Concentricity

I have seen shops spend weeks chasing straightness problems when the root cause was a spindle that was 0.03mm out of alignment with the bushing. Checking alignment takes thirty minutes with a test bar and a dial indicator. Here is the procedure I use. What I Check and In What Order I check alignment in a specific sequence because each step depends on the one before it: Spindle condition (runout at the taper) Spindle axis parallel to the way axis Bushing holder concentricity with spindle Bushing ID concentricity with spindle Workpiece axis alignment with spindle If I skip a step, I waste time chasing a problem that does not exist. ...

Helical gear shafts are used in industrial gearboxes, automotive transmissions, and heavy equipment drive trains. Many of these shafts need a through-hole for lubrication oil to reach the gear meshes or bearing surfaces. In my experience, the drilling quality directly determines whether the gearbox runs quietly for 10,000 hours or fails from oil starvation after 500. Common Gear Shaft Materials and Dimensions The shaft is typically 200-600mm long with a 10-30mm through-hole. The material is usually case-hardening steel like 20MnCr5 or 17CrNiMo6. The drilling is done before heat treatment when the material is soft, around 200-250 HB. ...