Making lathe from scratch and using mild steel plate? Why use cast iron?

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dman

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the bed has to be pretty rigid. a weld up frame might be doable but would be better if filled with concrete, at that point you may as well make it from concrete and save some welding. i can see a few ways of that working and maybe you can just use minimal steel and welding. depends on what you want to buy, what you want to make and what you want to salvage. if you get a decent surface plate you can make precision ways by hand scraping. look up mullernicks youtube channel. i imagine you can fix metal slideways to the concrete with epoxy or you can purchase linear bearings. you need to decide what yo use for a spindle but i will say many modern cnc machines have alignment adjustments on the spindle. the whole head is a seperate casting and it can be turned slightly to help make things square. i'd probably use cast iron on the slideways so they can be scraped into alighment, i'd make box ways rather than dovetails for ease or perhaps i'd have cast iron or mild steal pads that can be scraped into a perfect plain for a perfect surface to mount linear bearings to.
 

wildun

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Most of us who have considered building a lathe have also considered using all these alternative materials and of course they can be done. As someone has already mentioned, can it be done without already possessing a lathe or having easy access to one?
I once considered using large 'free cutting" (leaded) mild steel square material which I guess is still obtainable, - it seems to have similar "dead" and stable qualities as Cast Iron and it is easy weldable, as opposed to cast iron.
Also I considered building it out of SG Iron (if obtainable in large enough stock) and bolting and dowelling it together!
Usually what happens is that most of us just end up buying a good secondhand 'normal' lathe and modifying or adding to it to suit ourselves and getting on with it - you can sell it much more easily too!:D
N4ZOU, who is the manufacturer of the lathe in the picture you posted in another thread, ie. the one on the Boeing mobile cabinet? - it is almost identical to the one I just sold last year in order to move into a smaller home.
Mine was badged "Husky" made in Taiwan (circa 1980). It was a very accurate little 6" lathe - it wasn't perfect by any means especially in the headstock seal area, but I have regretted allowing myself to lose it ever since!
 

Tin Falcon

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mike nice home built lathe. interesting though the origial poster that stated the thread has not signed on hear in over a year. wonder if he purchased a lathe built one or moved to a different hobby.
tin
 

Wizard69

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I'm a new member here and just finished reading this entire thread. I'm not sure if the thread starter ever did build the lathe but I'm rather shocked at the discouragement posted in this thread. Most of the members posting here are focused on model engines which by enlarge are often more complex than a lathe. I say that due to part of my career being focused on supporting many small CNC lathes at a manufacture.

Now I would agree that one shouldn't do it to save money though that isn't an impossibility. One should do something like this for the same reason that people build model engines which is because the have an interest to do so.

One shouldn't engage in such a project without a clear understanding of what's involved though, just like you don't build a model engine without first understanding the workings. However lathes are very simple machines and there are very well documented approaches to building such a machine. Will you beat a cheap Chinese import on costs, probably not initially but you might after rebuilding that Chinese machine into a working tool. You can certainly do a CNC effort at a reasonable cost DIY. No matter what you build you will learn a lot, expand your skills and gain a new tool. I might advise against welded steel plate for example but that shouldn't imply poo pooing the whole concept.

I guess what I find perplexing in this thread is that this is a forum dedicated to building complex machines that finds building a simple machine to be an outlandish adventure. Makes no sense. Pursue your dreams if it is a hit and mis, gas turbine or a lathe.
 

Wizard69

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Nice!

I attended NAMES a few years ago and remember a scale model of a Hardinge HLV. Unfortunately I can't remember the gentleman's name but he Did one heck of a job on a fully functional model. It was scaled to the size that it would compete with watch makers lathes but it just highlights a range of possibilities here and that such projects are doable.
 

Entropy455

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I am one of the guys discouraging home lathe construction.

The typical hobbyist on these forums likely operates his lathe in excess of 100 hours, for every hour of respective model engine run-time.

