So a lathe walks into a bar... test
Added 2024-09-12 14:00:13 +0000 UTCWhat was the first thing I did when getting the free lathe? Measure how good it was. What was the second thing did? Pretend like that never happened. But not anymore. The time for a definitive test of the lathes performance has arrived... with a good old fashioned bar test. Not to be confused with the legal bar.... though that somehow seems fitting here too.
Enjoy!
(https://youtu.be/k5xigPfyTXI)
Comments
I don't have an answer on regrinding ways - it's a ludicrously obsessional thing to do, but I think that's why it appeals to you! I don't think I'd bother, but I think you'll regret it if you don't! Mainly I wanted to say how much I love the setup you came up with for hardening the Morse taper. It's 3 seconds of video, but it's perfect: the drill to hold the part, and to turn it to achieve even heating; the jar of oil to stop the rest of the part getting hot; and then the quill feed on the drill to quench everything. It's just perfection.
hollo
2024-09-15 16:27:24 +0000 UTCthe bed is hardened it shouldn't be machined or scraped, it needs to be surface grind. it does cost around $2K. the question is are you going to be at Renzetti's level of precision or can you live with it as is. For calculating cost, a pristine hardinge will not be free, it will be in around $15K, I would take that and half it as my max budget to get it to a super precision state.
Seta
2024-09-13 23:13:22 +0000 UTCOr…travel to AUS and meet Kurtis at CEE and have him do it for you.
legendary.jerry@gmail.com
2024-09-13 19:33:45 +0000 UTCThe obvious answer is to get a free mill that’s large enough to machine the bed of the lathe. That’s easily another year’s worth of content!
legendary.jerry@gmail.com
2024-09-13 19:33:02 +0000 UTCAnd then if you do decide it needs to be corrected, maybe scrape it in yourself (although making that tedious project an interesting video could be a challenge…)
Aaron Wood
2024-09-13 15:16:40 +0000 UTCI’m in the “don’t bother” camp. I would do two things: 1) run the test on your other lathe, so you have a comparison against a known quantity (in terms of how well it performs when making real parts) 2) just start using the lathe, maybe being cognizant of the spot to work around when chasing sub-thou tolerances. And then, after a few projects, you’ll know if it’s actually a problem or not. You could chase perfection, over and over again, without actually _using_ the lathe. And which do you prefer? Making it perfect, or using it to make things?
Aaron Wood
2024-09-13 15:15:02 +0000 UTCI got a 1947 myford ML7 at home which has got an incredibly worn bed just visually and I got it for nothing from a neighbour not to unlike yours and I'll definitely be refurfacing it and super acurate some day so I'd say treat yourself. I'd love to be able to make high accuracy work on that some day
troublogaMing
2024-09-13 11:44:13 +0000 UTCLet me be abundantly clear: I am not a machinist. I am, however, someone who's been forced to use either cheap tools or second-hand equipment that always needs significant rebuild and TLC. Sometimes it doesn't matter (I love my pitted and scarred leg vice) and other times you can bring something back to life better than it ever was, but there's no use replacing the tires if the wheels, bearings, axle, and struts will all need to be replaced as well. At some point you have to say "This does what I ask of it" and call it a day.
Michael Faragher
2024-09-13 02:06:59 +0000 UTCStop trying to temper through friction heating! :D The use of thermal mass to protect the non-heated areas was entirely what I was going to suggest, so good work there. The bed is a known issue, and you can work around it until you forget in the middle of a project. That being said, it's not like you don't inspect the parts as you approach your final dimension. Getting something super-precise may require grinding anyway. Ask yourself what specific operation you'd do that required those tolerances, and if you'd end up doing the last step on another machine anyway. A final concern: You don't know what's going to happen when you pull that bed off. When machines wear out, every part that's connected to the replaced part is also worn. Sometimes you need to do a simple part swap and end up replacing entire assemblies. If you pull that bed, you may need to inspect or replace everything that touches it. That's significant potential time and monetary cost. Also the bushing in the cross-slide seemed positional as much as anything. You might want to refurbish or replace that for maximum accuracy and holding power.
Michael Faragher
2024-09-13 01:53:31 +0000 UTCOne other question, what was the spec on the lathe when it was brand new?
