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1 How accurate is a digital caliper? Uniform measurement pressure is very important, but as this varies depending on the  user, a FMS pressure device is recommended. A "Measurement Rule" is that the accuracy of any measuring instrument  should be at least 5 (preferably 10) times more accurate than the tolerance being measured. A digital caliper should therefor not be used to measure dimensions with tolerances less than 0.06mm / 0.0025 ins. up to 100mm / 4 ins. The most accurate measurements with a digital caliper would be comparative measurement i.e. use of a reference standard for comparison. Most threads from M6mm / 1/4-UNC" have a pitch diameter tolerance of at least 0.1mm / 0,004ins.
2 Are there threads that cannot be measured with FMS thread inserts? Probably not. The limiting factors will be the pitch (not less than 0,5mm / 48 T.P.I.), the diameter on internal threads (min. 6mm / 0,25ins.), and the tolerance on the pitch diameter (preferably at least 0,06mm / 0,0025ins.) The pitch diameter tolerance for a M6-6H (nut) is 0,15mm / 0.006 ins.
3 Can FMS inserts be used on other things than threads? FMS accessories and inserts can be used to measure external and internal recesses, grooves, holes, gear pitch diameter and much more. User imagination may be the only limitation.
4 What is the largest dimension that can be measured with FMS? The limitation will probably be the length of the calliper. Special FMS insert holders can be manufactured to increase calliper jaw length.
5 Can FMS accessories and inserts only be used with a digital caliper? No, but a digital caliper has the advantage of easy zero positioning (0.00) as well as SPC possibilities with data transmission (documentation).
6 Is FMS accuracy documented? FMS has been tested at an accredited laboratory with excellent results. A complete copy of the test can be sent on request in Danish, English or German. Report results
7 Are there other products that can do the same as FMS? Yes, but they are much more expensive and aren't as flexible. FMS is probably the most flexible, versatile and economic when compared to alternatives. Compare FMS with any alternative.
8 Why measure a thread when it's easier to use thread plug and ring gauges? Requirements to product quality constantly increase. When thread gauges are used for inspection they only tell if the thread is within tolerance or not. Measurement tells where the thread is in relation to the tolerance. This information is vital for correct machine set-up (faster and more correct set-ups) and for inspection (significantly fewer components need be checked when measuring than by gauge inspection). Many mistakenly believe that a tight fit beween the gauge and the thread is good. To the contrary, this gives increased wear on the gauges and the risk of rejection unless the producer and receiver use the same gauges for inspection. Compare total costs (gauge purchase, set-up time, inspection time, gauge calibration etc.) with FMS and alternative options.
9 Are tailor made FMS inserts expensive? FMS inserts can be tailor made for virtually all requirements. Send us a drawing or a sketch of what is to be measured and, if we feel we can make it to your satisfaction, an offer (at no charge) and delivery time will be given.  Most tailor made special FMS inserts (for threads, recesses, grooves etc.) cost less than Euro 150 and delivery time is usually under 4 working weeks from the date of order receipt.
10 How do FMS thread inserts work? FMS Thread insert measurement principle
11 If I have a question regarding, for example a thread? Phone or email us. If you already have bought FMS products the answer (if the question can be answered by us) will usually be free of any charge (customer service). If the answer requires extra work then a price will be given. There will be no unexpected "surprises"!
12 What is the difference between functional pitch diameter and pitch diameter? The functional diameter size is the pitch diameter size plus the cumulative effect in variations in lead (including uniformity of helix) flank angle, taper and roundnes. The functioal size is the measured value  of the maximum material size of a product internal or external screw thread.
     

More questions and answers will be added as they are received.