Conversion of a
Vintage Polaroid
Models • 95 • 150 • 110A/B • 900 • a100 • a250 • a350 • a450 • SX-70 • Holgaroid
Fitting the Finder & Flash - continued
The most important part of this fitting is to enlarge the mirror post hole. The 110A's original mirror post screw is too small and short to accommodate the 900's. To fix this, you must have a drill press and a threading tap for creating a larger screw hole to accept the 900's post. Without a drill press, you can not be sure your threads are properly aligned. If you don't have access to a press, I do not recommend this part of the conversion.
Luckily, I had been granted access to a large materials lab filled with fancy toys, like this bad boy.
You don't need something so fancy, just something that allows for a slow speed. And, of course, a vice is a must for this.
These photos show the camera has not been cut, as I had not done that yet when I was using the press.
To enlarge a threaded hole, you must know the size of the screw. In this case the hole needs to be enlarged to 10/32" (also known as a #2 BA).
First, find a 10/32" straight flute tap. Using the slower settings of the press, enlarge the hole with a slightly smaller drill bit. Switch bits to the flute tap and drill the threads very slowly with some lubricating oil, backing out even slower.

Test your new mirror post hole, should be smooth as buttah. If it is not, uhoh, something went terribly wrong.
Fortunately, I had some good help, thanks Mike B.
I've said numerous times that I won't be using the flash screw. The reason follows.
If you get lost at anytime, you can always click the link at the bottom of the page to come back here.
The Steps
parts & labor
what's needed to get the job done
basics of function
overview of how to use the lens and shutter
the back, the strap, the lens
remove useless vintage roll-film parts; lens
the rangefinder
removing, taking apart
cutter-bar & inner parts
more useless vintage parts that have to go
ready the back
cutting; fitting the packfilm back; odds n ends
acquiring a 900 finder
removal & appropriation
fitting the finder & flash
measure, drill & fit
aesthetics
remove & re-leather; paint
adding the back & flash
screws, tape & wires
putting it all together
replace rangefinder, strap, flash & side door
reset infinity
setting the focus stop
completed
admire the work
Information …
The Models
These are the models I have personal experience with and are used within this site.




