Has anyone please got an idea where I could get a bolt like this?

**mekanik** · 11-01-2015

If you can't make it yourself make sure it is made from height tensile steel, also take a sample and tell them to reproduce the radius were the dia meets the square, if this is done with a sharp tool it will produce a stress raiser.
Regards
Mike

**bmbaz** · 11-01-2015

if you know the material that the bolt is made of turn and thread one 14mm diameter then put the square on, the formula is 1.414 x across flats for the dia of a square, this should also be about the same weight if this cant be done I could knock you one up at work out of en8 or 19t

**suesi34e** · 12-01-2015

Dear bmbaz,

Many thanks for your help and offer to make me a bolt if I get stuck. I understand the 1.414 side of things. If I take you up on your offer please let me know what I owe you and I will pay you.

Many thanks

Suesi

**suesi34e** · 12-01-2015

Hi mekanik,

Thank you for you msg. I can't make one myself. However, I can tell what you are telling me is important although I am sorry I do not understand what you mean by "tell them to reproduce the radius were the dia meets the square" I could learn this I think it could be doing. You say if that is done with a sharp tool it will produce a stress raiser, so is there a time when a blunt tool is better?

Many thanks for the help

Suesi

**Neale** · 13-01-2015

Originally Posted by suesi34e

You say if that is done with a sharp tool it will produce a stress raiser, so is there a time when a blunt tool is better?

No, it means use a sharp tool, but with a rounded tip rather than a sharp angle at the tip. That would leave a radius in the corner rather than a square corner, which is good from a stress-reduction point of view. Any sharp change in dimension concentrates the stress at that point. It's very seldom better to use a blunt tool for anything!

**suesi34e** · 13-01-2015

Hi Neale

Many thank for your msg. I see what your saying and understand now.

I appreciate the help

Suesi

**mekanik** · 13-01-2015

Suesi
Dia is an abreviation for diameter ie 6mm the radius is formed where the diameter intersects the square section (like head of a bolt) when a bolt is torqued it actually increases slightly in length and loads the assembly,if there is a sharp junction a crack can propergate in that area especially if the item was subject to and impact. The radius helps to distribute the load, some of the guys on the forum have the software that can show stress analysis.
As for the cutting tool,NO there is no time when a blunt tool is preferable to a sharp one (to the best of my knowledge), in this case you would just produce a slight radius on the tip of the tool still maintaining the correct clearance angles. hope that makes some sort of sense.
Regards
Mike

**suesi34e** · 13-01-2015

Thank you mekanik, what you and Neale have said makes a lot of sense and I see where your coming from. It is a long time since I have had cause to look in my Zeus book but I will have a look through it as I seem to remember something about what your mentioning been in it.
I am very grateful of your help.
Suesi