A bronze bush rarely fails because the bronze was wrong. On the figures presented in this session, about a third of bearing failures trace back to inadequate lubrication and another fifth to contamination — better than half the total, before the material is in question at all. Fitment accounts for much of the rest. A few thousandths of an inch of interference at the housing changes the running clearance at the shaft, and that clearance is at once the variable with the largest effect on service life and the easiest one to control.
This is webinar three in the Kormax Smarter Engineering with Bronze series, and it comes in two halves. The first is fitment: how clearance and interference are calculated, how to read the hole and shaft tolerance tables, what to specify for surface finish and chamfers, and the two ways to install a bush — freeze fitting with dry ice or liquid nitrogen, and press fitting. The second is lubrication for bronze and brass components: the three lubrication regimes and how to tell which one you are in, what oils and greases are actually made of, and how to choose between them for bushes, pins and worm drives. Fifty-six minutes, with a live Q&A.
Part one: selecting the best alloy · Part two: machining techniques · Part three: fitment and lubrication
What the webinar covers
| From | Covered |
|---|---|
| 3:31 | What actually determines bushing service life — the full list of variables, and why clearance is the one worth controlling |
| 6:01 | Interference at the housing, clearance at the shaft — what holds a bush in place, and what a misaligned or loose fit does |
| 6:49 | Calculating the fit — the dimensions it takes, and the hoop stress and press-fit force behind the numbers |
| 7:53 | Reading the tolerance tables — hole and shaft designations under the JIS, ANSI, ISO and DIN versions, with a worked example |
| 10:11 | Surface finish and chamfers — why a mirror finish is the wrong target, and the figures to specify for shaft, bush and housing bore |
| 11:17 | Installation — freeze fitting with dry ice or liquid nitrogen, press fitting, break-in lubricant, and how to tell whether it went in correctly |
| 14:02 | Why lubrication matters — the share of bearing failures attributable to lubrication and to contamination |
| 15:37 | The three lubrication regimes — hydrodynamic, mixed / EHD and boundary, with examples of each and how to tell them apart |
| 23:56 | What a lubricating oil is made of — mineral and synthetic base stocks, and the additive package |
| 27:57 | What grease is made of — NLGI consistency grades, thickener systems, and solid additives |
| 30:50 | Bronze in service — coefficients of friction for bronze on steel, lubricated and dry, against the alternatives |
| 32:33 | Choosing a lubricant when there is no OEM recommendation — the questions to work through |
| 34:25 | Worm gears — why PEG base stocks are the best oils for worm drives, the aluminium bronze caveat, and why GL-5 gear oils are not recommended on bronze |
| 39:52 | A worked example — classifying a cone crusher by regime and specifying for it |
| 43:53 | The GL classification for gear lubricants, mapped back to the regimes |
| 46:15 | Live Q&A — break-in lubricants, the temperature at which EP additives turn corrosive to copper alloys, grease versus oil, and lubricant choice for bronze bearings |
