Sunday, October 31, 2010

Model 18 Gear Replacement Instructions

Notice: These directions are for a Model 18 sharpener. Models 19 and 17 are generally replaced the same way - directions for those models will be added too so that the specifics and photos match and cover anything that is different on those types of sharpeners. You can click on any of these photos for a close-up. At any time when you are handling the blade assembly, take measures to protect your hands! (guideline suggestions for this are in step 5)

Step 1 - Set up the sharpener as you would when it is ready to use. Tip it slightly forward and tap on the top of the sharpener a few times. This is to shake pencil shaving into the bin. Remove and dump the bin. Unplug the sharpener (safety first!) and turn it over as shown in the picture. Remove the 3 screws from bottom of the case. Yay! somebody already did this one for me! (heh..ok..that was lame)

Step 2- Remove the bottom cover from the case and put it somewhere safely out of the way. Put the mounting screws in this cover (turn it up with the feet down and use it like a holding tray). If you replaced the shavings bin (as shown in the picture), remove it and set it aside until after the repair is complete. Make sure you keep the screws separate from the housing cover screws (will be removed later). Putting the wrong screws in the wrong place can lead to a loose fit and your sharpner may buck and kick instead of running smoothly.

Step 3 - Lift the sharpener assembly out of the case. The center plate holds the motor on one side (right in figure shown) and the sharpening blade and housing on the other side (shown at left). For this repair, you will NOT be removing or loosening anything from motor assembly.

Step 4 - Remove the screws shown and set them aside so they will not be exchanged with the screws that hold the case cover. Pull the blade housing gently back and let it lay to the side while you swap (or install) the replacement gear.

Step 5 - Here is a front view of the blade housing removed and set t0 the side, wires still connected. In view are the blade assembly and a blade assembly guide. This guide has gear teeth that match the a gear that is part of the sharpening blade assembly.

In this side view, you see the blade gear, the blade assembly guide, and the blade assembly. Again, if you are replacing a gear that has completely broken, you may be removing pieces from inside the case rather than just swapping the gear.

Using a cloth or thick wrapping of paper towel or a work glove (make sure you do something to protect your hand from getting cut by the blade), get a grip on the blade assembly and pull it back to remove it from the sharpener. It may take some force to do this if there is still a gear or portion of the gear intact.

Notice that the shaft on the blade assembly has some flat side sections on it near the end. If you examine the shaft-mount on the gear, you will see that it also has flat portions in the end face that match up with the shaft . This locks the shaft in and keeps it from free-spinning so the gear will drive the blade assembly when it is turned by the motors main drive that engages to this gear.

Step 6 - Do a test fit of the blade assembly to the gear. This step does not take long and will familiarize you with what it takes to get a proper fit and aligment of the parts when they are replaced into the sharpener.

Step 7 - if the blade assembly guide came out when you removed the blade assembly, mount it back to the plate. Notice the proper direction and flush fit to the center plate as shown in the figure.

Step 8 - work the blade assembly shaft partially back into the guide and through the hole in the center plate. Place the replacement gear with it's collar section and shaft mount facing the center plate. Turn the blade assembly and match it up to the shaft mount in the gear's collar, then snap it fully into place. This should align the gear so it meshes with the small drive gear on the motor.

Step 9 - Replace the blade assembly cover back over the blade assembly. Fasten it back to the center plate with the mounting screws. Re-assemble the sharpener by working your way backwards through steps 3, 2, 1 and you should have lift-off!


  1. Do you have a replacement blade gear for the Boston model 18 sharpener?

  2. I am also looking to procure a gear for a Boston Model 18.

  3. I'm looking for the large gear for my Model 18... please email me:
    pmturso (*at*)


  4. Are you still selling these Large Drive Gears?

  5. Wow! I almost couldn't believe it when I saw you had fabricated a replacement gear! Love my old model 18, would love to get it working again. I see you're not currently selling on eBay. Will there be another lot? Feel free to email me: heartquest (+at+)

  6. I am looking for the replacement drive gear for the Model 19. I should have purchased a couple weeks ago but got sidetracked. Now I am not seeing any. Can you help me?

  7. Looking for the gear for the Model 18

  8. How do I know what model I have? my gear has 70 teeth and is about 2.125" diameter (to outer edge of teeth). Thx.

  9. Regarding my previous comment, it looks like I have the Model 18. Any gears left? If so, please email me at (at) gmail (dot) com. or let me know if you will be placing any on ebay.


  10. I'm looking for the drive gear for the boston model 18. Can you tell me where they can be found