50 Years of Service - Is it Time to Retire?

For over 50 years Criterion Machine Works has produced the DBL series of boring heads. These boring heads were designed for manual milling machines that predominately used R-8 shanks. The mounting end was chamfered to match the spindle diameter of the R-8 shank. 

DBL-202B Boring Head
Designed for Manual Milling Machines

In its day this was one of the most popular boring heads available. It offered the user a large range from .250” to 6.687” in diameter. The .001” on diameter dial adjustment was equal or more precise than other models available at the time. It was not uncommon for machine shops to be started with the purchase of a Bridgeport Mill, a set of R-8 collets, a Kurt vise and a Criterion DBL boring head.

CB-202B Boring Head
Designed for CNC Machining Centers

As CNC machining centers grew in popularity, we introduced our CB Style Boring Head. The CB series boring heads were designed with a larger mounting face to be compatible with the tool holders used on CNC machines. The larger mounting surface also gives a more rigid and stable connection for performing a boring operation. All the ranges and adjustability features of the various DBL models were maintained in the CB design.






The CB style boring heads will perform equally as well as the DBL style in a manual milling machining operations. Unfortunately, the same is not true of the DBL style the smaller mounting surface is a disadvantage in CNC machining center operations.

IMTS2010 Generates a lot of Interest in CBER

IMTS Visitors discussing CBER applications

IMTS 2010 generated a lot of interest in the CBER product line. The ability to convert standard ER collet holders into precision boring systems was exciting to many of the visitors to our booth. In the past modular boring systems required special tool holders most of which we unique to the manufacturer of modular system. The special holders increased the cost of the boring systems and limited the ability of the user to use different systems because of these costs.

CBER on Display at IMTS 

A number of our visitors wanted to discuss using the CBER products in their swiss machine as well as in live tooling applications for the mill/turn centers. Precision boring in these applications has not been common in the past because of the physical limitations of the holding systems. This is no longer the case because so many of these machines are tooled for ER collet holders.







We thank all of the visitors to our booth and look forward to working with you and meeting the needs of your precision boring requirements,

Manufacturer chooses Boring instead of Interpolation – Reduces cycle time by 50%

Products Engineering Corporation Combination Square Kit

Products Engineering Corporation (www.pectools.com) has been producing precision tools in Southern California since 1960.  One of their most popular products is a combination square that requires two precision concentric bores and two precision concentric diameters for the tool to function properly.

Combination square bodies waiting to be loaded on the pallet

Products Engineering Corporation manufactures their combination square bodies on a Haas VF-1 machining center with a Midaco pallet shuttle. Each pallet is designed to hold 19 bodies at a time. Michael Berlin, Quality Assurance Manager at PEC, explained that they had been circle interpolating the two bores with satisfactory results but each pallet had a 28-minute cycle time. He wanted to improve the cycle time and possibly the quality of the bores so he started researching alternative hole-making methods.

A pallet of bodies in the Haas

Michael contacted Criterion about the possibility of a boring system that could bore his casting without any additional hole preparation. One bore is 2.500” in diameter while the other bore is slightly larger.  It was decided that the Cri-Bore modular boring system would be the best choice for this operation. The Cri-Bore system would give him easy adjustability and the single point tool would produce the bore he required. We determined the appropriate SFPM for his material was in the 400 – 700 range with a feed rate around .002” per revolution.  Michael said changing from circle interpolating to boring has reduced his cycle time from 28 minutes a pallet to 14 minutes a pallet and improved the quality of his bores.

Because of the success of the boring operation, Michael Berlin contacted Criterion again to see if we could help him with the mating part. Michael asked if we had any products that could cut outside diameters on his vertical machining centers. He was using circle interpolation on these parts also and a pallet of parts was taking 47 minutes to manufacture. We proposed using the Large Diameter Cri-Bore System with the cutting tip turned 180 degrees and a counterbalance weight added so the correct SFPM could be achieved. Some minor modifications to the insert holder were needed so the existing fixturing could be used. The SFPM and the feed rate were the same for this operation as the previous. Products Engineering Corporation’s change to our LCB1.5 Modular Boring System reduced the cycle time for this operation by 16 minutes. In addition to the reduction in time there was also an improvement in quality on these parts. A pallet of combination square bodies now can be made in 31 minutes.

