I contacted a number of stringers, asked a few questions and the response to one question really has me worried.
I asked them after they had strung the racket what they used to check the tension or dynamic tension of the racket?
Here is the list of most used:
1. You cannot check the tension of a strung racket
2. Why would I check it as the stringing machine sets the tension
3. Why would I want to test it?
4. Those things don't work
To answer each one in turn:
1. Yes you can and here are 4 items that will do it
To see if you have any clamp slippage, string puller slippage or the your machine is pulling at the correct tension.
Also to have a reference point for when you check the racket at a later date to see how much tension is lost!
4. All of the above, The string tension you read on anyone of these items is now your reference tension (as above) and if you use the same piece of equipment to measure at a later date then you can see the tension loss.
So my advice to anyone before getting a restring carried out ask the stringer this question:
After you have strung my racket what do you use to test and record the Dynamic tension?
I will leave you to decide (depending on the response)if you want to use that stringer.