Correx Gram Force Gauge
medidor de tensión - dinamómetros
Tension Gauge - Federwaage Sales and Repairs Correx Gram Force Gauges are manufactured by Haag-Streit, in Switzerland. This is the ideal all-mechanical instrument used to measure and calibrate the pressure or force required to actuate micro switches, relays, electric contacts, friction torque, etc. - In aviation they are used as a component in Lift Transducers manufactured by Tronair.
- The feeler arm can be chemically sterilized for use by orthodontists, for tooth implants and in pediatric dentistry.
- Piano technicians will use the force gage to standardize hammer mechanisms.
- University labs have used the gages to measure biological response threshold.
- Repair shops, like us, use the gage to set proper return spring tension.
The Correx force gage fits easily in the hand, weighing from 4 to 9 oz. Except for the smallest 2 models, all have a maximum pointer. The accompanying photo (above) shows the Correx force gage with the round tip. They have been variously sold as tension and compression gages; more recently as dynamometers. The dials are graduated in both gram/pond and centi-Newton. We only offer the genuine made in Switzerland Correx tension gage. 
Correx model 30R is shown above with round feeler. The round tip is a flattened sphere, about 1mm in diameter. The feeler length is 1.25 inches. 
The flat tip (1.25" long) is illustrated above. Notice that both of the gages shown on this page have maximum pointers which allows you to take a measurement without having to observe the dial. Maximum pointers are not available on the two smallest gages. When taking measurements or when calibrating, it is important to keep the feeler at right angles to the direction of force at all times. Changes to this angle will result in erroneous readings. New Correx force gages do not come supplied with certificates of calibration. If certificates traceable to NIST are required, then we can provide them at an additional $75 charge. If ordering online, be sure to make this request. Allow an extra 10 days for certification. The dials are graduated both in grams/ponds and centi-Newtons (see notes below). Dial diameter is 37mm (up to 250g) and 65mm (from 500 to 2000g). There is no difference between previous black-bodied models and the current purple version. All gages are in stock. Distributors and repair shops may qualify for discounts. | Range (1) | Graduations (2) | Flat | Round | Your Price |  | | | | | 0.3 - 3 cN | 0.1 cN | 3F | 3R | 189.00 | 0.6 - 6 | 0.2 | 6F | 6R | 189.00 | 2 - 15 | 0.5 | 15F | 15R | 199.00 | 3 - 30 | 1 | 30F | 30R | 199.00 | 5 - 50 | 1 | 50F | 50R | 199.00 | 10 - 100 | 2 | 100F | 100R | 199.00 | 15 - 150 | 5 | 150F | 150R | 199.00 | 25 - 250 | 5 | 250F | 250R | 199.00 | Free Calibration certificate NIST traceable | | calibration request | (1) the range is both in grams and centi-Newtons on the same dial
(2) graduations are both in grams and centi-Newtons on the same dial You may order online by selecting any linked model number.
| Large model Correx | | | | | 
Correx tension gauges also come in 500g, 1000g and 2000g models as shown in the photo above. Here are some stats on these three models: - length of feeler: ~ 48 mm (1.75")
- thickness of feeler: 1,5 mm
- dial diameter: 71 mm maximum
- dimension of back (which is also the dimension of the body, not including the dial): 46 mm wide x 106 mm long
- maximum thickness (height) of the gage: 34 mm
- weight: approx. 260 g (about 10 ounces)
- accuracy: ±0.01 x (maximum dial reading + actual test reading) see more about this below
| Range (1) | Graduations (2) | Flat | Round | Your Price | | | | | | 50-500 cN | 10 cN | 500F | 500R | 339.00 | 100-1000 cN | 20 cN | 1000F | 1000R | 359.00 | 200-2000 cN | 50 cN | 2000F | 2000R | 399.00 | Free Calibration certificate NIST traceable | | calibration request | (1) the range is both in grams and centi-Newtons on the same dial
(2) graduations are both in grams and centi-Newtons on the same dial You may order online by selecting any linked model number.