A pallet of parts for OD Turning in the Haas

Completed parts ready for the next operation


A special Thank you to the management of Products Engineering Corporation for selecting Criterion for this project and allowing us to Photograph, Video Record and write about this project . If you would like to see the video log on to our youtube channel.

www.youtube.com/user/CriterionMW

More Chatter Check Your Overhang

I had the opportunity (and fun) of taking a technical call from a “New” customer not just to Criterion but also to boring. He was calling because the finish in his bore looked like a rasp it had some much chatter in it. He was attempting to make a 1-1/4” diameter bore 5” deep. His tolerance was +/- .002” and the material was 4140. The 3/4" diameter boring bar projected out of his boring head 8”. He had tried changing his RPM and changing his feed rates but nothing was working. He had slowed his RPM down to less than 200 hundred and his feed rate was less than .001 IPR; nothing was working for him.

We talked about some general rules of thumb for boring. First the depth to diameter ratio of a boring tool is critical to successfully boring a hole. The general rule for steel boring tools is 4:1, heavy metal boring tools is 6:1 and solid carbide tools is 8:1.  So his 8” projection with a 3/4” bar gave him a better than 10:1 ratio making it difficult if not impossible to achieve a satisfactory bore.

The second general rule is to use the largest diameter boring tool that will fit into the bore while still giving you clearance to evacuate chips from the bore. This gives maximum rigidity to your operation and helps to insure that you make the precision bore you need

The third general rule is to make sure your depth of cut is enough to clear the nose radius of the tool you are using ( I wrote about this in an earlier blog). His depth of cut was greater than the nose radius so this was not part of the problem.

The last issue we discussed was operating the tool at the correct surface feet per minute (SFPM) for the bore diameter. For his operation and the carbide he was using in steel with a hardness of about 30 R/C the starting point was 600 RPM with a feed rate of 2.0 IPM. This was based on the material he was cutting and the amount of off-set on his boring head.

The “Fun” for me was the customer had modified his program while we talked and had some else cut the bar so it only project slightly over 5” from the boring head. He asked if I could stay on the line while he tried the new program. I could hear the machine make the cut in the back ground and the customer describe it over the phone. He successfully bored the hole and was excited about what he had just learned. It is fun to help customers solve issues they have making their parts. If you would like us to try and help you with a boring problem don't hesitate to contact us. 

Modular Boring with HSK Connection

We have expanded our Modular Boring System with the addition of HSK 63A and HSK100A Tool Holders for the CB1.5, CB2, and CB3 size modular units. These New Shanks can quickly be connected to the Cri-Twin or Cri-Bore Modular Boring Systems as well as our CB Style Boring Heads designed specifically for CNC Boring.


The rigidity of the HSK andCB style connection and the strength of our dove-tail design gives you maximum strength and rigidity during the boring operations. Our modular boring systems are available with either .001″ or .000050″ direct reading adjustment dials.

Criterion also has a full line of V-flange, BT-flange, NMTB holders, and other holders and adapters to choose from. We have been producing Precision Boring Products for 75 Years.

We look forward to working with you on any of your precision hole making applications

When Does an Aerospace Company change the Plane?

The answer is when they have to bore a horizontal hole on a vertical machining center.

The combination of a right angle head and a CBER precision boring system allows anyone to change the plane.

Recently an aerospace company contacted us about an application they had for boring a horizontal hole on a vertical machining center. They knew were making boring heads that fit into ER collet holders so they inquired about the possibility of our producing a boring head to fit into an ER16 collet holder.  They had a right angle head that used ER16 collets and they wanted to use it for boring their horizontal hole.

We had just successfully finished our CBER16 prototypes and were beginning our first production run of parts so they would be ready for introduction at IMTS2010. We sent them one of the prototypes they asked if we could extend the range so they could bore a 1.000-inch diameter bore.  We designed an offset head to accomplish their request (The black insert holders in the photo).  An additional dilemma was discovered when the flush nut design collet nut was added as a requirement. We had to quickly do some redesign to the CBER16 so the flush nut could be used.

