Bolt thread what nut?

[Gary]

What nut will fit a bolt that is 5/16" x 18tpi?

5/16 UNF or 5/16 BSF or 5/16 BSW or will I have to measure the thread?

 

[CHJ]

Possibly 5/16" - 18 UNC (60deg thread angle)

or BSW (55deg thread angle)

Need to check thread angle, often DIY shop nuts will fit on either.

Not safe to use incorrect nut in high load situations.

 

[t8hants]

5/16x18 is the thread pitch of both BSW and UNC. If the bolt head is plain or only has the makers initials marked it is probably BSW. if it has either a circular recess or three lines at 120 degrees around the top it should be unc. Don't be tempted to wind the wrong one on, its bad practice.

G

 

[Gary]

Bolts aren't marked and I only have a metric gauge.

The bolts are Dakota from Rutlands if that helps.

 

[Digit]

From Dakota I suspect UNC. This may help though.

http://www.numberfactory.com/nf%20screw ... 0bolts.htm

Roy.

 

[Gary]

Nice link Roy, but means nothing to me.

Can someone translate or tell me what I should be looking at?

As I said, I only have a metric guage so couldn't measure the bolt.

 

[Digit]

Measure the bolt head across the flats, the AF dimension. IIRC UNC and Whitworth are different.

Roy.

 

[Gary]

They are T bolts, I don't see that option on the chart. ](*,)

 

[Digit]

My tee bolts from Dakota are UNC.

Roy.

 

[andycktm]

unc. Whitworth is from the arc,if if was a spare wheel off the flintstones motor then maybe...

 

[Gary]

Thanks Roy

I'll go with that, I can't see why mine should be different. \/

 

[brianhabby]

Whitworth is from the arc,if if was a spare wheel off the flintstones motor then maybe...

Or a camera tripod bush, they are ¼ & ⅜ Whitworth and still in regular use

regards

Brian

 

[Digit]

And just about every nice old car and steam loco in Britain and the 'Empire.'
I've still got all my old BSW spanners and they still come in useful even now.

Roy.

 

[Gary]

Cheers Roy,

Just got hold of some 5/16 UNC nuts and they are the correct size. =D>

 

[CHJ]

Whitworth is from the arc,if if was a spare wheel off the flintstones motor then maybe...

Or a camera tripod bush, they are ¼ & ⅜ Whitworth and still in regular use

regards

Brian

Not necessarily so for modern equipement.

Tripod Threads DIN 4503 / ISO 1222
1/4" - 20 UNC
This thread is used for rangefinder camera, roll film cameras (also DSLRs) up to medium format cameras, quick release plates and panoramic heads.

3/8" - 16 UNC
Some medium format cameras and almost all large size cameras as well as most of the connectors between tripods and panoramic heads use this thread.

The problem being that they will often interchange but can result in damage to expensive equipement if not of the correct thread form.