thanks - I’ll keep looking.
I have seen this model (great condition with sticker) go for 4000-5000 yen on Yahoo Japan, which I regret not buying. Unless that “Piston Sharp Ohto” Label is worth almost 10000 yen, I would avoid this.
3 Likes
Thank you -
I’ve got it and it’s nothing to write home about. I don’t understand the blue detail either, it makes it look like a ballpoint.
From the piston sharps, my favourite is the 1000 yen model by far. The half knock/full knock inscription near the cap looks amazing.
4 Likes
Since this post was made I have picked up two SP-10s, both of which do not retract the lead. They advance the lead perfectly, just no retraction. I ended up with the first one from Buyee (said NOS) but since we have no recourse in matters like this, I just chalked it up to a minor loss for the home team. I tried a few months later with a different vendor – same situation (said NOS) and that’s how I got my second busted POS SP-10.
Has anyone here had this problem with piston pencils not retracting and were you able to correct it?
I have dissembled and cleaned it but can’t seem to find the cause of the problem – mostly because it is a sealed unit.
I’d really like to add a (working) SP-10 to my collection. The good news is that these busted ones may be getting bifurcated on my bandsaw – just to see what’s on the inside. I need to get a better blade though – the one I have now is for resawing wood and would just tear the pencil to shreds.
I’ve not had this problem on the SP-10. But I did have it with the SP-20. And it was also a fairly recent purchase. The source problem was those massive OHTO lots we saw running on YAJ for quite a few months. The lots were deceptive. The problems weren’t just cosmetic wear with some models. Many of them had functional problems. My favorite is the SP-15 and I bought one of those lots. Half of them were junk. Either the mechanism didn’t work at all, or the retraction didn’t function.
Unfortunately, a few buyers who scooped up those lots have been reselling. And you can tell, because some of them have cosmetic challenges that were present in those lots. Elton is one of those sellers…
The real problem with OHTO in the piston series, at least with SP-15 and up, is that they can’t be fully disassembled. My guess is the piston function is delicate, with a linkage to the clip status window (blue/red indicator) so OHTO totally sealed it up. I can’t recall if the SP-10 has that same issue. How far can you disassemble it? Since there’s no status window in the clip, I’m thinking it might be fully disassembled.
1 Like
Have any other manufacturers produced a piston pencil?
Did OHTO manufacturer these?
You have to click twice to retract, it’s a “triple-clicker”
1 slow click the lead comes out
2 fast clicks the lead goes back in
edit: or something like that, I don’t have any with me to check it.
1 Like
Thanks - i’ll try that tonight. I also have a ¥2,000 model that will push the lead out, but once you retract it (it does retract as expected) the pencil will no longer push the lead out when knocked (the half-knock).
Not sure, is that like the black one here? I’ve only had these two
I can’t recall if you push once normally with a slow knock to get the lead out and retract with 2 fast clicks or the other way around. But at least in these two models it’s all in the way you click.
1 Like
its the black one
1 Like
Long press to retract, apparently
4 Likes
Can confirm that. I got a basic Ohto SP-5 from @Kiwi-d a while ago, the mechanism is pretty unusual but it works like a charm — unless I feed an insane amount of lead, as in that case the “long press” becomes unable to “eat back” all the lead protruded.
By the way, the diameter-to-length ratio of the barrel turns out to be just perfect for my hand; never felt this sensation with other MP’s, it’s just the spot-on amount of bulkiness and slimness. Pity is, the pocket clip is soldered to the rear cap, which I find terribly annoying while I rotate the barrel in my hand, but perhaps I can de-solder it and have one of the best pencils possible for my collection. 
2 Likes
Always considered that at least weight and diameter should be in play with the lead size. I think one the nicest ones in that department is the Pentel PMG, it’s quite perfect in terms of lead size, weight, dimensions, features, it’s all tuned up. Dangerous line of thought, though, because it can lead us to conclude that the nicest Staedtler 95 is the 09mm, not the others 
Or that the Promecha 1500 07 is the nicest to use, eh
1 Like
‘Millennium Reverse’ from Korea also has a ‘piston’ mechanism. They had all sorts of whacky colors, like pink camo etc. I only got the translucent blue and black versions. I think the brand is called ‘Minion’.
https://x.com/drifand/status/879874700804882433?s=46&t=OplFvNWwNQDS4Ixwdp9hQw
4 Likes
Thanks - I need to find one of these!
1 Like
I see some on Taobao though I don’t know if they ship to the states
2 Likes
Aside from the notorious nose cone cracking/splitting on the SP-5, another model that’s a real problem is the SP-20. At first it looks like it’s a gloss black plastic body, but it’s actually a thin metal with black enamel coating. The problem is the metal is too thin for the stresses. The outer body tube is friction fit, instead of screwed in. They often tend to end up cracking. When that Yahoo Auctions Japan account was selling huge lots of these pencils, you could see many of them had cracks upon close examination of the photos (some were high resolution enough to see good details). Of course, the seller also reused photos, so lots weren’t representative of what was shown.
I had waited a bit for someone to list one of these in good condition. And unfortunately I got burned. The seller had taken photos with the crack out of view. So I thought I was getting one in pristine shape. In any case, the fact that many unused examples have turned up with cracks, I’m suspecting that even if you get a mint one, eventually the metal is going to crack. It might even happen just from temperature swings.
The SP-30 is the most attractive model. I’m a sucker for brushed steel with etched black stripes. It’s nicely done here. Still, I think my favorite of the bunch is the SP-15. The grip is unusual. It’s multi-layered. And the clear polymer/silicone outer covering is very resilient. I’ve not seen any degrade and become sticky, even after all of these years. It also has a matching ballpoint, which is nice to have.
4 Likes
I have an SP-10 with a steel nose cone. Have there been different variants or has someone replaced the original cone with the one from the SP-15?
By the way, my both SP-5 have a cracked nose cone 
1 Like
Mine do too 
. If anyone has any spare SP-10’s or SP-10 parts, that would be cool.