Again the voice of the customer has given us a new product to carry forward. We will be adding extended range insert holders to our CBER16 and CBER20 precision Boring Systems.

If you need to change the plane or stretch the limits give us a call 800.854.7441 or e-mail us at cmw@criterionmachineworks.com we enjoy the challenges

Product Line Expands because of The Voice of the Customer

A couple of months ago we were contacted by a machinery dealer who had seen our ads for the CBER boring system (you can read about it in our earlier blogs). They wanted to know if we could make ER32 to ER25, ER32 to ER20 and an ER32 to ER16 adaptors. We discussed the application, which was to give their customer a quick-change system for their turning center that was tooled with ER32 collet holders. After looking at the request we determined we could do the ER20 and ER16 sizes but not the ER25.

ER to ER Adaptor

While we were working on the design we realized this would be a natural extension for our CBER system. Our customers will be able to take advantage of the boring ranges of the CBER20 and the CBER16 products in their ER32 holders. We will not be able to have everything ready for IMTS 2010 but we will have it ready by the end of the year. If you have any questions about the CBER system or the ER to ER adaptors please contact us at 800.831.7444 or by e-mail at cmw@criterionmachineworks.com.

Is Social Media as Industrial Marketing a Field of Dreams?

I have watched Social Media for a few years trying to determine if it was an appropriate venue to invest some of the advertising budget. In trying to unravel the “How To”, “Is there enough time in the day?”, “What is it really going to cost?”, “When do we make the leap?” and the most important one “Will anyone care?” I was sometimes paralyzed by those thoughts.



Criterion historically has sold through distribution and advertised in the traditional ways. This unintentionally built a level of insulation between our customers and us. It could take a few years to really get a message of innovation out in the market place. Our sales force would have to be trained. They would have to train the distribution sales force who would go and show the customers. We would have to print literature, design ads, issue press releases and display at tradeshows all of this taking a fair amount of time. Feedback from the market if it ever arrived at all would take time to come back through all of the channels that were built into the system.



I realized that if we participated in this personal forum called Social Media we would be opening the opportunity to deal directly with the individuals who use our products. We could instantly (something I have started calling the speed of Tweet) present new products or improvements to existing products to our customers but more importantly we can get instantaneous feedback from the most valuable people to our company the customer.



I must confess that I am still learning the “How To”, there is enough time in the day, its cost is part of the cost of doing business, we obviously have made the leap and as for “Will anyone care?” the answer is Yes! Those very important customers are starting to find their way out of the cornfield surrounding our Social Media field after only a few weeks.



As a company we still need to participate in the traditional marketing approaches but in the not to distant future I believe that Social Media will be part of the traditional marketing methods because it brings you right to the customer and the customer right to you.



Thank you to the customers who have already allowed us to play on the filed with them. We look forward to hearing and working with more of you as we grow together.




My final confession is I hope my competition does not react as fast as the customers have.

When You Don't Make the Cut You May Have to Live with the Chatter

We had a number of technical support questions this past week about unsatisfactory finishes in the bore. As we talked with the customers and potential customers we asked, “What is the depth of your cut?” and “ What is the nose radius on your carbide insert?”

The reasons for asking these questions is one of the most common mistakes made when cutting a precision finish bore is not leaving enough material in the bore so the boring tool can work properly. 

When the depth of cut is less than the radius on the insert 

(or boring tool) the cutting pressure builds up and tries to push the insert out of the cut. You can see from the arrows on the diagram that all of the cutting force is away from the cut and there is no cutting pressure trying to stabilize the tool in the cut.  

On the second diagram the depth of cut is greater than the insert which gives some stabilizing pressure from the end of the insert so the tool does not want to skip out of the cut.

A general rule of thumb is to have a depth of cut .005/.010” more than the radius of the cutting tool. This will give you a stabilizing force to help eliminate chatter from your bore.

There are many other factors that can affect the finish of a bored hole such as the rigidity of the fixturing, the depth to diameter ratio of the bore to the boring tool shank and spindle rigidity. We will try to give you common sense tips for these factors as we add to our blog.

If you have any questions regarding precision finish boring or modular boring please leave us a comment or send us an e-mail. We enjoy working with our customers to improve their manufacturing processes.

