I've heard @mrblaine reference these multiple times and just tried one for the first time yesterday. Frankly, I was shocked how well it worked. They self aligned, flung considerably less metal, and wouldn't punch through like a conventional drill. For the holes that required nutserts I used a dullish 17/32 bit. Reason being, a sharp bit will grab the sheet metal and deform it. I found this out the hard way!
I'm not completely following this, what's the spotweld cutter being used for? Fasteners not using nutserts?
Drilling the holes. In my case, I clamped on the Savvy rocker base and drilled through the holes.
The other thing that makes those outstanding is how little pressure you have to use pushing on the drill motor. Just make sure to use the lube they have for them on every other hole or so since we all like to spin them faster than needed and heat them up.
You use it to drill through every hole on the backer or rail for non Savvy applications. That gives you perfect location of each hole, no center punching, no guessing, just very accurate easy holes and locations for all the fasteners including the ones that get nutserts. Just go back after you drill and drop the rail, enlarge all the ones that get nutserts, install nutserts, put the rail on. The cutters make very clean round holes.
Interesting, my nutserts were for the same thread as the rest. Though similarly, they didn’t include enough.
We reference the 3/8" cutter because that is what works on the GR mini boat sides and everyone that puts a 5/16" nutsert behind a rail or backer should be using a 3/8" hole. That is because the hole in the slider is always slightly oversize to 5/16's and if you drill off to one side in that hole and then the nutsert drill bit goes off a slight amount and then the nutsert sets slightly off center as they are wont to do, then you can wind up with a hole you have to fix because the fastener won't start in the threads.
Great info! A great benefit for someone reading this before installing their sliders. I followed the GR instructions and drilled everything at 5/16" and then stepped up the nutsert locations to 17/32" and I actually did have issues with one nutsert location and I actually boogered up the nutsert threads. I still have to pull it back apart to redo that one nutsert, but it is not on the immediate to do list.
If all you want is 3/8" cutters, then the spotweld cutter set is fine and gives you three 3/8" cutters. If you want a kit that contains different sizes then you will need to buy a different rotobroach set. I think the kit I have goes from 5/16" up to 3/4".
The spot weld cutter in 3/8" just does 3/8" holes. If you want to do other than 3/8" hole, then get the set with different sizes. If you only want to do 3/8" holes and have some spare cutters, get the spot weld specific set. If you get the various sizes set, order some extra 3/8" cutters because you can NOT side load them or they will shatter.
