21 Mar 2025
I was reading on the Series 2 Club Forum about how rivnuts stuck up above the surface and how to seal the gap. Typically this is where the footwell and the floorboards meet. The problem arises when the caged nuts from the factory rust out and need to be replaced. Since they are welded on something else needs to happen.
Thinking about it I figured that I have an air tool that indents an edge, couldn't something which makes a circular indent be made?
At first I started thinking about 1/4-20 rivnuts. Looking around I found a scrap of 16 gauge steel and drilled a couple of holes in it to fit the 1/4-20 rivnut this needs an 11/32 hole for it to drop in.
I left 1/8 of an inch or so from the end,
Center punched it as close as I could get and drilled a 13/64 x 1" deep hole in it. Then tapped it for 1/4-20.
Hoping to be able to use a bolt to push down on the sheet metal and force it into the recess. I found a piece of tubing to slide over the 1/4" bolt to do the job. All the bits laid out;
Inserting the tool into the hole is when I realized it was too small, it was barely larger than the hole. Two and a half hours gone.......
The next day........
So I started over scaling up. I found some 5/8-18 grade 8 bolts and some old tie rod with a 5/8"id for a sleeve. Measured off 5/8" and cut it off with my tubing cutter. I have to say this was the hardest step to do in the whole job, it took around 300 revolutions of the cutter to make the cut! Both my arms got tired and I worked up a sweat. I wished I had a lathe throughout this whole job.
Double nutting the threaded end, both for strength and adjustment. Then drilling and tapping the hole for 5/16-24 thread.
This felt like it might work. I slid the tool into the hole and started cranking down.
I won't kid you it was hard and the 12point combo wrench started rounding off the corners. So I got out my 6pt 3/8 drive socket. It worked the best!
The recess was off center from the hole and the bottom was tapered, I checked the hole size and it had expanded. I stuck a rivnut in it anyway. It was way loose, so I tried installing it.
It took a LOT of cranking with my tool and 2 resets to get it tight enough to not turn by hand, Then I had to retap the threads........
I drilled another hole in the sheet metal, this time 5/16", to see how much the hole would expand and deform. It came out to 21/64ths. Same deal, conical recess, expanded hole. I tried a rivnut anyway. It too was hard to get tight. I feel if I had cut a notch in both holes they might have tightened up.
Hey, it worked, so now I knew the concept was feasible, just needed to get the right dimensions.
23 March 2025
Deciding overnight I could make it smaller and better I set off today by cutting down my last 5/8 bolt. I used my tubing cutter to mark an even line around the bolt and cut through it with my hacksaw. I wish I had a lathe......
Marking pen on the center and did the best I could to find the center, followed by drilling a series of hole up to 11/64 and tapped for 5/16-24 threads.
The bolt was cut to 2" of shaft length. I needed a sleeve, I guessed at 1mm longer than that. I wanted to have a flat bottom to the recess. So once again I used my tubing cutter to gnaw through the bit of track rod, another 300 or so revolutions!
This came out really good, the washer fits pretty good!
Here's the tool lay out;
A new 5/16 hole was drilled and the new tool was tried out. Again it takes a big tool to turn the bolt and deform the sheet metal.
The hole was centered more and the hole stayed the same size. I think because the washer was a little bit too large so the recess was again conical. I wish I had a lathe..... I drilled out the hole to fit the rivnut and put it in.
It set nicer in this hole and the threads did not need to be retapped
So it is doable. I asked on the G&R forum and the footwells are also 16ga.
Used;
5/8 bolt
5/16-24 bolt w/heavy washer and normal washer
5/8 ID tubing for sleeve
5/16-24 tap.
The first 2 rivnuts are loose enough in the holes I can spin them by hand.
I wish I had a lathe.
Here is a pic with the size scale, the left is the original, middle is proof of concept and right is final version.
24 Mar 2025
Oh I couldn't let it rest!
I took 2 of the washers I was using and ground then down to 15mm OD. Then I drilled a new 5/16" hole in my test panel and after cleaning it up I tried out the smaller washer set up.
I noticed that the bolt screwed in easier to the bottom out stopping point.
The washer really liked where it was and took a beating to come out!
For me the recess came out great, round and flat! Just like I thunk it up!
So what else but to install a rivnut? This time I used my small bastard round file to make 2 notches in the sides to help "lock" the rivnut in place.
Putting the rivnut in took 2 times with my tool squeezing it into place. I could have done more as it jiggled a tiny bit in the locking notches.
YAY!
