Ah, the Smith machine. The original machine solved the problem of not binding by having both sides locked by chains and sprockets. I never liked that so devised a version in 1982 in my factory that used linear motion bearings. No sprockets or chains were necessary. Now everyone uses linear motion bearings. I believe I was the first to solve this problem with these bearings.
Someone improved the machine by having a slight angle. When you do squats, presses and bench presses you don't go in a straight line but a curve. The angle of about 10 degrees makes a big difference. I also used stainless steel for the bar which had an internal high tensile steel bar. Pins were covered in polyurethane so there was no metal to metal contact. The machine that I made stopped just before your neck if you were bench pressing. So you couldn't get trapped in that exercise. All the bench presses, inclines and declines in my gym have safety catches so one can't impact ones face while using them.
The machine I made in the photo is probably the best such machine ever made. It has quality stainless steel parts. A chinning station, foot rest, and is angled at 10 degrees.
