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Reconditioning My HLV-H

you can go to YouTube and type or search Richard King Scraping and watch several movies my students have produced. Or Google your question then add Richard King practical machinist and you can find answers many PM members answered. To be honest I'm getting tired answering the same questions over and over. I've been teaching for over 40 years in person and online. You can attend one of my classes and learn how in 3 days compared to weeks and months online.
 
Famous YouTuber, Stefan Gotteswinter came to one of my German classes with fake (other brand) BIAX Scraper and tried a real Biax scraper. After that he sold the fake and bought a Biax. So you can't expect Biax quality with the fake scraper. I'm a believer in BIAX plus I'm a Biax distributor and the worldwide Biax factory Insructor. Being a professional Machine Tool Rebuilder for 55+ years. My advice is to sell your fake Biax and buy a Biax.
 
Richard,
As much as I value your advice, I’m not going to buy a Biax. Too much money. I’ll live with what I have. My understanding is that all power scrapers have chatter anyway. I would love to see a close up (macro) image of Biax scraping so I can see the difference though. If there is any now that I added damping to my home built unit.
Earlier, you indicated that you would be willing to advise on my HLV-H reconditioning job when I got around to it. That was very generous of you to offer and given your experience with these lathes it was much appreciated. Are you still willing to advise? If you think it would be a waste of your time, that’s OK. Totally your call of course. I do tend to ask a lot of questions!
Thanks so much for all of your help.
 
Buy a hand scraper then. I've advised you to much. My students who are members here can. I just tired of writing the same advise over and over. Have you Googled old treads like I advised? Over the years others have rebuilt Hardinges on here and wrote threads. You can look for them and link them in your thread. Will save everyone a lot of time. Your scraper is like a Yugo compared to a Cadillac in my opinion.
 
Buy a hand scraper then. I've advised you to much. My students who are members here can. I just tired of writing the same advise over and over. Have you Googled old treads like I advised? Over the years others have rebuilt Hardinges on here and wrote threads. You can look for them and link them in your thread. Will save everyone a lot of time. Your scraper is like a Yugo compared to a Cadillac in my opinion.
OK. Thanks for your earlier help. Sorry to have annoyed you.
 
My understanding is that all power scrapers have chatter anyway. I would love to see a close up (macro) image of Biax scraping so I can see the difference though. If there is any now that I added damping to my home built unit.
I'll try to do some deeper scraping at some point and get better pictures of it, but I can assure you that the Biax doesn't have visible chatter when used properly (sharp blade, right speed, stroke and material.) I can't really think of a reason that the chatter you are seeing will have a large negative impact, but it may affect the wear resistance (all those micro peak contact points), grit retention, or affect the perpendicular cutting performance during the scraping process. But that's just speculation, it may just be an appearance thing. If you can get prints that you are happy with, you will be able to establish how well it holds up over time.
 
I would like to thank all involved in this thread as the discussions about gibs being a bit thin at the centers, and the avoidance of false setting is an education for me. I would comment that the last slide re-work I did drove home the importance of machining proper geometry on the parts before starting to scrape. This was toughter to do than i thought.

One comment I would make is hardinge never did scrape the exerior of those compounds to any special degree, and if one wanted to pefect the art of finishing the surface for beauty, start with a chunk of durabar so you can perfect things.

Also pay special attention to the top of the cross-slide and the underside of the compound base - my machine at work was ALL buggered up from ham-fisters overtightening the lockdown cam.

Best of luck on the project!
 
I would like to thank all involved in this thread as the discussions about gibs being a bit thin at the centers, and the avoidance of false setting is an education for me. I would comment that the last slide re-work I did drove home the importance of machining proper geometry on the parts before starting to scrape. This was toughter to do than i thought.

One comment I would make is hardinge never did scrape the exerior of those compounds to any special degree, and if one wanted to pefect the art of finishing the surface for beauty, start with a chunk of durabar so you can perfect things.

Also pay special attention to the top of the cross-slide and the underside of the compound base - my machine at work was ALL buggered up from ham-fisters overtightening the lockdown cam.

