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Long Island Indicator Service Inc

Precision Tool Repairs, Sales & Spare Parts







Mahr Federal and Federal Gage
Indicator Spare Parts - Crystals

Federal Crystals


Crystals need to be inserted with a crystal press. If you need instructions, take a look at page 15.

  • Indicators beginning with the letter "A" use crystal W250 ... $4.90
  • Indicators beginning with the letter "B" use crystal W430 ... $5.90
  • Indicators beginning with the letter "C" use crystal W645 ... $6.90
  • Indicators beginning with the letter "D" use crystal W835 ... $12.90
  • Indicators beginning with the letter "E" use crystal PT06908 ... $18.00
  • Bezel screw for all the above SW380 ... $6.90


Old Style Mahr Compramess and Milimess


The crystals are no longer available for the old style Mahr Compramess or Milimess and the new crystals won't fit. The old style had flat edges and was held in place with a metal retainer. The new style is contoured at the edges and no retainer is necessary. The new style is also larger. Mahr has no replacements for these so, sad to say, the old comparators are beyond repair.


New Style Mahr Federal Indicator


These will have the typical light-green dial of gages made in Providence and the logo "Mahr/Federal" will be printed on it. They have a snap-on plastic bezel assembly with crystal installed and 2 tolerance markers. The bezel can be pried off using a flat blade screw driver. It is nearly impossible to install new crystals—standard crystal presses are not suitable—making it almost mandatory to buy the entire bezel-crystal assembly. Contact Mahr-Federal to locate a distributor in your area.

  • B size indicators such as model B2I ... BZ-1612

The old style metal bezels held in place with three small screws are no longer available. You can replace them with these new plastic bezels.


Q&A about your Federal Indicators


Q: I have a Federal D8IS 1" dial indicator that I have been using on my lathe for many years to measure carriage travel. Lately it has been sticking, so I disassembled it, cleaned all internal components, freed the sticky plunger and am now ready for reassembly. I have two questions: 1) How many turns should I give the hairspring for preload at zero (plunger at rest)? 2) Should internal wear points be lubricated, shafts, gears, rack? If so what do you recommend?

  • We use synthetic watch oil on the bearings and pinions but do not lubricate the rack (spindle) since this can actually cause stickiness in time. The hair spring has to be wound in such a way that it does not curl up when the spinldle is pushed completely in.

Q: I just bought a used Federal C81S dial indicator. When you manually push and release the stem it doesn't return to the same number. The rev counter is on 2 instead of zero. It seems pretty smooth. Can this be repaired?

  • It could be repaired but Federal parts are so expensive that you will probably find it is not economical. Try this: remove the back cover and check to see that the return spring is still attached to its post. The spring could have been dislodged and that would account for the symptoms you describe.


The above items constitute advertisements on behalf of and are not to be construed as endorsements by Long Island Indicator Service. We strongly believe in buying quality tools and gages, and urge customers to check carefully before making a purchase. If the prices appear unusually low, we suggest proceeding with caution.

Long Island Indicator Service Inc
14 Sarah Drive — Hauppauge NY 11788 — USA

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This page's most recent revision: 20 AUGUST 2016
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Original photographs and content copyright 2016 by JWGrum


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