Cri-Tip works with ABS or KA Connections

Our Cri-Tip Modular Boring System is one of the most versatile system available today. It is designed with not only interchangeable boring heads and insert holders but also interchanges with other manufacturer’s modular systems as well. This gives you versatility while allowing you to use your existing modular boring system components.

Cri-Tip Interchangeable Heads

The Cri-Tip Modular Boring System has 8 different bodies that can be converted into 54 different Boring Assemblies by just changing the Insert Holder or Bar Holder. Insert Holders and Bar Holders are available with .00005” direct reading or .001” direct reading dial adjustments. All Insert Holders and Bar Holders are heat-treated and satin chrome finished for toughness and durability.

Cri-Tip Modular Connections

The Cri-Tip Modular Boring System is designed so it can be connected to either the popular ABS connection or the equally popular KA connection. This allows you to take advantage of the Cri-Tip System without the expense of purchasing a completely new modular boring system. This is the first modular boring system designed to work between different manufacturer’s modular boring systems. In addition, the Cri-Tip System also has threaded adaptors available for connecting all of Criterion’s Boring Heads to the system.

We Can't Split an Atom but We can Split .0001 of an Inch

For years the industry standard was .0001” adjustment for “Precision Finish Boring” applications. The demand for closer tolerance Finish Bores pushed us to develop our Modular Boring Systems with .00005” (50 Millionths) adjustability. Putting this into perspective you would have to move our dial 60 graduations to equal the thickness of a normal piece of paper. We have accomplished this with a unique moving wedge design so the boring heads do not require a locking mechanism to ensure their accuracy during the cutting operation.




This Micro-Adjusting feature is an option on our Cri-Bore Modular Boring System, CB Boring Heads, Cri-Bar Adjustable Boring Bars and CBER Modular Boring System for ER Collet Holders



The Micro-Adjusting finish boring products have a .006” on diameter range for the micro adjustment. We use our standard .001” on diameter dial for making major diameter adjustments so you save time when making your initial set-up. We look forward to working with you on any of your Precision Finish Boring Applications.

Is it a Boring Head or an Adjustable Height Centering Tool Holder?

A few years ago we introduced a small boring head for use on drilling/tapping style CNC machining centers and small benchtop style machining centers. The boring head is 3/4" square and has a boring range from .035" to .580" in diameter. The direct reading dial is graduated in .001" increments.  The first cutomer purchased the boring head did so to use in a gang tooling set-up on his lathe. He was exicted about the fact that he could now adjust his tools so they would cut on center. This was an unexpected use for the tool but it spawned the idea of making an adjustable boring head that could use ER11 collets as the tool holder.

We are introducing the TMT-ER11 Boring Head at IMTS2010. This boring head has the same .035" to .580" range as the TMT-0750 Boring Head but the cuting tool shanks are not limited to 1/8" or 1/4". ER11 collets have a holding range from .019" to .275" so you can hold any type of tool in this boring head. You can now use it to boe small holes or hold small shank tools in a gang tooling set-up.

We look forward to showing it off to you at our Booth #W-2100 @IMTS. You can decide what its best use is after seeing it.

CBER16 is Being Introduced at IMTS2010

We will be introducing the new CBER16 size to our innovative ER precision boring system at IMTS2010. The CBER Boring System converts precision ER collet holders into Precision Boring Systems. The CBER16 will fit into most Swiss Automatic style turrets as well as many Right Angle Heads so you can now easily do precision boring where it was difficult to accomplish before.

The addition of CBER16 means the system now covers ER16, ER20, ER25, ER32 and ER40 collet holders. The system is capable of boring holes as small as .035” in diameter to as large as 1.700” in diameter. All of the CBER sizes have a standard .001” on diameter directing reading adjustment dial. The ER32 and ER40 sizes are also available with a 0.000050” on diameter Micro Adjusting Dial. All sizes will be available in a standard and a short length.

All of the CBER sizes have a locator flat for easy establishment of the adjusting axis as well as a convenient location to indicate from when closer adjustments than the dial graduations are required. The CBER systems do not require special tool holders but they do require that the collet nut does not have the extractor lip as it will prevent the boring system from properly being installed into the collet holder.

