DIY: Self Clinching Nut

[kinghong1970]

Self clinching nuts are basically what you see in many/most computer cases... tbh, threading a 16ga to 20ga aluminum sheet is not going to hold. and we've all messed with using a lock nut in the back but this is a bit cumbersome in some small spaces.

I've seen Lian-li cases use this often... they are stainless steel nuts that can be installed (via press) on aluminum sheets and have decent strength to fasten side panels and whatnot.

firstly, some good info resources i found on the web...
"The Basics of Self-Clinching Fastener"
Good source for installation requirements and types of fasteners
PEM fastener website with install animation reference

so doesn't seem that bad... and the usefulness... well... depends on the extent of your madness...

so as a quick test, i found some self clinching nuts at amazon.com and purchased 2 sizes, 4mm and 6mm fasteners.


first difficulty i've found was being able to drill appropriate sized hole with my limited drill bits... i have imperial sized drill bits whereas my samples were metric...

anywhoo, found something that seems to work and decided to give it a go...


first trial was a piece of aluminum 0.04" thickness

before breaking out my arbor press, i wanted to see if a c-clamp has enough force...


difficulty using a c-clamp is that the head swivels and so pressure applied is uncontrollable... i saw that the nut being pushed in on one side only as the head swiveled when i applied pressure.

but after numerous tries, it does work.. just not as efficient


so... time to break out the arbor press...

cheap at $45 from local harbor freight... buying this via mail order, freight probably more expensive...

did i mention cheap?

when i tightened the screw to fix the handle length, it just bends over... like butter...

so carefully peeled the plastic to give it a couple of tries... thinking to refund this...


and the results are much better... the pressure is applied more evenly... although there is still a bit of movement on the steel ram... and not quite machined flat.

(c-clamp install on right, arbor press install on left)

backside is a bit messy... i figure my drilled hole is a bit messy from start... and the pressure applied was not the best. but the good thing is that 1 ton was enough pressure to deform and push the aluminum around the clinch nut.


also, i did not quite peel the plastic all the way...

assembled it with some M4 screws

provides a nice and strong seam...

thoughts:
1) hole size needs to be as accurate as possible and i need to do further test after researching and finding the right size hole for the nut.

2) 1 ton arbor press does apply enough pressure to deform the aluminum to create a strong connection with the sheet.

3) strength is not bad... i tried to turn it with a vise clamp and it would not rotate... i can pull it out... but when pulled out, it will deform the sheet.



in conclusion, i think this is a very DIY-able method to fastening aluminum parts together... it does apply good strength and the amount of force required to un-seat a properly fastened nut will probably deform the case or aluminum sheets.

i will contact one of the vendor and try to get more "size-appropriate" nuts and drill bit to do a cleaner installation.

i will also return the 1 ton arbor press and order a 2 ton from grizzly...
probably the same manufacturer from china... but i want the headroom now that i feel that an arbor press is something i want to have.

i know that we have some members who are more experienced in working with this so i would appreciate your comments and advice.

thank you for your time.

cheers

Ape

[kinghong1970]

Self Clinching Nut: Round 2

well, not too much of an update... my shipment from Grizzly finally arrived.


this thing is HUGE compared to the 1 ton from Harbor Freight... and much better build imo.

first thing done was giving it a nice wipedown of all the Cosmoline gunk with Mineral Spirit and giving it a nice coating of Boeshield


this stuff is pretty nice... used it on my box and pan brake as well

Before...


After...


anyways, an another shipment from McMaster, more various sizes of PEM self clinching nuts


and picked up a bigger set of drill bits in 1/64 increments

so from left to right
Hole size 5/32 for 4-40 Thread Size, .056" Minimum Panel Thickness (Left)
Hole size 3/16 for 6-32 Thread Size, .056" Minimum Panel Thickness (Mid)
Hole size 11/64 for 6-32 Thread Size, .056" Minimum Panel Thickness (Right)


back side: (4-40 on right)


the 3/16 was a bit big for the 6-32 nut but it did give a cleaner backside... the 5/32 seem to work fine for the 4-40...

all tests were done on 3003-H14 Alum Alloy 0.05" thick

here's another shot of the "face"


well, now that i've gotten this to work, next, bending...
slowly and yet progressing...

thanks for reading!

[OldChap]

Here in UK we have Rivnuts and a hand tool to fix them.... Not sure how similar they are but the end result certainly is.

http://www.memfast.co.uk/

http://www.memfast.co.uk/shop/vclose...cat=2258005402

[kinghong1970]

OldChap,

i've played around with rivnuts... pro's and cons to both really...

a clinch nut stands out appx 2.5mm on the backside, and i find them much stronger than rivnuts and slimmer proflie than rivnuts.
rivnuts fastened w/o notching the hole can spin... whereas this one has little gear like teeth that the alum gets pressed around and filled in...

but otoh, rivnuts are easier to install, set of brain, good fingers, and some machine screws...

thanks for your feedback.

[charles_h]

Fantastic Albert; very nice guide!

Looks like you've got something in the works - at least I hope so.

[bluc]

Thanks for the info!! I was looking at keyed Rivnuts for my current project might see if I can find these over here in Australia cheers.

[Bobsama]

Here's a question--how functional is using epoxy to turn a bad pressing into a useable one?

[kinghong1970]

Fantastic Albert; very nice guide!

Looks like you've got something in the works - at least I hope so.

thanks Charles... at the moment, i'm trying to decide on what thickness the chassis needs to be... and the exterior bezels... running into a bit of problem... being that they need to support the case and yet have sleek look to it... anywhoo... sooon... hahaha

Thanks for the info!! I was looking at keyed Rivnuts for my current project might see if I can find these over here in Australia cheers.

anytime! i'm glad it was of some help to you... here's what i found for PEM distributors in AUS

Ampec Technologies Pty. Ltd.
garry@ampec.com.au
www.ampec.com.au

Complete Machine Tool Services Pty Ltd
michael@cmts.net.au
www.cmts.net.au

good luck!

