HLV-H Short Turing has Taper

majohnson · Jun 4, 2018

I been able to get some small parts to make. However the issue I am having is over the length of .6900 I need to thread, I have a taper just under .003. With the smallest diameter being at the 5C end of the piece. I have done several spring pass to try and cut out differences but no luck.

Billtodd · Jun 5, 2018

At a guess and assuming the lathe isn't completely knackered, your carriage gib is loose or damaged. I suspect the carriage is twisting as is is driven back and forth.

JRIowa · Jun 5, 2018

As Bill said, it's either the carriage or the headstock could be crooked. You have problems.
JR

Derek Smalls · Jun 5, 2018

Certainly could be a problem with the machine as stated above, but you did not state the diameter you are turning, the material, or what tool you are using. Are you sure that material is not simply pushing away from the tool further out from the collet? If the tool is not dead sharp, the material is really tough, or the diameter really small, a spring pass may not remove all the taper.

FredC · Jun 5, 2018

What Derek said. Before you start adjusting or taking the machine apart lets get some more info. Material OD is import and as well as the tool being sharp and on center. How far the end of the part is from the collet. Wrong collet and the bar not being properly supported when turning bars could cause taper problems. Materials like aluminum bronze really resist cutting and smaller diameters will bend away from the tool.

rons · Jun 5, 2018

majohnson said:
However the issue I am having is over the length of .6900 I need to thread

A general rule is that a bar came extend 2.5 times the diameter. More than that and I take very light cuts and make sure I am dead center with cutting height.

majohnson · Jun 7, 2018

I pretty much take light cuts most of the time. I did play with the he gibs some and it seem to help but there is still some taper.

I would like to find someone that could reline the carrier. The bed is still in good shape I figure doing it before it has any damage that requires the bed to be reground. It already has .003 taken of, so regrinding it might not even be an option at this point. I keep a lot of oil on the bed trying to get maximum life from it. Before I do any filing or use sandpaper, I cover the bed trying to care for the bed.

FredC · Jun 8, 2018

You are saying the machine has been rebuilt? The bed has already been ground .003? Before we unbolt the spindle housing or anything else that is drastic. Do some checks with an indicator.
Use the cross slide to indicate across the spindle face, the near and far sides of the spindle should read the same within a tenth of a thousandth. Indicate a precision rod, dowel pin or something like that till it is has little TIR near the collet and a couple of inches away, then traverse the length with the carriage.
Let us know what you get. If someone had the bed reground maybe the spindle got put back with dirt or chips between the front side of the dovetail and spindle housing.
Again I would not do anything like gib adjustments, removing the spindle housing or anything else drastic till I knew why I was taking that action. I watched an installer from Southwest Industries (the Travadial and CNC retrofit people) adjust the gibs on my new mill till he got the drag he wanted. Ended up wrecking the mill, I had it in storage for 3 years till we got time to bring it back and fix it. Turns out the installer was supposed to have adjusted the gib by indicated free play and not felt drag.

Billtodd · Jun 8, 2018

Is that 3thou" over 0.69 or 6.9 ? if the former then it has to be the carriage twisting (head stock error of that magnitude would be almost visible) even if the gib is binding it could allow the carriage to twist if it is bent, broken or dinged. (or perhaps there is swarf jammed in there somewhere.)

3thou over 7 inches is not good ,but I'd expect most of that to be flexing of the work piece ( for instance, My 1966 hlvh is better than a thou over that distance even with its obviously worn bed).

majohnson · Jun 20, 2018

I have some real dial indicator coming and going to regroup and remeasure things. The previous owner had a stop on the right front bolt and left the allen loose to swing the stop. I replace the bolt with the correct length and torqued all the allens that hold the spindle housing to the base.

There are 2 allen screws on the left side of carriage, are those to adjust the the carriage heigth? Then there is 4 more allens on the crossslide, if someone could let me know what they adjust. I am starting to feel like the lining inside the carriage has come apart. If there is anyone in Northern Colorado that rescrape the crossslide and carriage I would appreciate their contact info.

rons · Jun 21, 2018

majohnson said:
There are 2 allen screws on the left side of carriage, are those to adjust the the carriage heigth?

I think they are plugged holes for mounting the follower rest. The mounting points would be 2 screws on the left and 1 on the right of the carriage.

