Rack-A-Tiers BB3412 Bumper Balls

So I bought these along with a flexible bit and a placement tool. This was for a home-theater project running speaker and electrical wires through existing walls. I tried using the bit to drill through the top plate on an exterior wall with insulation. It ended up not working, however, since the bit would just get jammed up with the insulation when I tried. But I feel like I can still give a good review on these balls.First off, they slide in the bit really well, but seem to hold OK once you get them in place as long as nothing is pushing them down. Unfortunately, when I tried pushing them through the insulation they were getting pushed down. This was easily fixed, though, by wrapping some tape around the shaft of the bit. This held the ball firmly in place. I tried using both balls, but the bigger one is more useful, I think. It fits through a single-gang receptacle hole pretty well, so that's nice. Unfortunately, once I pushed the bit up the wall with the ball about 6 inches from the end of the tip I noticed a problem. The tip was hitting the exterior wall! I confirmed this with an endoscope camera I attached to the end of the bit. The bumper ball was doing nothing to help with this problem, which I thought it was supposed to fix. Maybe I just wasn't using it correctly. I feel like if the wall didn't have insulation it might have been easier, but even if it didn't have insulation I feel like the same problem would occur. I was able to use a klein bit placement tool, though, to center the bit on the top plate and get it vertical. This made the bumper ball useless since it didn't touch either side of the inner wall.In the end, this ball could be useful in some situations, but in mine it didn't work at all. If I had drilled using only this ball and not the placement tool I would have drilled through the exterior wall. The lesson is, make sure to get a bit placement tool.

I'm running new wire for a bunch of new outlets and thought these would make my life a whole lot easier, they did not. First, I had a hell of a time getting them into the wall, the larger one barely fits in a single duplex size hole, and you have to bend the drill bit just right. After I finally got it in the wall, I started drilling and drilling, and then realized my drill bit was outside. Next one caught the inside of the drywall just right, and caused the bit to contort and ended up ruining my bit by bending it. So now I'm out the $50 for the flexible bit, and the cost of these balls.

Well... These are an amazing idea and customer service from Tradegear is terrific. However, while the small ball was perfect, the larger of the balls did not work correctly. The rubber retainer must have gotten linked inside the ball. Tradegear was great and sent me a whole new set. Unfortunately the small ball again worked perfectly however the larger ball came apart when I test inserted the drill.I had waited a project on this and kind of needed this to work. I wound up replacing the brass sleeves, added a simple flat washer below the ball and then manually slid the rubber retainer on below that. Works fantastic. See pix.

Well I was surprised when I received this pair of balls. Let's just say I was expecting bigger and didn't think they would live up to my expectations. Also they were not proportional in size (silly me I did not look closely at the photo).I'll just let everyone know that these balls did not come with a carrying case, but my husband was able to fabricate a sack.Don't let the small size fool you they are definitely up to the task.

super useful! Much better solution than the typical flex bit placement tool.Caveat: I had to grind the inside a little with a standard drill bit because when trying to thread my flex bit through it, it was not going in. but once I did that, it worked like a charm.

Fits snuggly on my shaft.

I returned this item. I purchased this with the intent to use it on my 1 inch flex bit, but it didn't fit around the shank. There was no indication that there are some flex bits they don't work with so I was disappointed to find out it wouldn't work. I have been wanting a set of these for some time.ProsIngeniousConsNot a one size fits all

Larger ball will not slide onto or off of the vast majority of flex bits due to a rubber grommet which prevents the ball from slipping down. Literally impossible to force on even with oil. Had to drill out the inside diameter of the larger ball.