HLV-H bed plate regrind

JC Price · May 3, 2014

I'm finally renovating my 1968 Hardinge HLV-H. Here is a photo of the bed plate and casting:

Bedplate Thickness

After removing the rack and cleaning away gunk I can measure the thickness of the bed plate along its front edge. I get 0.8805 just in front of the headstock and 0.8810 at the tail end. I think there has been very little wear at these locations and so these values should be close to the original thickness. The worst place is about 10 inches from the front of the headstock where it is worn to 0.8682, or about 12 mills thinner. On the rear 45-degree surface of the bed plate there is a very clear wear step because the saddle does not reach quite all the way to the bottom of the bed plate. This step is also worst about 10 inches from the headstock, where it is 6 mills high. So it looks like my bed plate is about 12 mills concave on the top surface and about 6 mills concave on the sides.

The next step would seem to be to remove the bed plate, make a crate for it, and ship it off somewhere for regrinding. Could anyone here recommend a shop in the US that can do this competently? I talked to Hardinge about this about a year ago and they told me they will not regrind bed plates that are worn by more than 5 mills, so that does not seem to be an option for me. I plan to ask them if they still have replacement bed plates and how much they cost.

rob daniel · May 3, 2014

I can't recall exactly but the conversation I had with Hardinge was that the bed could be reground as long as less than 0.015 was removed. I had Schaffer Grinding in the LA area do the grind and I have been pleased with the results.
Rob Daniel

L Vanice · May 3, 2014

There are several Hardinge lathe rebuilders. I would start with a call to: Babin Machine Tool I hear they are very helpful.

And let us know the US price of a new bed plate. I found the UK price is $8042. http://uk.shophardinge.com/product.aspx?partNo=LH 0008042

Larry

Milland · May 3, 2014

Is it totally nuts to ask a grind shop if they could cut the top and dovetail angles while the plate is still on the main casting? That would take any distortion out from unbolting and reseating the plate. Not sure if this is an issue, maybe it's not worth thinking about if the mating surfaces are accurate enough (as you'd expect them to be with a Hardinge).

JC Price · May 7, 2014

Hardinge referred me to my local distributor, Hartwig. They quoted a new bed plate at $5045 and 50 days ARO, which seems reasonable to me. I haven't decided yet if I will replace it or regrind. Milland, that was suggested by one of the shops so I don't think it is crazy at all. I may go that way. I'll report back when I have more info.

JRIowa · May 7, 2014

While I may think you are nuts for trying to have a "perfect" HLV-H. The best grinder that I know of is Commerce Grinding in Dallas.

Make sure that you write a spec sheet to go along with your RFQ. I'm guessing flat within 0.001" and parallel within 0.001". You want the plate off the base.
JR

Jim Caudill · May 8, 2014

The last one I had done was by Process Equipment Company in Tipp City, Oh (937) 667-7624. They have changed hands since I used them, but the cost was $350 back in June of 2000. They had the ability to do very precise grinding over 8 ft long, so I figured the accuracy over the length of the Hardinge bed would be pretty darn accurate.

JC Price · Jun 16, 2015

Photos of HLV-H bed regrind

Just to follow up on this, I made a crate and shipped the bed to Gallery of Machines in Marathon, NY. They did the job for $1200, but I think it took longer than expected so they might not do a similar regrind for that price again.

Here it is on the way out of my shop:

And here some shots of the grinding operations:

You can see that we left the bed plate on the bed casting. The results look pretty, but I have not done any careful measurements yet to check flatness and alignment.

[Edit: actually I paid $1500 but that included shipping one way.]

Milland · Jun 16, 2015

Neat, although I'm a little surprised they didn't do the three surfaces in once setup. I guess if the base is true and planer to the V plate then the final surface grind is simple. You'll want to be extra careful in setting up the headstock again to be sure it's true to the plate. Have you planned your process for that yet?

JC Price · Jun 16, 2015

next steps...

Not really, but here's the general plan I have in mind. Comments appreciated.

