Help! Interapid 312B-1 contact point questions

I'm new to metal working and purchased an Interapid 312B-1 dial test indicator to help with milling setup, eg, vise alignment, finding hole
centers, edge finding, etc.
The indicator has the contact point positioned approx. 45 degrees from vertical (pointed out toward the front of the indicator).
Was hoping someone could recommend a contact point angle setting and how to re-position the contact point? Most of the pictures I've seen show the contact point set at vertical. However I've noted that the contact point for this indicator needs to be set at 12 deg. to the work piece for accurate readings. Based on the parts diagram posted online, the contact point apparently has a 210 deg. range of motion.
I attempted to loosen the two screws (one on each side of the housing) that hold the contact point pivot bushing, but could not get them to turn. Didn't want to apply additional force to loosen them until I was sure this was the correct procedure?
Also, the indicator contact point is tapered to a point versus the 0.08" dia. ballend contact point that I believe is standard with new indicators. Can someone please tell me which contact point is best suited to my intended uses?
Thanks.
Scott
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The Interapid indicator is designed to be used with the tip set at an angle as you mentioned. To change the angle of the tip just push it. It has a friction fit and will move after you reach the end of the travel. There is no need to loosen anything. The contact point that came with the indicator should be fine for what you are using it for. Carbide points are best when you indicate over long distances all day long as they wear better. Small diameter points are best for indicating small holes, drills, etc. Good choice for an indicator BTW.
Dan
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Hi Dan
Thanks for the quick response and simple solution to an obvious "beginner" question. Glad I didn't get out the "big" screw driver! :-)
For anyone researching indicators, I found an excellent comparision table at:
http://www.longislandindicator.com
Thanks again.
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Any time. Wow, nice site. It took me a while to find the DTI comparison http://www.longislandindicator.com/indicator.html
I agree with their ratings for the most part. I figured out which DTI's are junk and which are good the hard way. I wish there was a comparison like this around 25 years ago. I could have saved some money. I think that the Compac is the best, but I like my Bestest better than my Interapid. I usually on use the Interapid only for inspection due to the 12 degree thing. I might send those guys a couple of indicators for repair. Has anyone used them? And what did you think of them? I've got an old 50 millionths Bestest and a one tenth Interapid that could use repair. $67.00 seems a little steep, but if it's brought back to new specs it might be worthwhile.
Dan
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snip------

I've owned two Bestest indicators for over 30 years and wouldn't be without them. Aside from replacing the lenses, neither of them have given a moment of trouble.
Harold
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I just got a brand new one to replace the one that needs repair. The old one was broken back in '91 when I let a sevice tech borrow it. He crunched it by running a slide into it. I had it repaired and it's been fine ever since. A couple weeks ago I let someone use it and it flew out of his hand when he was taking it off of his Mag base. So, I'm thinking about getting it fixed again, but it's old and I'm not sure it's worth it. It still works but it seems to have a little side play, and the clock hand is a little skewed. A new bushing, crystal, and reset the hand it should be good to go for another twenty years or until I lend it out again. The Interapid works fine. It's just doesn't seem to be as smooth as a new one. Plus the clock face doesn't rotate with the crystal anymore. It moves about a quarter of what the crystal moves. Drives me mad, so I use it on the bench centers where I can use the fine adjust on the holder to zero the indicator. I'm thinking this should be a no brainer to fix and calibrate. $67.00 seems steep though. I have plenty of good working indicators besides. I scored a brand new Mitutoyo .0001" on Ebay for $12.00. In the plastic and perfect. I love it when people list stuff improperly.
Dan
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Dam, Dan, I don't know if you're a good guy, or stupid (no offense meant).
You're a lot more generous than I am. I DO NOT LEND TOOLS! Full stop! I've been very fortunate to have kept all my precision tools in pretty good shape, with the vast majority now over 45 years old. I got in just as Starrett went to satin chrome, so almost all of my tools are so finished. Thanks to never letting others use them, they're all still almost perfect. My one sadness is my vernier protractor isn't satin chrome, and it's getting harder and harder to read as I get older, thanks to poor eyes.
Like you, I can't quite warm up to spending $67 to have my one Bestest sent in for the crystal to be replaced. I'm seriously considering installing one myself (assuming I can buy one, that is), but it's not something I've done before. If you have any pointers, I'd welcome them.
Or, if you'd like to send me that .0001" Mitutoyo, I'll double your money! :-)
Man, what a great buy that was!
Harold
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    [ ... ]

    That prompted me to get another in satin chrome from an eBay auction.

