Save me from myself, please!

Dabbler said:
Many jobs can tolerate the .002 deviation in diameter caused by a .004 dip in the ways.
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A .004" dip in the ways makes a minuscule change in the diameter the lathe turns, the relative magnitude depending on work diameter. The vertical change is at the side of the round work, and near center the face that is getting cut is nearly vertical, inaccuracy changes little with small deviations, but gets relatively worse more and more quickly with severe wear and with smaller diameters. Still, lots of highly accurate parts are made on lathes with considerable wear in the ways. There are several ways (and combinations) to compensate for the wear while using the lathe.

The first thing to do is to carefully map out the actual wear in the bed, using the correct methods. Until then, we are just talking "maybe and what if."
 
I agree. I was trying to make a similar point. I should have not mention a specific, but it was the max error I calculated for 1/8" diameter.
 
Gentlemen- I thank this august group for the input. Turns out I could have left MY flak jacket in the closet!
Brino- good thoughts. I have enough "y", and about 1/2 the "x" required. Muddies THAT water significantly, I know.
Dabbler- your approach was, and still is, my original thought and intent. Most likely, that is how I will proceed. My curiosity and my desire to eliminate as much chatter as I can, on this admittedly flexy lathe, led me to dig out my kevlar.
Mark- I am at last gasp. I have inquired far and wide, no luck. Many beds better than mine have been turned into Chinese rebar. Shipping costs essentially eliminate the "used bed" market. I have several feelers out, and I am patient. Again, I have no pending aerospace contracts. LOL.
Holescreek- Indeed, that is the reason for the title of this post. I am a professional "fixer of things", and I completely understand your's and Brino's concept of "do no HARM"! My lathe has considerable sentimental value as well. BTW, beautiful work, and machine. "Expense vs. projected value be damned" has supported MANY industries. Man after my own heart!
 
Double e- sound advice. I have just enough knowledge and experience in this line to be DANGEROUS, hence, again, the title of the thread. I will apply your technique. Thanks to you all!
 
Atlas LATHES are not what you call precision LATHES, yes they can do nice work , but there just not made to be that precise. I owned a 12" many many years ago and it was well taken care of but it wouldn't produce parts to pass inspection. So I moved up to a Sheldon , what a much better and stronger lathe. So if your using a hobby lathe that's what you bought , if you work with lots of indicators to keep track on all movements or non movement you can turn out nice things . As they use to say YA can't turn a pig's ear into a silk purse.
 
Silverbullet- I appreciate, and understand, your take on this. At work, we have a VERY nice, mid 80's, lightly used, South Korean lathe of similar work envelope. That CARRIAGE weighs what this ENTIRE machine does. It makes me LOOK like I know what I am doing. It may, one day, go to auction. Perhaps I will follow it there. Gonna need a MUCH bigger VFD, or RPC. Until then, I will make do with what I have, work it with the great advice given here, and accept the results. Thank you!
 
Just a thought don't know if it'd work but they make a tape for repairing worn ways
 
There are a number of "build up" materials for lathes. The complicating factor is they are designed primarily for use in building the surfaces back up to align centers on the lead screws, and putting adjustment thickness back into worn gibs. In the case of a lathe with .004" wear the less expensive yet labor intensive solution is to scrape the ways.

On the machine in question the ways are not hard so removing that amount of material is not difficult. I think the bigger challenge is you need some rather expensive tools to do it. Unless you have a surface plate and appropriate straight edges, test indicators and scraping tools or the ability to borrow them, cost to purchase may exceed the value of the completed project.
 
Yes, sir! I am weighing the various options presented. The "point of diminishing returns" is not lost on me. I suspect I will simply use the lathe "as is", following Dabbler's advice. That said, I will undergo a knee surgery in a couple weeks, and will have 2-3 weeks to stare at, sceme and contemplate this. I will do my best to avoid doing any harm to MYSELF, my pocketbook, OR the lathe. Idle hands, blah, blah, blah.....No powertools while under the influence of pain meds, rest assured!
 
Ive got tools of my dad's that Id not trade for the latest and greatest tool on the market, It's what they mean to me and the memories are worth a lot. No one, certainly not me, can judge what your lathe is worth to you. I really was just responding to bring up what the materials are for and what it takes to use them and the needs and costs involved.

Good luck on the knee surgery, I'll keep a positive thought for you. Having been though more surgery than anyone should endure I suggest laying in a supply of interesting reading and lots of YouTube.
 
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