Building rear half of Raptar 51mm (2.04") f/1.5 taking lens?

Picked up for dirt cheap the front element section of the lens in the title. Unfortunately, no shutter/aperture housing and no rear elements.

I've been unable to find nearly any info, never mind a lens schematic or anything near that.

For starters I'll take the front half out of a Canon FL 50/1.8 and see what happens with this Raptar slid into place.

To be clear, I have the front half and would ultimately like to build out a rear half as close to original spec as possible, then mount it into a focusing body/mount that will allow infinity or at least portrait length focus on a 35mm SLR / RF (especially RF as I could then experiment with RF calibration).

Any and all thoughts are welcome as this is entirely new territory for me.

From A Lens Collectors Vade Mecium:
Cine Lenses for 16mm. The following are from many sources, including a Burke & James catalogue.
High Speed Cine Raptar f1.5 12.7, 25, 40, 51mm,

No lens diagram mentioned. An earlier 50mm f1.9 cine raptar is listed as a 6g/4c Guass from around 1947.
Raptar is a trade name of Wollensak.

Maybe these would help;
http://www.surplusshed.com/pages/item/w1005.html
(scanned copy of 600 different Wollensak optical drawings)
Or
http://www.surplusshed.com/pages/item/l3257.html
(Wollensak 50.6 mm micro Raptar)

There's a complete lens on offer now. http://www.ebay.com/itm/Wollensak-2-04-51mm-f-1-5-Raptar-7-Smooth-Mount-Lens-/322066819990

Not as inexpensive as you'd like but probably less expensive than a DIY rear cell and a much better lens than your front cell plus a DIY rear cell.

A complete 50 mm +/- f/1.5 Sonnar or a Soviet equivalent is probably a better bet. Already in focusing mount, ...

Thanks, all. That complete lens Dan linked to is what I believe this front half came from but I don't need the complete lens *that* badly at $1300 with 2 days left.

Will update if/when I make any progress on it.

Quick update, I tried this front half of a lens on the rear half of a Biotar that I have opened up for aperture blade repair. Used blue painter's tape to secure the halves together.

Results: quite soft but almost usable or great for pictorial type of effect. Wacky/odd bokeh but that was expected. I used a non-film camera for testing so I can't share results here but I think I will run some b&w through a Spotmatic with this combo hanging off the front just for kicks.