    What diameter is the bezel of the Bestest? For larger indicators (1-1/2" and up) I turn a replacement out of 1/16" Lexan (just a bit oversize for the measurement of the bezel), put a partial bevel on the edge, and then place it on a ring which is turned to contact at about 3/4 of the OD of the crystal, and press with a soft rounded surface (I usually buffer with the plastic lids from water cooler bottles) in the center using a small arbor press, while the bezel ring is resting on top of the crystal around the presser. As the center presses in, the OD raises a bit, and reduces diameter just a bit. When it is curved enough, the bezel ring will slip on, and then you relax the pressure, allowing the OD of the new crystal to expand and grip the bezel ring. (The crystal will retain a domed shape -- how much of one depends on how much the OD needed to be shrunk to fit the bezel ring.) Once this is done, peel off the protective plastic which came on the Lexan, and re-install the bezel ring on the indicator.
    Exactly how you remove the bezel ring from the indicator is a function of the particular brand and model. Some use screws which engage grooves on the indicator body. (Federal tends to be one example of this.) Larger Starretts tend to use a circular wire spring with three bulges in it. You need to rotate the bezel ring until one of them comes into view through a tiny hole in the ring, and press it in with a pin of appropriate diameter. You then press the ring forward a bit to hold that one disenaged, and rotate to find the next one. Once all three are released, the bezel ring will come off. Small Starretts like the "Last Word" have a bezel ring which is simply pressed on (a friction fit), but those also need a thinner crystal, and I've used some which I acquired with a repair toolbox from eBay. It is now time to see whether I can buy more of those. Anyway, those pre-formed crystals press in from the inside.
    I posted a web page showing a couple of indicators which I had re-crystaled, plus the tools made to do that particular size. (Every time there is another size, I need to make more tools. :-) It is too late tonight to dig up the URL, but drop me an e-mail and I'll dig it up, or perhaps ask here and I'll post it again.
    Enjoy,         DoN.
--
Email: < snipped-for-privacy@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
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wrote:

perfect.
getting
sent
installing
Thanks for the great response, DoN. I did exactly as you suggest when I rebuilt my Wilson Hardness tester, which apparently had been through a small fire. Lenses (the one mounted directly on the meter, and the cover lens, which protects it) were distorted, but not destroyed. It worked great, but I'm not convinced I'll be successful in finding material thin enough to make one for the Bestest, which appears to be 1.450" diameter. Right now it's held in by some masking tape, so it's very easy to remove and examine.
If you don't mind, please do provide the link and I'll explore your post. I'd contact you on the side, but my attempts of a few months ago didn't get through for some reason, as you may recall. There's certainly no hurry, I'm not using the shop right now, what with the house project hanging over my head. Just looking to the future.
Regards,
Harold
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    [ ... ]

    [ ... ]

    Hmm ... I ordered some sheets of the thinnest Lexan that MSC stocked at the time. I think that it was 1/16", but i may have been thinner. I apparently did not put the thickness information in the web page.
    If you can find some other flexible plastic that is thinner, the same techniques should still work. You might even try a side out of a big plastic Listerine bottle or something similar. Pick an area with little curvature, and heat it to let it flatten more (it will probably also shrink), and then use that as your starting material.

    It was a quick-and-dirty web page made some years ago. The URL is:
    http://www2.d-and-d.com/PROJECTS/Crystals/index.html
    It looks as though I only photographed the Federal indicator, and not the 5" range Starrett which I did not long afterwards.

    Probably because of spam from one of the other users of your ISP resulting in the mail server's IP address being blocked. Sometimes it is difficult to find what caused the blockage to open it up. (At least until spam ceases, and I can turn off all blocking. :-)

    I understand. The house certainly takes priority.
    Good Luck,         DoN.
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Well, I always look at it as being for the greater good. Where I work we sell machines, so we are doing turnkey's or service.

