Hardinge HLV-H won’t reverse when threading

lynxer · Dec 10, 2018

Recently got a HLV-H and of course purposely for threading.

The feed lever for threading only seems to have 2 positions forward (towards headstock) or off. I can’t reverse with the half nut engaged.

Is there something that I am missing? Something out of adjustment? A broken switch?

Thank you so much for the help!

rons · Dec 10, 2018

car2 said:
(there aren't any switches, it's all mechanical...do not thread with the motor in reverse). Cheers

I have threaded in reverse with the bit upside down.

tbirds · Dec 11, 2018

Mine would stop at random while threading; turned out to be a broken "shift lever" or "fork shifter", located inside the head stock's gearbox, as seen on the pictures;it's been removed on this picture; it is shaped like the letter C with 2 set screws attaching it to the shaft; make sure the set screws are not loose causing sliding of the lever on the shaft; this shaft has to be turned "clockwise" as seen on the picture with the Allen key, to pull it off; set screws loosened of course.
Another possibility is the tapered shear pin on the lead screw, close to the head stock; I've installed a small clamp on the pin, just to make sure it doesn't move on me
The shifter p/n: HLA0006245; in 2012, Hardinge's price was: 141$, but you can't buy directly from them; you need to go through a dealer which means a commission...
That's something worth looking at, if you haven't already done so.
Good luck.

lynxer · Dec 11, 2018

Thank you very much!

To me it seems like this shift fork set screw set up maybe the culprit.

I notice that the lever does not go all the way left. Basically straight up or just slightly left of center engages the lead screw. In videos I see it should be resting perfectly in the middle and going full left or full right of center.

How do I get at these said set screws?

Thank you guys so much for the help

tbirds · Dec 11, 2018

Remove the lower access panel on the head stock, as seen on the picture; you will see the shifter; it looks like a letter "C", and there is a set screw at 6 o'clock, and another at approx. 8 o'clock. Mine was painted black; on the picture here, the shifter and it's shaft have already been removed, but you can see the hole it would fit into...

Just added a picture of the shifter; with the lathe against the wall, this is the best I can do...you can see one set screw at 9 o'clock, and the other barely visible at 6 o'clock; you can also see the arm going up to the gears...

lynxer · Dec 11, 2018

Everything seems to be fine in that spot for me.

Really starting to drive me nuts!

lynxer · Dec 11, 2018

I just looked back to some photos from when I bought the lathe. I see the lever was also offset and not resting in the center.

Any ideas?

tbirds · Dec 11, 2018

lynxer said:
View attachment 244154
I just looked back to some photos from when I bought the lathe. I see the lever was also offset and not resting in the center.

Any ideas?

That by itself makes no difference; when the "feed-thread" knob is selected to feed, you can move the threading lever either way; nothing will happen even with the spindle turning. When "thread" is selected ( sometimes you need to turn the chuck slightly to engage the gear), moving the threading lever either way, engages the lead screw, and the apron moves either way.
This system is simple; I'm assuming your apron is moving towards the headstock, meaning the leadscrew is turning, and the half nuts engaged?, when you move the threading lever to the left?. I'm asking because you only mentioned the lever movement in your original post, not the apron movement.
Let's see: with the "thread-feed" knob in thread position, are you able to move the threading lever either way? You should. And, there should be a positive detent when selecting either side of neutral, and coming back to neutral.
Next: when the threading lever is in neutral, there should be "space" either side of the shifter fork: between the fork and the gears.
Let us know your findings...

lynxer · Dec 11, 2018

tbirds said:
That by itself makes no difference; when the "feed-thread" knob is selected to feed, you can move the threading lever either way; nothing will happen even with the spindle turning. When "thread" is selected ( sometimes you need to turn the chuck slightly to engage the gear), moving the threading lever either way, engages the lead screw, and the apron moves either way.
This system is simple; I'm assuming your apron is moving towards the headstock, meaning the leadscrew is turning, and the half nuts engaged?, when you move the threading lever to the left?. I'm asking because you only mentioned the lever movement in your original post, not the apron movement.
Let's see: with the "thread-feed" knob in thread position, are you able to move the threading lever either way? You should. And, there should be a positive detent when selecting either side of neutral, and coming back to neutral.
Next: when the threading lever is in neutral, there should be "space" either side of the shifter fork: between the fork and the gears.
Let us know your findings...

