Scraping a bed ways longer than my surface plate

Do any of you watch this guys channel? It can be done in sections but looks to be way more time consuming.
 
The video link got me thinking. Why not reach out to someone with scraping experience. Maybe email Keith Rucker at Vintage Machinery.org. He has a ton of scraping videos.

Tim
 
Hey Gang,

I am thinking ahead about some time when I may want to scrape lathe bed ways. All the videos I've watched show I either need to have a surface plate or precision straight edge at least as long as the bed. I have to believe this is not the case. Watching luthiers, when they level guitar frets, their leveler isn't longer than the guitar neck. So long as they have enough resting on the leveled frets, their work carries forward. I suspect leveling and scraping a machine surface is like that, but I cannot find the right keywords/catch phrases to see examples and/or instructions on how to do that. I can't seem to find a chapter in the copy of Connelly I got from the library, for example. Can someone please point me in the right direction?

Thanks,

Joe
I have personally seen B&S straight edges 15 feet long
arched type.
 
Do any of you watch this guys channel? It can be done in sections but looks to be way more time consuming.

Hey Gang,

I am thinking ahead about some time when I may want to scrape lathe bed ways. All the videos I've watched show I either need to have a surface plate or precision straight edge at least as long as the bed. I have to believe this is not the case. Watching luthiers, when they level guitar frets, their leveler isn't longer than the guitar neck. So long as they have enough resting on the leveled frets, their work carries forward. I suspect leveling and scraping a machine surface is like that, but I cannot find the right keywords/catch phrases to see examples and/or instructions on how to do that. I can't seem to find a chapter in the copy of Connelly I got from the library, for example. Can someone please point me in the right direction?

Thanks,

Joe
 
Connelly's book is missing one thing, an instructor to teach you what he is talking about. There are a series of operations you need to know to proceed.
On long bedways I would use an alignment scope and a tilting level to determine what needed to be done.
 
Leveling has problems if you use a standard level, an optical tilting level with an optical micrometer is needed,
then measuring with an alignment scope.

An alignment telescope and an autocollimator are both optical devices that can be used for different purposes:

Alignment telescope

Used to establish an accurate line of sight. The telescope has a very straight line of sight and a reticle, or crosshair, that defines the center of the line of sight. In alignment telescope mode, the field of view is often measured in minutes horizontally.

Autocollimator

Used to measure angular tilts or rotation of an object. The autocollimator projects a crosshair pattern out to the object being monitored. The device under test is placed in the optical path and reflects the light back into the autocollimator, which can then be inspected via the telescope functionality. In autocollimator mode, the horizontal measurement range is often measured in minutes.
 
I just saw an autocollimator sell at auction yesterday at Hutch Tech in Eau Claire. Maybe someone can correct but I think it went for less than 2 grand.
 
Ever try to level a lathe in plane which has a worn bed? If you place the levels on the worn areas you get inaccurate readings and confusing results. While I applaud this guys efforts and improved results the autocollimator is that it potentially falls into holes or worn areas. This is the same problem same problem as using a straight edge which is short.
If you work off the area under the head stock and right end you get near factory results. So, optics or a long straight edge either way the distance needs to be spanned. Or, as Mrben identifies lots of metal gets removed in an effort to find flat.

Daryl
MN
 
I just saw an autocollimator sell at auction yesterday at Hutch Tech in Eau Claire. Maybe someone can correct but I think it went for less than 2 grand.
An alignment telescope and an autocollimator are both optical devices that can be used for different purposes:

Alignment telescope

Used to establish an accurate line of sight. The telescope has a very straight line of sight and a reticle, or crosshair, that defines the center of the line of sight. In alignment telescope mode, the field of view is often measured in minutes horizontally.

Autocollimator

Used to measure angular tilts or rotation of an object. The autocollimator projects a crosshair pattern out to the object being monitored. The device under test is placed in the optical path and reflects the light back into the autocollimator, which can then be inspected via the telescope functionality. In autocollimator mode, the horizontal measurement range is often measured in minutes.

With Jig transits or Alignment scopes you can parallel the line of sight to the unworn ends of a lathe bed, then directly measure the wear with a target. Autocollimators require a calculation to get a usable number.

I can read a high area, slide the target back, remove metal, read it again. This work is interesting but practically speaking you learn the basics on the job and then you get the job , if successful you get more, studying optical alignment helps, owning instruments
helps, this hobby oriented platform means that most of you are clueless people with opinions, for example 3M
never sent an autocollimator out on a web line job, paper mills use jig transits and tilting levels because that is what works. I have an autocollimator as a fixture device
so I can line it up and if something moves or twists I know. I started learning this in 1971.
 
Ok....
Lets please get back to the OPs question.
Is there any way to efficiently and effectively and affordably scrape in a lathe without optics and longer straight edges?
I don't see it.
But I want to observe that this is a fair and reasonable question.
As an advocate for fun, affordable and safe shop practices I ask if there is an optimal approach to this question.

Daryl
MN
 
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