HLV-H original specs

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JIM MCGREGOR

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Does anyone out there have any information on what accuracy was quoted for a new HLV-H, or even a clone?

Did each machine come with a test report? If so an example would be appreciated.

Currently tring to rebuild one and wanted to get an idea on what was reasonable to expect if things go well.

Is there a specification for the bed dimensions after a regind? Thanks. Jim
 
Hi - I have a 1976 Hardinge HLV that I'm currenlty tearing down to rebuild.

I did a quick scan through my operators manual and didn't see any specs on tolerance, but one of the top Hardinge rebuilders, Babin Machine out in Boston, states that he rebuilds to orginal OEM specs. He publishes a test cut of

Test cut result:.000050”/ 3 inches taper

On my machine the ways on the cross feed and compound are pretty worn out and need to be rescraped, but even in that condition my machine would cut within 0.0003 over a 3" length. I believe the reason for that is that my bed plate is in great shape and is not "hour-glassed" near the headstock.

You can see that rebuilt to factory specs puts another zero in front of what my machine cuts!
 
Jim - I forgot to mention some things about the bed grind question you asked.

I've learned a few things about that topic from talking to Paul at Babin Machine. He's a friendly guy who has freely shared information with me, and I know to a lot of other Hardinge lathe owners as well - you might want to give him a call.

You will need to keep track of how much material you take off and add the same amout in shim stock under the bed
If there are existing shims under the bed plate then you know it's been reground at least once, and you'll need to factor that in.

It is also critical that the angled sides of the bed plate are parallel to each other and the center line of the lathe. Since the carriage follows that angled edge, if that gets out of wack then you'll have problems.

Over the years I've read a few horror stories about grinding shops ruining the bed plate to high temperature damage and other ways they were damaged.

I need to have this done to my lathe and I haven't researched the cost yet, but as with all things Hardinge it will be expensive! Since this is such a critical thing to get right I'm going to go with an experinced Haridnge shop on the bed regrind

Regards,
Don
 
Don, Thanks for that information. I had my bedway reground here in Ontario. There is only about 2 places that will do this work that I could find -and they were a 7 hour drive away! The one I picked insisted on bringing the bedway and base together so that any warpage due to it's 33 year previous life would not be a factor. His grinder was old but looked well maintained and I think called blanchard. He ground the top first and patiently let things cool between passes (2 days total). Only 0.002" were removed (according to his measuring) from the top and about the same from the sides. It looked great when I loaded it up and drove home.

Once home I did some indicator measurements by using the tailstock as a sliding base and contacting the underside dovetail. Before the regrind the indicator varied by almost 3 thou over the length of the bed. Now it varied by 1.5 thou -I was NOT happy. I constructed a better sliding indicator tool that had three point contact on top and two point contact with the dovetail. This tool gave the same error as using the tailstock as a sliding base. The largest error was exactly where the before grind error was (near front of headstock).

Finally I took the bed plate off the base and did micrometer measurements along both edges of the bed plate. The top grinding was not parrallel as expected. The grinder had actually only removed 0.0002 from each end and 0.002 from the middle low area. The grinding machine had simply followed the worn surface!

I also found that the base casting was low in the middle -based on a high spot test using an old camelback straight edge.

I decided to try surface grinding of the top at a local machine shop (30 minutes away). CMM checks were also done. The top grinding results were a big improvement, but now there was a high spot of about .0005 near the middle. I took it home and reattached the bed plate to the base. My indicator test now looked very good (no measured error) except at the extream tailstock end. High spot testing with the camelback high spot test also looked as good as I can measure. I guess the high spot in the bed plate was cancelled out by the low spot in the base casting.

A total of 2.5 thou is now removed from the original bedplate thickness, so another regrind could be done if required if I could find a quality facility. For now I will try 4 thou steel shim under the bed and start headstock alignment work. The extra shim thickness is the allow for rescrape of the tailstock.