1. Finish cabinet renovation so I have a working electrical and drive system
2. Put the bed back on the cabinet
3. Fit the saddle to the bed. Use Moglice for bearing surfaces under the saddle and against the back of the dovetail. Scrape the gib. (I don't have much skill in that department but I don't see how to avoid scraping the gib.) I'll need to work out how to position the saddle square to the bed and at the correct height for the lead screw.
4. Test fit the headstock and turn a test bar. Use an indicator mounted on the saddle to measure spindle alignment with respect to the bed. Adjust headstock alignment with shims and repeat.
5. Fit the tailstock, probably using Moglice again.

Mark Rand · Jun 16, 2015

Do you know how much they took off when grinding?

JC Price · Jun 16, 2015

Yes, I have thickness measurements from before the grind. You can sort of see them marked on the bed plate in the photo in the OP. The bed plate is now 14 mills thinner than it was. That's a lot of grinding!

stephen thomas · Jun 18, 2015

You want the plate off the base.
JR

JR - I take most of your posts as near gospel. So this is real curiousity. Why remove the bed plate for this type lathe for grinding and risk (admittedly small) opportunity for distortin when re-fit? My understanding of many or the replaceable hard way lathes made, (not sure about hardinge) was that the correct approach was to replace the ways, then touch-up grind them for final precision.

I can see that there is a lot of opportunity for corrosion swelling and mayhem under a bed like this. Perhaps the best approach would be to remove, clean scrupulously, and re-assemble with LPS or Boshield before sending out for grinding?

smt

JRIowa · Jun 19, 2015

Geez Stephen, That was a year ago. I read it now an wonder.

Seriously, Anything that we've rebuilt that has hardened ways, we strip. That's the only way you can do the big W&S.

I've lost all my hair to chemo. Maybe having more oxygen will help the 2 remaining brain cells. I doubt it, but I can always hope.

JR

TDegenhart · Jun 19, 2015

Did they also regrind the bevels on the edges?

Tom

JC Price · Jun 20, 2015

see photos

TDegenhart said:
Did they also regrind the bevels on the edges?

Tom

Yes, see photos in post #8. Second photo shows the edges being ground.

rons · Jul 10, 2015

JC Price said:
Yes, I have thickness measurements from before the grind. You can sort of see them marked on the bed plate in the photo in the OP. The bed plate is now 14 mills thinner than it was. That's a lot of grinding!

You might not like to hear this but...

When I talked to a rebuilder local to me about grinding the bed and remounting it
with material underneath the reply was "that's bullshit. We reduce the height of the
head". They had never done it any other way. I was not too happy with that.

JC Price · Jul 11, 2015

rons said:
You might not like to hear this but...

When I talked to a rebuilder local to me about grinding the bed and remounting it
with material underneath the reply was "that's bullshit. We reduce the height of the
head". They had never done it any other way. I was not too happy with that.

I don't understand the issue. My bed plate is now 14 mills thinner, so I have to build the saddle up so it will be at the right height for the lead screw and the rack. But why would I care if the spindle and tailstock axes are lower than they used to be?

rons · Jul 11, 2015

JC Price said:
I don't understand the issue. My bed plate is now 14 mills thinner, so I have to build the saddle up so it will be at the right height for the lead screw and the rack. But why would I care if the spindle and tailstock axes are lower than they used to be?

Does not the head mounting support have to be taken down by the same 14 mils. I cannot
tell from the pics.

For the HLV model the bed stops short of the head and that was what I was thinking about.

JC Price · Jul 12, 2015

rons said:
Does not the head mounting support have to be taken down by the same 14 mils. I cannot
tell from the pics.

For the HLV model the bed stops short of the head and that was what I was thinking about.

I see. On the HLV-H the bed goes right under the head. But I was missing something important here, so thanks for bringing it up. I think I will have to shim the head up 14 mills, since the spindle carries a gear that meshes with the quick-change box.

For now I'm still working on the cabinet.

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