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Scraping Question

benster

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#1
I recently acquired an Atlas 10 with a 54" bed. It has wear along the first foot or so of the ways. In order to scrape the whole bed back together would I require a straightedge that's around 54" long? Would a surface plate that long work if I scraped both sides in simultaneously?

Just pondering how I would go about doing it. This would be something to work up to as I don't have much scraping experience and the couple of grinding shops I've contacted haven't gotten back to me about surface grinding the bed.
 

Bob Korves

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#3
It is possible to scrape in a surface with a straightedge or surface plate shorter than the surface. That said, t'aint easy. That is for advanced scrapers with lots of experience. It is not at all for someone just starting out in scraping. Even just scraping in a lathe with all the correct tools and a mentor is a major project and difficult work for a beginner, and a patient mindset is required as well. Scraping with a shorter reference surface than the work surface requires careful observation and understanding in interpreting the patterns. It would not be done in two sections, but rather in overlapping
sections.

How much wear is present in the ways?

Edit: The reference surface should actually be somewhat longer than the ways to be correct, so the work will have full contact while sliding against the reference surface.
 
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Andre

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#5
Get a big plate, verify flatness somehow, then scrape.
 
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benster

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unless you know how to scrape i would not attempt it have it ground
Why would you not have it ground?

It is possible to scrape in a surface with a straightedge or surface plate shorter than the surface. That said, t'aint easy. That is for advanced scrapers with lots of experience. It is not at all for someone just starting out in scraping. Even just scraping in a lathe with all the correct tools and a mentor is a major project and difficult work for a beginner, and a patient mindset is required as well. Scraping with a shorter reference surface than the work surface requires careful observation and understanding in interpreting the patterns. It would not be done in two sections, but rather in overlapping
sections.

How much wear is present in the ways?

Edit: The reference surface should actually be somewhat longer than the ways to be correct, so the work will have full contact while sliding against the reference surface.
There's several scratches and knicks present as expected in a 50 year old lathe, mostly along the first foot. I haven't measured the wear but when I adjust the carriage to slide smoothly near the spindle its tight about a foot away.

I'll take a look at that book, looks like it'll answer a lot of questions.
 

Kernbigo

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#7
I use to have a atlas 54"and i don't think that is you problem. First stone or file the nicks, get rid of them. You have a hold down plate in the back side of your cross slide, adjust the bolts in the section the is tight, and i believe if i remember write there is also a flat gib there, adjust that also. I have scraped for 25 years and think for sure if you attempt that it will be a dis tater, more than likely it don't need it.
 

Bob Korves

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#8
Why would you not have it ground?



There's several scratches and knicks present as expected in a 50 year old lathe, mostly along the first foot. I haven't measured the wear but when I adjust the carriage to slide smoothly near the spindle its tight about a foot away.

I'll take a look at that book, looks like it'll answer a lot of questions.
If you read Kernbigo's quote carefully he was recommending you have it ground, just left out some punctuation. That requires a complete teardown, transportation both ways, and is pricey.

Lathes can have quite a bit of wear without affecting the accuracy substantially, and the wear can also be compensated for. You can stone off the high parts of the dings and scratches, and the low parts do not hurt anything. I do understand pride of ownership, but another way of looking at it is honest wear from decades of use -- provenance and patina. In the end it is your lathe and you should do with it what makes you happy.
 

chips&more

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#9
If you are making parts for NASA, then get a +$30K lathe. If not, then I would enjoy just having a lathe and living with its little quirks. The challenge is in you, not the lathe, to make good parts with what you have. It can be done. Many many folks on the HM are making excellent quality items on old and tired machines. A lot of it is in the skill and finesse of the operator.
 

benster

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Ya'll make some excellent points. I'll run it for another year or so and see how I feel then.

If you are making parts for NASA, then get a +$30K lathe. If not, then I would enjoy just having a lathe and living with its little quirks. The challenge is in you, not the lathe, to make good parts with what you have. It can be done. Many many folks on the HM are making excellent quality items on old and tired machines. A lot of it is in the skill and finesse of the operator.
Part of the problem is I design parts frequently at work that are spec'd within half a thou at 62 surface finish... Frustrating to get home and not be able to hold 2 thou!

