Opinions please....

Connelly's book is not so much theory as it is practical operating techniques from mostly deceased men with dirty overalls. That is a good thing. At its best, machine tool reconditioning is labor intensive, expensive work. Knowing how to do it right while also getting it finished to a high standard and also making money on the quoted work is part and parcel of what it is all about.

The straightedge technique of testing a lathe bed is only part of multi faceted approaches to getting the bed straight. Connelly also talks of using taut wires and other methods of confirming the existing topography.

There is no magic to this stuff, only understanding and pragmatism, and much of it is arcane and different than what we have been exposed to or what we might intuitively guess today. That doesn't make it wrong, but it also doesn't make it current state of the art. Machine Tool Reconditioning is a great view into the world of machine reconditioning circa 1955 when this old man was in kindergarten. The topography has changed, and so have we, and so have the ways that machines are rehabbed, for better and for worse, but mostly just changing to fit the changing world.

We are all learning, or we are saying "whatever!"
 
Bob Korves said:
Connelly's book is not so much theory as it is practical operating techniques from mostly deceased men with dirty overalls. That is a good thing. At its best, machine tool reconditioning is labor intensive, expensive work. Knowing how to do it right while also getting it finished to a high standard and also making money on the quoted work is part and parcel of what it is all about.

The straightedge technique of testing a lathe bed is only part of multi faceted approaches to getting the bed straight. Connelly also talks of using taut wires and other methods of confirming the existing topography.
Click to expand...

Agreed, there is definitely ALOT more to it than just checking some flat ways with a straight edge.
Connelly's text is excellent.

BEFORE YOU WATCH THE VIDEO BELOW:​
My hope is that we can get a constructive dialogue going to further unlock Connelly's information for a knucklehead like myself and those interested in machine tool reconditioning. This is only ONE aspect and attempt at checking the machine. There are a variety of other variables not discussed that are critical to creating a complete understanding of the current condition of the machine. DO NOT USE THE VIDEO AS A GUIDE. It is for the sake of conversation and better understanding. I'm under no impression that the content would be a guide to begin scraping. It's all in the spirit of learning and having some fun in the garage.

If you follow my Youtube channel, you will see that this is NOT published. That means the only place to watch the video is through www.hobby-machinist.com. It's like a backstage pass!!:geek: The video is also not as refined in terms of editing, because I want to avoid omitting any mistakes or pitfalls that I may have induced during the process.

 
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ThunderDog said:
Agreed, there is definitely ALOT more to it than just checking some flat ways with a straight edge.
Connelly's text is excellent.

BEFORE YOU WATCH THE VIDEO BELOW:​
My hope is that we can get a constructive dialogue going to further unlock Connelly's information for a knucklehead like myself and those interested in machine tool reconditioning. This is only ONE aspect and attempt at checking the machine. There are a variety of other variables not discussed that are critical to creating a complete understanding of the current condition of the machine. DO NOT USE THE VIDEO AS A GUIDE. It is for the sake of conversation and better understanding. I'm under no impression that the content would be a guide to begin scraping. It's all in the spirit of learning and having some fun in the garage.

If you follow my Youtube channel, you will see that this is NOT published. That means the only place to watch the video is through www.hobby-machinist.com. It's like a backstage pass!!:geek: The video is also not as refined in terms of editing, because I want to avoid omitting any mistakes or pitfalls that I may have induced during the process.

Click to expand...
My first question is about your straightedge. Has it been checked against a KNOWN accurate reference surface? The other issue is with the type of straightedge. Yours has a very high aspect ratio, length divided by height. That means that it is long and skinny, relatively. If you look at a camelback straightedge, it has much more rigidity due to the lower aspect ratio. Cast iron is pretty stable, but it definitely moves, temporarily with heat issues and permanently as internal stresses gradually work their way out. It did not appear in the video that the straightedge has been scraped in since you got it. If what I think I am seeing is correct, then you are using an unknown to calibrate an unknown, which is a hopeless task. You can use a known flat and planar surface to check an unknown. I think you can use your straightedge for doing this work, but it will have to be constantly reassessed to see if it is in at the moment. Just a couple degrees of warmth on one side above the other will warp it, so try to have everything at the same temperature for doing any work with it, and don't hold the center portions with your hands. Also, it needs to be checked against a surface plate that is in current calibration so you know its past and present, otherwise it becomes yet another unknown, further confusing the results. Good on you for posting this work and your video! There are too many quiet YouTube demonstrations of beautiful scraping work with absolutely no comments on how it was done. "Magic happens here" is about all we can glean from them.

And please know that I am NOT any sort of expert on this, far, far from it. I am also trying to learn these dying arts and skills. I will be attending a Richard King scraping class at the end of March, and hopefully that will help. Richard is about the only one still teaching this craft publicly in the world, and he keeps talking about retiring. Five days of classroom along with hands on work is not a lot, and it is not cheap. I will be paying VERY close attention. Ulma Doctor has been to one of Richard's classes and has been my mentor for learning whatever few skills I have. Thanks, Mike! Some of us need to get this stuff figured out before all the real pros are gone.
 
Thank you Bob.

I too, really want to take Mr. King' s class. I need to see if/when he will be near the mid-Atlantic.
The straight edge is not known regarding current condition. I do have a 40" camelback and an 18"x36" cast iron surface plate. I will do some checks regarding the inspection tools and surface plate on hand. Perhaps a video exploration of Sec.9.11 and Sec.9.12.?
 
Great stuff, ThunderDog! Thanks for the ride along.

I wonder if the difference in the wear pattern from front to back is a sign of a previous setup that did NOT account for bed twist. As the carriage moved along the bed, its relative force on each side would change as it traversed the twist.
 
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Great video! While I personally don't think I'll be chasing the kind of accuracy that a hand scraping job can achieve, Like you it's just good to have the knowledge of where the wear is located / how to measure for it and how to remove any twisting / bending in those ways. Like your other videos - always an entertaining and learning experience.

You are definitely one of the "good guys" of this site. The right attitude and approach, and as always, thanks for posting
 
ConValSam said:
Great stuff, ThunderDog! Thanks for ride along.

I wonder if the difference in the wear pattern from front to back is a sign of a previous setup that did NOT account for bed twist. As the carriage moved along the bed, its relative force on each side would change as it traversed the twist.
Click to expand...

I was thinking the same thing. The machine has lived a life working for the government, then a school district, then sold and sat, and now me. Tough to know for sure, but it seems like twist may have not been accounted for at some point.
 
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