads are the choice for removing larger amounts of material. They are built more rigid, to handle the increased depths of cut, torque and axial forces needed to efficiently and consistently make the passes to remove materials.
Fine boring heads
Fine boring heads are best used for more delicate and precise removal of material that finishes the work the rough boring head started. They are often balanced for high-speed cutting since that’s the best approach for reaching exact specifications.
Twin cutter boring heads
Most boring heads feature one cutter that cuts as its feed diameter is adjusted by the machine. There are twin cutter boring heads that can speed up cutting and add versatility. For example, the Series 319 and other BIG KAISER twin cutter boring heads include two cutters that can perform balanced or stepped cutting without additional accessories or adjustments by switching the mounting locations of the insert holders that have varied heights.
Digital boring heads
Traditionally, adjusting boring heads has been painstaking and time-consuming, especially when it’s done in the machine. It’s easy to make mistakes when maneuvering to read the diameter dial and adjusting it to the right diameter. Digital boring heads have a LED that makes precise adjustments much easier.
Since cutters are on diameter of boring heads and not their face, they are not able to initiate a hole on a flat surface or raw material. Especially in smaller bores, fluted drills called starter drills can be used to get the hole started before rough boring.
Specialty boring heads
Back boring and face grooving heads, as well as chamfering insert holders, are available for some of the most common secondary operations, after a hole is bored. We produce specific heads with cutters at the appropriate angles so each of these operations can be done without manually moving the part, changing the tool or adjusting the cutter angle.
Modular boring tools
Since limiting length-to-diameter ratios is so crucial to boring success, it’s extremely valuable to be able to make your tooling assembly as short as possible. Our modular components are based on a cylindrical connection with radial locking screw that allows for the ideal combination of different kinds of shanks, reductions and extensions, bars, ER collet adapters and coolant inducers.
Looking for some help finding the right boring equipment for your next job or new machine? Our engineers are here to help. Get in touch with us here.
Written and edited by Bernard Martin
PowerCOAT Collet Nuts provide up to a 75% increase in holding power!
One of the most important elements of the toolholding 'system' is the collet nut. Each toolholder "system" consists of a precision ER tool holder that comes with a special "Power Coated" high power nut that holds tighter than any other nuts.
According to Techniks, the 'Power Coat' nut is the secret to their high holding power. Because it holds so tight, the 'Power Coat' nut improves T.I.R., extends carbide tool life, and improves finish in heavy milling operations.
Techniks recommends that for best results always tighten the nut to the proper torque using a torque wrench with a tightening stand, and never over-tighten the nut because this can damage both the collet and the collet pocket.
To demonstrate the difference between an uncoated and coated collet nut, Mike Eneix, from Techniks did some testing.
He took an uncoated, imported nut and put it to the test against the Parlec PowerCOAT nut. Mike took them to the limit to see which one gives you more holding power. Check out the video below!
What makes the difference?
As anyone knows who has changed a flat tire on their car, tightening down a nut on a 60 degree thread involves some friction as the mating metal surfaces interact. That's why nuts can be a bit 'hot' to the touch when you take them off. The objective with the "Power Coated" nuts was multifold:
First Techniks needed to reduce the coefficient of friction on the thread angle to enable more lubricity for the nut to tighten down farther. As we all know 'heat' causes metal to "grow" so what may at first appear to be tight, in fact, loosens, as soon as you stop tightening it.
Second they needed to make sure that the front surface of the collet that engages the shorter 30 degree taper on the front of an ER collet did not 'twist' as the night tightened down.
Both problems really involved reducing friction and through a combination of engineering tolerances and unique coating process we believe that we've found the most economical solution to eliminate the use of cheater bars and collet over torque. Here's what they've found out in testing the "Power Coated" Nuts:
“Power Coat” is an innovative, permanent coating that increases clamping pressure of the nut up to 75% compared to standard ER nuts. More holding power reduces the chance of spinning the shank of the tool inside the collet, which can cause premature failure of the collet.
The Difference Between a Swiss Type CNC and a CNC Lathe & the Cutting Tools Used in Each
A Swiss type CNC automatic lathe and a CNC lathe, they are similar lathe machines, but did you know they are completely different?
