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Yep, there is a thread right now like that. Everyone suggesting machines outside his parameters.
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Suggested Sticky
- Thread starter Jim F
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I did some additional work today on incorporating the narrative that Jim, ArmyDoc and Extropic submitted into the checklist. This will be the deep dive/long form. The short and sweet version will be a simple instruction in the sticky. As promised, I’m trying to pull together something we can all look at and live with but isn’t too onerous for newbies but allows for flexibility in the approach. See the sticky for edits sometime tomorrow.
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That kind of advice can really confuse, lead to bad decisions, and even scare people away. I see it a lot on mill selection too.
The only potential problem I foresee with the questions asked simply on a scale of 1 to 5 approach is if it is used to say, "if your average score is 1 or 2 get a small lathe, if your average score is 5 get a big one". That doesn't work, because the questions are independant.
Each one is something the person needs to consider, and be able to answer, but the answers need to be taken as a whole and weighted as according to the individuals needs. For example. If you want to turn things that are 10 inches in diameter out of steel, you will have to get a very large lathe. But if you want to turn things that are under 2 inches in diameter, primarily brass and aluminum, that does not mean you will be happy with a smaller lathe. It may be that you want to easily turn both metric threads and imperial threads without resorting to change gears. In that case you would still need a larger lathe, because those are the only ones with a universal gear box.
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I don't view these questions a something that goes into a black-box formula that spits out a number that translates into "buy this specific machine." This is a subjective process, and each answer can have a lot, or very little influence in the context of the overall picture. If someone were to circle the answer to each of the questions in on VTCNC's form, my guess is we'd all come to a similar, and relatively narrow view of which machine types and configurations are appropriate.
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I think if we are not careful we will equate the word newbie with (for want of the polite word) ignorant.
I very much doubt if any "newbies" are totally clueless or have never done any kind of manual work (not necessarily mechanical or metal work) if they are seeking a lathe.
But I wonder how many newbies actually know the the meaning of all the acronyms that are mentioned so lightly such as qctp etc. that we give out ad- infinitum.
Might be worth adding other names those acronyms may be known as such as compound or top slide etc.
I know I didnt at the beginning. Still dont know a lot of them.
I see a document that has a variety of lathes with their pictures, say a generic type, and a collection of similar lathes with those same characteristics and general price range etc.
For example
Generic Asian 9 x 20 lathe,
examples - JET BD-920N 9 x 20 lathe, (not just BD-920N) and other makers.
price
what it comes with
its specifications and what they actually mean if unclear
its pros and cons
Some personal insights from those who have used that model
Can it be used as is straight out the box or does it really need some careful checking and adjusting first.
The check document could aim the reader to the collection of lathes document as a starting point with the suggestion the lathes either side of the choice will also satisfy the criteria.
I very much doubt if any "newbies" are totally clueless or have never done any kind of manual work (not necessarily mechanical or metal work) if they are seeking a lathe.
But I wonder how many newbies actually know the the meaning of all the acronyms that are mentioned so lightly such as qctp etc. that we give out ad- infinitum.
Might be worth adding other names those acronyms may be known as such as compound or top slide etc.
I know I didnt at the beginning. Still dont know a lot of them.
I see a document that has a variety of lathes with their pictures, say a generic type, and a collection of similar lathes with those same characteristics and general price range etc.
For example
Generic Asian 9 x 20 lathe,
examples - JET BD-920N 9 x 20 lathe, (not just BD-920N) and other makers.
price
what it comes with
its specifications and what they actually mean if unclear
its pros and cons
Some personal insights from those who have used that model
Can it be used as is straight out the box or does it really need some careful checking and adjusting first.
The check document could aim the reader to the collection of lathes document as a starting point with the suggestion the lathes either side of the choice will also satisfy the criteria.
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Ignorance is curable, stupidity is terminal.
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I'm a bit confused of what to make of this (just quoting your post as this is the most recent modification of the earlier).
If it is to come up with some magic number that translates to "the one" how? From David's follow up it sounds like this is not the case.
If this is just criteria to think about, then why use this format which seems overly complex. Why not just take each of these categories and put into a paragraph or two explaining the basics of how things are rated (what is swing and how is it different from the in my opinion, far more useful swing over the carriage) and go from there.
When I took a welding class one of the really helpful things covered in class was how to evaluate a welders specs.
A common thing that I see when people are asking about a lathe to buy is a lack of understanding how to look at specs and compare between two machines. It could be helpful to take a spec sheet from a lathe and break it down step by step explaining what these mean.
Some specs can be unintentionally deceiving, for example foot print and the full actual space required are generally not the same, with the foot print often several inches smaller. This could be a critical factor when trying to squeeze in the biggest machine possible.
Similarly the nominal size (9x20) vs the actual size are frequently rounded (often up, but sometimes down), taking the common 10x22 size, some are a true 10" swing, some are only 9-1/2".
The very common 9x20 is listed as a 9x20 by Jet and a 9x19 by Grizzly. Same lathe and both are accurate measurements, Grizzly sells their version with a slightly longer live center so 19" between center, Jet sells their with a dead center giving 20". Both are also in reality an 8.75" swing, so reading the specs matters if you are buying with the assumption that the nominal size is the actual size.
Bed width is rarely discussed, but but this is what makes many 11" lathes much heavier than a 10" and the 14" much heavier than 12-13" lathes. Where a manufacturer increases bed width can make a significant difference between two "same size" lathes.
Rambling a bit now...
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I did a trial run with a member who's looking to buy a new mill and lathe. He sent me a DM asking for suggestions on what lathe to buy. So I sent him Vtcnc's worksheet and asked him to send it back answering each line as best he could. He did that, and sent it back in an hour. I looked over his responses, and came to some conclusions in 10 minutes, then sent him a reply with my observations and suggestions. Attached is the exchange. I'd be interested to hear your reactions to this - both in terms of it's effectiveness, as well has how I did in making suggestions (my knowledge of lathes outside the PM, Acra lineup is pretty limited).