Does it cut near the headstock? Or is it too loose?
It cuts well near the headstock when I adjust the gibs for this area. If I move it farther out it becomes stiff and I worry I'm wearing out the feedscrew/gears excessively.
 

cjtoombs

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#12
As far as scraping lathes go, the Atlas is probably one of the easier ones, given that it is flat bed. You will need a straightedge, preferable one longer than the bed, as you will need to scrape the bottom of the ways as well. One option is to watch Ebay, you will occasionaly see Atlas lathe beds on there for sale from people parting out lathes. It's kind of buying a pig in a poke, as you don't know if it will be worn out as well. Given that Atlas/Craftsman lathes were mostly purchsed by hobbyists who don't use a lathe like an industrial user would, I suspect you are much more likely to find a good lathe bed than a bad one, so the chance may be worth taking if you can find one close and for a low enough price. It does require patients, though, as it can take some time for the right deal to come up.
 

4gsr

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#13
I've had Don's grinding service surface grind my mill table several years ago to remove all of the idiot marks. Cost me about $200 bucks. They may, may not touch a lathe bed, I don't know. Besides SG the top, both of the outside faces of the bed will have to be touched up too. They probably have the most wear of any of the surfaces. You might even ask around for a shop that has a fairly large CNC mill sitting idle. One that can handle around 60" x-travel. There's a lot of idle machinery in the Houston area right now, you should be able to get a bargain on machining! Be amaze how nice a job they can do on a nice CNC mill.
 

chevydyl

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#14
You would also need an inside 90 gauge, to keep the sides of the bed on the inside and outside of each flat way 90 degrees when scraping, there is a bearing surface under the flat as well, for the carriage, you have to measure everything and determine where the wear is, the top of the wide way or under, the outside bearing away from the operator is probably worn..... I own a 12 inch and have looked it over thinking about scraping it

Think about the tool pressure, and what forces it's causing, that's more than likely gonna be how the wear shows up
 

benster

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After using the lathe for a couple months I've been able to get a better feel for it and have mostly eliminated any of the ill effects the wear has caused, either through adjustment or locking gibs whenever possible.

I did contact several grinding shops in Houston, I either got no reply or no quotes. You think more places would be itching for work with oil the way it is right now...
 

astjp2

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#16
Most of the old lathes were not ground, they were planed. While not cheap, if you get someone who knows how to get everything setup, it would make the lathe like new. Tim
 

Uglydog

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#17
Scraping old cast can be difficult even if she is a high quality casting.
I don't know why, but it seems to get more difficult with age. I'm referring to the metal, and not the discomfort your shoulders may experience after hours of scraping.
You might elect to have the bed "stress relieved" before scraping.
Additionally, some beds are "flame hardened". I don't know about Atlas.

Daryl
MN
 

chevydyl

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#18
I've heard of a guy scraping an atlas, they aren't hardened, pretty soft, they ding easily
 

graham-xrf

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#19
I have recently acquired a South Bend 9c from eBay for truly crazy bargain price. Everything covered in clean oil, and it looks like it has been somewhat cared for - I mean, not abandoned rusty state like we see in some of those "before" pictures.
Even so, there has to be at least a clean-up, and checking out which bits might need fixing or replacing.
This leads to my questions..
Suppose there is enough wear to warrant re-grind, or scraping of the ways. This must surely mean that some parts in the apron would be affected.
Is it that the rack gear needs adjusting with shims?
What happens about the lead screw position? It can't really go anywhere, so what gets modified?
Is it that if any grinding/scraping is contemplated, it cannot be minor, being as it needs to remove at least the thickness of a shim (if that is what is used)?

I don't really know how a professional re-grind operation gets the new surfaces stay in line with the spindle, but I imagine the way is to line up with the unworn regions at the ends, where the original decorative flaking can still be seen.
 

cjtoombs

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#20
If you know how much is taken off both the bed and the bottom of the saddle then depending on how the drive is (power cross feed or no?) then you could take that amount off the top of the apron and the lead screw should allign with the half nut. If you have power cross feed, then thing would get a bit more complicated, as raising the apron would effect gear meshing for the power cross feed. This will give you a bit to think about. Maybe a pro will come on here and let you know what they do in this situation. You might consider getting the book Machine Tool Reconditioning by Connelley, as it goes into a lot of detail on alignment.
 

