win_burrington

<p>Did Minox just increment the serial numbers of their enlargers across model lines rather than types? I have a Model II, Type 2202 (color) and the serial number on the major parts is #12222. I see that there are many Model II, Type 2203 (B&W) that have serial numbers on both sides of this serial number. If there is no easy answer, is my best bet to check Heckman's "Variations in 8 x 11"?<br />Thanks.</p>

<p>You have already done the difficult work. The easy part is the finish. Stainless is very easy to blacken and it is at the molecular level. There both commercial places and makers of coating kits that are easy to use at home. Since stainless has at least 14% chromium, the blackening "baths" convert the chrome in the stainless into sulfides and they are dark grey to a "light" black color. The luster depends on the surface finish before blackening. A light bead blasting with Aluminum Oxide will give you a satin dark grey/"light" black finish. The finish also reduces the galling that is typical with stainless should keep the spool moving freely. The normal thickness of these coatings is 0.00006 to 0.0001", (that's 1/10 of one thousandth inch) so any concerns about dimensional issues should be moot. Stainless firearms are routinely treated this way and require no fitting or grinding to reassemble after treatment.<br>

(I also made just a Minox cassette from stainless a couple of years ago to see if it was feasible to make these on my small CNC mill. I only made a block, solid version but it fit in all my Minox's. I found that 303 was the easiest to machine. I would think that this would be helpful in keeping the material in the slit area from work hardening. What material was this cassette made from?)</p>