You got that right. ......and for those comparing it to valve guide knurling I have this to add. Valve guide knurling is an accepted practice in OTR truck engine repairs and can also still be a good practice for automotive applications. Before your heads explode, I'll tell yall something most of yall may not know. A knurling tool is nothing more than a thread cutter. I'm sure most of you know that. The knurler is run through first, threads are cut in the guides and then a reamer is run through to get the final size. Here's where the fun stuff is. Just like taps and fasteners, there are fine thread and coarse thread knurling tools. Using the fine thread tool removes too much metal and doesn't leave a lot of support. Those are the knurled guides that wear quickly. If you use a coarse threader, that will last a long time. Usually close to what a new guide lasts. Ask any machine shop that does OTR and industrial or railroad engine work and they'll tell you real quick not only does knurling save a lot of money, but it also works well. All this talk about piston knurling is for the birds.