page 61

Long Island Indicator Service Inc

Precision Tool Repairs, Sales & Spare Parts







Lug Back
for Compac, Mercer and Tesa dial indicators


Your large 58 mm diameter Swiss made Mercer, Compac or Tesa YR and Tesa YE dial indicator probably comes with a plastic flat back. Four large slotted screws hold it in place. If you buy the optional cast metal lug back, you simply remove the plastic back and screw on the metal lug back using the same four screws.

Compac and Mercer are identical because they're the same indicator, sold under two different brand names. Tesa uses many of the same parts. These metal backs will fit all Compac, Mercer, Tesa YR and Tesa YE indicators made in Switzerland. They will not fit the old Mercer indicators made in England.

Every manufacturer (Starrett, Teclock, Mitutoyo for example) has slightly different specs for their indicator backs. As a result, you will have to use the manufacturer's own. They are not interchangeable between manufacturers.


Mercer indicator with optional lug back installed. The flat back has been removed.


If you're not familiar with the difference between on-center and off-center lug backs, take a look at these diagrams. They speak words.

on-center (left) and off-center (right)

The hole in the lug is 6.4 mm which equals .25". The dimensions given are metric (in millimeters) and correspond to the large (Ø 58 mm) indicators shown above.

The smaller models, with 40 mm diameter bezels, such as Compac 353E have a correspondingly smaller back but still have the quarter inch hole. There is also another difference: The small indicators do not have removable plastic backs. The indicators have a solid case. The optional lug back mounts directly onto the case using fours screws (not included). When you buy the small model lug backs, you will also receive four screws for this purpose.


Compac, Mercer, Tesa YR and YE (but not water proof)

Order No.

2015 Price

Lug Back On-Center with 1/4" hole for all 58 mm Ø models



Lug Back Off-Center with 1/4" hole for all 58 mm Ø models



Metal Back with 8 mm fixed shank for all 58 mm Ø models



Metal Back with M6 internal thread for all 58 mm Ø models


84.00 (*)

Set of 4 screws for the above backs (58 mm models)



(*) while supply lasts

Compac, Mercer and Tesa (including water proof) (screws included)

Lug Back On-Center with 1/4" hole for all 40 mm Ø models



Lug Back Off-Center with 1/4" hole for all 40 mm Ø models



Brown & Sharpe TESA 16.39008SComparator Measuring Stand, 0-5.5" Range, 6"x4.3" Measuring Face, No Arm


Books by René Urs Meyer

The Companion Reference Book on Dial and Test Indicators … page 178
Repair Manual for Swiss-made BesTest and TesaTast Indicators … page 177
Starrett 711 Last Word Indicator Repair Manual … page 199
Interapid Indicator Repair Manual … page 208

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

Contact us
Shopping CartSales TermsRepair ServiceHome

This page's most recent revision: 14 JULY 2016
All Rights Reserved

Original photographs and content copyright 2016 by JWGrum


Interested in metrology? Join our group on Facebook by clicking on the link above.