Comments on HLL-H headstock and tailstock allignment are welcome. Jim
 
I wish you had asked these questions before you sent it out. I am a Journeyman Machine Tool Rebuilder and have been rebuilding Hardinges for 30 years, working with the local MN Hardinge distributor doing mechanical repairs and scraping. A Blanchard is a vertical spindle shafted rotary grinder and not accurate at all and leaves spiral grind marks... The bed has to be ground on a precision surface grinder or a way grinder. It takes a shop that has ground them before. Recently I checked with Hardinge on grinding the bed of a HLV. Here is what they said.

Yes…we do offer this service….I’ve checked with the customer service team and the price is approximately $1200.00 with a 5 day lead-time.

If this is something you buddy wants to pursue, he can call into our parts\service team (607-378-4295) and they will provide the necessary details for him to get the unit refurbished. He might also check out the website section for repairs\rebuilds at http://www.hardingeus.com/index.asp?pageId=272 to get more information.

I have taught scraping classes at Hardinge here in the States and in Taiwan where they build their CNC machines. Hardinges are considered super precision machines as are jig bores, jig grinders, Swiss type grinders, etc. They should be ground and scraped to .00005" per 12" with 38 to 42 points per sq. inch. A conventional machine like a engine lathe or Bridgeport Mill is ground or scraped to .0002" per foot and 12 to 20 PPI.

I would also like to see you install Turcite on the bottom of the saddle as it helps eliminate the stick slip that is common with older Hardinges. I would use plastic shim under the bed and not steel as the steel shim is a pain to punch the holes and de burr them. I used to use steel before the plastic became popular and accurate.

My friend is a gunsmith and he has also talked to Babin about one of his CNC threader systems. I believe he said Babin charges $500.00 to grind the beds. I would want him to tighten up his spec's for me though.
 
Hi Richard,

I'm the Cummins guy in Indiana that was talking to you about your scraping classes right before Christmas. Hope to get to your Wisconsin class...

Tough luck for Jim on his Blanchard grinding experinece, but it did make me wonder if when restoring a Hardinge you need to first scrape the cast surface on which the bed plate attaches as well as regrind the bed plate..? I had not considered that before - what is your recommendation for that please?

My 1976 has some type of "plastic" under the saddle, but I don't think it turcite. Any idea what Hardinge used back then..?

Richard - I have to ask, a test cut of .000050" taper on a part sticking 3 inches out from a collet is not accurate enough?
That's .000016 per inch! Wow - if that's not accurate enough what should it be on a HLV? I didn't realize my HLV could be that accurate

I hope I did not misrepresent Mr Babin's work. I do know that top aerospace companies and medical research companies send their HLV's to him for rebuild and CNC conversions - those are pretty exacting industries. I did copy the tolerance from his website, so I would assume it is accurate.

Thanks for sharing your knowledge and experience on this
Don
 
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dwent said:
Hi Richard,

I'm the Cummins guy in Indiana that was talking to you about your scraping classes right before Christmas. Hope to get to your Wisconsin class...

Tough luck for Jim on his Blanchard grinding experinece, but it did make me wonder if when restoring a Hardinge you need to first scrape the cast surface on which the bed plate attaches as well as regrind the bed plate..? I had not considered that before - what is your recommendation for that please?

My 1976 has some type of "plastic" under the saddle, but I don't think it turcite. Any idea what Hardinge used back then..?

Richard - I have to ask, a test cut of .000050" taper on a part sticking 3 inches out from a collet is not accurate enough?
That's .000016 per inch! Wow - if that's not accurate enought what should it be on a HLV? I didn't realize my HLV could be that accurate

I hope I did not misrepresent Mr Babin's work. I do know that top aerospace companies and medical research companies send their HLV's to him for rebuild and CNC conversions - those are pretty exacting industries. I did copy the tolerance from his website, so I would assume it is accurate.

