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Frequently Asked Questions

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

What happens when the seal holding the pads together breaks?

You quickly replace the seal and the plug that holds it in. With other brands of

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

HQC® Quick-Change Collets - 17884 ??

What is the operating range of a Quick-Change collet?

The operating range is ±
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64 " (.393mm) for under a 2" diameter, and ±
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32 " for a 2" diameter and over, when used on multi-spindle automatics for bar stock work. The operating range of the collets when used on CNC lathes is -1/64" (.393) to +.008" (.20mm). Note that the best grip is with a full bearing, which is at the rated size of the collet. As the stock gets larger, the collet will grip at the edges of the slots; as the stock gets smaller, grip- ping will be at the center of the gripping surface.

We continually have breakage of closing fingers and pins. Will this continue with Quick-Change?

Considerably less breakage is what our customers tell us when the HQC System is used 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 risk overtightening of your closing mechanism.
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.

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 ten collet heads for their eight 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.

Quick-Change

Collet 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.

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 manual wrench with a standard
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.

I’ve experienced breakage problems with other Quick-Change collet systems? How will the HQC

®

system hold up?

The Hardinge HQC design incorporates much thicker wall sections in the highly stressed areas of the collet head and body, and has much more contact area between the head and body than other quick change systems. These features provide much less chance of breakage, maintaining productivity and eliminating costs associated with replacements, damage from crashes and downtime.

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