Hey guys, I just finished my mini lathe tooling plate, I made it so it has huge capacity and two tool posts that accept up to 1/2" and up to 3/8" tool bits.

I will be running turbocnc, will I be able to change tool offsets on the fly? On the big lathes at work that have a similar configuration, we just call them all the same tool with different offsets, its like this: M6 T1 2 or smething similar, I dont remember as it is conversational code.
If I cant change offsets, I would have to measure between tools and that would flat out suck for programing and changing the tools etc.

I havent gotten it hooked up to a computer yet, I am waiting for my spindle encoder and breakout board from cnc4pc. I have previously had the lathe running with big nema34 motors from my mill.

Jon

Nice work Jon. This is a very similar configuration to Dave K (the author of TurboCNC).

Yes TurboCNC does tool offsets. Same code - M06 T01. You will need to have a line before to get you clear of the work (say G00 X60 Z20) as TuboCNC won't automatically go to a defined tool change location.

You will want to use V4, as it has separate offset registers for tools and part offsets. The description of how to set up your tooling file is on Page 17 of the V4 Manual.

thanks,
I was just thinking, I could use a fixture offset, the reason being is that its going to stop for a M6, Thats mainly what Im conserned about, I wanna see this thing fly through the part from start to finish, through all the tools that I have on there.

Jon

Can you change fixture offset values programmatically during the program run?
I know it can be done with Fanuc controls. I've done it. See bottom of web page.

http://www.programmingunlimited.com/fMacA.htm

You could also setup your tooling plate for gang tooling.

http://www.gangturn.com/omni_page.htm

WayneHill, Its just like changing fixtures on a mill, it uses basicly the same software, or exactly, It is in turbocnc. If I was to change over to Mach2 Im sure they have some sort of change tools on the fly type of a thing.

Thats a lot of tools in such a small spot, I doubt I'll ever need more than 3 tools. am thinking about making a chuck adapter to stick onto the back tool post spot like I made for my quick change tool post, or even just use that one.

Jon

I was just setting up to make some ER-16 tool holders on my lathe. I'm using a Phase II QCTP and four tools for this job. TurboCNC is great for this stuff.

On a mill, if you have a tool length sensor, you can have TurboCNC touch off within a program and set your offset on the fly. Can't see this really working on the lathe though with two dimensional offsets.

Wayne, that ganged tooling looks sweet for a production environment. How do you do height adjustment? I mostly do one offs on my hobby lathe, so the Phase II is fine.

Do you actually get good repeatability with the qctp?
also, instead of using a length sensor, I have fixed tooling and touch off all my tools before I run the program.

Jon

JFettig,
Nice...I noticed that you have a 4 post and a QCTP...any story behind that?

the story is that i can set offsets for both tools, and go from tool to tool without changing anything and have repeatability.
I use the 4 post because I have it, its the origional tool post, you can use whatever size tool that fits in there because its upside down and the tool height is on the bottom side.

I just made a new handle for the x axis(dont have the electronics for the cnc done yet) and I can use it to its fullest travel, like I can either use it for parting and front one for turning, or use it to turn down the end like I have it set for now and the other one for turning or whatever I feel fit for it.
We do this often at work, but with up to 3 tool posts, you just have to make sure the tools clear the part when changing.

Jon

The repeatablity of the Phase II wedge type AXA is fantastic. By far the most rigid and repeatable part of my Mini-lathe conversion.

ooh, it sthe wedge type, I believe that would be a little more acurate, I know from my experiences the piston type doesnt have a very good repeatability. One thing that can mess with repeatability is if the height changes, thats one thing to watch out for.

Jon

I bought this QCTP during a business trip to the states, and but the time I'd gone through the rigmaroll of ordering it, getting it at a hotel, and then dragging it back to europe, I wasn't going to muck around saving 30 bucks for the piston type. From all I have read, the wedge type a rock solid, and the piston type are a bit dodgy.

I have mostly made one off parts so far, so repeatablity has not been tested under fire. The QCTP really is the most rigid part of of my set up though.

How are you doing tool height setting? Since I only have 5 tool holders, I find I'm still canging bits regularly, and mostly take test cuts to adjust to the center height. I tried measuring and setting center height with calipers, but couldn't get it very accurately. Really need to take the time to make a tool setting fixture, but haven't thought one through yet.

Basicly how I measure my tools is I eyeball them at first, Im getting pretty good:p then I take a test cut off the end and see if it leaves a tit, if it does then you can see which way to move it. They have a locking nut ontop of the thumbnut that I often set.

I also just have the stock tool holders, and I broke off a cheap ball hex wrench in one so I am kinda stuck with that tool in there, really sucks because its a 45 degree champfer type tool(thats all I have been using it for), so I gotta somehow get that out, I also would like to find more holders.

Jon

How are the tools set of commercial CNC Lathes for height? Cutting until the tits gone is what I've been doing also, but there must be a better way.

Actually a lot of times we just eyeball them and fix them if they are off when we use regular quick change tool posts. We also have 8 position tool posts that you unscrew the handle and turn it and tighten again, that one has a precision plate so its always on center. With the big machining centers, most of the time the tools are upside down and thats acurately, the screws push down on what you would call the bottom of the tool onto a precision top, so no matter what size tool you put in there it will be centered. this is how my back tool post is, although I need to take off another thousandth for it to be dead on, just afraid Ill go over.

Jon

In industry most of the machinists I know already have it close, and just fine tune it in the control, until the tit on the part is gone. I am sure there is some special technical way out there, but for us guys, that might be the best bet. Maybe u could try milling a piece of steel like this




and set the tool height where the six is, just a though, not sure if it will work or not ( you would push tools against that flat which is dead even with the spindle)

The only use of this idea I have seen is from John Moran's site:

http://www.gadgetbuilder.com/DieHolder.html.

I just got the Phase II from Enco on sale w/ holders for 89.00 I bored out the stud for my 10mm stud on my 9X20 and it fits really nice. At first it looked large, even on the 9X20, but once mounted its perfect. A really nice change for the better. Running the tap down the center of that bolt was a trip, I was sure it was going to snap, but it didn't and the sleeve set up worked out perfectly.

Wow JFETTIG you made my day to see the same lathe that I bought made into cnc could you tell me what you used stepper or servo motors and what size

Hey Brihoo2k, Glad I could make make your day:)

I am using 272oz-in motors from automationdirect.com

I sell cnc kits for the mini lathe off of my website jfettigmachines.com

I have been running this cnc for some time now, I am quite happy with it.

Jon

I have his lathe kit for steppers and it works quite well. I have the Hobbycnc kit with the 200oz-in motors and it works well although I haven't had enough time to do a thourogh shake down everythings seems to be up to snuff!