I was wondering last night--if 30 degrees is a good angle for the slant bed, why not 60 degrees? How about 90 degrees? Assuming linear ways, they are not dependent on gravity to keep them in engagement. Why not put the Z axis behind the spindle and have a vertical X axis? Am I missing something? The context is a small (Sherline-sized) homebrew with linear ways.

Thanks,

Randy

I think if you sketched up a concept and figured out how much material went into it the machine would be much heavier than a conventional machine. The basic frame structure would have to be L shaped. With a small machine such as you are considering this is probably no problem but with large industrial machines it could be a factor.

You are quite correct about the linear ways not caring about which way is 'up'. If you had a big reinforced concrete wall handy you could bolt a conventional machine to it and now you have it :) . Although it is likely that the weight of the machine itself would cause distortion leading to inaccurate operation. The bed of a lathe is machined sitting level, the casting has to sag a little between the supports but when it is installed and levelled for use the sag will be the same as when it was made. If you rotated it 90 degrees now the sag due to its weight will be perpendicular to the direction it was machined; the machine would be warped downward which is sideways from the conventional view. The original sag would turn into an upward bow which would be outward when looking at it hanging on the wall.

Thanks for the reply, Geof. I just wanted to see if there was anything obvious that I hadn't thought of. Of course, on a large machine there would be significant gravity effects and that would take some FEA to get right.

But my machine will be tiny--the 3-jaw chuck in the picture below is 2.4" diameter. The lathe will use a couple of small THK linear actuators I got surplus a few years ago, and the headstock from my Sherline lathe on a spacer. Baseplate is a chunk of aluminum tooling plate. I will probably experiment with slant-beddedness by just tilting the whole thing up on some supports.

Best regards,

Randy

For a small lathe having the spindle close to eye level with the tool coming in from the top might make it very easy to use. Totally unconventional but you would not need to stoop over to try and see the tool and settings things up could be more convenient. This would probably work for big machines but the structural challenges are more serious.

This idea is about as far outside the box as the one I had a while back for an upside down milling machine. You would not need to worry about re-cutting chips when interpolating a hole or cutting pockets :) .

In the early days of cnc,Dean Smith & Grace a well respected British lathe buider,built such a machine as you describe.They called it a Monarch,and it was an extremely rigid machine.Had some form of concrete base.By the eighties you couldn`t give them away,due more to the GE550-1050 controls more than anything else.I haven`t seen one in years and sometimes wonder if there are any left.
Mark

www.ems-fife.co.uk (http://www.ems-fife.co.uk)

...with the tool coming in from the top

Ooooh, that's even more out-of-the-box than I was thinking. I like it! The linear ways won't care what direction the cutting forces are coming from. Instead of a rear cutoff toolpost (the only rear thing I've seen on Sherlines) a rear cutting post. Since I don't plan on turning anything more than about 1/2" diameter on this lathe (specifically small-scale model railroad wheels) there won't be a problem fitting front and back toolposts. And maybe one more in the middle for drilling and face work.

Thanks again, Geof, for helping rip that box apart...

Best regards,

Randy

In the early days of cnc,Dean Smith & Grace a well respected British lathe buider,built such a machine as you describe.They called it a Monarch...

I haven't found any pictures of that, Mark. I'll keep looking. When I search for "Monarch" I find endless pictures of 10EE toolroom lathes...

But look what I just found:

http://www.machineco.com/Lathe_CNC_8x16_Boxford_Mod-125TCL_stkP0159.jpg

which is a little bigger than what I'm considering.

On the other hand, I guess it's not toally unknown to just bolt a lathe up sideways like Geoff said:

http://www.micksmisc.com/wp-content/uploads/2007/04/cnclathe.jpg

Best regards,

Randy

Obviously the box was already weakened :) . And 'far out' ideas turn out to be close in.

Course you could turn you pictured late up on its end, Chuck facing up, mount the lengthwise axis on the in/out axis and then you'd have a VTL. :)
The reason for a slant bed design is to get the chips to fall to the bottom of the machine. This is the same reason horizontal mills are preferred for high production use over verticals.
Rear feeding tools are used so the machine won't be so deep and the operator can get closer to the chuck for loading.
Over the years lathes have been built in just about every orientation imaginable.
On a small lathe like this you've got lots of options so you might want to build a strange configuration just for the wow factor when you show it to others.
Bob

Randy,you will struggle to find a pic of a DSG Monarch on the net.It`s well over ten years since I`ve saw one in the flesh and I doubt there are any left.
The Boxford you linked are quite common,I know a guy who has four larger versions of these,all needing retrofits.The Boxford software is another problem usually leading to a retrofit.
Mark.

Mark, I just found this video and two others by the same guy:

http://www.youtube.com/watch?v=ck-JyqBouqM

He's using Mach3 to control his Boxford. Maybe your friend can talk to him. Mach3 is really nice software. My Tormach mill uses a customized version and I really like it (having used TurboCNC for several years on my Sherline mill)

Best regards,

Randy

On a small lathe like this you've got lots of options so you might want to build a strange configuration just for the wow factor when you show it to others.

Maybe I'll just mount my Sherline upside down. Most of the chips end up on the floor anyway... :D

What would really be wow would be finding a tiny power chuck to fit the Sherline spindle. Then I could crank out my model railroad wheel blanks by the dozen!

Best regards,

Randy

....What would really be wow would be finding a tiny power chuck to fit the Sherline spindle. Then I could crank out my model railroad wheel blanks by the dozen!

Best regards,

Randy

Make yourself one based on a 5C collet; spring closed compressed air opened. All you need on the machine is the ability to orient the spindle and have a relay output to open an air valve.

Make yourself one based on a 5C collet;

[Kirk mode]

Must...resist...feature...creep...must...focus...on...task...at...hand...must...utilize...available...resources...most...efficiently...

[/Kirk mode]

I won't even *mention* my fantasies about a Parlec ER20 collet chuck and some duplex bearings...

:D

Best regards,

Randy

It is not feature creep to build something that is useful. Feature creep is when you incorporate something that is flashy but has no practical use.:D

I work at a biotech company designing laboratory equipment. I define feature creep as delaying the introduction of a product for "it will be so much better/versatile/gizmoish if we add XXXX" to what is already a perfectly functional, tested, product prototype that meets the original specs. It's not as if there is a law prohibiting introducing an improved, Plus/XL/GTI version 6 months down the road. :D

I have the Sherline headstock, the Bison chuck, the linear slides and the tooling plate right now. I can put together the lathe this weekend if I keep focused. I can always look at the gizmoish autofeeding headstock concept later on, and in the meantime make lots of my wheels, 5 or 6 at a time...

Best regards,

Randy

When you are exposed to true feature creep perpetrated by someone else it does make you sensitive to it. I am financing a start-up that is developing customized computer access devices for people who have a physical disability; my 'bright young guys' periodically have to be beaten around the ears to remind them we have to get a product out and selling before the money runs out. Tghen they can do all the 'neat' stuff.

It all goes back to that old hack my boss used on me. "The time comes in all projects when you must shoot the engineer in order to finish the job". Then after I was "downsized" he had the guts to call me up to get the info to finish it up. Guess what the reply was.

"The time comes in all projects when you must shoot the engineer in order to finish the job".

In my experience it is "The time comes in all projects when the engineers must shoot the marketing people in order to finish the job." It would be novel to be in a situation where the engineers were actually calling the shots! :violin: It is invariably the marketeers who think up new features to add when the development is 80% complete...

Best regards,

Randy (obviously one of the engineers)