| About the feelers | | | | | Correx feelers come in two forms: the flat feeler (somewhat like a screwdriver blade) and the round feeler (which actually comes to a blunt point). These feelers are solid, non-magnetic metal. There is no pre-drilled hole like you'll find in some other force gages. It's important to acknowledge that any modification to the feelers is likely to affect the gage's calibration. If you're tempted to drill a hole through the flat blade, then make it as close to the tip as possible and only as large as necessary so you don't drastically change the mass of the feeler arm. The Correx force gage measures most accurately at the very tip of the feeler and that's why you want to make sure all forces, including hanging weights, are applied as near the extreme tip as possible. The feelers are made of a relatively soft and pliable metal. If it ever bends out of shape you can easily straighten it with your fingers. If they're damaged beyond help, we can install a new feeler for you. | About Newtons and Ponds | | | | | Newton (N): In the meter-kilogram-second system, the unit of force required to accelerate a mass of one kilogram one meter per second per second, equal to 100,000 dynes. The inner scale on the Correx force gage is calibrated in centi-Newtons. The outer scale on the dial is calibrated in grams and ponds. This outer scale is used for calibration purposes when weights are suspended from the feeler arm. Pond: the metric unit of force seen on the outer scale of the Correx force gages. A pond is the gravitational force at mean sea level on a mass of one gram; thus it is equal to .980665 centiNewtons. The pond has disappeared from many applications because it is not an International Standards (SI) unit. These gages are not available with ounce-force or pound-force scales. Rather than making conversions, which is likely to introduce errors, you'd be wiser to find another manufacturer's force gage with the correct dial graduations. If you decide to convert, here are some equations: - 1 pond = .98066 centiNewton (cN)
- 1 centi-Newton (cN) = .01 newton
- 1 centi-Newton (cN) = .036 ounce-force
- 1 centi-Newton (cN) = .0022 pound-force
- 1 Newton = 100 cN
- 1 Newton = 0.225 pound-force
- 1 pound-force = 4.448 Newton
- 1 pound-force-inch = 0.113 Newton-meter
- 1 Newton-meter = 8.851 pound-force-inch
| SPI and other equivalents | | | | | Here are the equivalent model numbers as used by SPI and other distributors. If you know their number, then you can find our number. | Our Number | Old Haag-Streit Number | New Haag-Streit Number | SPI Ordering Number | | | | | | | | | | 3F
3R | 0333.0003F
0333.0003K | 1001688
1001673 | 31-001-1
31-016-9 | | | | | | 6F
6R | 0333.0006F
0333.0006K | 1001689
1001674 | 31-002-9
31-017-7 | | | | | | 15F
15R | 0333.0015FM
0333.0015KM | 1001690
1001675 | 31-003-7
31-018-5 | | | | | | 30F
30R | 0333.0030FM
0333.0030KM | 1001691
1001676 | 31-004-5
31-019-3 | | | | | | 50F
50R | 0333.0050FM
0333.0050KM | 1001692
1001677 | 31-005-2
31-020-1 | | | | | | 100F
100R | 0333.0100FM
0333.0100KM | 1001693
1001678 | 31-006-0
31-021-9 | | | | | | 150F
150R | 0333.0150FM
0333.0150KM | 1001694
1001679 | 31-007-8
31-022-7 | | | | | | 250F
250R | 0333.0250FM
0333.0250KM | 1001695
1001680 | 31-008-6
31-023-5 | | | | | | 500F
500R | 0711.0500FM
0711.0500KM | | 31-009-4
31-024-3 | | | | | | 1000F
1000R | 0711.1000FM
0711.1000KM | | 31-010-2
31-025-0 | | | | | | 2000F
2000R | 0711.2000FM
0711.2000KM | | 31-011-0
31-026-8 | | Correx Tolerances and Calibration | | | | | Calibration of the Correx force gage is effected by suspending the appropriate weight from the very tip of the feeler arm. During this process, the arm must be kept horizontal. The reading should then be taken on the gram/pond scale of the dial. The gage should be tested at 2 or 3 different portions of its range, in both directions. If the instrument does not calibrate according to tolerances as calculated below then it must be returned for servicing either to us directly or to another qualified repair and calibration shop specializing in mechanical tension gages. Calibration can also be effected using non-mechanical force measuring equipment for comparison. For all Correx gages, the following manufacturer's tolerances are guaranteed: Tolerance = ± 0,01 x (maximum dial reading + actual test reading)
For example: on a 100g gage, the reading of 60g has a tolerance of
±0,01 x (100 + 60)g = ±1,6g
