What's your favourite thread size?
Discussion
CrutyRammers said:
I was recently buying some unf bolts, I forget the size, 5/16 probably, and there were 2 different pitches being sold as unf. WTF is that all about?
UNF = unified national fineUNC = unified national coarse
Probably calling them both unified as shorthand.
Used to be identified with contiguous circles on one of the flats on the head, but cant remember seeing any like that for a while..
Essel said:
CrutyRammers said:
I was recently buying some unf bolts, I forget the size, 5/16 probably, and there were 2 different pitches being sold as unf. WTF is that all about?
UNF = unified national fineUNC = unified national coarse
Probably calling them both unified as shorthand.
Essel said:
Used to be identified with contiguous circles on one of the flats on the head, but cant remember seeing any like that for a while..
It's still in older drawings/specs, but not required if the fastener is already suitably identified with its part number etc.I like 1/4 BSP
But also
M16... if only because, these are chonky old bolts with nice heft and I am still amazed how someone at work managed to shear one in half when the thread got jammed whilst screwing the bolt in. So we have some pipe work with a flange where one bolt is missing because the other half is stuck in the thread.
But also
M16... if only because, these are chonky old bolts with nice heft and I am still amazed how someone at work managed to shear one in half when the thread got jammed whilst screwing the bolt in. So we have some pipe work with a flange where one bolt is missing because the other half is stuck in the thread.
1/4 BSC.
Worked for someone who thought they knew everything about engineering, trying to explain to him about different thread forms, and how yes you can force a BSP fitting into an NPF fitting they are not the same, and they don't really fit. Far better to get the correct fittings.
Worked for someone who thought they knew everything about engineering, trying to explain to him about different thread forms, and how yes you can force a BSP fitting into an NPF fitting they are not the same, and they don't really fit. Far better to get the correct fittings.
Huntsman said:
Not so.
Iso metric standard has a 60 deg thread form.
BA thread form is 47.5 degrees.
BA does not have the truncated top and bottom of the form like metric.
Its true that the BA starting point is a nominal 6mm diameter and 1mm pitch, but the series is most certainly not metric.
I don’t really want to get bogged down in the minutiae of thread nerdling. The form degrees are neither metric nor imperial,they are degrees. Also have a look at this. Basically BA is a metric system converted to imperial so it would be accepted by the engineers of the day. It predicted that in the future metrication was the way to go.Iso metric standard has a 60 deg thread form.
BA thread form is 47.5 degrees.
BA does not have the truncated top and bottom of the form like metric.
Its true that the BA starting point is a nominal 6mm diameter and 1mm pitch, but the series is most certainly not metric.
http://www.stubmandrel.co.uk/workshop/18-reference...
InitialDave said:
Essel said:
CrutyRammers said:
I was recently buying some unf bolts, I forget the size, 5/16 probably, and there were 2 different pitches being sold as unf. WTF is that all about?
UNF = unified national fineUNC = unified national coarse
Probably calling them both unified as shorthand.
Essel said:
Used to be identified with contiguous circles on one of the flats on the head, but cant remember seeing any like that for a while..
It's still in older drawings/specs, but not required if the fastener is already suitably identified with its part number etc.CrutyRammers said:
InitialDave said:
Essel said:
CrutyRammers said:
I was recently buying some unf bolts, I forget the size, 5/16 probably, and there were 2 different pitches being sold as unf. WTF is that all about?
UNF = unified national fineUNC = unified national coarse
Probably calling them both unified as shorthand.
Essel said:
Used to be identified with contiguous circles on one of the flats on the head, but cant remember seeing any like that for a while..
It's still in older drawings/specs, but not required if the fastener is already suitably identified with its part number etc.
1/4-20. The nearest the yanks get to the M6. But just as good as the version from this side of the pond ( unlike the Office)
Thread is wider though so you can screw them in quicker, they do tend to release with a ping though, if you're using a 3/16 T-Bar it can shoot a pain through your elbow.
We use panheads a lot ( which of course are 5/32 hex) and if the hex hole gets rounded off (because some t
t decided to try and undo it from tight with a ball end) it's big enough to get a centre punch on to the head and undo it that way.
Thread is wider though so you can screw them in quicker, they do tend to release with a ping though, if you're using a 3/16 T-Bar it can shoot a pain through your elbow.
We use panheads a lot ( which of course are 5/32 hex) and if the hex hole gets rounded off (because some t
t decided to try and undo it from tight with a ball end) it's big enough to get a centre punch on to the head and undo it that way.
wolfracesonic said:
A left handed one? 
I've been meaning to reply to this one...Years ago I was working nights and for whatever reason I had to work a late shift, 2pm~10pm. One of the blokes was setting a vertical machining centre with a Heidenhain control and the job required a left handed thread.
I was busy setting my own job but could see he was struggling as other blokes were wandering over to look at his program but he was still running the job in fresh air, ie not cutting material. Once I was up and running I offered to help and he explained he couldn't get the spindle to run anti-clockwise to tap left handed despite using an M04 in the program.
I asked him to show the tapping cycle and before he saw what I was doing I'd rewound the program, called up the tap and had the machine tapping left handed.
He asked what I'd done and I refused to tell him on the grounds that if he knew that he'd know as much as me,,,
He then checked the program and couldn't see what I'd done so asked again... Once again I refused to tell...
About two hours later it was almost time to go home so I finally relented and showed him which line I'd altered to tap left handed and he still couldn't see it so I showed him the exact piece of code I'd changed.
'How the f
k did you know that?'My reply of 'I was bored last night so read the manual for want of anything better to do' was not well received
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