Mechanica restoration

Pentel Mechanica 0.3 1st edition, in all its shiny and restored glory:

I bought it relatively cheap some time ago, but when I got it, it was in incredibly poor shape. The clip was bent and glued to the body, the lead hardness selector badly sunburnt (almost white), several deep scratches on the body, among those the name of the previous owner written x3 times, the grip almost wouldnt turn. When I was able to unstuck the clip, a shadow remained where it previously was (almost in the middle of the body).

Let’s see some photos of the disaster

Things I did to restore it

  • Disassemble the grip section, clean it of metal dust, lubricate it with silicone grease
  • Remove the clip, straighten it, remove the glue with peg wood + acetone
  • Resurface the body, 800-1200-1500-2000-Polywatch-Copy paper
  • Polish the lead hardness selector with polywatch

Now, the grip is smooth, the plastic looks almost good as new and the heavy discoloration on the hardness selector is gone. It’s not bright orange, but it became a very nice and uniform peach color. Thankfully the white color was very superficial. After refinishing the body, it’s mostly shiny, but slightly matte in some places. I’ve done that grit progression on other plastics and it was enough (you can usually skip grits on plastic and it will look fine, unlike metal) but I guess I should have spent more time on the 1500 and 2000 steps.

The thing I’m the happiest about is that I could remove the scratches without losing the faceted body, I took great care on only sanding one face at a time and sanding all of them equally. That, and how the lead selector turned out. I don’t mind the discoloration, but I hated it being uneven. I would even say that I prefer this pastel peach to the bright orange.

The plating coming off on the middle ring is something I don’t mind at all. To me, that’s like the true proof that it’s a 1st edition mechanica. Honestly, 1st edition mechanicas with a shiny middle ring have either been conserved in a medical grade vacuum chamber, never touched by a human being or are frankenpencils.


Beautiful work! Real passion for saving this mechanical pencil. It’s shocking how such a wonderful instrument can end up so horribly abused by a previous owner. I just don’t understand the lack of reverence.

It looks great now. Do you intend to make regular use of it?


Thank you! This one was from a former Japanese civil engineer, I guess it was just thrown in a pen case for many years and then stored in a basement until his son sold it.
I do intend to use it! Actually I use all of my most expensive pencils. That’s one of the reasons why I like buying them with a few scratches. This one had too many scratches for my liking though haha. My H3003 was almost NOS except for a faded sticker and it took me a few months until I got comfortable with the idea of using it.


Well as the saying goes, “Life is short. You never know how long it’s going to last!”

My general approach has been to collect vintage mechanical pencils that interest me, but those that I really like and would wish to use, I buy a backup… and then use the one that has most signs of use. I’m good about babying and protecting them. But I kind of did learn my lesson about traveling around… I had a discontinued ZEBRA Sharbo X multipen attached by an elastic loop to a notepad. I thought it was totally secure… but somehow it wasn’t fool proof. The pen fell off at some point. Never recovered it. So I tend to keep all of my vintage, discontinued writing instruments at home. Only on occasion, I’ll take one with me and use a dedicated case with padding. I used to take my “lesser” 0.3 Mechanica with me on some trips (very minor signs of use, and case is missing cardboard support & papers), but after prices have gone so high up these days I stopped. I’ve got an H-2003 that’s pretty well worn, with some metal pitting to the finish. I think I paid ¥7000 for it. So I do sometimes take that one traveling. Meanwhile, there was one in even worse condition that just sold for ¥9505 (ヤフオク! - PILOT パイロット HOLDER ホルダー 0.3 ダブルノ...).

A first edition Mechanica is rare, but given the flaws it still has, really no reason why you shouldn’t use it and enjoy it. There’s something so satisfying about using that huge steel protection tube. It’s kind of magical the way it just slides back inside, then mates with the tip to form a collar that looks naturally permanent.


Yes, when I say that I use them I mean on a desk! Using a $200+ vintage pencil as an EDC is a bit too much for my heart to handle. I have plenty of cool pencils that I can easily replace if I lose them :smile:

Speaking of the H-2003, I have one for which I paid ¥2500 last year (yes there is no typo on that price) but there is a crack on the plastic and can’t be used + the owner’s name is very deeply engraved. I plan on restoring that one as well, but it’s a much more difficult project. My idea is to slightly widen the crack with sandpaper, fill that and the engraved name with black epoxy resin, and then resurface it like I did with this mechanica.


