gustav Posted January 16, 2017 Report Share Posted January 16, 2017 Got my hands on one but not sure of correct way to use. When setting & reading should you wind it out until it just makes contact or carry on until it will go no further? As always any help greatly appreciated. Many thanks,Gustaf. Quote Link to comment Share on other sites More sharing options...
washerboy Posted January 16, 2017 Report Share Posted January 16, 2017 Has it a thumb ratchet? Quote Link to comment Share on other sites More sharing options...
figgy Posted January 16, 2017 Report Share Posted January 16, 2017 Ive always worked on when it's touching and just drags slightly, if you turn until it won't go anymore you will damage it by stressing it to where it will not read true and need recalibration. Quote Link to comment Share on other sites More sharing options...
gustav Posted January 17, 2017 Author Report Share Posted January 17, 2017 Has it a thumb ratchet?There is no ratchet, the adjusting knob at the head of the shaft turns in both directions. Gustaf. Quote Link to comment Share on other sites More sharing options...
gustav Posted January 17, 2017 Author Report Share Posted January 17, 2017 Ive always worked on when it's touching and just drags slightly, if you turn until it won't go anymore you will damage it by stressing it to where it will not read true and need recalibration.Thanks, that is what I have done but I have the concern that it seems to be imprecise, in that it leaves room for error. What I want to be an exact engineering measurement is relying on human judgement. Gustaf Quote Link to comment Share on other sites More sharing options...
washerboy Posted January 17, 2017 Report Share Posted January 17, 2017 Ones I use at work have a ratchet so that it clicks when it gets to the size of the bore, just like an outside micrometer Quote Link to comment Share on other sites More sharing options...
figgy Posted January 17, 2017 Report Share Posted January 17, 2017 (edited) You need to use a gauge peice to check it against. So it could be a 1cm cube a ball bearing anything constant that you know the exact measurement of. You then turn until it just grips this object and read the scale see it matches. If it's close turn until it reads true and feel the tension required by backing off and re measuring. You will soon get the feel of what tension needed to get a true reading. Hence the reason need ones have a ratchet to make it easier to reproduce the right tension time and again. When both measuring surfaces are clean it should read zero when closed Edited January 17, 2017 by figgy Quote Link to comment Share on other sites More sharing options...
Bazooka Joe Posted January 17, 2017 Report Share Posted January 17, 2017 Bore micrometers need calibrating with setting rings see the link, but they are an expensive option. Slip guages can be used but again expensive if you haven't any, aAny old cube or ball bearing will be inconsistent & give in-accurate calibration. http://www.higherprecision.com/products/bore-gages/fowler-bowers-replacement-xt-setting-ring-54-332-004 Quote Link to comment Share on other sites More sharing options...
gustav Posted January 17, 2017 Author Report Share Posted January 17, 2017 You need to use a gauge peice to check it against. So it could be a 1cm cube a ball bearing anything constant that you know the exact measurement of. You then turn until it just grips this object and read the scale see it matches. If it's close turn until it reads true and feel the tension required by backing off and re measuring. You will soon get the feel of what tension needed to get a true reading. Hence the reason need ones have a ratchet to make it easier to reproduce the right tension time and again. When both measuring surfaces are clean it should read zero when closed Either I have not explained myself properly or I am being exceptionally stupid even by my standards! How does one use a solid object to check an instrument that is intended to be inserted into a gun barrel? Sorry to have to bother you again. Many thanks, Gustaf. Quote Link to comment Share on other sites More sharing options...
figgy Posted January 17, 2017 Report Share Posted January 17, 2017 I've got the wrong end of the stick thinking you had a normal micrometer. As above you need a slip ring. When I said a cube or ball bearing I meant one you know the exact measurement of to use as a calibration gauge. Quote Link to comment Share on other sites More sharing options...
Mice! Posted January 19, 2017 Report Share Posted January 19, 2017 As bazooka says you need a setting ring for the mic, a cheaper option is a telescopic gauge normally in sets that you then measure with an outside micrometer as it just measures across two points Mice Quote Link to comment Share on other sites More sharing options...
Salopian Posted January 19, 2017 Report Share Posted January 19, 2017 I make shotgun bore gauges and wall thickness gauges . I will measure both bores and barrell thickness free of charge to PW members. Quote Link to comment Share on other sites More sharing options...
bakerboy Posted January 19, 2017 Report Share Posted January 19, 2017 Great offer from a great Bloke, who knows what he is talking about. Quote Link to comment Share on other sites More sharing options...
figgy Posted January 20, 2017 Report Share Posted January 20, 2017 Salopian do you have a website for your wares? Quote Link to comment Share on other sites More sharing options...
bakerboy Posted January 20, 2017 Report Share Posted January 20, 2017 (edited) Salopian do you have a website for your wares? I am not sure whether Peter has a web site. If you PM Peter he will talk you through, he is very knowledgeable and very helpful, plus of course a bl%dy nice bloke Edited January 20, 2017 by bakerboy Quote Link to comment Share on other sites More sharing options...
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