The title of this post might sound like I'm trying to initiate a controversy, but really, I'm asking out of my ignorance.

Some of you may know that I have both the lathe and mill, and both are manual machines. I know very little about CNC work. I'm just an ol' crank turner..

What I'm wondering is, what do you guys/gals do when you have a very simple milling job to do? Do you have to run a program even for the most mundane milling chores?

For instance, say I have a piece of metal, 2" x 2" x .25 thick, and I need to mill off one edge just to clean it up. I would simply mount it in the mill vise, and in about 30 seconds would have the job done.
What would I have to do if my mill were CNC? I notice that in most pictures of CNC milling machines they do not have handles on the steppers. Do you have to start up the computer just for one of these simple jobs?

I'm trying to decide if CNC would be useful to me. I've made some fairly complicated things, but most are one-off. An exception would be gears. I've made quite a lot of those, and I can see where a CNC rotary table would be good for indexing.

Maybe some of the members can give me examples of common uses for their CNC mills.

Thanks,

Dean
http://tinyurl.com/DeansProjects

Dean...whats nice about CNC is you can use it like an auto feed with digital readout for the quick and easy stuff.....I use mine like that all the time

using Mdi (Manual Data Input) you can tell any axis to go anywhere at any feedrate you want

or you can just Jog your axis at the desired feedrate......Some use handwheels also on their Steppers, I Prefer to do everything using the Computer

Hope this answers your question

Dean,

I am struggling with that exact concern. I have all of the equipment and software to get the mill running in CNC mode, but I can't reconcile loosing the flexibility of being able to "crank" the mill manually for simple machining. I am sure it is ignorance, but it seems a greater process to get simple tool paths set up than simply doing it.

How does one do simple machining in CNC mode?

Rick

I think Brian, said it very well.

I've run manual machines all my life and it's a new kind of "feel" to run a CNC just using an MPG/Pendant. It really comes down to how well you know feeds and speeds because you lose that true "feel" of the cutter removing the material. It's actually un-nerving but no worse than hitting that cycle start but and letting it run itself for the first time

In my setup, I use a Shuttle Pro 2 as a pendant and I can switch each axis at any given time and the center wheel jogs .001" at a time and the outer ring to that wheel can be turned left or right making the axis go either way as well and at a variable speed too. Think of it as a power feed setup for all 3 axis' in the palm of your hand -

Hope that helps a bit?
Dave

I wouldn't say you loose flexibility, you gain other abilities that you did not have before so you increase flexibility. When you increase the flexibility of anything though you also increase complication in using it too.

In operation things are the same up to the point where you make chips. That is fixturing, and locating the part are the same (except you are jogging the machine not turning a handle.) When doing a 'manual' type operation you have to think about things a bit different though. You have to plan a bit further ahead as far as speeds/feeds but you can do anything with a CNC that you can do manually.

I feel your hesitation Dean. I was a hand cranker. I then moved on to CNC. I did like it, for certain things. Personally I think it's a big pain in the rear for the simple machining. I got sick and tired of starting up the comp. just to like you said clean up and end. So now I'm back to hand cranking. Like you I make mostly one off type projects. Cnc is mostly for the production folks or if you happen to have a complex part. Like others have said you do lose the feel and for me I just couldn't stand not knowing what the cutter was doing. As for the gear making you mention, Sherline does have the automated rotary table with it's own pendant. That would at least simplify the division process. Anyhow my two cents worth, not even in this economy.

Rick

Dean,

Based on your example above, the only time you'd lose vs manual is the time it takes for the computer to boot up. Once booted, all you have to do is jog over to the cut then make the cut using the jogging control. I think of this as a combined DRO and power feed. Youl wouldn't have to write any code.

I like the fact that I can touch off on X, Y, and Z and then use manual data input, which is very easy, to tell the mill to go to any location on my part. Nice for drilling several holes, etc.

I am pretty much a one-off type as I build model engines. I've found the CNC lets me cut very small parts that I'd have trouble with manually, though it can certainly be done. Also I've had to make changes to a part and rerun it. Once I've changed the drawing, and rerun the CAM program to generate the code, the revised part was quickly run off. Much quicker than starting over with hand cranks. Of course now I am taliking about CAD and CAM which add time to the process on the front end, but save time once you start the cut.

