Mill and Lathe Recommendations for High School Machine Shop

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dampfmann
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Mill and Lathe Recommendations for High School Machine Shop

Post by dampfmann » Fri Feb 07, 2020 8:11 am

Hello,

The school district where I live has decided to offer metalworking classes again after many years of absence from the curriculum. Imagine classes that teach students machining fundamentals and has them creating small projects, such as single-cylinder oscillating steam engines or machinist puzzles.

Currently, the shop space is limited to 110v, single phase electricity. I am seeking mill and lathe recommendations in the knee mill and bench lathe sizes. Full size Bridgeport mills and large engine lathes, although ideal, are out of the question - at least for now until the program gets up and running.

Given the power and size constraints, what machines would you recommend for the new shop? The initial proposal has them purchasing 3-1 machines from Smithy. What are the limitations of 3-1 machines? I have never seen them used in machine shops. If anyone has knowledge of their pros and cons, it is much appreciated.

Thanks in advance and I will try to answer your questions as best I can.

Sincerely,

Marty

curtis cutter
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Re: Mill and Lathe Recommendations for High School Machine Shop

Post by curtis cutter » Fri Feb 07, 2020 9:01 am

What is the floor construction?
Gregg
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dampfmann
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Re: Mill and Lathe Recommendations for High School Machine Shop

Post by dampfmann » Fri Feb 07, 2020 9:42 am

curtis cutter wrote:
Fri Feb 07, 2020 9:01 am
What is the floor construction?
Concrete. Ground floor.

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SteveM
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Re: Mill and Lathe Recommendations for High School Machine Shop

Post by SteveM » Fri Feb 07, 2020 9:49 am

Nice to see shop coming back. I wish you all the best of luck.

Maybe some of us can chip in and send you some tooling once you get set up.

The limitations of 3-in-1 machines? Size, rigidity, quality. Kind of like anything - something that does everything does nothing well.

If you buy 3-in-1 machines, you will only be throwing them out at some point when you realize that they are inadequate.

You would be better off buying the right machine first, even if it means you have to buy fewer because of budget limitations.

Is there a physical reason you can't get a Bridgeport in?

You could look at Rockwell and Clausing mills, but because of their size they appeal to home shop guys, you may end up paying more for them than a Bridgeport. I've never seen one of those for less than $2,000 but I have seen usable and not worn out Bridgeports for under a grand.

As far as lathes, stick to something less likely to break. If you get Atlas 618's, you're going to be looking for replacement compounds shortly.

South Bend was the school shop standard, but don't discount Logan and Sheldon. I think the Sheldon is a better lathe in many respects.

What sizes of projects do you anticipate? Will a 9" lathe do, or do you need to go up to a 13".

Remember that you can run a VFD that will input 110 single phase and output 220 3-phase, so if you see a screaming deal on a 3-phase machine, don't dismiss it right away. Home shop guys are not as knowledgeable about phase converters and tend to shy away from 3-phase machines, so the 3-phase machines may go for less.

Ideally, you would want all the same machines, but that's going to be tough. The only way you might do that is with 9" South Bend lathes because there are so many out there.

Steve

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Re: Mill and Lathe Recommendations for High School Machine Shop

Post by whateg0 » Fri Feb 07, 2020 10:18 am

I concur with the observation that 3 phase machines often go for next to nothing just because most hobbiests aren't familiar with how to power them. That does seem to be changing lately though as more people are introduced to vfds. My son's school has several GMC knee Mills and 14*40 lathes, similar to a jet or enco or grizzly. I know toward the end of his last semester in that class, one of the lathes was tagged out and they were having trouble finding parts. Be sure to get something for which parts are available because they will be operated by people who are still learning and stuff will get broken.

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NP317
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Re: Mill and Lathe Recommendations for High School Machine Shop

Post by NP317 » Fri Feb 07, 2020 12:22 pm

Consider asking Grizzly if they are willing to help set up your shop with donated machines and/or tooling.
They might recognize the value in that relationship.
RussN

dampfmann
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Re: Mill and Lathe Recommendations for High School Machine Shop

Post by dampfmann » Fri Feb 07, 2020 12:28 pm

"Nice to see shop coming back."

It has been a long time coming, but schools are finally realizing the college pathway is not for all students. There are plenty of bright students who would rather do hands-on work than attend college classes.

