Carborundum Wheels

Is your dental lab staff taking care of the carborundum model trimmer wheels?

Nov. 6, 2014
Dental lab technician Craig Pickett offers steps to help your carborundum model trimmer wheels last much longer. A few steps of proper care are all that are needed.

Carborundum model trimmer wheels are the most economical and overlooked pieces of equipment in the laboratory setting. They are literally “ridden hard and put away wet.” To help you get the most life from your wheel, it’s wise to incorporate the following practices into your laboratory.

1. Clean the wheel – Buildup of ground gypsum on the wheel face is the single most contributing factor to poor performance in cutting. Remember that wet ground gypsum is a very sticky substance, and it will return to a hardened state as the gypsum crystals re-form from the “slurry” state the user created. Make sure that the wheel is wet before beginning to grind, and then flush the wheel with water after each use. Do not just turn off the machine. You can clean the face of the wheel on a regular basis using Simple Green soap and a stiff brush to remove gypsum buildup in the pores of the wheel.

2. Don’t grind in the same spot – Consistent grinding in the same spot on the wheel wears away the carborundum and thins the wheel. Vary the place you grind across the available face of the wheel to create even wear and longer life.

3. Take the wheel off – On a regular basis, undo the holding device on the wheel and clean it to make sure that the slurry particles do not enter threads or holders, and lock them into place. If you wait until it’s time to replace the wheel, you may not be able to remove it without damaging the holding device.

4. Clean behind the wheel – Most trimmers have a “backing plate” that the carborundum wheel lays against. This backing plate can collect the slurry from the grinding process and layer it out on the backing plate like silt. This will throw off the balance of the machine and cause uneven and faster wear to the carborundum surface. Access to the reverse side of the backing plate is limited, and the plate should not be removed from the motor shaft as these are balanced at the factory. Use a long spatula and simply scrape any silting material from the plate.

5. Doing a quick flush – You can flush out sediment from the wheel and machine by leaving the motor running and the water on. Then lift the sink end of the drain hose above the height of the water inlet tube. The trimmer will begin to fill with water and slosh around the inside of the trimmer. When the water starts to splash out the front of the machine, lower the waste tube back into the sink. Loose waste material will run out of the machine and into your trap. Do this on a regular basis and the silt will not form as quickly.

6. Don’t reverse the wheel – Many practices and labs flip the wheel over to “get more use” from the wheel. This practice can lead to disaster. Wheels become thinner in the area where they are consistently used. When you “flip” the wheel you begin to use the same corresponding area on the opposite side, creating an overly thin area as compared to the outer edge of the wheel. The outer edge is thicker and larger in circumference than the now thinner inside portion of the wheel. The outer edge lags behind the inner portion on startup, causing the wheel to flex in the

thin area and fracture or explode while rotating. This is potentially a very dangerous situation. Carborundum wheels are inexpensive compared to length of use or injured staff. Just replace it when it loses its cut.

7. Purchase wheels designed for your machine – There are plenty of deals out there on all kinds of wheels. Make sure that you’re getting a wheel that was designed for use on your machine. These are the wheels that were tested for life and function with your machine and will give you the best performance for your dollars.

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Craig A. Pickett, AA, RG, CDT, TE, NBC certified in crown and bridge with technologist designation, is the Dental Technical Support Manager at Whip Mix Corporation. Before joining Whip Mix he managed in large and small crown and bridge /ceramic laboratories, owned Pickett Fabrication in California, and represented J.F. Jelenko & Co., Whaledent, and Dentsply as a Technical Sales Rep. As a 30-year CDT with over 35 years of C&B, ceramics, and industry experience, Pickett now assists in developing and evaluating new products, and represents Whip Mix by presenting technical clinics in the U.S. and internationally. He is the recipient of the 2014 NADL Excellence in Education Award. Learn more about Mr. Pickett on LinkedIn.