And the maximum reading on the 100g gage has a tolerance of
±0,01 x (100 + 100)g = ±2g = ± 1 graduation
New Correx force gages do not come supplied with certificates of calibration. However, the manufacturer guarantees that they are accurate according to the above calculations. If NIST traceable calibration certificates are required you will have to request them at the time of purchase and we will provide them at an additional fee. Alternately, you may send them to a calibration lab of your choice. Correx force gages may be returned to us for calibration at any time. The manufacturer suggests a 3-year calibration cycle. Please note: We have removed calibration instructions from this page at the manufacturer's request. The manufacturer advises us that repair tools and calibration equipment (weights and adapter sleeves) are currently not available for sale. Furthermore, the manufacturer does not encourage end-users to perform their own repairs or calibration. Long Island Indicator Service has this equipment and we can perform these calibrations for you. Special thanks to Russ Rowlett of the University of North Carolina, Center for Mathematics and Science Education; Sunit Mahajan of the Thayer School of Engineering at Dartmouth College; and to Laurent Gasser of Haag-Streit, Switzerland. | What will go wrong? | | | | | The Correx gage will remain accurate as long as you don't open the back cover and attempt to make any adjustments to the springs or the screws you'll find inside, and as long as you don't alter the length or shape of the feeler arm. The manufacturer suggests re-calibration every 3 years, but you may want to do this more frequently if you're suspicious about the way your gages have been handled. On the surface, you may find that the feeler arm has become bent. It is a soft metal and you simply bend it back into shape using just the pressure of your fingers. Resort to small pliers only if necessary. When bending, keep in mind that the arm moves on a pivot inside the gage. Too much pressure will break the pivot resulting in a costly repair. If the arm is badly damaged, it can be replaced (send it to us for repair). If the dial hand gets stuck, it may be touching the dial or the glass or, most likely, the white plastic spacing ring which is just underneath the dial. These are things you can probably correct yourself. Remove the ring which holds the bezel in place and the crystal will come out easily. Now you gently bend the hands as necessary, or you can rotate or reposition the spacing ring so that it isn't in the way. If the crystal is scratched or the tolerance hand no longer functions, just replace the entire crystal, which can be ordered from us. After long and heavy use, especially in corrosive environments, the bushings may wear out, giving a lot of play to the hand or to the front pivot. You may have to consider replacing the gage at this point, since that can't be corrected. Other problems arise if the gage is dropped or hit, or if it becomes contaminated with liquids or dust. You will want to have it professionally serviced and subsequently calibrated. As with any precision gage, store these in clean, safe places when not in use and always be on the lookout for problems which might affect the accurate interpretation of your data. | Repairs | | | | | | Correx mechanical gram force gages are unquestionably the best made instruments of this type. The manufacturer states that they are maintenance free and should be checked for calibration accuracy once in three years. Should the instrument require repair, Long Island Indicator Service has spare parts, original calibration equipment supplied by the manufacturer, and over 40 years of experience with this particular gage. | Correx Spare Parts | | | | | - for 15 g to 250 g models: crystal complete with maximum pointer assembly #333-60 ... $59.00
- for 15 g to 250 g models: white plastic spacing ring #333-67 ... $7.60
Other spare parts are currently not available for sale. Correx force gages should be sent to Long Island Indicator Service for any repairs and calibration adjustments. | International Orders | | | | | We can ship Correx force and tension gauges to many international destinations. The Harmonized Tariff Code for these gages is 9024.80.0000 (dynamometer - dinamómetros). US Export Schedule B code is 9017308000. Please contact Mr René Meyer for information and to obtain a pro forma invoice. |
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