Point being - unless one can properly harden & grind the ways, the lathe is going to have a short working life – even a small bench-top lathe. . . .
 

Tin Falcon

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Personally : I think the real issue here is time. If someone wants to spend the time to build a lathe it can be done . But with a little shopping one can find a suitable lathe for a few hundred dollars . can a lathe be built cheaper than buying one maybe maybe not . add the labor value doubfull.

but like I said earlier if that is the branch of home engineering you choose why not we build engines for fun why not a lathe.
Tin
 

Wizard69

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I am one of the guys discouraging home lathe construction.

The typical hobbyist on these forums likely operates his lathe in excess of 100 hours, for every hour of respective model engine run-time.
I don't dispute that, in fact it sorta supports my position. People spend far more time building their model engines than it would take to build a lathe.

Point being - unless one can properly harden & grind the ways, the lathe is going to have a short working life – even a small bench-top lathe. . . .
Well this is highly debatable and depends upon many factors including just how the lathe is designed.

But let's consider the issue of the ways. Lets say you do need to have them ground, what is the difference between taking your custom machine to a machine rebuilder for a grind or a person rebuilding an existing lathe that needs a bed reground? People doing engine builds often buy casting kits because they aren't interested in casting themselves and nobody blinks an eye. Like wise friends are often engaged to handle operations a builder might not have tools for.

I would totally agree that a DIY lathe is a terrible idea if the reason is solely to try to save money. It is very hard to compete right now with the low end Chinese iron even if you need to rework it upon arrival. However trying to save money isn't the only reason to build your own machine as it can be an educational endeavor in and of itself or a person simply might be interested in the technology.

The discussion becomes far more interesting when the design is not run of the mill or a CNC effort. Here I believe you can save money and get better results going the DIY route. At least for a lathe you can, as most low cost commercial CNC efforts seem to be focused on milling machines.

So in the end I believe if done for the right reasons why not? I've read enough model engineering magazines over the years to realize that hobbyist build far more complex machines to aid in the manufacture of their engines. There are more that a few tool grinders and cam grinders out there that make the average lathe look simple.
 

Wizard69

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Yes these are the reasons, for fun or the educational value. The economics of doing so is of course highly debatable. Just like building an engine based on centuries old technology is not wise if you simply need an engine.

I follow some of the Gingery sites and frankly these guys are building their machines with eyes wide open. They realize that the expense of the build process means that they won't save money on their lathe build. However that isn't why most pursue Gingery builds. It is more about the learning process than about the finished lathe. That being said you can build a Gingery mill and end up with a machine that really has no analogue in the commercial market. Or you can build a shaper that can only be had used these days.

Personally : I think the real issue here is time. If someone wants to spend the time to build a lathe it can be done . But with a little shopping one can find a suitable lathe for a few hundred dollars . can a lathe be built cheaper than buying one maybe maybe not . add the labor value doubfull.
If one acknowledges this reality then they are apparently going into the project with open eyes. If so why not?
but like I said earlier if that is the branch of home engineering you choose why not we build engines for fun why not a lathe.
Tin
Exactly! I would not suggest a DIY lathe is a good idea for everybody, but if your interests lay in that area and you understand the realities, I say have a good time. Considering how many tools and fixtures get built to support a hobbyist shop, a lathe shouldn't be looked upon as excessive. Especially in the smaller sizes.
 

goldstar31

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I thought that people would know L.C Mason who wrote books on building miniature steam engines but seemingly not. So he also published a book called 'Building a Small Lathe'

I seem to have owned the book at one time and recalling that this was constructed from steel.

But having said that, I suspect that some of the Holzapffel lathes had wood beds.
Again, somewhere in Model Engineer that someone built a lathe from concrete.
For those who have heard of the early Unimats, they had steel bed bars in zinc alloy castings-- and they are still about.

