Over the years,I've read and heard repeated warnings by various experts that driving a blank onto a morse tapered spur center while it's on the lathe will damage the bearings. It would of course, damage an obsolete outboard cup (
Hi Arch
I've made this comment before, that a car or truck can go down the road at 70 MPH or more, keeping al that weight up while hitting bumps and ruts, and doing this day after day, while in most cases no one ever takes a second look at them.
Then when someone wants to hammer an essentially sharp object into a soft medium (wood), cries are heard, that one is destroying the bearings by doing so.
Ever looked at the hammer drill people use, those iddy biddy bearings get whacked a thousand times and just keep on ticking.
Running a bearing at high speed with constant high side pressure, developing high heat will ruin a bearing much faster, even that will take some time to happen, as first the lubricant will run out or degrade, and than the frictions will get higher and the head ultimately will destroy the bearing.
With lathes the biggest problem IMO is the cheaper bearings used, with only shields in them, that do not keep out the dust and grit, those will die untimely, not by driving a wooden stick onto a sharp spur, and that is my opinion.
Have I damaged bearings ??, yes I'm afraid so, I do confess to have hit large ball bearings with a sledge hammer to get at the balls, we played games with them, when my Dad found out, he was not impressed, I do remember that.
Don't remember what the bearings came out of, it was wartime material, and the bearing balls where at least an inch in size as I seem to recall.
Have fun and take care Leo Van Der Loo
Steelies!! They were banned from most marble contests and horrendous arguments broke out between seven year olds over whether or not to allow them.
When you hit a glass marble with a Steelie, you could sometimes see the chips fly.
(Do flying chips get this back on topic?)
I bang the center off lathe first with a rubber mallet. Then, if needed, bang the wood when mounting.
Just remember to always wear your safety glasses when shooting a steelie at a glass marble. :)
Ah yes, I had a hard lesson in the facts of life when about seven I sadly learned that an older boy said that we were playing keepsies. His shooter was a ball bearing, mine was a big aggie. Don't remember if we were playing big ring or little ring, but he always lagged closer to the line, shot first and the games were over before I got to shoot.
On topic or off doesn't matter as long as it will pry up posts from old friends like Rick & Dave plus the always welcomed comments from Darrell, Leo and Lobby. Thanks y'all.
Leo, I don't know if it's true, but I've heard stories that in WW2 B29s were hit and damaged by steel balls when they bombed the Nazi bearing factories. Maybe some of those bearings landed in Holland.
Turn to Safety, Arch Fortiter
Lots of experts out there, but most folks take convention as wisdom.
I'm guessing that if you drive enough on the inner race you might be able to shorten the life of the bearing. I remember the way to get steelies, which played against steelies in my neighborhood, was to put the outer race on two blocks and drive the inner. The cold chisel method resulted in more damage to the chisel than the hardened races.
Now with preloaded tapered roller bearings, you could screw up the preload and get more damage faster. Or tapered sintered bronze. Maybe that's where it comes from.
Sounds like one for MythBusters. A large axial force, whether by hammer or arbor press, can and does damage bearings. Ball bearings can carry a large radial load, but their ability to carry an axial load is a fraction of their radial load. Hence the warnings. I doubt that the light whack of setting a spindle on a drive center is going to cause problems in a heavy duty lathe.
Most commercial lathes' spindles are retained by the front set of bearings alone; not the rear set, which are often made to float, but occasionally both. l have never seen a case of the spindle being held in place by anything else except the bearing(s) such as the pulley. How could it/? The pulley is not fixed to the headstock. It is the front set that takes all the abuse, hence they are often larger, double, or roller bearings instead of ball. Mine is an 1.5 inch bore double angled roller bearing, weighs about five pounds.
Dan
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