Best of luck on the project!
Thank you! I do have a practice piece and I think I have figured out an attractive scraping mode. I am currently working on machining the top of the cross slide and it is as you describe. Unfortunately by the time the surface cleaned up, the angle graduations were all but invisible in one area. So now I’m trying to figure out how to re-engrave it. Yet another rabbit hole to explore! Also in question is mixing engraving and scraping on the same surface. Might have to leave that surface unscraped.
 
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Yeah, one of the advantages of the Biax's high gear reduction and heavy wobbler is there's a lot of torque and rotational mass behind the stroke motion and so it has a really consistent and powerful cut. I'm still super impressed that you built your own machine, but it will need more refining to reach the Biax level of quality I think.

As for Mr. King's advice, I believe what he is saying is that it is important that the gib be parallel in the cross-sectional width from top to bottom to make sure it doesn't create a false set and appear to be tight when it is not.

Below is a quick picture, not showing the longitudinal taper, but what can happen if the gib slot doesn't have the proper (green) cross-sectionally parallel faces. The lower example is what can happen if you don't match the gib slot faces without the gib in place.

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It is perfectly possible to scrape a gib and ways where it shows 100% contact with all the gib faces when printed, but have a double taper to the gib so it wedges itself tight at the bottom giving a false set. It will feel tight and properly adjusted until vibration and load cause it to climb up to the top which creates space due to the secondary taper and the ways become loose.

By printing those two (green) faces to each other by manipulating the top slide without the gib so that the faces contact but the plane of travel is maintained, you ensure there will be no secondary taper. Then when you scrape in the gib you know it will also be cross-sectionally parallel and will not change its set. He also seems to recommend relieving 40% in the middle of the lengthwise section of the gib's contact face by ~15-25 microns to extend the life of the reconditioning.

Obviously these are some of the final steps, it is assuming that the non-tapered dovetails are parallel and everything has been scraped flat and planer with each other. There are some good examples of doing this on YouTube.

I think your lighting looks great, taking photos of a scraped surface is maddeningly hard, and your pictures clearly show how well relieved you blade grind is, so I'm wondering if he was complaining about my scraping (which certainly has some edge marks) and got confused.
That is an excellent explanation of the gib problem Richard was talking about! I was having trouble getting my mind around what he was saying (mostly because it didn’t have anything to do with the subject at hand, perhaps he had someone else’s thread in mind, nonetheless very important for what’s coming on my project) but your description and illustrations made it perfectly clear.
 
Well damn. After letting this stew for a while and hearing critiques about the chatter I am thinking of doing away with scraping for appearance. I'm convinced now that the chatter is caused by large amounts of gear noise in the transmission of my scraper that cannot be remedied without huge amounts of time and or money. And after looking at it for a while that chatter adds a look to the scraping that isn't pleasing at all. But from what I have read, the chatter issue is just a matter of appearance. It has no adverse effect on function. So I'm planning to go on with the HLV-H project with my chatter prone scraper since it will have minimal scraping that is visible. Function over form!
 
I think the look isn't too bad, it was a valiant effort to make your own scraper for sure. Keep thinking about it, you may find a solution (flywheel on the final drive?)
 
I am a beginner at scraping but what I found is that scraping dovetails required an iterative process of checking flatness with a straight edge, checking alignment with a kingway type tool, checking fit with the gib for both smoothness of travel over the entire length and shake test with an indicator. Them repeating the entire process several iterations. My point being parts need to be flat and in alignment in 3D so some iteration is required. Dont worry too much about PPI yet because you might be back to mess with alignment. I am sure an expert would require way less iterations than me.
 