About the damaged H-2003… I have to wonder if you could utilize the barrel from a used H-1003. If not, the repair plan you have sounds sensible.

EDIT: Oops. No, I’m sorry. I was wrong. I just compared the two… and they’re not compatible. Bummer.


Yeah, it seems your best bet is to attempt the repair. Keep in mind this plastic is a bit fragile… although not as bad as the 2nd release of the H-1003. Unfortunately the H-1003 has a different barrel and is not compatible. The difference is in the rear.


Thanks for checking! Yes, I will try to just restore it at some point. I need to get some good epoxy resin first.

I went through the 1500, 2000 and polish grits again spending way more time on each and the result went from 50% shiny to 95% shiny. It was bothering me a lot before but I think I am happy with the result now.

Sparkle sparkle :sparkles:


Awesome job! I’ve restored a couple of plastic barrels like this and sanded down just like you but the last two steps were x20, and interestingly, Fleetwax for fiberglass boats.


Thank you!
I’m not familiar with x20, I tried searching it and I found some foam pads.
What’s your recommendation for removing the matte parts? With my process I could make shiny only some parts of the body. Also, it’s a fingerprint magnet now, which I guess also has to do with the fact that I need a few more high grits to properly polish it.


Ack sorry. Typo. I meant X2.0. Meguiars Scratch x2.0. It’s made for automobiles but it work’s fantastic on plastic.

I also use the heck out of micro-mesh pads. I get mine from the company I use for guitar parts but you can get them from plenty of other places. The pads go up to 12000 grit.


I’ve also got some micromesh pads… although they’re a bit worn down and I’m probably going to pick up some more. Amazon has some for a good price. I’ve got a plastic polish kit that comes with 3 grades: 3 (moderate), 2 (fine), and 1 (polish). It’s very forgiving. I used some recently to remove painted lettering on a massage pen (it’s a cool looking thing, but the lettering looked silly, so I buffed it out). Looks like it came that way. I’ve been meaning to use it on my user Mechanica to see if it’ll remove the fine patina, built up from the previous owner.

I also have some diamond paste, 2 grades (can’t remember the rating off hand right now). I got it for sharpening electric razor heads. I’ve not yet tried it on plastic, though. I am expecting it may be a little more abrasive than the plastic polish kit. Have you used diamond paste at all?

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I don’t use the diamond paste that comes in the syringes in particular but we use a polishing compound called white diamond as one of the last steps when we make jewelry. It’s pretty much the same in that it has crushed diamonds in it as the abrasive. Final step in polishing gold or silver is red rouge which uses ferric acid as the abrasive which is close to 100,000 grit. (I know we’re mostly talking about polishing plastic in this thread. Sorry)


Don’t worry about talking about metal polishing as well! I love restoring things and I am very interested in learning how to polish metal and how to redo plating sometime.

But on the topic of plastic polishing, what’s your usual grit progression? although I was able to get a better finish on this body after spending more time on the 1500 and 2000 grits, I can’t seem to be able to leave it completely shiny, and I wonder if it’s because I should have gone through more grits in between (e.g. a 1000 grit one, but I think that’s unlikely since there are no visible scratches, just a slight matte feel) or I just need some of those micromesh pads.

About amazon products, I’ve seen some sandpaper going up to 10000 grit but I feel like it either can’t work or it’s higher grit than advertised. I have never seen sandpaper of finer grit than 2000 sold in brick and mortar stores so to me it smells like Chinese marketing.


Wow! What an amazing job. It would be nice to have some videos of the whole process.


Hi, thanks for the nice comment! I actually thought about it, but in the end taking a good video is also a lot of time and effort and opted not to.
For the H-2003 with a cracked body, I may make a video. It’s also much more appealing for the H-2003. This one went from dirty to shiny, but it could be used from the beginning, there was nothing really broken. The H-2003 is dirty AND unusable, so it feels more like a restoration.


I’m looking on Amazon for some micro-mesh and see a lot of options. Can you recommend what would be best for small scratches, etc.?

There’s a square foam pad set (30 pads) you can get for around $12 USD (LINK). It ranges from 320 to 12000 grit. There’s another set that uses different colors for the grit rating, which is nice, but you get only 9 compared to the 30 of the other, its lowest grit is 1500, and it’s more expensive at $17.

For scratches beyond just surface, I usually start with 3000 on plastic/resin and 1000 on brushed steel. YMMV. If you’ve got brushed steel with a patina you want to hide, you can experiment with a few grades to get the brush detail you want.