That’s totally OK.
For a “d” that ellicits howls in an otherwise mainstream design, see Perpetua.

hhp

Eric Gill had a thing about “d” and not only in Perpetua
Gill Sans “d” (but not on all weights)
Joanna “d”

Yes, I’m old, but I’m d-lightful!

Of course old Eric didn’t draw all of the Gill Sanses — some were done by anonymous draughtsmen at Monotype. Maybe that d-feature is the clue to which are Eric’s and which are not… : )

Exellent point, Bert!

Maybe Typophile can start a new topic area— “CSI:Type”

Not OK to my eyes. On the d, the bottom serif balances the top one, which is prominent in old syle or transition fonts—which yours seems to be. In the ‘a’ you don’t have a serif above it on the same stem, so the design problem is different. Putting the a tail on the d looks weak to me.

All depends on how the whole face is done, so it might end up looking good in context, but not right now side by side.

NO! YOU’RE DOING IT WRONG! ; D

You can draw a single letter any way you want. If you’re drawing a logo for a product or making a sign, each letter can be its own little gem. No rules. But, it sounds like you want to build a typeface. Typefaces are systems of interchangeable parts that repeat and have to function in any combination, giving a consistent pattern. There’s room for expressiveness, but it has to be distributed and balanced across all the components (letters).

In my opinion, Eric Gill never really understood this functional difference; he was a lettercarver till the end.

Try setting a few words where the shape repeats: hidden, padding. Then some where the d is paired with similar shapes: armada, audacious. Is your u going to use that tail too? Set words that combine the d with anything else, v, s, t, b, m, n, o. You might want to spend some time drawing the “boring” letters like d, r, i, n, that make up a significant proportion of printed text. If your types have several strong letters and several weak ones, that doesn’t help the typeface, or the reader. You’ll want to have the same confidence in drawing s or j that you have drawing an a. Even a lettering artist needs that skill. Type designers these days are called upon to not only deliver these alphabets but ones from other scripts like Cyrillic and Hebrew.

Look at Jeremy Tankard’s Enigma. In it there are a lot of unconvential shapes, yet he makes them work. It’s not impossible, but it does require a lot of attention to consistency and harmony among the different parts. It’s type, not lettering. Same with Goudy’s Californian. It works.

Please share more of your alphabet when you get it digitized, Will.