DIY lathe design question

[darkzero]

My first "lathe" was a drill press and a Dremel grinder.

My first "mill" was a Dremel & Dremel drill press attachment. That Dremel was the very first power tool that I got in my life when I was 15 yrs old. I still have that Dremel but the bearings are bad now, I wonder why.

My first "lathe", well first time I used a "lathe" was a brake lathe that I used to machine 2 pulleys off a Honda harmonic balancer. Had no idea what a lathe was at the time & that I was technically machining the pulley.

 

[WCraig]

It’s definitely worth picking a knowledgeable community’s brains about this before diving in and doing something obviously silly. I appreciate the input. I do suspect there’s a reason it doesn’t seem to be common practice...I just wish I knew exactly what it was. I don’t think it’s a notion without merit. I’d like to suss out any undiscovered checks, though. It’s always dangerous to see the possible upside and not be able to identify the downside.

Thanks for checking your equipment, Hawkeye. An existence proof more recent than 100 years ago (the approximate age of the books I posted pictures from) is useful and encouraging.

AIUI, Myford's ML7 lathes used an offset design for decades:

... The spindle was offset from the bed centre line towards the rear - a feature the makers ingeniously claimed in their first publicity sheet: "The distinct advantage of the offset is paramount when turning large diameters, the degree of rigidity being equal to that of a bed 5-inches wide with the headstock centrally disposed."

Myford Lathes

Disclaimer: no personal experience, just happened to be reading about Myford's products the other day.

Craig

 

[Stefants]

AIUI, Myford's ML7 lathes used an offset design for decades:

Myford Lathes

Disclaimer: no personal experience, just happened to be reading about Myford's products the other day.

Craig

Good stuff! Thanks! I think for the overall design I’ve had in mind, I’m planning to offset the spindle to the back. How much to the back is yet to be determined, but it seems like an idea for which there is precedent and (as of now) no solid detriment to point to. Again, we’ll see how long it takes for me to get to building...still plenty of time to change my mind

I appreciate everyone’s feedback!

 

[Iceberg86300]

Don't forget about the tailstock & steady rest. Both will need the same offset of the headstock if they are to be included.

Also, symmetry is a very nice thing. Humans tend to gravitate to it & this shows in our designs, but it can also be very useful. A symmetrical design tends to be easier to manufacture. Symmetrical castings of a bed/base/headstock variety not only behave in a more predictable manner but they also facilitate easier manufacture. If patterned & cast on its side the parting line can be straight down the middle, where any cores are also likely to be placed. Something with a pure "A" frame can theoretically be patterned & cast upside down w/o a parting line.

An "A" frame on top of a box with a slight negative draft, also cast upsidedown, puts the parting line anywhere below the ways. So the headstock & ways are pressed into the drag (bottom) portion the mold where they would be most likely to get the best fill with the least amount of inclusions/impurities (when fed & vented correctly). Thus making the most important parts of the castings the most sound as all the junk floats the top. This would also make it fairly easy to accurately place a core for spindle location. Cores could also be easily stacked above the drag to create cavities/structure in the base.

This would be just for "simple" two piece molds, but I think you get the idea. I don't have a lathe in front of me to analyze but I don't remember seeing many in which the headstock protrudes over the base. At least on small/med engine lathes w/o bolted in headstocks.

Doing so could throw a pretty big wrench into things by breaking up the parting line into multiple planes when before it was contained by one.

Just some extra stuff to think about!

Sent from my SM-G900V using Tapatalk

 

[martik777]

Hubert Elffers , an 80 year old built this in 3 years: http://www.lathes.co.uk/elffers/

Then there is the Stepperhead: http://www.lathes.co.uk/stepperhead/

 

[Stefants]

Iceberg, your points are well taken regarding manufacturability. For all the problems that may come with concrete, I think some of those casting issues are easier. You have some more mold flexibility when you don’t have to worry about incinerating it! I did cast aluminum in a homemade Gingery style charcoal foundry in high school...I’m familiar with the challenges you’re talking about. And in a “build and sell lots of them” world, I think they’re very legitimate considerations.

Martik, those are some beauties . I have no doubt I’m setting my sights a little lower, but I’m hoping for an interesting ride.

Here’s my wood lathe in its current incarnation. My long term intent is to add ornamental capability...I have grand designs for lots of headstock tweeks to make that happen. As it is, it’s kinda neat to have a homemade treadle powered machine to make file handles with . I got this far about the time my daughter came along 7 years ago. Been pretty stagnant since then.

 

[savarin]

The Essential Documents: What You Need to Read Before You Build These Projects - My CMS

From the Founder, Pat Delany: My role: to revive the original concrete lathe concept, to update the technology by 100 … Read More →

opensourcemachinetools.org

 

[C-Bag]

The Essential Documents: What You Need to Read Before You Build These Projects - My CMS

From the Founder, Pat Delany: My role: to revive the original concrete lathe concept, to update the technology by 100 … Read More →

opensourcemachinetools.org

Crazy, never heard of Yoeman before. This would seem to solve the major hurdle of building the frame of the lathe as I could never see how you could deal with casting the frame out of iron and then machining it.

 

[Stefants]

Having read about Yeoman’s lathes from wartime, I am quite surprised that the general concept did not catch on with the DIY community. Casting aluminum isn’t beyond reach, for sure, but concrete is certainly a lower bar. And a big, heavy, vibration damping concrete base has appeal (concrete’s dimensional instability is another story). At this point, since Pat Delaney‘s site is not actively kept up to date, and the wiki space where a lot of the information he had assembled is defunct, it seems like the prospect of a concrete machine is slipping back into the ether. Maybe there are good reasons for that. There are certainly a lot of folks out there willing to say that it’s a terrible idea. But I would like to see for myself.

The only place I have seen the idea actually put into practice is here:

Concrete Metal Lathe

Concrete Metal Lathe: I've wanted a large CNC lathe for a long time...key ingredient to that being a large lathe. Unfortunately most places that sell these lathes want a large sum of money in exchange. After some searching on the internet it turns out one could build a…

www.instructables.com

For all the thought that was seemingly put into the concept, it seems a number of shortcuts were taken in this particular incarnation that don’t necessarily make it the best test of capability. That said, the results this guy got are encouraging enough to make me want to try it myself.

I’m currently doing my homework regarding concrete. Super plasticizers, pozzolans, and fiber reinforcement, oh my! I think the countertop world has made the right composition for a machine a thing to be avoided...but I’m not certain yet. They tend to advocate loading up the concrete with polymers and flexy fiber bundles...I think I want rigid and not flexible for a machine. My first step is some basic concrete exploration...

 

[Stefants]

While I like my wood lathe, I didn’t really want this thread to be represented by 2x4 construction! This is closer to what I’m envisioning for these purposes...