Posted: 9/8/2011 1:37:40 PM EDT
A friend of mine at my last job found this among his uncle's tools (he was an engineer that worked in the high-tech/ aerospace industry near Salt Lake City). It's obviously a Starrett micrometer of some sort but what has us stumped is, given the odd shape of the anvil, what exactly does it measure?
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There are a few odd tools around here. ETA: Micrometer for bearing races or something like that? I would agree except that with a normal mike the piece being measured is held between the anvil and the tip of the probe. In this case there is nothing I see to hold the work snugly as the anvil is mounted 90 degrees to the probe tip. The projecting arms have a spring-loaded ball at each tip (clearly seen in the pic) but what in the world holds the other side in place? |
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There are a few odd tools around here. ETA: Micrometer for bearing races or something like that? I would agree except that with a normal mike the piece being measured is held between the anvil and the tip of the probe. In this case there is nothing I see to hold the work snugly as the anvil is mounted 90 degrees to the probe tip. The projecting arms have a spring-loaded ball at each tip (clearly seen in the pic) but what in the world holds the other side in place? The probe tip probably sticks into the center of some crucial gear, pulley or wheel. You apply pressure with your fingers to keep it steady and then dial in the micrometer into the edge of the gear/wheel/pulley. Probably to measure wear to see if it's still in specification. |
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There are a few odd tools around here. ETA: Micrometer for bearing races or something like that? I would agree except that with a normal mike the piece being measured is held between the anvil and the tip of the probe. In this case there is nothing I see to hold the work snugly as the anvil is mounted 90 degrees to the probe tip. The projecting arms have a spring-loaded ball at each tip (clearly seen in the pic) but what in the world holds the other side in place? The probe tip probably sticks into the center of some crucial gear, pulley or wheel. You apply pressure with your fingers to keep it steady and then dial in the micrometer into the edge of the gear/wheel/pulley. Probably to measure wear to see if it's still in specification. Best answer I have seen so far! Thanks for being a grown-up (did you read any of the other responses? I thought school was back in session!). |
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Quoted: You DID post this in GD...Quoted: Quoted: Quoted: There are a few odd tools around here. ETA: Micrometer for bearing races or something like that? I would agree except that with a normal mike the piece being measured is held between the anvil and the tip of the probe. In this case there is nothing I see to hold the work snugly as the anvil is mounted 90 degrees to the probe tip. The projecting arms have a spring-loaded ball at each tip (clearly seen in the pic) but what in the world holds the other side in place? The probe tip probably sticks into the center of some crucial gear, pulley or wheel. You apply pressure with your fingers to keep it steady and then dial in the micrometer into the edge of the gear/wheel/pulley. Probably to measure wear to see if it's still in specification. Best answer I have seen so far! Thanks for being a grown-up (did you read any of the other responses? I thought school was back in session!).  |
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I think that is a shop-made tool with a Starrett micrometer head in it (the heads are available separately for just this sort of thing).
The black casting looks a bit rough for a commercial product. I would guess that this is a custom piece of inspection equipment for measuring the curvature of some part that is not a complete circle, but has an arc of curved surface on it that needed to be checked. What material is the white "pivot"? |
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Quoted: A friend of mine at my last job found this among his uncle's tools (he was an engineer that worked in the high-tech/ aerospace industry near Salt Lake City). It's obviously a Starrett micrometer of some sort but what has us stumped is, given the odd shape of the anvil, what exactly does it measure? http://i72.photobucket.com/albums/i187/tenmikemike/002.jpg Cam mike. . |
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On the obverse side of the body casting see if there is a model number in the casting. It should look kinda like this: No. 233 ( number will vary ) Then you can look up ( for instance ) Starrett No. 233 micrometer....it'll pop up on the web. It does look like a factory tool to me. The body casting is very indicative of Starrett stuff from at least the 70s up to at least the early 90s. |
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I think that is a shop-made tool with a Starrett micrometer head in it (the heads are available separately for just this sort of thing). The black casting looks a bit rough for a commercial product. I would guess that this is a custom piece of inspection equipment for measuring the curvature of some part that is not a complete circle, but has an arc of curved surface on it that needed to be checked. What material is the white "pivot"? That "pivot" is merely the same steel anvil you see on a normal mike. Its just the way my kitchen light hit it makes it look that way. |
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It is specially made to measure a specific part (probably round) which has a hole centered to fit over the anvil.
The spring loaded balls are to hold the item firmly against the anvil via the aforementioned hole. Either to measure thr concentricity of the item or to verify center on the hole. |
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Well, this is just a WAG, but for some reason, given the info you've mentioned, I'm thinking that it is meant to check the cams on a radial aircraft engine. Whatever it is meant to check would have to fall into a fairly narrow range of curvatures to work well with that geometry.
It really looks like a 2-D version of a spherometer. ETA: if the part being measured was nominally cylindrical, then a plain old micrometer would work fine. It could also be used to check roundness rather than diameter (a standard mike measures only diameter, and there are many shapes that have constant diameters yet are not round such as the rotors in a Wankel engine) |
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dikfer What's a dickfer? http://images.eonline.com/eol_images/Entire_Site/20091119/300.bono.chaz.lc.111909.jpg 
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dikfer What's a dickfer? http://images.eonline.com/eol_images/Entire_Site/20091119/300.bono.chaz.lc.111909.jpg no don't tell me is this Chaz Bono ? OMG |