Here's a question--how functional is using epoxy to turn a bad pressing into a useable one?

hmm... not sure if i can help but the only place i've used epoxy is for my bathroom vanity top on cherry slab...
are you asking to use epoxy to fix metal?

perhaps some pics can be of more help?

[Bobsama]

hmm... not sure if i can help but the only place i've used epoxy is for my bathroom vanity top on cherry slab...
are you asking to use epoxy to fix metal?

perhaps some pics can be of more help?

I mean using a product like J-B Weld to bond together the (loose) sc nut to the aluminum plate.

[kinghong1970]

duh, sorry, it's monday and my brain is still on the weekend mode.

i've thought about it... but honestly, i felt that even with a 1 ton press, i was able to achieve enough of a pressure to fix the SC nut tight enough for most machine screw application on alum sheets.
when i tried to pry the nut out, it can be done, but it will require enough force to deform the sheet first.

the biggest concern was to make sure you have as close of a hole as possible to the requirement and clean the hole... deburring is a must.
as you can see from my 2nd trials, even when the drilled hole was not exact and a bit loose, the fastened nut held well... and more importantly, the face side (flat side) remained clean.

i worry about jb weld application, don't want to create a mess on the thread... nor do i feel quite necessary to take the additional step to fasten this.

hope i've answered your question...

[Manicdan]

you have inspired me to try this out

i was originally thinking of tapping 58 holes so i can use thumb screws, but this actually seems easier, although more expensive.

planning on using clinching nuts on 1/8" thick aluminum L beams and i found them on mcmaster at 12$ for a 50 pack. the build wont happen for months so dont expect an update next weekend.

[kinghong1970]

coming soon... test 3 with flush nuts...

[Hondacity]

I mean using a product like J-B Weld to bond together the (loose) sc nut to the aluminum plate.

j-b weld will hold things together, i experimented with some nuts and bolts and they're pretty much welded lol. hammering it or ln2 submersion didn't make it crack.

i used the 2 tube ones. i forgot its name.

[kinghong1970]

you have inspired me to try this out

i was originally thinking of tapping 58 holes so i can use thumb screws, but this actually seems easier, although more expensive.

planning on using clinching nuts on 1/8" thick aluminum L beams and i found them on mcmaster at 12$ for a 50 pack. the build wont happen for months so dont expect an update next weekend.

also, tapping just aluminum sheets is not going to be strong enough... if your sheets are quite thin... hence i started playing with scnuts.

[Manicdan]

^ it would be 1/8" thick aluminum and using 6-32s thread, so it works, just a real pain keeping it strait (was going to use a drill press to help tap) and the threads did feel a little loose, but work well. however time and effort and how easily it is to make a mistake, clinch nuts just seem the way to go.
plus the name sounds weird and thus i like them more.

[kinghong1970]

Self Clinching Nut Part 3: Flush Nut

so the previous type of SCNuts left a threaded cylinder on the back side...
this type, as the name implies, installs flush to the surface.

the contenders:


the middle one, sadly, i did not have alum sheets thick enough to test it.

problem with drilling holes... i get a 3 sided wobbly hole instead of a perfect circle... wondering what may be the issue...


my solution...


results...

but have to take it slow... making sure the hole does not get too big...

Flush Nut installed:

as you can see, i needed practice in getting the hole clean and of proper size.

Back Side is almost flush...


and of course, to congratulate myself... a new toy from Chinese Harbor Freight... meh, cheap but gets it done...






now that i know that i can work with 0.05" with ease, i think i'll need to place some order for some sheet goods...

[Manicdan]

omg i love those flush nuts, they look so professional on the back side

[kinghong1970]

yep, to my surprise, 2 ton presses the steel nut into the sheet and installs nicely...

[s0lid]

Hmm gotta look where i could get some M3 and M4 flush nuts around here. Got good press drill and 20 ton hydraulic press in my dispose at the moment

[Waterlogged]

Yo kinghong, what's up? Excellent topic

btw, Mcmaster sells these as "captive nuts" and they are also known as "insert nuts".

[kinghong1970]

WL!!! how are you?!?!

yea, i'm loving Mcmaster... and Fastenal as well... but it seems i can buy it all from McMaster at the moment.

still tinkering... still trying to see what mess i can get myself into!
thanks for your comments!

[s0lid]

Got my M3 flush nuts today.



50 in each bag, different coating. Nothing else.

1.5mm steel sheet, 4mm drill and ~2.5 tons of press.





Works alright. I used a bit too much pressure and too soft metal at the back of the steel sheet, the back of flush nut sunk into it hence that test piece is bit bent
And the metal piece i used as counterpart certainly was not too thin, about 6cms of casted iron with thick layer of paint. Gotta locate chunk of hard metal from somewhere before i start building the next project.

[kinghong1970]

nice... but are you trying to install flush nuts on steel?
check on the applications... imo you can apply on soft metals like copper but on steel, maybe you are better off with rivnuts.

and you have to check to have clean hole... deburr all your holes... a clean hole is a happy hole!

[s0lid]

I'm not trying. I already did!
Works just fine and certainly won't come off without pliers and lots of force.

Yeah, gave the hole a quick filing but that was just a test run, clean the edges better when i actually start using those.

[SpuTnicK]

Can Self Clinching Nuts be used with out drilling a through hole? What i mean is there are specs saying the min thickness of a sheet to attach it to, say 1mm. So if i have 3m thick sheet and i drill a 2mm hole will Self Clinching Nut be able to fasten(using simple press and anvill) in that hole?