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Posted: 12/11/2007 1:22:28 PM EDT
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I got bored this afternoon, and thought I'd try this: I started with a bunch of A1 sight dials, so I could screw some up. Edited to remove pics Then, I mounted one on a rotary table on the micro-mill. Edited to remove pics I used a 3/8" end mill and rotated the table to shave off the numbers. Edited to remove pics That part worked out pretty good. I don't remember the DRO setting, but it was well under 0.050" and the wheel was not too thin, which was one of my concerns. If it was, I was going to have to machine a whole new wheel, a PITA. Edited to remove pics Then, I mounted a jeweler's end mill (about 0.035") in a chuck on the mill, to engrave the "R" and arrow. Edited to remove pics I got about halfway through the "R", then went too fast and broke off the end mill. I think my speed may have been too low for such a small cutter as well. So, I got pissed off and mounted another cutter in the Dremel, which was a huge mistake. Finally, I filed it a little, then simmered it in Lauer parking solution for about 20 minutes. This is really cool, since it fizzes while in solution, which really makes you think that something is happening. Edited to remove pics After I took it out of the parking solution, I rinsed it off, and dunked it in Cosmoline while still warm. Edited to remove pics The end result, pretty good parking, with a little green tint from the cosmoline. The "R" and arrow look really bad due to my Dremel Edited to remove pics Compared to a real one (photo from uxb). Edited to remove pics Next steps & lessons learned: I'll try it again, using more patience with the engraving. That part would be really easy for someone with a CNC setup or an engraving machine. I have plans for a pantograph, and I may try to build that, and mount a Dremel to it, unless I can find someone who can stamp or engrave. I'm also thinking about homebrew parking, with phosphoric acid from one of the cleaners at Home Depot, steel wool and manganese dioxide that I got from eBay. I'm just fooling around with this stuff, so any suggestions are welcome. I'll post an update when I get around to trying again. |
Hey, thanks...that will be really useful if I build the pantograph. It has a 4:1 ratio, if you trace something, the engraving is 1/4 size. 
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I might try that. I went down to HF the other day (there is one about half an hour from me in Newport News) and looked at the stamp set, the font was a little different so I didn't buy it. I may have to reconsider, though, after this experience. The curved part of the arrow shaft was not one of the harder parts, just stick the end cutter down 0.050" and rotate the rotary table. I screwed up the whole arrow including the shaft trying to do the head. ETA: I measured the font size, and found that 1/8" was way too big, and 1/16" was too little. I did a Google search and bought a set of 3/32" stamps from Hobby Tool. We'll see how those work when they get here (UPS Ground  ).
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Good idea - measure twice, cut (stamp) once.  3/32 is probably right-on! should make your retro reproduction more accurate. Thanks for the link - adding to my favorites. |
Me too!!! or two or three...  Edit with question: If you mill off .050" or .040" would you have to cut an equal amount off the tip of the detent? ...and then an equal amount from the tits on the sight tool? 
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Didn't find that to be a problem. Update: got the 3/32" stamps yesterday, and they look really good. I was surprised that the stamps looked better when I stamped the dial after parking instead of before, though. Strange. I tried to take some pics to post, but they didn't come out well since the parking is so dark. I'll try again later... |
Great idea that I'm sure lots of folks have thought of (like me), but didn't have the ability, means, or nuts to try (like me|
To take a good pic, use a couple more lamps of light on it and force the flash ON. I just thought of something - to make the arrowhead use the "V" character from a 1/16" stamp set FIRST and then use your scribe to draw the arrow shaft back away from the center of the V. Crossing fingers for you...VAAR |
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Thanks for the photo tips. I suck at that. I used the "Y" for the arrow, but both it and the "V" are really too big. Look at how small the arrowhead is on uxb's original dial relative to the size of the "R." I tried to mill part of the "Y" off with an 3/8" HSS end mill, but it just made a lot of noise. Anyone know what kind of cutter I need to mill a hardened steel stamp? |
I used a fine hand file, and refinished with Norrells Colt Grey. |
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I have a bottle of Norrell's Colt Grey, but I'm going to try to anodize mine myself first, with sulfuric acid, distilled water, clothing dye and a 12V power supply, like this guy did with his telescope parts. If that doesn't come out, I'm going to put the Norrell's over it. If I just wanted a great finish and didn't like to tinker, I'd send it to US Anodizing. |
Did you blast the area afterward, or whatever else, to blend the file work into the surrounding area? |
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