The Hillman Group 55437 Universal Ball Knob-Fits 5/16, 3/8, M8, M10,,Black, 3 Count ( Pack of 1)

Used for the control levers on a backhoe. Threaded on firmly and feels solid enough to last. Just be careful that you don't over-tighten them. It's a fairly soft plastic so if you keep turning it after it has bottomed out on the shaft, it will strip pretty easily. Probably not a good choice for a high load/high stress application but works great for light loads like control levers.

I installed these on my stand up drill press, mine is older and was missing one knob, and the other two were in need of replacement. I had to drill and tap them for my specific size as mine required a larger hole, easy, looks and functions great.

Good quality..perfect fit on my Kubota throttle accelerator lever. And they ship 3 in a pack so I have extra in case I ever need them.

I used these knobs on an old drill press I’m restoring to use in my shop. I was not to sure about something that was a universal fit but the price is right and the reviews were mostly favorable so I took a chance . The best I can determine is the hole is tapered so that the top of the hole fits the larger studs and the bottom fits the smaller studs. Mine were about 9mm and everything worked great. I did not feel the need to use tools to tighten it up just my hands. I’m sure I could have stripped it out if I wanted to do that but for me I would have had to use pliers. I’m very pleased with the results. The finish is lightly textured which should provide a secure grip and is more a flat black than glossy.

I really didn't know what the diameter was because it didn't really say, but its about 1.5 inches.The holes were a bit small for me so I just drilled the plastic out about .410" then just screw them into the thread ends of a handle , the metal threads cut its own threads tightly into the ball knobs.I used 3 of them to replace the cracked handles on my Grizzly drill press. Worked out nicely.

Does what it should

Like many old Delta models, my radial drill press has a plain metal rod for the downfeed control. The Hillman 55437 Universal Ball Knobs make nice ends for it. I opened the holes in the knobs to 7/16 inch and pressed them on. Drilling and tapping for set screws was easy but really wasn't necessary. I added an uxcell Revolving Handle Grip to one end by drilling and tapping the knob with an 8mm thread, and the tightened handle has just the right thread length to clamp everything to the handle rod.

Good quality replacements. Thought I was ordering one, three came in the box. My bad, pleasant surprise lol. A+