HQC Quick-Change Collet Systems

 "Do I need to lubricate the Quick-Change collets?"

"Yes. We suggest using Dow Corning BR-2+ or Kluber Altemp Q NB 50 grease on both the collet seat in the spindle or spindle mount and the outside diameter of the collet. This should be repeated every 8 hours."
 "I machine a lot of short parts. Are there problems short chucking with Quick-Change collets?"

"Yes & No. When gripping parts that are longer than 1/2 the length of the bearing of the collet, you should have no problems. You may experience problems when your parts are shorter. Because the collet does not have a shank, it will have a tendency to collapse in the back when there is no stock to grip on. Gripping a part that is only 1/4" long will be very difficult. You can help the situation by making a stop with a diameter the same as the low tolerance on the chucking diameter of the part. With a chucking diameter of .500" that has a tolerance of -.005", the work stop bore should be .495" to .4945". This will help stop the collet from collapsing in the back."
 Should I buy a manual wrench or do I need a hydraulic wrench?

"A hydraulic wrench and power unit is required on a multi-spindle automatic. The work area is too confined and the reach too long for you to comfortably and quickly change the collets. For CNC lathes, a 3/8" ratchet wrench works great. If you want to increase your speed, a hydraulic wrench will do it."
 I have a CNC lathe and the bar stock seems to be running on the plus side of the nominal stock size. Can I get the collet to open up a little more to handle that diameter variation?

"Yes. You can adjust the collet to open approximately .008" more. During setup procedure, the collet body or the draw tube adapter was set with a .030" clearance between the front of the body, or adapter, to the back face of the spindle mount. This amount can be decreased to .005", which will allow the collet to open approximately .008" more. Make certain there is at least .005" clearance, otherwise the face of the body/adapter will hit the back of the spindle mount and cause damage to the assembly and/or the machine tool."
 "We continually have breakage of closer fingers and pins. Will this continue with Quick-Change?"

"Our customers tell us they experience considerably less breakage when using the HQC System on automatic screw machines. This is a result of being able to use less force to hold the bar. Because there is no shank on the collet, less draw bar force is required for the same gripping force. Because the collet can handle a wide chucking range, you won't have to change collets when the stock varies or over-tighten your closing mechanism."
 "What happens when the seal that holds the pads together breaks?"

"You quickly replace the seal and the plug that holds it in. With other brands of quick-change systems, the entire head has to be sent back to be re-vulcanized. This requires an inventory of extra collets to make certain your production is not interrupted. We are told that most shops that use the vulcanized style system purchase a minimum of 10 collet heads for their 8 spindle automatics to reduce the downtime. This additional expense is not required with the Hardinge HQC System. The only item required is an extra set of seals and about five minutes of time. If your shop requires collet heads for ten different stock sizes, the cost for extra vulcanized collets will be in the thousands of dollars. The cost for an extra set of Hardinge HQC seals is around ten dollars."

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 "How often do I need to remove the Quick-Change System and clean the spindle?"

"Use the same schedule recommended by your machine tool builder. The seals on the HQC Quick-Change System create a better seal than master collets, helping to keep chips and sludge away from the back of the collet. You must still clean your spindle on a regular basis or you will eventually have problems."