Hardinge TM Spindle Lock

Hmm. I was hoping the parts breakdown might be of some help, but apparently it has me stumped as well, even after perusing the diagram for that assembly for a while, and inspecting the lock pin and the bushing from my machine, after taking them apart.

I was suprised to see that there's actually knurling under all the paint on the knob!

The diagram seems to imply there's some kind of a lock screw that might be accessed from *inside* the column. My next take would be to remove the belt access cover on the opposite side and see if I could visualize this around the other side of the spindle.

Most of the hardinge diagrams are drawn quite well, so wherever there are threads, they show the hidden lines that represent the thread roots on a male part. According to this, there would be no threads on the OD of the bushing.

I can also see the parting line inside the bore of the bushing, where the bushing ends and the casting of the column picks up. There seems to be some kind of hole beyond that which suggests the lock screw might actually exist.

The diagram shows the external setscrew as a) being a single screw and b) entering the bushing from the top. In my machine it's actually two short 10-32 screws, one to lock on top of the inner one, and they enter from the bottom of the bushing.

The other intesting feature about the parts list, is that they show an item associated with the lock assembly as a "spring" and there are no springs of any sort, any place in mine. I wonder if the pin is supposed to be self-retracting on these machines.

I think that a conversation with somebody who works on these for a living could explain a great deal of the mystery.

After cleaning the glop off the pin, I'm going to give the knob a treatement of oxpho gun blue to make it look nicer. The bushing on my machine also has about a quarter inch thick layer of paint covering it, maybe I'll keep on trying to find the secret there. I'll let you know if anything becomes obvious. I'd appreciate a reply here from you if the yahoo group has the solution.

Jim

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Nothing yet, Jim. Mine is just like yours, two setscrews from the bottom, no spring. I'll follow up on your inside inspection idea today, since mine is disassembled. I'll get in there with a mirror and flashlight.

I'll post what I find out.

Pete Keillor

Hmm. OK, I was wrong on the lockscrew inside idea. There's nothing in there but the casting. I wounder if the bushing is simply a snug press fit inside of the column casting? That would imply one could drive it out from inside, once the spindle were removed.

While inside, I realized two interesting things.

1) there are supposed to be three belts, mine has two. What's that thing down inside the column? Oh, the third belt, broken. Maybe time for new belts for that, eh? 2) how come the power feed pulley is so far at the end of the shaft? Ah, the pulley is *very* loose, I can slide it back and forth. The setscrew's come undone. Easy fix.

I think we need to talk to the guys who made these things, to figure out the bushing.

Jim

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I got three replies on the yahoo group so far. Marty Escarcega and Dick Streff left it in place and painted around it. Jim Schwitters drove it out from the inside.

I'm leaning toward giving that a try.

Pete Keillor

If all you want to do is paint the casting, then maybe leaving it in would be best. Will the bushing ever fit as tightly after being driven out and then driven back in? The knob should only require a coat of grease to mask it during painting.

Or, you could do what the folks did who painted mine: just slather paint all over it! The comment about it the bushing's fit becoming less tight from extracting it is well taken.

Jim

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Well, I heated the boss and tried several pretty good whacks on a piloted tool from the inside. It didn't budge. I'm going to leave it because I'm fearful of damaging the casting or bushing. The reason I wanted to remove it was to allow easier shaping and sanding of the filler I'll need on the outside of the casting. The bushing has a boss which stands above the surface of the casting, but I'll just have to work around it.

Pete Keillor