George Balock
2024-09-12 22:12:12 +0000 UTCMaybe I;n\m not as picky as you are, but to me a half a thou is within spec.
George Balock
2024-09-12 22:11:00 +0000 UTCWhy not take the bed to the surface grinder and make new gibs for the tail-stock and carriage to mate with the slimmer profile?
Adam
2024-09-12 21:31:26 +0000 UTCMaybe some understanding sole would do it on the inexpensive. You pay all shipping. Lean scrapping, videos on youtube. Plus you learn something
Ralph McCoy
2024-09-12 20:58:44 +0000 UTCI am in the minority here but I think you should send it out. The reason it's a big decision is you are trying to avoid doing what you really want to do.
JM
2024-09-12 19:44:40 +0000 UTCGreat work as always, Brandon! Love seeing the lathe finally get the attention it deserves. In terms of the actual question at hand, my take is this - 1/2 thou is a negligable tolerance at best of times, so spending a considerable amount of money as well as time just to chase the zeroes is not needed. My lathe runs a 4thou taper, yet I've managed to make numerous parts on it that still function just fine. I know that "just fine" isn't entirely what you aim for, and as engineers/machinists, perfectionism is a character trait, but I do think there should come a point where it becomes a diminishing return. On top of all that, as much as I'm enjoying this build, I think some variety is a healthy approach in terms of content. At the end of the day, regardless what you decide we will all still watch it religiously purely for the entertainment value and the amount of work that goes into making these videos. P.S. - glad to see the surface grinder get some action once again 😁 as a surface grinder-less person, I'm always happy to see it get used.
Erik D. Radzius
2024-09-12 16:50:49 +0000 UTCI would leave it alone. But you have other considerations like the content value of the bed lapping project to dampen the cost. I rather watch you do other things but will keep enjoying and supporting you in any case :)
Jose Rodriguez
2024-09-12 16:16:51 +0000 UTCLoved the humor in this one. Great job!
Max Goldstein
2024-09-12 16:11:17 +0000 UTCHey Brandon I am not a machinist I will preface this by saying that. But I do watch a lot of Machining videos and I was wondering what you think about maybe re-scraping that bed to try and get it flat I don't know if that would work in your situation but I have been watching a bunch of rescraping videos lately and to me it seems like that may help on getting that flat.
brad lamberes
2024-09-12 16:06:14 +0000 UTCIf you were running a shop that required tolerances tighter than a half a thou, and you were making those parts on repeat for a very long time, then I'd say it would be justified to send your bed out. Given your current situation (and I apologize if I'm wrong and you are doing work like this) I think it's absolutely not worth spending all that money for something that's easily worked around, or doesn't even lead to an "out of tolerance" situation to begin with. Down the road if you design some tooling and you want your tooling to reflect your pride in your work, and you know you'll be turning out (pun intended) many many many of these tools, then at that point yeah I'd say it's justified. Here is another potential solution. If the bed itself is a removable piece, is it possible to take the same approach you did with the quill of your tail stock? Could you effectively shorten the bed length so the area of wear in question would be shifted out of the way entirely? Is that worth losing maybe an inch or so between centers?
Kyle Wellman
2024-09-12 16:00:01 +0000 UTCI think scraping the ways yourself would be a fun project. Only if the other lathe cuts straighter as a fall back. You know...just in case :) Vintage Machining has tons of videos scraping in ways on old machines.
Carlo Fenwick
2024-09-12 15:53:44 +0000 UTCAt sub thou, don't material temperatures, carriage/compound deflection, part deflection, bearing accuracy etc all start to play roles that become increasingly difficult to identify and isolate? You could chase tenths, or you could let future project results tell you if you need to.
Steven Bierlink
2024-09-12 15:26:46 +0000 UTCNot worth it, unless you have a reason for it. Not a machinist, but its my understanding you can learn to work with the wear in a machine.
Jeffrey Britton
2024-09-12 15:01:34 +0000 UTCGreat job Brandon, 5/10ths does not equal 2K lol. Unless its going into outer space lol. Keep them coming!
Jeffrey Spoor
2024-09-12 14:44:06 +0000 UTCVery convenient, I needed a good example of how to align my tail stock!
Isaac Stemple
2024-09-12 14:33:50 +0000 UTC
