PFCKEBottle Jack Valve Release Screw Knob for Harbor Freight Hydraulic Press 3/8”Dia Valve Release Screws，Made of 6061 Aluminum

Works great on a harbor freight press.

But it works great

This is a fabulous idea. But a couple of notes -- first, I had to use a file to tweak the jack and this device to let it slip on. It wasn't much, but about 5-10 thou of interference means there was no way to force it into place. Second the knurling on this device was almost invisible. They definitely could have made it deeper or ignored it entirely.

I have one of these on a Harbor Freight 20 ton bottle jack. It works well. I ordered a 7/16 to be used on a new 12 ton I was going to pickup from Harbor Freight. The item description has a picture showing compatibility with 6, 12, and 20 ton jacks but Harbor Freight does not make a bottle jack smaller than 20 ton with a release screw that has a cross bar through it compatible with mounting this type of knob. All of their bottle jacks that are smaller than 20 ton use a flattened round rod for the release screw. Their daytona line has a release screw with a square T on it but it is too large to fit in this knob. The funny thing is that the compatibility picture shows a jack with a flattened round rod screw but that style does not fit this knob.

First, this is a cool idea- just clamp a permanent knob to your jack pressure release and you don't have to fidget with the end of the handle, finding some pliers... and it works well.Now I did notice something that surprised me, from the pics I expected it to be nicely machined, well I'm not sure how this thing was manufactured, but it is not machined per se. The threads had to be machined somehow, the slot might be, but the rest is, I don't know, cast. Whatever it is it is precisely done and it's nice, but it's not cut and machined. Even if the knurling is not knurling, it doesn't have the raised bite that knurling usually has, I'm guessing that this might be cut or something, they are just cuts in the surface, with no raised edges. and the whole thing is coated with something, maybe a powder coat?Either way it's a nice looking piece that works well.