This subject always gets lots of posts with very different opinions. Kind of like discussing religions.
I have built two conversions. Tried rivnuts in beginning on first van but determined that the $30 McMaster-Carr tool made it very difficult to put in a rivnut in a hole in the roof rib. Three hands required. Two on the wrenches and a third to hold the rivnut up into the hole. Quickly changed to Plusnuts. Type of tool makes a difference. The advantage of the McMaster-Carr tool is its size because it is small enough to be used in places a large tool would not fit.
Another advantage of a Plusnut is the hole diameter is not critical and they work in hex holes. The Plusnut feet extend much further than a Rivnut bulge.
A disadvantage of the Plusnut is they are longer. Several places in the Transit have holes that the Plusnut cannot be fully installed because end of Plusnut hits steel behind the hole before flange seats against wall hole. I found that after Plusnut is partially installed you can start the install process to shorten the Plusnut and when it is shorter it can be pushed the rest of the way into the hole so install can be completed.
Had no difficulty installing the Plusnuts with the inexpensive McMaster-Carr tool. Used existing holes for 1/4-20NC Plusnuts. Light tap with hammer gets the Plusnut into the holes. Used plated mild steel Plusnuts with SS bolts. Did not use thread lube. Did use tread lube where I had a SS bolt and elastic stop nut in 80/20 structure. Installed without a torque wrench by "feel".
After I had completed the Plusnuts without difficulty someone here or on the Sprinter site mentioned that there is a flange under the head of the Plusnut that prevents it from seating against the hole steel. Never noticed the flange when installing them. The suggestion was to put a star lock washer on the Plusnut before installing the Plusnut. Excellent advice. I would use the lock washers if I ever need to install Plusnuts again. Makes sense when you look at the Plusnut.
I did have to use a tap to clean up the threads on a couple of Plusnuts. Probably caused by not keeping the tool perpendicular to the wall hole. Never had a spinner.
I have built two conversions. Tried rivnuts in beginning on first van but determined that the $30 McMaster-Carr tool made it very difficult to put in a rivnut in a hole in the roof rib. Three hands required. Two on the wrenches and a third to hold the rivnut up into the hole. Quickly changed to Plusnuts. Type of tool makes a difference. The advantage of the McMaster-Carr tool is its size because it is small enough to be used in places a large tool would not fit.
Another advantage of a Plusnut is the hole diameter is not critical and they work in hex holes. The Plusnut feet extend much further than a Rivnut bulge.
A disadvantage of the Plusnut is they are longer. Several places in the Transit have holes that the Plusnut cannot be fully installed because end of Plusnut hits steel behind the hole before flange seats against wall hole. I found that after Plusnut is partially installed you can start the install process to shorten the Plusnut and when it is shorter it can be pushed the rest of the way into the hole so install can be completed.
Had no difficulty installing the Plusnuts with the inexpensive McMaster-Carr tool. Used existing holes for 1/4-20NC Plusnuts. Light tap with hammer gets the Plusnut into the holes. Used plated mild steel Plusnuts with SS bolts. Did not use thread lube. Did use tread lube where I had a SS bolt and elastic stop nut in 80/20 structure. Installed without a torque wrench by "feel".
After I had completed the Plusnuts without difficulty someone here or on the Sprinter site mentioned that there is a flange under the head of the Plusnut that prevents it from seating against the hole steel. Never noticed the flange when installing them. The suggestion was to put a star lock washer on the Plusnut before installing the Plusnut. Excellent advice. I would use the lock washers if I ever need to install Plusnuts again. Makes sense when you look at the Plusnut.
I did have to use a tap to clean up the threads on a couple of Plusnuts. Probably caused by not keeping the tool perpendicular to the wall hole. Never had a spinner.