Thanks for sharing your knowledge and experience on this
Don
Click to expand...

That's .0002" per 12". Which I consider standard conventional machine tool spec's.
Hardinge "Super Precision" is part of there name. .0002" per 12" is not super Precision.

I say Super Precision is .00005" per 12". I will write my friend at Hardinge and ask him what they guarantee on their rebuilds. I'm not saying he does bad work, but I would tighten the spec's is all. His .00005" might be the push away spec he uses so close to the collet is zero and out 3 " it is +.00005" toward the operator so compensate for for push-way. I just scraped a Drake CNC Thread Grinder that the checked with no off-set and it was .00002" in 12". It's possible to do it, just have to be patient.

They use to use a white Nylon I think was .010" thick. I think you can still buy it from TRi-Star, but I usually machine out .020 and put in a .030" piece of Turcite. My friend should get back to me in the morning.. I will cut and paste you here what he says.
Good night. Rich
 
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Richard, Many thanks for your Hardinge rebuild information.

I may have taken on too much with this project with my present level of scraping skills and Hardinge mechanical background, but I will keep plugging away.

I can see getting the bedway reground properly at Hardinge as a workable option -perhaps when the snow lets up in spring. For now I will see how things work out with what I have.

I will be attaching a new 0.031" turcite saddle lining. The original looks like teflon about 0.011" thick and is imbedded with grit. The back dovetail teflon strip looks good and will be left in place for now. The original way wipers on the machine were completly brittle/damaged and appeared like roofing tar??

A 0.0035" steel shim will be placed under the bed plate to compensate for 0.0025" grind thinning. I hope the additional 0.001" will be enough to compensate for tailstock wear and light scrapping for oil retention.
I plan to loosely attach the bed plate to the base and see if I can get the headstock front to back alignment close before tightening all the screws.

I'm hoping to avoid scraping the headstock mating surface for now. Will try to get 0 to 0.0005" horizontal/vertical test bar deflection to operator at 12" from headstock. Jim
 
That's great, I wasn't only recommending just Hardinge, but a grinding shop that has done them before. That white thin original nylon was a poor design, the oil groves go though it and oil and works under it and loosens it. Be sure NOT to cut the oil groves through the new turcite. If you contact the mfg of turcite the explicitly tell you never cut trough the material as this lets the oils and coolants into the epoxy and eats it away. Think of a tent with holes in it, not good. If you don't know be sure to epoxy the etched brown side. Follow the Turcite or Rulon instructions. Be sure to add the epoxy from Rulon or Turcite into your calculations, the glue usually has .003" glass beads in it. Be sure to ask who ever you buy it from about this. I also spray a wax release agent on the bed plate and careful slide the saddle onto it and let the glued Turcite cure on the bed.

Also be sure to take of the sheet metal cover on the backside of the saddle, remove the aluminum plate, pull out the metering units that are attached to copper tube that feed the oil points on the saddle and cross-slide. Replace the meter units and clean and blow out the lines and holes. Take out the oil pump and unscrew the the filter and clean it in mineral spirits. If your not familiar with the metering units, they are small jets that meter the amounts of oil flow to the oil holes. I buy mine from Lube USA for about $8.00 each. You will be fine. When you scrape the Turcite, grind your scraper blade at 12 deg's neg. Write or call anytime if you have questions. Rich
 
Richard, I followed your recomendations with the turcite and that seems to have worked just right.

I was able to get the headstock aligned with the bed at 12", but I can see some linearity errors that make me think the bed regrind is at fault.

Tailstock alignment did not work out, I could get it good in one location, but when T.S. moved and locked down 3 " closer to the headstock it was off 0.0015. I think also due to the bed grind errors.

I have sent the bed to Hardinge for regrind and will cross my fingers.

In a previous post I mentioned that the bed base casting has a low spot in the middle - maybe 0.0005??? Could this be normal/acceptable or should it be scraped flat?


Thanks. Jim
 
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