Silly Question Time

[Robert Greenwood 1Participant @robertgreenwood1]

Hello,

I was wondering if somone could help me out on this.

I'ts been many years since i have read a drawing of this type, as you can see from the image i wan't to know what 3 x .189 holes means? i understand that 3 x stands for the amout of holes but i don't undertsand what the .189 means?

I am use to working in imperial but can't remember seeing this.

Thank you very much!

Cheers

Rob

 

Edited By Robert Greenwood 1 on 13/01/2015 14:04:43

[Robert Greenwood 1Participant @robertgreenwood1]

[Speedy Builder5Participant @speedybuilder5]

3 Holes each hole 0.189 inches in diameter. This would be a number 12 drill (Nearest fractional drill is 3/16 inch diameter). I am guessing that the holes are either for 2Ba bolts or (perhaps 3/16 BSF – which are not quite so readily available).
BobH

[BikepeteParticipant @bikepete]

Presumably just 0.189 of an inch, i.e. just under 1/5 of an inch. So just the decimal way, rather than fractional, of expressing the size in inches.

A quick lookup e.g. here suggests a 4.8mm or No. 12 drill would be used to make that size of hole.

[steveteeParticipant @stevetee]

A long time since I worked in Engineering , but .189 is 1 1/2 thou larger than 3/16" . So a 3/16 rivet or screw would go through the hole, but it would be quite a tight ( transitional) fit. Does that make any sense.

Where I worked it would have been represented as 3/16+.0015 , probably with some limits applied . From what I remember if just the size in fractions was given it would be plus or minus .005 , the .198 would represent a dimension with a tight tolerance on it.

[Robert Greenwood 1Participant @robertgreenwood1]

Thank you very much to both of you!!

Very quick responce!

[Raymond HodgesParticipant @raymondhodges20973]

its also 4.80mm

ZEUS Precision data charts Metric Revision

Regards

Ray

[NJHParticipant @njh]

Hi Rob

They do say that there are no silly questions – only silly answers. What you have here – to your sensible question – is 5 sensible answers and just one ( my!) silly answer!

QED

Norman

Edited By NJH on 13/01/2015 15:23:48

[Neil WyattModerator @neilwyatt]

What I don't understand is why the holes aren't marked 3 x No. 12

Neil

[Bodgit Fixit and RunParticipant @bodgitfixitandrun]

Posted by Neil Wyatt on 13/01/2015 18:02:38:

What I don't understand is why the holes aren't marked 3 x No. 12

Neil

Could be that they realised that someone might not know what a No. 12 was, unless they were ordering a chinese takeaway?

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