FredC · Jun 21, 2018

"The spindle housing to the base" may be the source of your problems. There is a set screw in the back of the spindle housing that tightens against the back of the dove tail and is responsible for spindle alignment to the bed. It MUST be tightened before you tighten the caps crews holding the spindle housing to the bed. If the previous owner had any of the 4 cap screws loose and crowded that stop maybe he shifted the spindle housing out of alignment.
If this is the cause and chips got between the front dovetail and the spindle housing, you will need to remove the spindle housing and clean everything and reassemble. Do no do this till you have verified this is the problem by checking several things.
The spindle will not be in line with the tailstock if this is the problem. You will need to check the travel of the carriage to make sure something is not wonky there and causing the problem. I would still wait till you have the indicators and know the whys and wherefores there before doing anything drastic.
There are no adjusting screws on the carriage or cross slide that will fix your problem, as Rons mentioned the screws or screw holes you are seeing are for accessories.

rons · Jun 21, 2018

majohnson said:
The previous owner had a stop on the right front bolt and left the allen loose to swing the stop. I replace the bolt with the correct length and torqued all the allens that hold the spindle housing to the base.

Just be glad you don't have to deal with a HLV model. The 4 allen bolts are inside the head casting.

majohnson · Jun 21, 2018

The thing was a pig when I bought it, they never cleaned anything. I pulled the set screws and they are all blind holes. I cleaned the rack again, using a tooth brush and then use a small hone on the face, it help free up the carriage. I also found one of the alignmet pins for the rack that was proud, tapping that help one the last 3” of the carriage travel.

Thanks for help!

rons · Jun 22, 2018

I think the most important thing is the metal underneath the junk. If it's not pitted or dented then a little cleaning is no sweat. I looked at a Graziano once and the head stock looked like the operator had banged a wrench there waiting for his cutting operations to finish.

Richard King · Jun 22, 2018

The bed sets on 3 points on the cabinet so it can't twist. The bed could be worn near the headstock as most lathes are. You could remove the head and clean under there. If it still cuts a taper you could shim it over a bit so it cuts straight, not the best solution but will work. The tail-stock isn't adjustable side to side like most lathes, so shimming the head will make drilling small holes a pain. You may have to pull the bedplate and have it reground if the ways are worn up front.
Look at page 17
..Sometimes there is a round shoe in the bottom of the set screw hole that makes it look like it's a blind hole.

I used to rebuild Handinge lathes and have taught classes at Iverson in Chicago one of the remaining Hardinge authorized rebuild centers. :-)
Hardinge HLV-H Maintenance Manual

majohnson · Jun 22, 2018

Taper

How close does the carriage ride next to the rack? The 2 allen screws closest to the headstock had burrs from someone not supporting the tool when they tighten the rack down. The other item I came across was the hole in the carriage for the threading stop rod. It was pack with fine paste consistently of metel fines and oil. As the carriage would get close to headstock it was binding on the stop rod. I had cleaned the right side hole but somehow overlooked the other headstock side.

Between cleaning the stop rods pass hole and getting rid of the burrs my error factors is down to .0004 over 1.250. I use the info about the material and 2.5 multiple. That clearance on that pass through isn’t much. I used .050 allen wrench it was the only thing I had small enough to go through the hole.

I am open to ideas or suggestions.

rons · Jun 23, 2018

majohnson said:
Between cleaning the stop rods pass hole and getting rid of the burrs my error factors is down to .0004 over 1.250. I use the info about the material and 2.5 multiple. That clearance on that pass through isn’t much. I used .050 allen wrench it was the only thing I had small enough to go through the hole.

I am open to ideas or suggestions.

Place a indicator on the inside taper of the nose and spin the handwheel slowly for one revolution. The spec says +/- .000025. Then do the same thing on the outside taper of the nose.

Make a reference mark on the headstock and spindle collar. Use tape with a fine pencil line. Eject the spindle and flush out the bearings and palm in new grease. Install spindle back into head and align with your pencil line. A Hardinge service guy told me to use the reference line idea. I did this on my machine when I was first getting familiar with it. Hardinge would charge you big for this work.

majohnson · Jun 27, 2018

The head is quiet, it aeems tight as well. It has 3 lines that coincide with slots of the 5C collets on the inside. I worry about opening a can of worms by pulling out the spindle. My measuring tooling only go to .0005. I would like to take it apart but worry about costs and availability.

rons · Jun 28, 2018

The HLV owner must extract the spindle assembly to replace the upper belt.
The HLV-H owner replaces the upper belt through a hole in the headstock.

HLV-H Short Turing has Taper

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