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.
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
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.
