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Collet Questions
  1. Do you sell ER style tapping collets that have the internal square in the back?

    Currently we do not. One of the reasons we don't is because in most cases it is not needed. Misconception is that taps often slip when used in normal ER style collets. This is not the case as long as you always try to use the proper size collet. Proper size collet is when your tool shank is as close as the largest capacity listed on the collet without being larger than that size shown. Tapping collets should be used when using larger size taps with coarse pitch and when form tapping larger size taps. Simple rule of thumb, if the tap shank is 60% or smaller than the maximum clamping range of that collet style, save your money and use a normal collet. For example ER32= .750 X.60=.450 diameter.

  2. How much should I torque ER style collets nuts?

    The following torque ratings are for solid ER style collets nuts. Bearings collets nuts are not as strong so reduce these values 15%

    When clamping on shanks 30% smaller than collets maximum capacity, reduce torque value 40%.

    In most cases a light oil film on tool holder thread is adequate. Collet and collet seat should be clean and dry. 

     

    ER8      10-12 FT-LBS 

    ER11     15-25 FT-LBS

    ER11M   15-20 FT-LBS

    ER16     30-40 FT-LBS

    ER16M   25-32 FT-LBS

    ER20     50-55 FT-LBS

    ER20M   40-48 FT-LBS

    ER25     70-80 FT-LBS

    ER32     90-110 FT-LBS

    ER40     120-130 FT-LBS

    ER50     140-150 FT-LBS

     

  3. How much should I torque SK style collets nuts?

    The following torque ratings are for solid SK style collets nuts, standard and high speed style.

    When clamping on shanks 30% smaller than collets maximum capacity, reduce torque value 30%.

    In most cases a light oil film on tool holder thread is adequate and recommended. Collet and collet seat should be clean and dry. 

    SK6     20-25 FT-LBS 

    Sk10    45-50 FT-LBS

    SK16    65-70 FT-LBS

    SK25    90-95 FT-LBS

  4. If most ER collets have a range of .039" (1mm) , why do you stock ER collets in 64'th increments?

    Even though ER collets have a range of about 1mm accuracy and grip is always reduced the more you collapse the collet. Take a letter "F" drill for example. The shank is .257 inches. Most tooling suppliers would recommend a 9/32 collet. We feel that offering a 17/64 ER collet would be a much better match and help increase grip and reduce runout.

  5. What is the difference between standard collet nuts and bearing collet nuts?

    Bearing nuts have a rotating sleeve that isolate nut rotation from the collet while it is being torqued. This distorts the collet less and allows more torque to be transmitted to the collet. Accuracy is sometimes slightly improved. Bearing nuts are not balanced as well as standard collet nuts. Due to the rotating balls they are not balanced to G2.5 @ 20,000 rpms. Bearing nuts are slightly weaker than standard collet nuts, due to the thinner cross sections and internal ball race. Torque must be reduced 15% compared to standard collet nuts.

  6. Why should I choose the ER Collet System?

    The ER collet system is a very versatile system. MariTool offers ER collet chucks in many gage lengths and profiles. Between ER8, 11, 16,  20, 25, 32, 40 and 50 you can get exactly what you need for your application. We also have ER collet chucks with Mini Nuts (last digit of tool part number will have an M). These Mini Nut style tool holders have slimmer necks and collet nuts for even more clearance. MariTool also offers some ER collet chucks with tapered shanks (designated with a T in the part number). These tapered collet chucks are longer in gage length while still offering great rigidity. With this variety of sizes, gage lengths, and profiles you can get the exact tool holders for the tool shank size you need to hold and clearances you need. Below are the ranges for each collet system.
    ER8 .03-.196
    ER11 .03-.3125
    ER16 .03-.4375
    ER20 .03-.5625
    ER25 .03-.6875
    ER32 .03-.875
    ER40 .125-1.1875
    ER50 .250-1.339
    MariTool stocks one of the most comprehensive catalog of ER collets. We stock metric, English in both standard and coolant sealing styles. We also carry Inch collets in 64'th sizes so you are assured a proper collet is available for any shank size.