Small Nutserts for Plastic or Alternative?

[thr3squared]

I am making a switch panel for my truck that will mount under an aftermarket head unit. The mounting hardware will be one M4 screw on either side.

The kicker- the mounting surface is plastic and I only have 0.47” (wide) of surface to work with for the nutserts (or similar) and most I’ve seen need a 1/2” or more. The main reason I wanted to use a nutsert was to make the panel removeable without dismantling the dash if I had a wiring issue.

Any other ideas or suggestions? I thought about epoxying hex nyloc nuts behind the dash instead of an insert. That would hold the screw tight and eliminate the need for a lock washer.

Cheers!

 

[cmandp]

I'd look into using heat set plastic inserts if the head unit adapter has the thickness. https://www.mcmaster.com/94459A150/

You can melt them in with a soldering iron with a standard tip. They sell special installation tips too that fit the minor diameter of the thread but I never forked over the $20 for one.

 

[thr3squared]

I haven’t seen those before, pretty cool application.
I’m not sure if the thickness of the plastic will be sufficient for those but I’ll check - my guess is it’s pretty thin.

 

[mike93lx]

How often do you need to be able to remove this? If rare, you could just pull out the dash kit and that would allow you to glue the panel in place, greatly simplifying this install

 

[Jeff Ivers]

I would not use nylocks. The gripping force (resistance) on them can transfer to the material they are glued to and break the plastic. Why not use automotive panel nuts (not sure of correct name) - the type where a nut is afixed to a u-shaped piece of metal that slides over the panel and when the bolt is tightened the u-shape clamps the panel?

 

[oldmachinenut]

https://www.amazon.com/dp/B00OVWAF1C/?tag=atomicindus08-20

 

[thr3squared]

I would not use nylocks. The gripping force (resistance) on them can transfer to the material they are glued to and break the plastic. Why not use automotive panel nuts (not sure of correct name) - the type where a nut is afixed to a u-shaped piece of metal that slides over the panel and when the bolt is tightened the u-shape clamps the panel?

Are these the style you're referring to?

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[thr3squared]

How often do you need to be able to remove this? If rare, you could just pull out the dash kit and that would allow you to glue the panel in place, greatly simplifying this install

Ideally not that often. I'm only using two of the three switch holes (ill have a blank-off for the third), so if I want to add another I will need access.
The backs of the switches wont be exposed even if I remove the dash kit because there sitting in a little pocket (like for your cell phone or whatever) under the head unit.

 

[thr3squared]

https://www.amazon.com/dp/B00OVWAF1C/?tag=atomicindus08-20

Will those work in plastic?

 

[kerrynzl]

I am making a switch panel for my truck that will mount under an aftermarket head unit. The mounting hardware will be one M4 screw on either side.

The kicker- the mounting surface is plastic and I only have 0.47” (wide) of surface to work with for the nutserts (or similar) and most I’ve seen need a 1/2” or more. The main reason I wanted to use a nutsert was to make the panel removeable without dismantling the dash if I had a wiring issue.

Any other ideas or suggestions? I thought about epoxying hex nyloc nuts behind the dash instead of an insert. That would hold the screw tight and eliminate the need for a lock washer.

Cheers!

Use metric countersunk nutserts
4mm is only 8.5mm across the flange.

 

[Grant Gunderson]

Self clinching nuts, could also work for your application.

 

[oldmachinenut]

Will those work in plastic?

I have used them many times in plastic. I drill one size smaller then use a hand reamer to make sure the hole is just big enough for the insert. I do the same when I install them in metal.

 

[mike93lx]

Ideally not that often. I'm only using two of the three switch holes (ill have a blank-off for the third), so if I want to add another I will need access.
The backs of the switches wont be exposed even if I remove the dash kit because there sitting in a little pocket (like for your cell phone or whatever) under the head unit.

You could just cut away the back of the pocket.

I do this all the time. Think through an elaborate solution to a problem because it's fun and interesting then end up choosing the simple path. Just throwing the idea out there

 

[MP&C]

A press nut from the back side would be less likely to want to pull through the plastic. These are made for plastic.

Nuts, M4 x 0.7 mm Thread

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[WoodsTruck]

For his thin plastic application, would heat be the better way to set these press in nuts to keep from cracking the plastic?

 

[MP&C]

For his thin plastic application, would heat be the better way to set these press in nuts to keep from cracking the plastic?

I was worried they might pull through if over tightened

 

[Jeff Ivers]

Are these the style you're referring to?

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

That is one of several variations I have seen. Some work with sheet metal screws instead of bolts.

 

[kerrynzl]

I'd look into using heat set plastic inserts if the head unit adapter has the thickness. https://www.mcmaster.com/94459A150/

You can melt them in with a soldering iron with a standard tip. They sell special installation tips too that fit the minor diameter of the thread but I never forked over the $20 for one.

Thanks for that link. [I've never heard of these until now]

I just looked at this video of these. This would be the winner here

 

[thr3squared]

A press nut from the back side would be less likely to want to pull through the plastic. These are made for plastic.

Nuts, M4 x 0.7 mm Thread

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

These get pressed in from the back side of the panel correct? That installation tool is $$$ wow. I may be able to get access to an arbor press...could I use a small C-clamp to press it in?

 

[thr3squared]

You could just cut away the back of the pocket.

I do this all the time. Think through an elaborate solution to a problem because it's fun and interesting then end up choosing the simple path. Just throwing the idea out there

I am VERY guilty of over complicating a simple job just because I'm trying to be creative haha. And you are right, once the panel is in place there is no need for the "pocket" any longer.

 

[thr3squared]

Use metric countersunk nutserts
4mm is only 8.5mm across the flange.

For these would the flange size "S" be the thickness of material required?

 

[cmandp]

These get pressed in from the back side of the panel correct? That installation tool is $$$ wow. I may be able to get access to an arbor press...could I use a small C-clamp to press it in?

Yes, from the back side of the panel in your case. You always want self-clinching nuts being pulled into the material when you tighten the mating fastener.

No you don't need the special hand press. Yes you can use other methods to install them. I usually end up using a bench vise with some aluminum to keep from marring the work. An arbor press would be great if you have one or access.

I've not used the soft material version MP&C linked to but that seems like the least amount of work. Drill the correct sized hole and press the nut in.

 

[thr3squared]

After much research and measuring I finally had to go back to my original plan of epoxying a nyloc behind the dash kit.

I experimented with rivnuts I had on hand and without a washer for backing (for which there was no room) it deformed the plastic. The plastic wasn’t thick enough for a PEM from the back side. And so it went. I’m sure there are other specialty fasteners out there that I didn’t find, but for now I’m happy with the result.

Now onto the pictures!



I did countersink a couple of the prototypes but ultimately went with button head hardware.



Cut the dash pocket for better wiring access




Nuts epoxied in place



Mounted and done.