In this article, the kind folks at NTK Cutting Tools will introduce the 4 differences between the cutting tools used based on the mechanical structure of Swiss CNC automatic lathes and CNC lathes.
What is the difference between a “Swiss CNC Automatic Lathe” and a “CNC lathe”?
Swiss CNC automatic lathe & CNC lathe: Since the machine structure, workpiece, and size are different, it is important to select the cutting tool accordingly. Now let's take a look at the features of cutting tools used in CNC automatic lathes.
Difference 1. Holder
The holder is an important component for achieving chip performance. I will explain the difference between the holder used on a Swiss type CNC automatic lathe and a CNC lathe.
Holders for Swiss CNC Automatic Lathe
CNC Lathe Holders
Difference 2. Insert geometry: Positive inserts and Negative inserts
CNMG... DNMG...: If you are familiar with machining on CNC lathes, you likely know about insert geometries. The Swiss type CNC automatic lathe is the same type of lathe, but if you are thinking of machining with the same insert, be careful!
Inserts such as "CNMG /CNGA..." and "DNMG/DNGA ..." used on CNC lathes have many corners, and the cutting edge is honed or chamfered (edge preparation) and have excellent cutting edge strength. These inserts are ideal for shearing the workpiece material.
On the other hand, when a negative insert such as "CNMG/CNGA..." is used on a Swiss type CNC automatic lathe, cutting resistance tends to be high and "chatter" and "work deflection" occur. We recommend using a "positive style" for Swiss CNC automatic lathes.
Swiss-type CNC automatic lathes machine workpieces that are smaller in diameter and require higher precision than machining on a CNC lathes. High cutting resistance causes “vibration” and “dimensional defects”, so using a “positive insert” with a relief angle to reduce cutting resistance and achieve stable machining.
Difference 3. Insert tolerance: G-class and M-class
The table above compares the “M” class commonly used on CNC lathes with the “G” class and “E” class commonly used on Swiss SNS automatic lathes. The 3rd letter in the insert part description identifies the tolerance class. Insert such as CNMG… and DNMG… have an M class tolerance. On the other hand, inserts such as DCGT… and CCGT… have a G-class tolerance.
As shown in the table, the insert tolerance is very different between the “G” and “M” class. Corner length (m) and insert IC (dia. D1) tolerance affect the accuracy of the cutting edge position, or workpiece dimensions. Thickness tolerance (S1) affects the height of the cutting edge.
Swiss-type CNC automatic lathes require high precision machining of small diameter workpieces, so “G-class” or “E-class” with higher tolerance than M-class are used. Also, the upper and lower insert surfaces of G-class and E-class inserts are polished and the outer edges are ground with high accuracy which achieves excellent sharpness.
For Swiss CNC automatic lathes, it is strongly recommended to use inserts with “G-grade” and “E-class” tolerances.
Difference 4. Coatings types: PVD vs. CVD
Coating is an important factor in determining the performance of tools and the quality of workpieces. There are two main types of coatings - CVD and PVD. Which coating is suitable for Swiss CNC automatic lathes?
Inserts like “CNMG” and “DNMG” used on CNC lathes are generally CVD coated. CVD coatings can be thick films compared to PVD coatings and have excellent abrasion resistance.
But, because it is a thick film coating, it is easy to cause deterioration and there is a disadvantage of a rough coating surface.
Swiss-type CNC automatic lathe machining requires high precision, sharpness is important, so PVD coatings are more suitable due to thin film coatings achieving sharp edges.
As shown in the figure above, PVD coatings have excellent sharpness, dimensional stability, and welding resistance making it the ideal coating style for Siwss-type CNC automatic lathes.
Do you still have questions about the difference between tooling used for a Swiss type CNC lathe and traditional CNC lathe?
NTK offers a large lineup of tools specialized for CNC automatic lathes. If you are having issues machining, please consider contacting us for technical advise.
Technical Support Blog
At Next Generation Tool we often run into many of the same technical questions from different customers. This section should answer many of your most common questions.
We set up this special blog for the most commonly asked questions and machinist data tables for your easy reference.
If you've got a question that's not answered here, then just send us a quick note via email or reach one of us on our CONTACTS page here on the website
Our technical section is written by several different people. Sometimes, it's from our team here at Next Generation Tooling & at other times it's by one of the innovative manufacturer's we represent in California and Nevada.
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