At this juncture ,the surface is barely scratched- because I have a brass one!
 

blighty

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wheres that can of worms........ i've just started getting the bits together for a home built lathe and the main "lathe" bit is made from Granite.
 

aarggh

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I don't think (at this stage anyway) I would want to build a lathe, but I can certainly understand others wanting to. And the mention of cost savings come up quite a bit, but I think that quite often people simply use that as a crutch to more or less justify the activity in the presense of others, even though they know it's most likely going to uneconomical. My mates at work think i'm completely and utterly mad doing many of the things I do, but I enjoy it, and at the same time, I can't fathom how they spend 4 years building a Linux based control system for their cars! Or spend $1000's replacing a perfectly good engine with another larger engine to get that little bit extra horsepower, on our congested roads!

Horses for courses. Whatever floats your boat, and however you have to justify it, fine! I'm just glad I've managed to wear down my wife (took me many, many years), to the point so I don't have to justify anything for the sake of it, so long as it doesn't impact bills or shopping, it's okay.

Oddly enough, one thing that has little use nowadays, that I would really, really love to buy or build, is a shaper! I'd be absolutely stoked if I had one, I just love the whole concept of them, but many would consider that bizarre! My wife however would just roll her eyes!

cheers, Ian
 

ZipSnipe

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Well I didn't build my own lathe but I did build my own milling machine and by the time I was finished I spent $700. This was at a time I could have went to Harbor Freight and picked up a Mini Mill for $400. Also as soon as I was finished there was a deal for an rf 30 mill drill $200. So yeah had aI waited a lil and looked around I would have found a deal or two.

The two reasons why I built my own was economics and therapy. Therapy being the main reason. If I could do it over, I would have bought a Mini Mill

Now I am dropping another $500 into it but it will make the machine well worth it.

If you need the therapy go ahead and build ya a lathe. But honestly I would hunt for deal somewhere, auctions , garage sales. Speaking of garage sales, right after I bought my 9x20 chinese lathe for $500. I stopped by a garage sale that had a Atlas 9x30 lathe, with the works for tooling ,milling attachment, quick change tool post etc. all in pristine cond. and all for $300, needless to say I cried when I got home.
 

Traian Dumbrava

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Hi everyone maybe not the right post here,but need some to give me a quick help regarding about grey cast iron 250 grade or ductile cast iron 500-7(sg).
My intention to build my own milling machine and I'm in stage to build the head for it but not sure what of the top cast iron to use. Any help? THANKS
 

Robsmith

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G'Day Pete,
I'm in NSW and about 20 years ago I bought a "SMITHY CB-1239 XL Lathe-Mill-Drill" Imported from Anne Arbour Michigan USA. It was very reasonable priced, three in one that wouldn't take up much space ( about 6 feet long) and Good ole USA American made quality. Imagine my horror when the giant crate arrived with MADE IN CHINA stamped all over it. ha ha . Well after 20 years of use it has a little wear. all which is repairable. So I reckon that if you went the Hare and Forbes way … you won't go wrong. I've looked at them and they are a slightly better quality and finish than my "smithy" plus technology is up there as well. Just my 2-bobs worth.
 

Ironmanaz

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I recall reading about the world's largest engine lathe maybe 40 years ago. It was a steel weldment. bolted together for transport on 6 semis,
They moved it to powerplants for overhauls to turn the 50 ton rotors. The design allowed placing metal exactly where needed,and it was very
stiff.
 

SmithDoor

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You at one it was cheaper to use cast iron. Some types tools like shears and brakes have been manufacturer for 100 years.
The mache tools (lathes & Mills) I saw was in the 1970's made to look like castings.

I think for holding back steel is cost of making look like castings.
The will look different want the manufacturers dope the casting look.

Cast iron and concrete is same for ridges. Steel is about 2 1/2 x more ridge (modulus of Elasticity of cast iron is 11,600 {note some high grade cast iron will go to 19,00 not what use in machine tools} and steel is 29,600 )
 
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