What Was The Likely Reason For Collecting These.

My father was doing a couple of things with his collection that don't make a lot of sense to me. One thing that I don't really understand is why he collected plate blocks from the presidential series. He had dozens (hundreds?) of copies of plate blocks for a few stamps in the presidential series, mostly confined to the three cent Jefferson (807) but he collected others, too.

Why? I would appreciate any thoughts on what he might have been doing. It's possible he just liked the series, and he obviously did, but I would think he had to have some other purpose in mind to purchase so many.

Did your father purchase large lots of stamps to feed his collection(s) and end up with things that he did not necessarily seek but did not want to toss?

No, he would go to shows or stamp shops with specific items in mind. I have his notes for which block numbers he was looking for, but there's no indication why he was interested in them. I was hoping that it was a thing that collectors did years ago and that someone with experience would know what he was getting after. I would guess he was looking for a particular variant, but I wouldn't know what that is.

At the end of the day, I'm just trying to understand his US collection. It wasn't huge, and it certainly wasn't valuable, but he had some interesting stuff.

Was he collecting " round robins " of all plate blocks positions for each plate number of the 3c Jefferson?

Did he have a copy of the Durland Plate Block Number Catalog that lists all plate numbers and positions for most issues?

Had he sorted the blocks by shade?

These are questions that first come to mind.

Another would be did he have access to a large amount of 3c Jefferson sheets for postage during the Prexie period and just kept all the plate blocks out of habit?

Etc.

The focus was probably not shades or varieties of the 3-cent Prexie.
From this statement,


it sounds like he was trying to collect a set of every plate number, and possibly every position.

Here is a snippet of my checklist for the 22-cent Prexie, which used 6 plate numbers (and 4 positions of each) for a total of 24 numbers/positions.


I think the 3-cent Prexie has a total of 356 plate numbers (and 4 positions of each) to form a complete collection.

A typical collector tries to fill his (or her) album with one copy of every stamp pictured. At a certain point, that can get expensive to fill the remaining spaces. Trying to get a complete set of plate numbers and positions of a common stamp can be an equally challenging hunt to fill the missing spaces, and for a lot less money. The Prexies were in active usage for a long time and are a popular set for collectors to specialize in, with many sub-specialties in postal history, cancellations, EFO varieties, plate numbers, etc.

He was doing his "personal challenge"
Very few of us are Bill Gross or Elon Musk or Bill Gates so we try to find a challenge that can be solved with a limited budget.

My challenge is to find all tab marking positions of certain booklet and booklet pane issues. That can be a huge challenge. I just finished a complete collection of Western Samoa booklets - only took me 30 years for the 20 or so booklets that island ever issued. Also I'm trying to get complete plate number sets for the cheapest W/F booklet panes (the cheap ones are cheap because there were so many plates....)

Your father's challenge obviously was a complete set of plate blocks. Given the huge number of plates for that issue, that is no small feat. Cudos to him and he certainly enjoyed filling another empty slot on his voyage.

Thanks for the input. I don't think I will ever know what he was getting at, but Zebraman's suggestion that it was every plate number/position feels likely. I will double check the numbers to see if that explanation makes sense.

He never got back to confirm, but I think ZebraMan nailed it.