Quick Change Block Systems

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Quick change block systems are designed to make it easier and faster to switch between the tools that you need. In addition to allowing for easy tool exchanges, the block systems also offer a secure hold that will keep tools, equipment and workers safe. If you find yourself frequently switching between machines to get the right application, the quick change block systems will allow you to bring less equipment while still getting the results you are looking for. With two different holder and base designs, you can choose the best quick change block system for your equipment, including a design for machines operating at 400 horsepower or higher and machines operating at less than 400 horsepower. 

QC100 Base

  • for machines more than 400 horsepower

QC110HD Holder

  • for machines more than 400 horsepower

QC110B Base

  • for machines less than 400 horsepower

QC110H Holder

  • for machines less than 400 horsepower


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Assembly Instructions for QC100 Base, QC11OHD, and Quick-Change Units

NOTE: System is held together by the taper, not by the bolt.
The following assembly process is critical. If the block and base are
not assembled properly, excessive movement between the two units
will occur and the system may fail prematurely.

Assembling the Block/Base for Welding
Choose Method 1 or 2 to assemble the quick-change block and
base prior to welding. To make sure the block and base are
positioned properly on the drum, use the cutting tool point as the
locator point.

Method 1: Lightly Hammered
1. Place the quick-change block in the base. In this position,
the front of the quick-change block will protrude out from the
base about 1/4"- 3/8".
2. Lightly hammer the front of the block "T" section to seat the
block into the base.
3. Properly locate the base unit on the drum and tack weld
into position.
4. Check alignment. Finish-weld the base unit to the drum.
The quick-change block can remain in the base or be
removed during the finish weld.

Method 2: Press-Fit
1. Pressing the quick-change block and QC100 base together is the
most precise method of assembly.
2. Secure the base in a pressing fixture that enables 10,000 pounds
of pressure to be applied safely.
3. Press the block into the base using 10,000 pounds of pressure.
4. With the block pressed in the base, the unit can be tack welded to
the drum and then finish welded.

Assembling the Block/Base after Final Welding

Follow Step 1 if the quick-change block is not in the QC100 base .

If the block is in the base, proceed as follows:
1. Hit the block on the front of the " T" section four to five times with
a 4-to-5 pound steel hammer. This will drive the block into the
base to a point where the front of the block protrudes out in front
of the base by about 1/8" to 3/16".  At this point, the two pieces
will be locked together by the tapers.
2. When hit, the block/base unit will start out making a dull "thud"
sound. As they become properly seated, the "ringing" becomes a
high-pitched sound as the block and base lock together.
3. Once the block is seated , install the bolt supplied with the holder
and torque to 60-70 pounds. DO NOT SEAT THE QUICK-CHANGE
4. Operate the machine four to six hours.
5. Check blocks and bolts. Reseal any loose units and re·torque any
loose bolts according to Step 2.
6. Check all block assemblies after 10 to 12 hours of operation . All
units should be tight at this point. If some units are found to be
loose, disassemble, and re-assemble per Step 2, above .
7. Block and base units that have been tightened twice, as noted in
Step 2, are considered locked together by the tapers . They should
remain locked together under normal working conditions. It is
normal for bolts to be loose. Loss of bolts completely from a
properly assembled unit will not be detrimental. The block/base
unit is sufficiently locked together by the tapers.

Changing Worn Blocks
1. To remove a worn block from the base, hit the back of the block
as close as possible to the top of the base with a 4-to 5-pound
hammer. Be careful not to damage the base.
2. Remove the block and clean any debris from the base.
3. Install the new block according to directions in Step 2.

If you have questions about assembling the QC100 base and the
 QC11OHD , contact your Kennametal representative for assistance.