Clearing A Lead Jam From An Ohto Super Promecha PM-1503P Drafting Pencil

The Ohto Super Promecha PM-1503P Automatic Drafting pencil is what appears to me to be a 3rd generation Super Promecha. It's by far the best looking and the best designed of the series. The 2 predecessors that I'm aware of, the PM-1000S and the PM-1500S (see fig. 2) both have the unique feature of being able to set the maximum lead sleeve exposure length via a spring loaded threaded adjustment tubular wheel in the end cap of the pencil.

The PM-1500P Series lacks this feature and for a good reason. It was redundant (and probably costly to make) so it was unnecessary. The threaded tube sets the maximum length of the lead sleeve that is exposed when the lead sleeve is exposed regardless. The lead sleeve is exposed or hidden by turning the grip. With the grip all the up the lead sleeve is fully exposed, within the limits set by the adjustment in the end cap. With the grip all the way down the lead sleeve is completely hidden. But the grip can stop and expose only a portion of the lead sleeve any where along it's length of travel. Starting to get the picture? There were 2 devises that could do the same job, but in slightly different ways, so why keep both? So the lead sleeve length adjustment in the pencils end cap was finally drooped on the current model. So while this article focuses on the current model Super Promecha, it can easily be applied to the other 2 models with a slight variation.

Lead jams are not as common as they once were. This is due in part to better quality pencils as well as better quality lead. They also occur more readily in the smaller diameter lead sizes, mainly the 0.3 mm size. Despite this some pencil manufacturers have decided to leave clean out rods out out their pencils. Ohto is not one of them. So if you do experience a lead jam and have to clear the lead sleeve you'll have the proper tool to do the job. When lead jams do occur they can stop up a pencil instantly and the only thing that will get it working again is to clear the jam.

To clear a lead jam from the PM-1503S (and any other 1500S series pencil) follow these simple instructions. First remove the push button to expose the eraser. Remove the eraser and beneath it will be a very small diameter length of wire called a clean out rod. Keep the eraser and clean out rod out but replace the push button before proceeding or else you'll dump the lead from the pencil! Next rotate the grip counter clockwise, lowering the grip and hiding the lead sleeve (see fig. 2).

Once the grip is all the way down, remove the end cap. Be very careful
at this point as the end cap is under spring tension from a large spring housed inside the grip. This spring is what allows the grip to stop at any point in its length of travel and maintain its position. To remove the end cap tightly grasp the grip in one hand while grasping the end cap in the other and twist the end cap counter clockwise to unscrew it from the grip. Make sure that you do not lose the grip spring (see fig. 3)! The grip spring may stay in the grip or come out with the end cap, either way remove it and secure it and the end cap somewhere safe for a short period (see fig. 3A).




The lead sleeve is now partially exposed . To fully expose the lead sleeve reverse the direction of the grip, stopping just short of fully removing it from the threads (see fig. 4).

Now you are ready to remove the lead sleeve. Be careful here as well as the lead sleeve is also under tension by a small spring that sets tension for the tubular wheel that sets the max. length of lead exposed per click. To remove the lead sleeve, which is polished stainless steel, you may need something to give you added grip, such as a rubber jar lid opener, as the lead sleeve is on extremely tight. Grasp the body tube with one had, right where the rubber "O" rings are positioned (I used to think that these rubber "O" rings were purely decoration, but I've since learned that they serve a purpose. They are the grip used to help the user remove the lead sleeve). While grasping the lead sleeve in the other hand turn it counter clockwise to remove it (see fig. 5). Once the lead sleeve is free of the pencil, remove the spring and secure both in a safe place (see fig. 5A).


At this stage any further handling of the pencil proper will probably cause changes in the setting for the max. lead length per click as the tension has been removed from the tubular wheel that controls the setting. Secure the rest of the pencil in a safe place.

Next, take the lead sleeve and place it large end down on a hard surface like a desk or counter top. Hold it there with one hand and while using the eraser as a handle, insert the clean out rod into the mouth of the lead sleeve with the other hand and push down. You should feel some resistance as the clean out rod encounters the lead jam. Push past this resistance, it shouldn't take much force at all to clear the lead jam. When pulling the clean out rod out of the lead sleeve you should feel the resistance of the rubber lead retainer on the clean out rod suddenly give way. That's fine and should be expected. If you feel no resistance at all while removing the clean out rod then check the debris under the lead sleeve for a small black "top hat" looking device. Without the lead retainer the pencil will not work.

Should you find that the unlikely has happened and the lead retainer has become dislodged, click on this link to find out how to replace it.

Should all go well, and it should, retrieve all the pencil parts and reassemble the pencil simply by reversing the steps for disassembly. Once assembled the pencil should now be in working order. You may have to reset the amount of lead exposed per click as the disassembly and reassembly procedures may have disturbed this setting.

For the 2 older models that I have mentioned in this article the procedure will be very much the same with the following exceptions: There is a tubular wheel that controls the max. length lead sleeve espouser in the end cap of the 2 pencils along with a spring, visible through the opening in the end cap. Use caution when removing the end cap as the spring in the end cap slides inside the spring that is inside the grip. The 2 springs can become entangled, pulling the smaller spring from the end cap. It could therefore get lost causing the lead sleeve espouser function to become non functional. This part of the pencil will not work without the spring; The lead sleeve is not under spring tension as in the newest model and does not have as wide a base. Take extra care when pushing the clean out rod into the mouth of the lead sleeve as the lead sleeve can easily move and the thin wire of the clean out rod easily punctures skin.

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