I put double ended motors on my Taig and installed cranks. In time I removed the cranks and put them on Ebay. I did replace the cranks with plastic knobs, but rarely touch them.

Bottom line, I feel CNC adds to flexibility, as several above have said. You can still crank the machine or go as far as you want into full CNC control. You just have more options.

Regards,

Chuck

I have two of the Sherline rotary tables, one that will be the fourth axis for the CNC, and the other that I use manually. Be warned, the reason that I own two is that Sherline does not make the units to covert back and forth, they are either manual or CNC compatible.

That being said they are extremely well machined and have a silky smooth movement.

Rick

Thanks to everyone who has taken the time to reply. There are some interesting thoughts and opinions for me to chew on. I'm thinking it will take me a while to mull the whole thing over. I'm so comfortable turning the cranks that I sometimes wonder if I'm missing out on something good, or if maybe I'm just better off doing it the old way.

The fourth axis RT is the most appealing to me because I don't need a computer to run it. Just 'round and 'round...

So, a couple more questions that may seem elementary to the rest of you but..

The little Shuttle (looks like my TV remote). Does it have to go through the computer, or will it go right to some kind of controller and just run the steppers sans computer?

Chuck, when you say "touch off XYZ", is that a program function that finds edges, or does it depend on manually finding edges and telling the computer that each one is a certain zero?

There are quite a few folks here that use CNC. Is it a hobby for you, as in, you simply like running the machine for fun, or are you making production runs of items for sale?
(Nothing wrong with either one of those things. Half the stuff I make is just because I want to make it. The other half is because someone wants to buy it.)

Dave said something like "it comes down to how well you know the feeds/speeds". Heck, I don't know the numbers, but I listen to "baby" and she tells me how fast I can go. Tactile feedback tells me all I need to know as it is. I would have to experiment with all this if I go the CNC route. I see broken end mills and a fuller scrap bucket in my future...

Thanks again,

Dean
http://tinyurl.com/DeansProjects

Dean,

The little Shuttle (looks like my TV remote). Does it have to go through the computer, or will it go right to some kind of controller and just run the steppers sans computer?

The shuttle is a USB device and was originally used for video editing but Art over at Artsoft wrote a plug-in for use in Mach 3.

There are quite a few folks here that use CNC. Is it a hobby for you, as in, you simply like running the machine for fun, or are you making production runs of items for sale?
(Nothing wrong with either one of those things. Half the stuff I make is just because I want to make it. The other half is because someone wants to buy it.)

both



Dave said something like "it comes down to how well you know the feeds/speeds". Heck, I don't know the numbers, but I listen to "baby" and she tells me how fast I can go. Tactile feedback tells me all I need to know as it is. I would have to experiment with all this if I go the CNC route. I see broken end mills and a fuller scrap bucket in my future...

I'm sure we've all been there, and if you haven't broke/scrapped anything, then you're not working on anything

Just wanted to comment on the differences in the manual and CNC Sherline tables. I've converted a "manual" Sherline table as they're much cheaper going that way and there is no difference mechanically as it's the same gear setup and only the fact that it has a motor mount makes it different. It's really just a way for Sherline to get a few more $'s out of you.

Dave

Dave,

Those bastards!!!!!

Oh well...

Rick

indeed.......but I can't blame them for trying...

Dave

Helllo Dean,

"Chuck, when you say "touch off XYZ", is that a program function that finds edges, or does it depend on manually finding edges and telling the computer that each one is a certain zero?"

There are some macros available that automate the "touch off" or referencing the edges and top surface of your work piece. The macros utilize the probing function in MACH. Works great.

You can also "touch off" or find the edges manually with an edge finder and other method and enter the zeros into the MACH using the keyboard.

I also have a Supermax manual mill and do a lot of my work on it. I enjoy both manual machining and CNC machining and find that each has a place in the hobby machining I do. I got into the CNC as it was interesting and I just didn't want to end up 15 years down the road wishing I'd tried the CNC.

Regards,

Chuck