Bill, I’ll document the whole dial indicator refurb?process somehow. ?It looks slightly different for the various makes and models out there. ?Having said that, Steven Spielberg I ain’t! ?My new Samsung S23Ultra has amazing?video and photo capability. ?I’ll probably just mount that close by and do a series of really short overview, before,?disassembly, cleaning,?reassembly, and after recordings to put up on YouTube. ?The crystal issue can probably be a couple of episodes itself.
Thanks, George H. Meinschein, P.E.
Firearm and Ballistics Engineering LLC 150 Brittany Drive Freehold, NJ 07728 gmeinschein@... Cell#: 732-580-1736
On Thu, Dec 14, 2023 at 11:38 AM, Bill in OKC too via groups.io < wmrmeyers@...> wrote: George, I've never done such work. Last I worked with acrylic sheet in anything remotely resembling "fancy" work, I made a cover for a lab scale. That was about 50 years ago or so. I'd be interested in some detail on what and how you're doing on this. I have a couple of indicators that could use a new crystal sitting around here.
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY!
Expect in one hand, expectorate in the other. See which one gets full first.
On Thursday, December 14, 2023 at 09:05:22 AM CST, George Meinschein via groups.io <gmeinschein@...> wrote:
Guys, Thanks for the input.? I can get a dozen 4"x6" sheets 0.040" thick from Amazon for $8.00 and delivered for free.? A dozen 8x10 sheets are $14.00.? I've been using the vise method to bend the crystals that I have removed and replaced so far.? I seem to have a 50 year collection (probably a 90 year collection if I add my father's stuff) of odd and end shaped knobs, buttons, rubber feet, PVC fittings and so on that allows me to get the right combo of contours for bending the crystals in the vise.
Now, I'm thinking of using a mini fly cutter to plunge into the sheet and cut out the crystal with the proper beveled edge in one operation.? Double-sided tape or maybe hook up the vaccum pump to hold the sheets down.? Phones are usually quiet here between Christmas and New Years Day.? So, I might get a chance to experiment a bit.
Thanks, George H. Meinschein, P.E.
Firearm and Ballistics Engineering LLC 150 Brittany Drive Freehold, NJ 07728 gmeinschein@... Cell#: 732-580-1736
Sent with secure email.
On Thursday, 14 December 2023 at 04:19, eddie.draper@... via groups.io <eddie.draper@...> wrote:
Melt shaping OUGHT to work on any thermoplastic (of which both Acrylic & Polycarbonate are examples). If you want to avoid it breaking or cracking, use Polycarbonate rather than acrylic, but note that it scratches nearly as easily. Both machine easily with normal tools, and quickly take a polish to fully transparent if the final cut is very fine, followed by metal polish such as Brasso or Solvol Autosol (for car chrome) on a cloth. No idea what the equivalents are outside the UK. You could try machining a convex one out of a thicker piece without heating, and if you only did the outside, it would slightly act as a magnifier.
Eddie
------ Original Message ------
From: "Andrei" <calciu1@...>
To: "[email protected]" <[email protected]>
Sent: Thursday, 14 Dec, 23 At 05:58
Subject: Re: [SouthBendLathe] Dial indicator crystals (new rabbit hole for me!)
I always wondered how they domed the crystals without optical distortions. The glass ones are ground or melted over a mould, but what about the plastic ones? Does melt shaping work on them, too?
Get
Hello George I usually don’t have much to say on the group, but on this occasion, I may be able to help. Like you I also repair gauges. Normally I buy replacement crystals from G-S Supplies in NY . No commercial connection just a happy overseas customer for more than 20 years. They are great to deal with. The website has a lot of data about crystal sizes and types. Prices are reasonable. That said, I have made a few crystals because G-S does not carry/make many of the bigger sizes unless you want to order 500. Biggest problem I have with that here in Australia is finding acrylic sheet thin enough. But I’m sure there is a supply in the US. Turning is the only method I have tried but a punch would probably do just fine and if necessary you can turn a bevel afterwards. As to the bevel edge I can’t speak for every make and type of gauge, but many regular size gauges made by Mitutoyo, Starrett, Federal, Standard, etc. use bevel edge crystals. However, that only applies to domed crystals (by the way they start out flat and you deform them to fit the bezel). But (there is always a but) some gauges including ones made by the above makers have flat crystals and no bevel. Hope that helps. Cheers John Bates Sydney, Australia First off, I apologize for any cross posts. Lately, I’ve been fixing a few “parts only” dial and dial test indicators that I picked up on eBay. I’m thinking about getting some 1/25” clear acrylic sheet and making some nice new dial crystals. Anyone ever worked with acrylic sheet? Is this something I’d knock out with a punch and die setup? I did see one guy on YouTube make his dial crystal on a lathe. Clamped the acrylic sheet between two silicone rubber pads and turned the O.D. The Mitutoyo crystals have a beveled edge, so maybe the lathe is the way to go. Thoughts and comments from the the collective group brain power please! Thanks, George H. Meinschein, P.E. Firearm and Ballistics Engineering LLC 150 Brittany Drive
Freehold, NJ 07728
gmeinschein@...
Cell#: 732-580-1736
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-George M.
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-George M.
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