Pan Head Bolts

[Neeves]

I have some pan head bolts, I think that is the name, and at the top of the shank, as part of and 'under' the domed head, they have a square section that is designed to fit into a square recess - this then locks the head (so that you can tighten the nut at the other end)

The question is - are these simply called pad head bolts?

I ask as you can source other pan head bolts with a recess in the head to accept an alan key.

 

[Crazy-Diamond]

www.westfieldfasteners.co.uk

I use this excellent company, have a look.

 

[Spirit (of Glenans)]

Bolts with a domed head, and a square section under, are called coach bolts.

 

[PetiteFleur]

Coach bolts or carriage bolts - Stainless Steel of course. Lots of suppliers on ebay.

 

[rogerthebodger]

Carriage/coach bolts

Pan head bolts slotted or phillips/pozi

 

[Old Harry]

The last 2 pix are pan hd machine screws

 

[Neeves]

Crazy Diamond - excellent, I have taken a look

Thanks all, so quick - what a knowledgeable group of people.

Jonathan

 

[rogerthebodger]

The last 2 pix are pan hd machine screws

Yes generally when the thread goes all the way to the head it called a set screw but it also depends on the length of the threaded portion of the bolt/set screw.

If you have a short bolt the thread length can be the same as the length of the bolt.

A M10 x 25 long bolt will have a thread to the head but a M10 x 30 long will have the thread up to 4mm from the head

A M10 x 100 ling bolt will have a thread 26 mm long and the rest plain where as a M10 x 100 long set screw will be threaded all the way to the head.

 

[Neeves]

Having opened up this cornucopia on bolts....

Is there a reason why a bolt fully threaded is called a machine screw - why not call it fully threaded. Are part threaded bolts made a different way from 'machine screws)?

Jonathan

 

[VicS]

Having opened up this cornucopia on bolts....

Is there a reason why a bolt fully threaded is called a machine screw - why not call it fully threaded. Are part threaded bolts made a different way from 'machine screws)?

Jonathan

It isn't .... It's called a "set screw" although Ive known them to be called "set bolts"

 

[rogerthebodger]

Having opened up this cornucopia on bolts....

Is there a reason why a bolt fully threaded is called a machine screw - why not call it fully threaded. Are part threaded bolts made a different way from 'machine screws)?

Jonathan

Now you have opened a bag of worms.

Screw is a generic term for a pin with a raised helix and a head used to attaching items together.

A bolt is cheaper to make then a set screw of the same size as the thread is shorter.
The shear strength of a bolt is greater but the tensile strength is the same as a set screw

Example
Machine screw
Wood screw
Self tapping screw.
Screw clamps
Machine lead Screws
etc.

Then you have the verb To screw have a many meanings like "to steal an item or defraud someone.

Screwing is the action if fitting a screw fastening.

Then the is the other screwing being of interaction between consenting people.


Lead screw on a machine tool

 

[duncan99210]

So, essentially, whichever way you look at it we‘re screwed.....




I‘ll get my coat.

 

[RichardS]

If it can take a nut, it's a bolt. If it can't take a nut, it's a screw.

Everything else is just flannel.

Richard

 

[Stemar]

I think you'll find flannel doesn't take a screw very well.

It stains too easily

Sorry, I'll get my coat...?

 

[MM5AHO]

for stainless fixings (watch which stainless though, order the stuff you need), check out Aruncas an eBay shop. (no relation, just satisfied customer)

 

[AngusMcDoon]

Crazy Diamond - excellent, I have taken a look

Thanks all, so quick - what a knowledgeable group of people.

Jonathan

If stainless you need to choose you material, A2 or A4, and temper grade, 50, 70 or 90. If the bolt it's replacing is higher than the standard 50 grade it will be marked on the head. (Higher temper grades can be tricky to buy in small numbers). Then you need to get the correct torquing value which depends on the material, grade & lubrication. Google knows. That's if it's in a critical location (this type of bolts attach the beam hinges on Dragonfly trimarans, a critical location if there ever was one). If it's to hold you garden bench together then it probably doesn't matter.

 

[Rappey]

What about bolts with rolled threads rather than cut ?

 

[RichardS]

What about bolts with rolled threads rather than cut ?

Errrr .... those are bolts, no question.

Richard

 

[rogerthebodger]

What about bolts with rolled threads rather than cut ?

With rolled threads the diameter of the unthreaded part of the bolt could be smaller then the diameter of the unthreaded part of the cut thread bolt.

 

[Rappey]

I came across some extremely expensive titanium bolts with rolled threads used for satellites! Apparently standard cut threads made the bolts weak !