HLV-H Belt Pulley Shaft - WTF???

benha · May 20, 2015

So I've been running my lathe a fair bit over the last couple of days, doing something I rarely do which is turning between centers.

To make a long story short, I had a scare where I thought I'd buggered the spindle bearings, but what it really turned out to be was that the idler shaft that supports the pulleys between the motor belt and the spindle belt had migrated out of the outside bearing and the pulleys/belts were cattywompus.

See photo.

Looking at the service manual, there doesn't appear to be anything to retain the shaft. Looks like it just floats free in there. That seems remarkable...

Is this a "common" issue that people just keep their eye on? Or is it a symptom of something I should be trying to fix?

atomarc · May 21, 2015

Benha,

I haven't ever even..seen your model lathe but I'm pretty darn sure that shaft and attached pulleys have to be captured in those bearings with something. This would be basic machine design 101. A couple of split shaft collars of the proper ID would do the job fine, but I'll bet there are some factory snap rings missing or some locking collars. :eek:

Stuart

Paul Babin · May 21, 2015

You are correct in that there are no collars to capture the pulley shaft onto the brg cradle there.
I see a piece of belt cording in the picture and a "chunk" of belt missing will cause vibration and oscillation that could have caused the shaft to come out of the brg support. Proper alignment will allow for some float of the assembly on the support brgs without coming off.
The spindle belt does not appear factory as it should be a cogged belt for both spindle and motor.
The spindle belt is definitely the harder of the two to replace so best to get proper belt.
FYI: I have found that the last few batches of factory spindle belts we tried we not made properly. Seemed to have some sort of twist in them causing vibration and problems. I have used non-factory belts lately until such problems are eliminated from new factory belts. Gates Multi Speed 1626V597
Good luck
PB
PS: Love that word: cattywompus by the way.

benha · May 21, 2015

Thanks, Paul.

I just ordered a pair of Gates belts (1626V597 & 1626V380). Even managed to get a "Memorial Day Discount" from vbeltsupply.com :-)

Hopefully that improves the overall system some. I'm surprised that the belts on it aren't the correct models given that my uncle is the only prior owner of this machine and he was meticulous about such things, but it is what it is.

Changing the belts will be a good opportunity to make sure everything is cleaned, lubed, etc, and to learn a bit more about my machine.

On a vaguely related note: While doing my recent project I had several instances where the spindle stalled during a cut. I was surprised by this because the cuts weren't that deep. In retrospect it's probably because the belts were screwed up and it was adding considerable friction to the system. Regardless, I'm curious what the overload protection systems look like on this machine, both for the spindle motor and for the carriage motor. Is stalling those things a giant issue, or are things pretty well protected?

-Ben

atomarc · May 21, 2015

Both ends of the shaft show fretting/rust. This means they have been moving in the bearings and will probably not fit tightly. I have worked on all kinds of machinery for almost 40 years and have never seen a shaft captured in bearings with no means of retention other than the press fit of the shaft..never! Maybe your lathe is a first, but I'm skeptical.

Stuart

benha · May 21, 2015

Well, I would tend to agree with the observation that it seems odd. That said, there's very clearly nothing in the manual about anything to do with retaining that shaft, and Paul's business is in restoring these things and he says there's nothing to retain it, so I'm siding with the "this one's different" assessment.

But yes. Weird.

Oh, and it's not really a press fit. It will move laterally without too much effort. You slide it out of the bearings in order to change the belts.

Mark Rand · May 21, 2015

atomarc said:
I have worked on all kinds of machinery for almost 40 years and have never seen a shaft captured in bearings with no means of retention other than the press fit of the shaft..never! Maybe your lathe is a first, but I'm skeptical.

Stuart

The pulley is attached to the shaft. the shaft floats to allow the belts to centralize. On the HLV (no -H), the shaft was fixed and the pulley assembly had the bearings. That's a lousy design, since the bearings are held in by welded collars at the end of the assembly. The HLV-H makes more sense.

PS, It's not rocket surgery to turn a new shaft for the HLV-H out of some 4140-PH or similar.

PPS, The books I've seen didn't quote notched/toothed belts for the HLV-H, even though they may be standard issue now. Were they available in 1960? Expiring minds want to know.

:cheers:

MilGunsmith · May 21, 2015

The pulley shaft in my HLV-BK floats also.

atomarc · May 21, 2015

Looks like this old dog learned a new trick although, IMHO it's real strange to have a shaft "float" in the bore of a roller bearing.

Stuart

Mark Rand · May 21, 2015

MilGunsmith said:
The pulley shaft in my HLV-BK floats also.