Yes, When I move the lever to the left, the lead screw brings the carriage left towards the head stock. Move the lever right and it stops. I do NOT feel any detent moving to the right. Looking inside the cabinet from the bottom I can see a sheft fork type thing on the shaft. When the lever is engaged to the left it makes contact with the shaft coming out of the "On-Off/Low-Off-High" Lever. When trying to move the lever to the right the fork does not make contact and looks like it has stopped about 75% of the way over.

I am thinking that something is not allowing it to go over in and engage the dog. Maybe someone changed the belts at one time and removed a shaft?

lynxer · Dec 11, 2018

car2 said:
Does it behave the same regardless of what the 1/2/3 selector and/or gearbox selection is?
Any other noises etc in different gear-settings?
It sounds like something has slipped/come loose, or is not fully engaged in the gearbox controls (you do have the threading stops so they're not interfering(?)). I haven't taken them apart, and mine is an E/M so not much help. The manuals have good pictures of the asm and disassembly. You can look at the gearbox running in low speed/feed and actuate the threading fwd/rev to see what should happen (don't change gears while running of course).

One other thought, the selector knob bushings are easily bound up with old oil, make sure that the 1/2/3 knob is actually engaging in the proper position (the shaft for the knobs should have a flat, and the knob has a spring-detent to position them, but a good way to check is to look in the gearbox to see that gears are aligned). It's common the knobs get shifted around on the shaft, and/or are difficult/impossible to turn until freed up--not sure if this would produce your issue, but should be checked.

(Changing the drive belt doesn't require tampering with the gearbox itself, only the spindle engagement "feed" thread gear, which is working).

You see, I am only feeling position 1 and position 2. I have no position 3 to go back. Somewhere along the line I am out of sync.

Will look more tonight. It is driving me crazy!

lynxer · Dec 11, 2018

car2 said:
I was referring to the gear-range selector *knob*, not the threading fwd/rev lever. Have you tried putting the gearbox in different positions (selector *knob*, and *gearbox* shift lever) to see if that affects anything.

Ahh OK OK yes

Sorry for the mistake on my part. Yes I have tried and no difference between any of them.

tbirds · Dec 11, 2018

Interesting! It looks like as you say, something is preventing free movement of the threading lever in one direction; mine makes contact both ways on that speed lever.
This leaves a couple of possibilities: one is the fork shifter inside the head stock with the 2 set screws; I replaced mine some 6 years ago, and I don't remember the fine details; I think there should be holes in the shaft for the set screws for proper alignment, but it would be easy enough to remove the screws, move the shifter, check those holes, and at this time, verify the operation of the lever; if it's the same, then the shifter is eliminated.After that, I don't have any good ideas. Everything else is inside the head stock, which I never opened up. The next item could be the small stop rod going inside the apron; that's the one with the detents on it inside the housing; I measured mine excluding the jam nut, and it measures 1" to the face of the housing with the threading lever left, and barely .250" lever at right, for a total movement of approx. .750"; but we already know you won't meet those measurements; you'll stop at about .500" in neutral, but worth measuring.

Mark Rand · Dec 11, 2018

With the back covers off the gearbox and the lathe in threading mode, look at what the selector fork and the dog clutch it moves are doing as you move the lever from one side to the other. The lathe shouldn't be on for this, but you will probalby want to turn the slindle by hand as you do it.

It's possible that the circular rack that the pinion on the lever's shaft has been assembled offset to one side during a previous dismantling and needs re-assembling one or two teeth over. It's just possible, but extremely unlikely, that there's a burr or bit of crud that stopping the dog clutch moving all the way over.

In all of this, one assumes that the collars on the actuating rod that goes through the apron aren't preventing movement of the rod in one direction. I got puzzled by a similar lack of movement in one direction after my son had used my HLV and found one of the collars locked up against the right-hand rod/leadscrew support bracket. :crazy:

lynxer · Dec 11, 2018

That is what I am thinking. The lathe was for sure disassembled at one time. How do I remove/reassemble the lever and the shaft it goes into? I see a nut on the back of the head stock...

lynxer · Dec 11, 2018

Thank you all so very much for the help!

I got it working!

I loosened up the shift fork set screws. Ran the shift fork by hand back and forth. Saw it was all working. (Machine off) and then put the lever in the center. Put the shift fork exactly in the center of the two dogs. Tightened them down and we are in business!!!!!!

Frustrating day at work wondering and researching!!!!

Thank you so much for all of the in depth replies. I learned something today.

rons · Dec 12, 2018

car2 said:
More specifically, when using the threading carriage stops; manual says (in bold) "do not use carriage stops when headstock spindle is running in reverse". I haven't tried this to see what happens, but have heard a couple of stories. Cheers

The manual does say that. That restriction limits left hand threading to a shoulder.

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