Maker Pro
Maker Pro

Low-Profile Temporary Metal Rivets

Ian

Administrator
Aug 23, 2006
1,486
Joined
Aug 23, 2006
Messages
1,486
I'm on the lookout for a product, but I don't know if they exist or what they would be called - hopefully someone here may have come across them before!

I'm building a CNC machine that will have a spoilboard with an array of holes drilled in to it (maybe in a 100mmx100mm grid) - I want to use these to hold down workpieces securely with a clamp system. Most people drill these holes and then bang in tee nuts from the other side, providing a screwthread to give a secure anchoring point for a jig/clamp.

Instead, I was hoping that there was some form of temporary metal rivet that I could push in to a hole and secure with some sort of spring mechanism. There are Cleco fasteners (demo here) which look like they would work, but they would protrude too far above the workpiece. I'd ideally want a low-profile version of this, if it exists.

Has anyone seen any sort of fastening mechanism that may fit the bill?
 

Tha fios agaibh

Aug 11, 2014
2,252
Joined
Aug 11, 2014
Messages
2,252
Have you considered metal threaded inserts? They are incredibly strong when applied with epoxy.
You could opt for something like push in anchors like used in automotive, but are probably not strong enough.
 

kellys_eye

Jun 25, 2010
6,514
Joined
Jun 25, 2010
Messages
6,514
Not so sure anything so temporary as a 'spring-loaded' device would afford the pressure/clamping levels necessary to ensure safe location of the material.

Are you willing to risk losing a milling/cutting head and a damaged design for the sake of a few minutes using 'secure' bolts?

I recall seeing a spoof picture in a car magazine for a 'clamp on cylinder head' design for ease of servicing........
 

Ian

Administrator
Aug 23, 2006
1,486
Joined
Aug 23, 2006
Messages
1,486
Have you considered metal threaded inserts? They are incredibly strong when applied with epoxy.

That's my fallback, but I'm hoping I can avoid using tee nuts if possible - as I'll need to re-do them each time I replace the spoilboard. I was hoping to just use the CNC router to drill an array of holes and use a clamping mechanism that could use that alone. I suspect I will need to go down this route in the end though.

The tee nuts I mean look a little like this (below). Is that what you meant by metal threaded insert?

shopping.jpg

Not so sure anything so temporary as a 'spring-loaded' device would afford the pressure/clamping levels necessary to ensure safe location of the material.

Are you willing to risk losing a milling/cutting head and a damaged design for the sake of a few minutes using 'secure' bolts?

Good point. I'll be working with aluminium plates sometimes, so perhaps using a jig/spring combo isn't going to be enough to hold it in place if something goes wrong.

It's not so much the time saving I'm aiming for, but a way to avoid having to have the spoil board contain so many tee nuts that are wasted when I replace it.

Perhaps a better idea would be to have a 2 layer spoil board, with the lower section containing tee nuts and the upper section just holes. These could be bolted together and only the top section replaced when required. If I align the boards and run the same cutting GCODE, it should work well (in theory).
 

Tha fios agaibh

Aug 11, 2014
2,252
Joined
Aug 11, 2014
Messages
2,252
inserts.png
I was thinking about these threaded inserts.
You insert them from the top. They sit flush or slightly below the serface. Outer threads screw into the wood when installed and inner portion is factory drilled/tapped to accept a screw. When installed with a drop of epoxy they are really strong.
 
  • Like
Reactions: Ian

Ian

Administrator
Aug 23, 2006
1,486
Joined
Aug 23, 2006
Messages
1,486
Thanks - as it happens I've got a box of those already, so I'll try this out :).
 

kellys_eye

Jun 25, 2010
6,514
Joined
Jun 25, 2010
Messages
6,514
There are also these type of inserts:

Insert.png

I use them a lot for mounting monitors in my workshop - the hex head (standard metric thread inside) allows you to get a real good tight fit (giggidy).
 
  • Like
Reactions: Ian

Tha fios agaibh

Aug 11, 2014
2,252
Joined
Aug 11, 2014
Messages
2,252
They have a hand insertion tool for them but I prefer to use a cordless drill or drill press to put them in so even feed pressure can be applied and they go in plumb. If you do it by hand and they may go in crooked or strip out the hole.
It sounds like you've used them before. Even so, its not a bad idea to practice on a piece of scrap wood.
 
  • Like
Reactions: Ian

Ian

Administrator
Aug 23, 2006
1,486
Joined
Aug 23, 2006
Messages
1,486
Cheers guys - I'm going to scrap the temporary rivets idea and go for these inserts :). The ones I've got look a little closer to the ones that @kellys_eye posted (with a flange).
 
Top