A Noob venturing into fabrication... step by step... Self Clinching Nut: Self clinching nuts is 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 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
A basic shop vise works on them too. I've countersunk them in 1/4" plexiglas with good results as well. -Of course you have to use epoxy instead of pressing them there.
Might work if you're drilling smaller holes. Eg. You only need a 600W drill press capable of 4500RPM if you're drilling a 2.7mm hole (for M3 tapping) in aluminium. 3000RPM for mild steel and deduct another 15% for stainless steel. You can check out the charts here: http://www.flowdrill.com/parameters
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!
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...
thank you IanW for your advice... i think it may also have to do with hand holding the plate and drilling it with a hammer drill as well... but i'll be sure to try out lower speed on a drill press next time.
slower should help massively. Whenever I'm drilling metal, the drill barely turns. Takes a bit longer than just going full whack, but it gives great results. Never had a problem with wobbly holes. Much safer to get the plate held with something other than hands too, as if the drill bites, and the sheet starts turning, it gets nasty, although with the slower speed its less of a problem, unless its a very small piece of sheet, then it just shreds your fingers rather than your whole arm,
A step bit should help lots. It would generally have the steps you need (check the clinch-nut datasheet for the drill size needed) and the drilled holes are perfectly circular (unless your chuck is off-center) without burrs.
no kidding... in my nub days, tried to pop a 80mm hole on a drill press... scared the crap out of me seeing the side panel doing a frisbee spin on the press...
problem with G-Clamp is that it has a swivel head and the surface is also not quite flat... it is not impossible... just not so clean. a fairly large sized clamp should give enough pressure to fix a SCNut onto alum sheets. i'd use a masking tape or something to hold it in place while applying pressure. if you have a vise, that could also be another method... but most vise have grid/teeth on the faceplate that will leave marks on your panel.
great info. I'm new to the captive nuts thing. I don't plan on using a lot of them, so a vice is probably going to be the route I take. I too recently bought that exact same bending brake from Harbor Freight. Got it on New Years Day on sale with a 25% off coupon. So far I'm pleased with how it works, although I wish it could do box bends.
the trianular hole is because the drill loses it's steering when you o trought the sheet before all of the drills "cutting edges" has submerged the surface (aka made a hole a couple of milimeter below the surface) and becuse of that loses it's stering and gets a lot of pressure on the 2 cutting edges and makes them "jump" and then it gets more and more triangular. You can help this by lowering speed (smaller jumps, none if you go slow enought) OR you get a countersunk tool with atleast three cutting edges/a guidetap in the same diameter as the center hole and can go at any speed you want! (depends on the material and witch kind of tools/material you use ofcourse) so the problem lies in the drillbit itself, 2 cutting edges makes it wobbly, 3 or more a lot more stable, if you ever have tried to drill with a hammerdrill in concrete, you know the hole always wander of a little bit, if you go to a professional store and get a drill with 3 or 4 cutting edges you wil get perfect round straight holes every time and as a bonus it will also drill sraight trought the steel reinforcers in the concrete. Sorry for the sidestep about concrete but the difference is so much bigger in that material so it's easier to compare. Hope this wall of text helped someone, if you wonder anything just pm, english it not my native language so there might be a lot of spelling and wrong used words in it
wall of text very helpful kelmannen! much appreciated... i tend to rush things in excitement... next time i'll use my drill press instead of a hand held hammerdrill. slow does seem to do the trick.