Be sure and see our booth @IMTS2010 W-2100

If you're making your plans to visit IMTS be sure to include us in your show planner.

You can access the IMTS Show Planner right on the IMTS website under Floorplans.  We're located in the West building.

We'll be displaying the the new products that you're seeing here on our blog.

This year we're talking about cycle time savings!

Check out the picture on the right.  This is where our booth is located. Our booth W-2100 highlighted in red at the right.  

When you click on our booth you can see some of the featured products.

But be sure and stop by for a first hand look at some of the newest time saving Modular Boring Products and Adjustable Boring heads for both CNC Mills and Swiss Turning machines.

Large Diameter Bores? You may already own what you need.

Criterion’s large diameter boring system increased the production of one of our customers in Wisconsin from one part per hour to fourteen parts per hour! This production increase reduced the boring machining cost by 93% of what it had been. Criterion’s modular boring system will PAID FOR ITSELF in 1 week!

The LCB1.5 modular boring system is designed around Criterion’s standard 1-1/2” diameter Cri-Bore modular boring head, a series of extender bars  and a tool holder. 

By using Criterion modular boring heads, that you may already have in your shop, you can use the extender bars to machine larger bores and even install the heads 180 degree around and machine the OD of a boss.


Did you catch that? That means that the LCB1.5 boring heads can also be positioned so they turn a boss on a part–eliminating the need for additional set-ups on other machines.


The use of counterweights allows the system to operate at the recommend SFPM for the carbide inserts. Doing this extends the carbide life—as well as decreases the production times required for carbide boring.

So the bottom line is this: If you have some of our CB1.5 boring heads in your shop, you only need to purchase our extender bars in many cases.


Go out on your floor and take a look around and see if you've got some of our modular boring heads already. Here's what to look for:

CODE NO.	TOOL NO.	A MAX. BORE	B MIN. BORE	C OVERALL LENGTH	D BAR DIA.	INSERT I.C.	INSERT STYLE	THREAD
25337	CB1.5-BD-TP	2.700	1.585	2.480	1.500"	.375	TPGT/TPGW	7/8-20
25341	CB1.5-BD-CP/DI	2.700	1.585	2.480	1.500"	.375	CC or CP	7/8-20

Download our complete LCB1.5 Boring System information in PDF format.

Boring Heads that fit into your ER Holders!

The CBER boring system converts precision ER collet holders into precision boring systems, the company says. The CBER16 boring system, which fits ER16 collet holders, is capable of boring holes from 0.035" to 0.944" in diameter. 

All of the CBER sizes have a standard 0.001" on diameter direct reading adjustment dial. The ER32 and ER40 sizes are also available with 0.000050" on diameter micro adjusting dial. All sizes are available in standard and short lengths.

The boring system is designed for right-angle boring heads, live tooling adapters and other machines that utilize the ER style collet system.


The CBER precision modular boring system converts ER collet holders into precision boring systems. The system fits into ER20, ER25, ER32 and ER40 collet holders and is capable of boring holes from 0.035" to 1.700" in diameter. All CBER sizes have a standard 0.001" on diameter adjustment dial. The ER32 and ER40 sizes are also available with a 0.000050" on diameter adjusting dial. All sizes are available in standard and short lengths.

Criterion 202B Balance Kit operates at speeds up to 5,000 RPM

Criterion Machine Works has introduced a balancing kit for their 202B boring heads. 202B boring heads now can be operated at speeds up to 5,000 RPM. 

The balance kit is a series of 4 weights, 6 shafts and a balance chart. When the weights and shafts are assembled in the correct combinations the boring head can rotate at 5,000 RPM with out introducing vibrations to the operation. 


Criterion also provides complete Modular Boring Systems so you can select standard components instead of investing in special boring tools. The Cri-Bore and Cri-Twin Modular Boring Systems will stand up to not only your toughest metal removal requirements but also your tightest tolerance requirements. 


Criterion’s Boring Heads, Boring Bars, Boring Tools, and Modular Boring Systems have been the Industry Standard for over 70 years. Criterion is proud to be your Partner in Precision Boring. For more information, please visit www.criterionmachineworks.com