I know the feeling. I used to use an eye loupe on occasion, now I use it all the time.

I decided to take the Interapid and the Bestest and try repairing them myself. I figured what the heck, if I screw it up, I can still pay the $67.00. You can order a new crystal for the Bestest for around $7.00 to $9.00. I haven't ordered one yet, but I did remove it, clean it up, and put it back. I also reset the clock hand, and tightened up the joint where the tip screws in and swivels. The end result checking it with gage blocks on a surface plate were good. Repeats dead on. It read the difference between a .0500" and a .05005" gage block. I also checked +/- .002" and it read dead on. I still have a little side play though, when I slide the gage blocks sideways under the tip I get between a 50 millionths and one tenth movement on the dial. I think that this is just wear in the bushing, as this indicator has been used for indicating machines its whole life. I'm going to try polishing the crystal with diamond compound, If that doesn't work, I'll just buy a new one. I'm going to keep using this as a secondary indicator, for dialing in tools in a CNC Swiss that's dripping with cutting oil. The Interapid was a little trickier. I removed the two screws behind the clock mechanism that hold it to the body, this causes the clock spring to unwind. There are two holes on the back that allow you to unscrew the bezel. Once I had the bezel off I removed the crystal and cleaned it, along with the clock face. I put it all back together and gave it a little oil, and it now looks and feels new. Then I realized that I couldn't rewind the spring and get it assembled with the crystal installed, so I took the crystal off, wound the spring and put it back together. This is a real PITA. It took about five atempts before I got it right. There is a spring loaded gear rack that the gear on the clock engages. The clock has to be wound exactly the right number of turns and you have to catch the gear rack exactly in the middle. Once I got it all together, I checked it the same way as the Bestest. Repeatability was dead on, and there was no side play. But right away I see the big reason I don't like Interapid's. There was error reading between different size gage blocks, because I wasn't at twelve degrees. It took a couple of times to get the indicator set right. I had it mounted to a Starrett surface gage, so as you use the fine adjust on the surface gage it changes the angle. Grrr. Having had both DTI's apart, I have to say the Interapid has heavier construction and it had less schmoo in it, so it seems to be sealed better. It's far more likely to survive being dropped than the Bestest. But, the Bestest is more sensitive and easier to use. I also check a Wilson Wolpert .0005" DTI that I bought in a Dutch auction on Ebay. It's Chinese, but for five bucks, I figured what the heck. I'll be damned if it isn't spot on. It seems to be fairly heavy as far as the construction, so for a low budget knock-around on the knee mill indicator, I'd give it a thumbs-up.

No way. The Mit has a narrow round body and a small dial (which is hard to read) but it fits in places that the others just won't go, so it's a keeper.

That's nothing. I got a Mitutoyo Quick Mike for $125.00. List price is around $430.00. Listed wrong. But my all time biggest steal was a Gaertner Toolmakers microscope. It's the type with the tilting column, rotary table, and the angle measurement through a second eye piece. It has a quadra-check DRO with printer, and a Mitutoyo light source in addition to the built in ones. It came with all of the table accesories (bench centers, v-blocks, etc), three eye pieces, several lenses, filters, etc. And if all that wasn't enough, one of the wooden boxes had a Starrett croblox AAA set of thin blocks, .010-.0119" in it. All perfect. All for the princely sum of five hundred bucks. At the time I bought the Gaertner there were several Mitutoyos and Nikons going for three to four times the money. Fools! I was the only bidder. The optical quality of this scope blows away anything else I've ever used. Oh, then there was the Gov't surplus gage block set I bought. It was listed as missing several blocks. $35.00. I get the set and am taking out the blocks, cleaning and inspecting them when I notice the box rattles. I look through the holes and there are blocks underneath. Yup, they were all there. The only blocks that were ever used were the 1" and 2". I'm guessing they used these for calibrating mikes. So, now I'm on the hunt for those blocks. Gotta love Ebay.
Dan
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Dan, Oil is a no no. For indicators. It will eventually harden and become sticky with time. BTW I and co workers have had good luck with Long island indicator over the years. Rick R

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I only oiled the bezel where it rotates. It couldn't get any stickier than it was.
Dan
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