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.

For the full line of Ohto Drafting Pencils please visit our friends at JetPens.com.

Ohto Super Promecha PM-1505P 0.5mm Pencil

I have quite a few drafting pencils, including a Ohto Promecha SP-503M 0.3mm, some simple in design, and some a bit more complex in design. But none of them are as complex as the Ohto Super Promecha PM-1505P. Of course none of them have all the features of the PM-1505P either. Ohto pulled out all the stops in the design of this pencil. The result is one of the most unique drafting pencils available.

Where to start, well, I guess I'll start with a few technical details. The PM-1505P is 152mm long from lead sleeve to push button making it the longest pencil in my collection, taking the spot over from my Pentel Graph 1000 PG1003. The grip is a whopping 11mm in diameter, making it the fattest pencil in my collection, taking the crown from my 2 Mitsubishi uni Kuru Toga pencils. The 12 sided body is about 8mm across the widest flats. The balance point is 81mm from the push button, making the pencil bottom heavy, and it weighs 18.5 grams, coming in second heaviest in my collection being beaten out by my other Ohto.

One of the first things that I do when I get a new pen or pencil is to take it apart. Within the first 10 minutes of receiving the Ohto I had it completely stripped to the bare bones. The PM-1505P breaks down into 13 components/systems: The push button/lead grade indicator - the upper tube w/lead grade indications, the outer tube w/lead grade indicator window, and the lower tube which fits onto the lead reservoir; the removable pocket clip and retaining nut; the upper body; the lower body; the end cap; the tension spring; the grip sleeve; the lead sleeve and tension spring; and the integral clutch assembly/lead length adjustment wheel/lead reservoir. This is the greatest number of user removable components of any automatic pencil that I have seen to date, more than twice as many as the average drafting pencil.

While I am the curious type and a tinker by nature I would suggest that the average user do nothing more than adjusting the various user adjustable parts of the pencil. These happen to be the lead grade indicator, the removable pocket clip, the lead length and the lead sleeve length. The lead grade indicator, which is part of the push button, is, to me, a bit more complicated than it has to be. To move the window to the desired lead grade it is best to remove the push button from the pencil. Grasping both knurled nuts in thumb and forefinger of each hand loosen the nuts by twisting them in opposite directions. Set the lead grade by turning it to the desire grade. Hold it and the top nut together while twisting the bottom nut tight again. Replace the push button.

In order to remove the pocket clip first remove the push button. Grasp the nut above the pocket clip and twist it off. Remove the pocket clip them replace the nut. The pencil can now be rotated in the hand while writing without the pocket clip interfering. This is a feature that I like a lot because I tend to rotate the pencil automatically. With some other pencils with non-removable pocket clips the pocket clip tends to rotate into the web of my hand making writing uncomfortable.

Another feature of the Super Promecha that I like very much is the lead length adjustment feature. With my other Ohto, an SP-503M, I have to be satisfied with the length of lead one click produces, or click it a second time and adjust the length of lead by hand. Two clicks produces too much lead and it breaks easily. But a single click's worth of lead is almost too little! I have a habit of pressing the push button on a pencil to produce more lead when the lead has worn down only about 1/4 to 1/3 the way. When I do this with the SP-503M I get too much lead again. With the PM-1505P I can adjust the lead length from0.2mm a click to 2mm a click. I have mine set to produce a fraction more than 0.2mm a click. It takes 3 to 4 clicks to produce enought lead for me to write with. This way when I press the push button while writing I get only about an extra 1/4 or 1/3 the lead I started with. To adjust the lead length turn the wheel inside the window just above the grip. Turning it to the right shortens the lead length, turning it to the left lengthens the lead length.

The lead sleeve length adjustment on this pencil is an improvement on the previous design. On some earlier designs not only was the maximum length of the lead sleeve adjustable by a wheel in the tip of the pencil the lead sleeve was retractable as well. Someone at Promecha must have realized the redundancy in this for now the 2 adjustments are combined into a single adjustment, a much simpler design. The lead sleeve is actually of a fixed design being attached to the hidden inner workings of the pencil. The end cap, which on other pencils has the lead sleeve attached to it, serves as a housing for the fully enclosed fixed sleeve and clutch assembly. The end cap screws into the hollow grip sleeve and is held under tension by a spring inside the grip sleeve. To adjust the length of the lead sleeve, from 0mm to 4mm, simply turn the grip sleeve, which moves up and down along the bottom portion of the pencil. The spring provides enough tension to keep the grip and end cap in place. Other than to hide the lead sleeve for the purpose of carrying the pencil in the breast pocket I can't see much use for the adjusting lead sleeve length. I keep the lead sleeve set at the maximum 4mm length.

The PM-1505P is an attractive pencil being all silver with black lettering and accents. There are four black rubber or plastic rings spaced about 9.5mm apart just above the lead length adjustment area. Other than aesthetics I can see no reason for them. As an aesthetic accent they look nice though. The grip sleeve is finely knurled and non-biting yet it offers a very good gripping surface. All the knurled nuts are coarsely cut so they provide good gripping surfaces as well. On top of the push button is a black sticker with silver lettering indicating the lead size. The lead grade indications are black against a silver background. On in all a very attractive pencil indeed.

The pencil is mostly made of metal. The only major plastic part that I can see is the lead reservoir and there is no real reason for this even being plastic. In some plastic bodied pencils I've found metal lead reservoirs. But it does not detract from the pencils performance. The exterior parts are made of brushed aluminum. The lead sleeve is made from bright stainless steel. The 3-jawed clutch assembly is all brass. Over all, even as complex as the Super Promecha is it is a very well designed and constructed pencil. I am very impressed with the design and over all quality of this amazing pencil.

The pencil writes as well as any high quality automatic pencil should write. There is no wobble of the lead in the lead sleeve, in fact the fit is so exact I half expect to see lead shavings every time I click out more lead. The over sized grip is surprisingly not too fat, for me at least and the finely cut diamond pattern on the grip is not only aesthetically pleasing to the eye but very comfortable to the fingers. Being bottom heavy the pencil rests comfortably in my hand and is easy to direct. The weight feels good, it's a solid feeling reminding you that you have something substantial in your hand, something of quality.

So if you can only afford one new automatic pencil this Christmas or if you want a pencil that's customizable to suit your writing style or if you just want an amazing pencil go to JetPens.com and buy yourself an Ohto Super Promecha PM-1505P today. You deserve it.

Many thanks to Jetpens for providing the pencil for this review.