Lares 330E – JC (Jacobs Chuck)
Repair Procedure
1. Lares 330E –JC Handpiece
2. Lares Disassembly Punch (00024L1)
3. Lares Back Cap Wrench
4. Small Flathead Screwdriver
5. Small Channel Lock Pliers
6. Wire Reamer
7. Push Pin
The Lares 330E – JC is one of the lightest high speed handpieces made. It also has one of the
smallest heads, making it a favorite for pediatric dentists. Unfortunately, this handpiece often
fails prematurely, especially with regards to the front bearing, making it a source of frustration
for both doctors and repair techs, alike. This handpiece can be converted to a pushbutton style
handpiece by simply following the repair procedure for the Lares 557 Turbo – PB (following this
section). The pushbutton back cap does make the head a bit larger, however.
STEP 1
Try to determine the problem before opening the handpiece. Insert a high speed
bur (see Step 2 below), checking that it inserts smoothly and tightens securely.
Twist the bur manually to feel how smoothly it turns. Attach it to your air hose
and run the handpiece (if you can). Check that air pressure is at 38 p.s.i.. Listen
for the appropriate pitch at full speed and for a smooth rundown. Check the water
spray – it should be a fine mist. Attempt to cut a shell to test the torque.
Disassemble the handpiece following the instructions below.
DISASSEMBLY
STEP 2
Most repair techs will not have the original Lares bur tool and therefore, must
improvise, as seen in the photo to the left. Grasp the chuck nut with a pair of
small channel lock pliers. Then, using a small flathead screwdriver, twist in a
counterclockwise direction one or two turns – just enough to loosen the bur and
not remove the nut. To insert a bur, simply reverse the process.
STEP 3
Remove the back cap using the Lares back cap wrench. Unfortunately, these
wrenches are only available to dentists who use this handpiece. Luckily, they
usually have quite a few of them and will share one with you, if you ask nicely.
