What are these called? To accept Allen Key bolts

[quyeno]

Hi everyone

I'm new to wood working and planning my first project to make my own Parallettes. They're used to practice gymnastics. I want to make my own because they are ridiculously expensive for what they are....wooden poles and wooden brackets! I'm going to copy a design which allows the parallettes to be dismantled for travel. It's very easy to make even for a beginnner like me and I have access to a work bench and vertical drill jig. However I'm a bit stumped on a certain part I'm trying to source. I have attached a picture of the kit I am copying. As you can see from the red arrows; the end of the bars and brackets have holes in them to accept Allen Key bolts, the kind you find in DIY furniture.

What I want to know is what are those parts that are in the ends of the poles and the brackets? I imagine its some sort of plastic or metal threaded 'plug'.

Any help would be great!

Thanks
Quyeno

 

[IHc1vtr+]

Threaded inserts

http://www.ebay.co.uk/itm/20-PACK-M8-x- ... 4adb2a2720

 

[marcros]

Or insert nuts if you go to screwfix. http://m.screwfix.com/p/insert-nut-type ... wwodhLEApA

Allen bolts are socket screws- with the head type- csk, cap, cheese etc.

 

[jordec66]

Hi, they are usually called insert nuts.