Taps

MD Technology TT2″ family utilizes powder metal roll form taps. With roll forming, also known as cold forming, taps you not only get better thread quality you also alleviate the hassle of getting chips on your table. Specs up to 2B are capable with roll form threading.

For complete tap size list click here.

For additional tap data click here.

Get 8,000 – 10,000 holes per tap* due to the fact that your machine is doing the positioning and not a secondary manual operation.  Tap up to 180 holes per minute.**

Do you think self clinching fasteners are better? The threads in those nuts are actually made with roll form taps as well. There are some added benefits with tapping rather than inserts. Such as:

• Extruded and tapped holes can be used from both directions, unlike fasteners.
• Roll formed threaded holes won’t fall out, unlike fasteners.
• Reduced manual labor, unlike fasteners.
• Remove a process from your job cell, unlike Fasteners.
• Reduced inventory costs, unlike fasteners.
• Roll formed tapped holes meet or exceed ANSI standard torque specifications, just like fasteners.

Still not convinced? Here is a torque comparison between a leading fastner companies product and extruding and tapping with the TT2″. Extrude and tap vs. Self-clinching fasteners.pdf

MD Technology tapping tools use a ball lock system. This means no tools are required for tap changes, reducing overall downtime!

There are a number of different coatings offered to maximize tap life in your material.

Recommended Tap Coating Based on Material Types

* (depending on tap size, material and machine type)
* If treatment is not specified, Titanium Nitrade (TiN) will be supplied.

Description of Treatments

TITANIUM CARBONITRIDE (TiCN)- is a special physical vapor deposition (PVD) coating, which includes titanium nitride.  TiCN hardens the surface to approximately 90 Rockwell C and has a lower coefficient of friction than TiN.  TiCN works particularly well in abrasive and gummy materials and in high speed, high production applications.

TITANIUM NITRIDING (TiN)- provides a layer of titanium, which is applied to the tap surface with the PVD method.  This treatment reduces the coefficient of friction and hardens the surface to 80-85 Rockwell C.  The TiN treatment is ideal for the majority of forming applications.  This treatment is not recommended for tapping titanium and has performed poorly in high nickel alloys, brass and galvanized steels.  Titanium Nitride is the standard treatment on all Stub Jarflo taps.

CHROMIUM NITRIDE (CrN)- provides a coating applied with the physical vapor deposition method (PVD).  CrN coating has a hardness of 75-80 Rockwell C.  This treatment is designed for titanium and high nickel alloys and has worked well in galvanized steel applications.

CHROME PLATING (KF1-B)- provides a layer of hard chrome which is electrochemically deposited on the surface of the tool.  This treatment reduces the coefficient of friction and helps prevent galling.  This treatment works well in brass applications.

STEAM-OXIDING (J-100)- provides a diamond blue/black finish that stress relieves the microstructure of the tap and provides an oxide film that reduces galling.

NITRIDING (NQ-5)- case hardens the cutting tool surface to 66-68 Rockwell C and provides increased wear resistance with a black surface finish that acts as lubricant to reduce frictional heat and galling.

BRIGHT- provides no surface treatment.  This condition has been used in brass applications with some success.

Description of Tap H/D Limits

The basic goal of all tapping functions is to insure that the external part (bolt) correctly mates with the internal threads (nut).  Not only is it important that the hole is large enough to allow the bolt to enter the hole, but it is equally important that the hole is not so large as to create a loose fit. The H-Limit’s are used to adjust the size of the pitch diameter to provide for a good mating of the external parts.

The H-Limit number is an indicator, which provides information regarding the specific pitch diameter (P.D.) of the tap.  This indicator shows the amount over the Basic P.D. the Actual P.D. of the tap was ground.

The metric equivalent to H-Limits is D-Limits.  The Metric tolerance for D-Limits is slightly larger than the tolerance for H-Limits, but for our purposes we will assume they are the same.

You can use the following chart to determine what the H-Limit’s P.D. is, notice that the tolerance for any h-limit is .0005” or +/-. 00025”.

PITCH DIAMETER LIMITS FOR TAPS THRU 1” DIAMETER

H1 = Basic plus .0000” to basic plus .0005”
H2 = Basic plus .0005” to basic plus .0010”
H3 = Basic plus .0010” to basic plus .0015”
H4 = Basic plus .0015” to basic plus .0020”
H5 = Basic plus .0020” to basic plus .0025”
H7 = Basic plus .0030” to basic plus .0035”
H10 = Basic plus .0045” to basic plus .0050”

Where: Basic = Basic P.D.

The one reason for the specialization of the pitch diameters is the various gauging standards.  The two primary gauging standards are 2B fit and 3B fit.  A 2B fit is the most commonly used thread class for general applications.  A 3B fit is used where closeness of fit and or accuracy of thread elements are important.  The 2B fit has a larger tolerance and requires a larger H-Limit than a 3B fit.

Also remember that the H-Limit for a cut tap is different than the H-Limit for a form tap.  This is because cut taps will cut slightly larger than their P.D. while form taps will thread to their P.D.