Maybe some of us can chip in and send you some tooling once you get set up.

Thanks! I will keep this in mind.

Is there a physical reason you can't get a Bridgeport in?

The issue has more to do with available classroom space. The thinking is Bridgeports would take up too much space in the shop.

Ideally, you would want all the same machines, but that's going to be tough

I think this is a big issue and why the thinking is to buy new. Obviously, new full-size lathes and mills cost considerably more than new bench-style lathes and knee-style mills. It's all about trade-offs.

Thanks for the information so far!

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Re: Mill and Lathe Recommendations for High School Machine Shop

Post by John Evans » Fri Feb 07, 2020 1:27 pm

Most all of the imports will suffer from lack of parts availability sooner rather than later ,used American has the same issue only now. The next question is how many of each machine are you planning to buy? I can not say it firmally enough stay away from 3in 1 machines and drill/mills. Saw in a Grizzly catalog a 32" table knee mill that was 110 single phase I'm pretty sure,would be the minimum I would think suitable.Lathes 12X36 are available in duel voltage 110/220 single phase,again that would be the minimum . Back in the early 60s when I took machine shop class the lathes were South Bend 9X36 ,10 or 12 of them as I recall with one or two bigger. If I were doing this I would have 3-4 lathes or better to each mill. You can learn much more about metal cutting when using a single edge tool on a lathe compaired to the mutli edge tools used on a mill.
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tornitore45
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Re: Mill and Lathe Recommendations for High School Machine Shop

Post by tornitore45 » Fri Feb 07, 2020 1:49 pm

Many have made negative comments on 3 in 1 machines.
In addition to all the negatives the long and constant requirement to change set up is even more of an impact when the class is time limited.
The student will spend 1/2 the class to reconfigure the machine.
The genial idea is to let some machines set up as lathes and some set up as mills, student move the project on the appropriate machine. Then what is the point? Just have lathes and mills.
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Glenn Brooks
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Re: Mill and Lathe Recommendations for High School Machine Shop

Post by Glenn Brooks » Fri Feb 07, 2020 2:16 pm

I’d be in favor of staying away from 3 in 1 machines.Seems like These style machines will disadvantage the program and the students right out of the gate. They don’t represent the types machines used in industry, and likely won’t give students the kind of experience they will need to start learning acceptable procedures and methods for metal working. So the kids will take the class and not benefit as much as the could from the experience.

Better, if at all possible, to equip the program with new, standard design stand alone lathes, even if smaller size than you ideally would like.

Buying used, old hobby equipment should also be off the table, if at all possible. Worn out lathes are frustrating to work with in the best of times, particularly when you are trying to teach best practices and encourage students to achieve acceptable tolerances. There’s also the aspect of constantly eating up instructor time fixing old machinery and keeping all the classroom equipment in operation. Nothing worse than enrolling 20 students and only having 15 machines available.

Also cheap, effective 110v -220 v VFDs are available these days that can power small 220v equipment. So you needn’t be limited to 110 machines, even if that is the only power source in the space you have available.

Also You might try contacting any machine tool venders or commercial production shops in your local area and ask about supporting your program start up with industry grants, discount rates or possibly (new) machine donations. Somebody might step up and help out.

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Re: Mill and Lathe Recommendations for High School Machine Shop

Post by earlgo » Fri Feb 07, 2020 2:37 pm

Try to avoid Craftsman/Atlas lathes or any other lathe with the rectangular bed ways. The carriage gets sloppy after a few years, and they are too flexible for good work, especially with crash-prone users. AND they use the lead screw for non-threading carriage feeds, thus wearing the lead screw accuracy.
The bed will wear out and the carriage up and down slop will cause all kinds of issues.
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whateg0
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Re: Mill and Lathe Recommendations for High School Machine Shop

Post by whateg0 » Fri Feb 07, 2020 3:25 pm

Another reason to avoid Craftsman/Atlas lathes would be similar to what somebody else said about machinery used in industry. Typical small lathes like that are going to lack a dedicated traverse feed, relying on the leadscrew for it. Industrial machines won't work like that. Similarly, the threaded spindle is not something they are likely to encounter later on, not that they will likely be changing chucks in class anyway. But if the lathe has the ability to brake the spindle, a threaded chuck could become a projectile, even if the chances are remote.

Dave

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