graham-xrf

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If you know how much is taken off both the bed and the bottom of the saddle then depending on how the drive is (power cross feed or no?) then you could take that amount off the top of the apron and the lead screw should allign with the half nut. If you have power cross feed, then thing would get a bit more complicated, as raising the apron would effect gear meshing for the power cross feed. This will give you a bit to think about. Maybe a pro will come on here and let you know what they do in this situation. You might consider getting the book Machine Tool Reconditioning by Connelley, as it goes into a lot of detail on alignment.
Thanks for your reply. At least for the South Bend 9c, it being the least endowed, there is no power cross feed, which makes things simpler. I have the book, downloadable from this site in 6 chunks, and indeed it does address alignment. Scraping the ways has to involve removing unworn metal to get the new bearing surfaces below the worn parts, while at the same time progressing toward, or retaining alignment. It is a simultaneous process.
The book does not cover what to do about apron, cross-feeds, and suchlike other than to make the point that it is the main surfaces that are the priority. All other dependant slides, shafts and parts "can be moved".
Folk on this site have restored lathe beds, either by themselves, or by having them re-ground professionally. Therefore, they will have a list of consequential issues - things to be fixed. I think, maybe, what I am after might already be somewhere on this site.
 

4gsr

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#22
Graham,

If you don't find what you are looking for, let us know, many of us have vast knowledge of machine rebuilding/reconditioning experience! I myself have rebuilt several lathes over the years including my dad's 9" South Bend Lathe. Just let us know. Ken
 

graham-xrf

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Graham,

If you don't find what you are looking for, let us know, many of us have vast knowledge of machine rebuilding/reconditioning experience! I myself have rebuilt several lathes over the years including my dad's 9" South Bend Lathe. Just let us know. Ken
Hi Ken
Many thanks. I am thinking there will come some point when I get in deep enough to need some pointers.
Right now, the first things are to get the drive arrangement up and running, and carefully start exploring.
I have a 600mm straight edge, magnetic base dial gauges (2), and various measuring kit (Mitutoyo, Kanon).
I guess that before long I might need a surface plate and a air compressor. Clean-up comes first, and that includes the clutter around it!

One question that comes to mind is.. does one start from the bottom and work up?
Put another way, can work to fix up (say) top parts like cross slide, compound, etc. be done independently of attending to the main ways?
It occurs to me that some efforts may be wasted, and parts have to be visited again if one tackles things in the wrong order.

What is the received wisdom about a tray underneath? This lathe is on a 1/4" welded steel plate bench top with a hole cut for the underneath belt drive. Not that I expect to be using lots of coolant. I just think a tray helps stop stuff from rolling off the back, and is easier to wipe up than the floor.
 

eeler1

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#24
To the OP, If its evenly worn over first 12", you could just make short parts.
 

4gsr

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....snip.......
What is the received wisdom about a tray underneath? This lathe is on a 1/4" welded steel plate bench top with a hole cut for the underneath belt drive. Not that I expect to be using lots of coolant. I just think a tray helps stop stuff from rolling off the back, and is easier to wipe up than the floor.
I've seen all sorts of contraptions over the years to capturing shavings, oil, coolant. 1/4" plate sounds like a over kill to me but if it is working go for it.
 

graham-xrf

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Perhaps I should have made it clear. The 1/4" plate is the top surface of the welded bench, made of 2" angle.
It is flat all the way to the edge. It has a hole under the headstock for the drive belt from underneath.
Already some bits rolled off the back. When I get this proper mounted to the concrete, it won't be so easy to retrieve stuff that made it off the back. Even if not a tray, maybe some sort of ledge stop around. Some wood strips?
I had thought a stainless tray, possibly rescued from the food industry, modified a bit, would be nicer.

Sorry - nearly off topic. This is early days. Be sure, I will be getting to some precision measuring/evaluation/restoration. My first scraping experiences so far have been confined to learning/practising on a pair of neglected V-blocks. Surface plate is 1" thick 6" diameter glass optical flat that suffered a small scratch near one edge, so dumped. Spotting is "Micrometer" brand Prussian Blue, though I found a 200ml tube of "Pebeo" brand red ochre oil colour from eBay works just as well, and has advantages in it's own way, and is much lower cost.
 
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