Must be a tad newer than my 1952 vintage one then. I'm jealous

benha · May 22, 2015

Okay,

Spent some time pulling the old belts last night. Getting the spindle belt out is a giant PITA. Ended up just cutting it. Not sure how the new one is going to fit through that opening, but I guess it's possible given there're pictures in the manual of it happening :-)

I noticed that the gearbox has years of accumulated, hardened grease in it. Adding a ton of friction to the works. Am I going to mess up any bearings if I go in there with a bit of kerosene and a toothbrush and clean that stuff out before lubing again? I did a bit of work with WD-40 and a brush and got the big stuff clear, but I think a more serious solvent would help...

-Ben

specfab · May 22, 2015

Regarding the design philosophy at work here, I would have to conclude that the fellows at Hardinge must have decided that allowing a degree of freedom in the axial location for the shaft, seeing that the pulleys are fixed to the shaft as retainers, would help to self-center with respect to belt location and shape. Perhaps this was a far-sighted attempt to lengthen belt life, knowing it is a big PITA to change out the belts.

Doozer · May 22, 2015

Yes it does go against conventional bearing application theory,
but it works because I suspect the shaft is hardened.
Oil the shaft to bearing race interface once and a while,
it will be fine.
Both my HLV-H and my Tsugami lathes are this way.

--Doozer

FredC · May 22, 2015

I just changed the lower belt on my AHC. The pulley shaft has the same arrangement. I lifted up the motor base to make slack and pushed the shaft over to one side and the old belt slipped out with a little trouble, the new belt was not as stiff and was easier to get it in. I thought it was Hardinge's design to make it easy. I have an HLV-H, a Tsugami chucker and the AHC, all have the same design. All run fairly well centered on the floating pulley. I have not messed with the leveling of the floating shaft on any of them, but I would guess leveling that shaft would correct the floating pulley if it was not centered.

jim rozen · May 23, 2015

I did both belts on my HLVH at work a while ago, and it wasn't as bad as it looked.

Trick with the upper belt (memory from a while ago...) is that you open up the small hatch
that is over the pick-off gears on the end of the spindle. Then you extract a shaft that
the gear rides on, this gives clearance to slip the belt over the *end* of the spindle.

The shaft looks like it's impossible to remove as it is a snug fit into a blind recess.

Trick is you take the bolt that retains the shaft, and thread it into the *end* of the
shaft so it becomes a push-out bolt to extact the shaft. You do need a fair bit
of clearance around the rear and left side of the machine to make the job easy.

dkmc · May 23, 2015

My HC is the same design.
I think the manual says to put a bit of grease on the shaft where it floats in the
bearings...

Billtodd · May 23, 2015

atomarc said:
Both ends of the shaft show fretting/rust. This means they have been moving in the bearings and will probably not fit tightly. I have worked on all kinds of machinery for almost 40 years and have never seen a shaft captured in bearings with no means of retention other than the press fit of the shaft..never! Maybe your lathe is a first, but I'm skeptical.

Stuart

No Really :-) the hardinge idler shaft just floats between the bearings with an inch or two of free space. The only thing that keeps it centred is the two belts (it has to move to allow for the changes in speed)

A split belt or a very worn one can cause the pulley to oscillate if the speed is right it'll pop the shaft out of one side BTDT :-!

Belt changing on the hlvh is a matter of faith and sacrificed knuckles . it defies logic that a large belt can fit through such a small hole. Follow the instructions in the manual , say a prayer for th bothers hardinge and push;-)

benha · May 28, 2015

Update:
The new belts arrived approximately 24 hours after being ordered. Nice job, vbeltsupply.com!

I got everything cleaned up and put back together with minimal fuss.

That said, the belts are pretty tight:

I had to lift the motor almost to the furthest reach of the adjustment screw (which doesn't bother me too much for new belts.)

But more concerning is that it seems like the distance between the two outside plates of the pulley system is a little too narrow. Especially when the speed is set to max the belts can bind to the point that the machine can't start spinning without a little help. Even had some smoking in high range - high speed. It does seem to have improved some after an hour or so of use, but there's clearly still a fair bit of added friction in the system due to this.

Is this "normal" until the belts wear in a bit? Or is there an adjustment to the overall width of the pulley system I should be fiddling with. It's not discussed in the manual, but.......

-Ben

Billtodd · May 30, 2015

That doesn't sound quite right :-( hlvs can struggle to started at full speed (hi or low) and repeated starts can trip the overload on even a loose machine.

The two belts are slightly different lengths ,just wondering if your supplier has accidentally sent two short ones?

Edit: You may have to adjust the upper and/or lower speed stops to prevent it overloading

benha · Jun 1, 2015

It doesn't seem like a length issue as much as a width one, though I could be wrong.

The belts are labeled correctly anyway.

I guess I'm just going to run it for a while and see if it wears in. At the very least I doubt it hurts anything to run it this way...

HLV-H Belt Pulley Shaft - WTF???

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