Well I've started getting into manual scraping of the dovetails. I did some work earlier on the compound dovetail (non gib side) and decided it wasn't good enough. I'll try again on that later. I worked on the cross slide dovetail (non gib side) and am pretty happy with the results. 0 to .0001 along the length seems remarkably good to me. Is this accuracy typical of scraping projects or was I just lucky?
I took a look at the carriage next and was pretty disappointed in what I found. I set the carriage up on the surface plate (see pic) with the (non gib) z axis dovetail square to the surface plate within .0002"/10". In this position, the x axis dovetail was out of square by .0055" in 11". Is that normal? It seems like a lot of scraping is in my future.
More later.
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Testing it with it setting on the edges is not the way its done in my opinion. I would first look at the cross slide positive side (non gib side) on the saddle and cross slide looking for wear and no wear. Measure the unworn areas (area at bottom of way that didn't touch and it's original) that I call a ridge. Then scrape the saddle bottom with a straight edge to be sure the slide ways are not high in the middle by rubbing and hinging for pivoting the SE to find the fulcrum points. Relieve the middle on the saddle bottom middle as I bet it's high in the middle because as it wore it wore on the .front leading edge. You only scraping it to prepare it to be match fit to the bed after you know there not ot high in the middle. Then match fit it to the being. A detective and scraping the tailstock end as much as the front side was worn.
Keep in mind the top saddle front dove tail needs to be square to the bed, not square to the headstock. Eventually you will align the head stock to the to the bed out of square soo when you face it is concave .0002" in. 12". You can see this check on YouTube done by my student Kieth Rucker under his leblond lathe rebuild video.
The squarness check is done with a granite or. Precision blade square. You method using the magnetic cylindrical square mounted on the clearance side is ripe for errors and not the way the factory scraped it. It looks cool, but you need to build the machine like your building a house from the bottom up. Meaning scrape saddle bottom keeping it square to bed, then the cross slide, etc.
 
Testing it with it setting on the edges is not the way its done in my opinion. I would first look at the cross slide positive side (non gib side) on the saddle and cross slide looking for wear and no wear. Measure the unworn areas (area at bottom of way that didn't touch and it's original) that I call a ridge. Then scrape the saddle bottom with a straight edge to be sure the slide ways are not high in the middle by rubbing and hinging for pivoting the SE to find the fulcrum points. Relieve the middle on the saddle bottom middle as I bet it's high in the middle because as it wore it wore on the .front leading edge. You only scraping it to prepare it to be match fit to the bed after you know there not ot high in the middle. Then match fit it to the being. A detective and scraping the tailstock end as much as the front side was worn.
Keep in mind the top saddle front dove tail needs to be square to the bed, not square to the headstock. Eventually you will align the head stock to the to the bed out of square soo when you face it is concave .0002" in. 12". You can see this check on YouTube done by my student Kieth Rucker under his leblond lathe rebuild video.
The squarness check is done with a granite or. Precision blade square. You method using the magnetic cylindrical square mounted on the clearance side is ripe for errors and not the way the factory scraped it. It looks cool, but you need to build the machine like your building a house from the bottom up. Meaning scrape saddle bottom keeping it square to bed, then the cross slide, etc.
I should have done a better job of explaining my method. I was actually trying to measure squareness to the z axis dovetail, albeit in an indirect way. I measured the distance from the non gib z axis dovetail to the flat surface (see pics) that the cylinder square is on. Top and bottom were exactly equal and since the flat surface is a very nice ground finish I thought it would be ideal for the cylinder square. I put a shim between the surface plate and the apron end of the carriage to get zero along the length of the square. That was when I discovered that the non gib x axis dovetail was .0055" lower at the apron end.
I really hope that this is an OK way to check it because unfortunately there is no ridge at all left.PXL_20240202_173146526.jpgPXL_20240202_173109319.jpg
 
"Then scrape the saddle bottom with a straight edge to be sure the slide ways are not high in the middle by rubbing and hinging for pivoting the SE to find the fulcrum points. Relieve the middle on the saddle bottom middle as I bet it's high in the middle because as it wore it wore on the .front leading edge. You only scraping it to prepare it to be match fit to the bed after you know there not ot high in the middle. Then match fit it to the being. A detective and scraping the tailstock end as much as the front side was worn."
I've been looking at the HLV-H carriage and am having a hard time trying to apply your advice to what I see. There is no wear here since the Teflon is long gone. Should that be restored first?
 
I recently had to repair a flaw on my unmentionable 13x40 lathe saddle. The flat bearing surface of the cross slide closest to the chuck was exposed by 0.050". Any and all debris was wicked into the horizontal sliding surface and turned into glitter.

I set it up in the mill and trammed it with a gauge pin in the front and rear of the dovetail and cut the leading edge of the saddle back so the cross slide over hung by 0.025". I then reinstalled the cross slide, tightened the gib and milled the exterior taper off of the slide. It was out by 0.006" in 10". then I could install a piece of flat stock to side creating a drip edge that sheds debris.

The point being, it's the saddle dovetail that determines the travel axis, not the edge of the cross slide.
 








 
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