cogging of Hardinge lathe spindle

Run it first. Check the headstock over the bearings for over temp. Start off just as slow as you can, then increase the speed 500 rpm at a time until you get to 2500 rmp..at 15 minute increments. keep checking for heat.

However..based on your description of the machines condition..Im gonna bet the bearings are toast. Folks strip stuff off broken machines, not machines in good running condition.

Btw..the BK designation indicates its British made under license.

Gunner

"If I'm going to reach out to the the Democrats then I need a third hand.There's no way I'm letting go of my wallet or my gun while they're around."

"Democrat. In the dictionary it's right after demobilize and right before demode` (out of fashion).

-Buddy Jordan 2001

I have a feeling you are right about the toasted bearings, I have read the instructions you prepared about repacing them (Thanks). Would you happen to know if the bearings in this machine are interchangeable with those from DV-59? I am thinking of buying one of these for parts.

stan

What, to remove the bearings from a donor machine, and installing them in yours? That's not done. By the time you remove them from the donor machine and re-install them on a different one, you might just as well purchase electric motor grade bearings and be done with it.

Basically the price of admission to the 'change a bearing in a lathe headstock' school is about a hundred bucks per bearing. That's not a lot considering what you get for your money. Take yours apart, clean the old ones, find out what went wrong, re-install them a couple of times to get the drill down pat, then do the real ones.

You may well find that just getting the spindle *apart* is so much fun you might want to go into the machine tool re-building business!

Jim

Most likely, an angular contact pair in the front, and single angular contact bearing at the back, run in approximation of radial mode. Often the outer race of the single rear bearing is totally unconstrained in the axial direction, in hardinge's setup of that era.

For gunner, photos of the headstock that got those new bearings:

Jim

Why do they use an angular contact bearing at the back. If it floats axially I would think the radial clearance would change.

stan

jim rozen wrote:

Exactly right. I cannot answer your question sir, all I can report is what I find when I dismantle those headstocks for repair. Yes, the rear bearing is a high precision angular contact *single* which is run unloaded in the axial direction. I cannot make any judgment about hardinge's original design engineering other than to make the SWAG that maybe it was less expensive, and simpler for them to use angular contact singles at the rear, simply beause that meant they did not have to stock two different types of bearings. Another guess might be it was easier for them to get angular contact bearings in the precision grade they needed, than true deep groove radial bearings.

If you want to read a discussion of what I did when replacing the bearings in a BB-59 headstock, go here:

Cut to the chase though, I'm going to try to load that rear bearing up a teeny bit so it it almost has some preload on it. By "almost" I'm figuring on reducing the axial clearance to a couple of thousanths. To do this though, I had to flip the bearing around so the OD thrust face is pointing to the rear of the headstock, which is not the way it was when I took it apart.

Remember though this headstock's been apart several times in its life though.

Jim