Looking for information on Pentel PMG manufactured between 1972–1975

[Jose]

Hello everyone,

I’m writing this post to gather more information about Pentel PMG mechanical pencils manufactured between 1972 and 1975.

Below is the information I’ve personally confirmed through my own collecting experience.

Characteristics of 1971 PMG:

•Double-thread mechanism

•Uppercase logo on the barrel

•A clip engraved with a lowercase logo

•Aluminum lead hardness indicator ring

•No sticker, or pre-JIS sticker

Characteristics of 1976–1979 PMG:

•Single-thread mechanism

•Lowercase logo on the barrel

•A clip engraved with a lowercase logo

•Plastic lead hardness indicator ring

•JIS inverted triangle sticker

If anyone has Pentel catalogs from 1972 to 1975, or owns PMG models from this period with identifiable details, I would greatly appreciate any information or documentation you could share.

Thank you very much in advance!

[nimrodd]

Are you talking about this pencil? This is from the current Pentel Pencil Book.

[DarkwingDuck]

[griffisu]

The two mechanisms from the side looks very similar to PG2003’s mechanism Pentel Accugraph difference between versions - #15 by griffisu , I’d guess they are the same, but I don’t own any PMG to compare.

[DarkwingDuck]

[Jose]

Left: manufactured in 1970,

right: manufactured in 1971.

The parts of the product on the right are identical to those shown in the photos posted by nimrodd.

[Jose]

Thank you, I’ve read the file.

Through multiple cross-checks, I’m confident that the product shown in the photos posted by nimrodd is from 1971.

What I’m trying to clarify is whether the PMG mechanism was changed to use the same mechanism as the PG5 starting in 1972.

In the photos I posted, the pen on the right still has a pre-JIS sticker, yet it uses the same double-helix mechanism found in PMGs from 1970–1971.

If the PMG had switched to the same mechanism as the PG5 in 1972, we should expect to find at least one PMG with both a pre-JIS sticker and the same mechanism as the PG5. However, I haven’t been able to find any confirmed examples so far.

This leads me to suspect that the PMG may not have adopted the same mechanism as the PG5 until around 1976, rather than in 1972.

For this reason, I was hoping to find information or catalogs related to PMGs manufactured between 1972 and 1975

[Jose]

Thank you for the photos.

I believe the product on the left in the first photo (the PMG with the JIS sticker) was manufactured sometime between 1976 and 1978 or 1979.

[DarkwingDuck]

On the left has a 77 date code, the other two didn’t have codes.

[Jose]

the PMG in the center of the first photo appears to have been manufactured in 1970, but its material seems to be slightly different from the GRAPH PENCIL 3rd generation that I own.

[nimrodd]

One way to tell if it is 1972 to 1975 is if the inner reservoir does not have a Date Code. Pentel received their JIS Permit number in 1975 and had to start date stamping their pencils. The first date codes I have found are from December 1975 (751200).

I have 8 PMG pencils at home and I will look at them to see what I can find.

[DarkwingDuck]

Here I thought I was cooking with 3…. 8 is madness!!!

[nimrodd]

Most were in with a lot of other pencils.

[Jose]

Among PMGs marked with “m/m”, if no date code is present, it may be reasonable to consider them as having been manufactured between 1972 to 1975

(provided that a sufficient number of such examples can be confirmed).

[Jose]

I’ve found a PMG that appears to have been manufactured between 1972 and 1975.

[Jose]

It is estimated that the PMG used the same mechanism from 1970 to 1975.

[Jose]

Based on this photo, I had thought that the mechanism changed in 1972 when the lineup shifted from GRAPH-II to the PG5…

But seeing the changes in the PMG has made things confusing..

[nimrodd]

I sat down tonight to analyze my 8 PMG pencils. Four of these are in my current Collection, two are in a couple of PMDS-4 Designer System IV sets (set of PMG, PG4, PG5, PG7 & Leads) and 2 are extras with problems.

Pentel PMG Generations.pdf (50.9 KB)

It looks like there are 2 Versions and 2 Generations in each
Version 1 - Connector is part of body and reservoir screws in from the front
Gen 1 - Original clip with PENTEL running down the front. The lead hardness ring has 2H/H/HB covering half the ring. Cleanout pin on plunger is straight.
Gen 2 - Modern clip with Pentel on ring around body. The lead hardness ring has 2H/H/HB spaced around the ring. Cleanout pin on plunger has dip for friction fit.

Version 2 - Connector screws into body and reservoir drops in from the back, Modern clip, Cleanout pin on plunger has dip for friction fit.
Gen 1 - Connector 2 End piece is M5.5-0.5 thread. Unknown lead hardness sticker.
Gen 2 - Connector 2 End piece is M6.0-0.75 thread. Lead hardness sticker has 2H/H/HB/B spaced around sticker.

[Jose]

Thank you for checking.

The PMG shown in the photo with the two stickers is also a Version 1, Gen2 model.

In your opinion, until what year do you think these models were produced?

[nimrodd]

One additional piece of information. What holds the inner reservoir in place (keeps it from spinning when putting on the tip).
Version 1 - Obviously, the larger thread is what holds it in place.
Version 2, Gen 1 - The reservoir drops into a 6-sided slot at the tip end of the body.
Version 2, Gen 2 - The reservoir drops into a 12-pointed slot at the tip end of the body.

@Jose Now to your question. I don’t know that there is a way to tell how long the Version 1 PMG was being produced, as there are no dates to help us with that. At this time, you find that ones with the Pre-JIS Triangular (PJT) sticker all appear to be Version 1. Unless we find some with the PJT sticker that are Version 2, we cannot say for sure that all with that sticker are not Version 1.

But, as I listed in my PDF above, the Version 2, Gen 1 PMG that I have does not have a date code, so it is possible that it could be from that era.

So, really there is not a sure-fire way to set an ending date for the Version 1 PMG.