CNC mill tooling recomendations

[Tin Falcon]

guys I have been in the dreaming planning stages of converting my little seig 2 mill to cnc for I guess a couple of years. I have the Stirling steel plans , have started machining the parts and have purchased the hardware for the conversion . I have my eyes on a couple of viable electronics packages I can afford.
the question I have is what do you guys the ones with home /hobby CNC mills use for quick change tool holders that have preset tools. I like the idea of the tormach but cost more than the mill or the cnc electronics. Some suggestions please !! BTW my mill has the 3 MT taper.
should I just try to collect onies and twosies of drill chucks and mill holders ,look for sets at Enco or ?? What do the guys with home cnc experience consider a basic starter set when it comes to tooling I know this varies with the part but how have you addresses this hurdle if you even see it as one. As far as tool holding now i just use a set of 3 MT collets from Little machine shop I also have a ER collet set.
Pleas help
Tin

 

[sparky961]

I haven't done a lot of completely automated stuff with my CNC controlled mill/lathe yet because I haven't completed the Z-axis drive conversion yet. The machine really wasn't designed with this in mind, in my opinion, so it's been a real challenge.

That said, having the capability to do complex angles, and circles on the mill, radii and special profiles on the lathe, and generally keep everything accurate and repeatable without counting turns and keeping a notebook full of calculations, is a wonderful asset.

My tooling complement is no different from what I'd be using manually, since the computer and I work together. Everything is set up just as I would without computer - it just takes care of the number crunching (Computer Numeric Control).

 

[cfellows]

Tin,

Are you planning to replace the acme screws with ball screws on your mill? If so, where are you getting them?

Chuck

 

[BobWarfield]

Tin, a couple of comments.

First, as to the matter of a tooling system. The reason for these is repeatability on the exact position of the end of the tool in the spindle more than anything else. But there is another way to deal with that. Personally, for a lot less than the cost of the TTS at $600, you can build a powered drawbar and an electronic toolsetter.

Here is a link to my powered drawbar:

http://www.thewarfields.com/cnccookbook/CCMillDrawbar.html

and a picture:

You'd have to see what the equivalent is for your machine, but it saves tremendous time swapping tools in taper. Total cost was under $100 and worth every penny.

Next step is to get that repeatability. Except, there's a better way, and that's to use a toolsetter. This is essentially a little electronic switch that's highly repeatable. You use a macro in Mach 3 (don't worry, it's been done and you can just borrow the work of others rather than having to write one). The switch sits on your table somewhere and the macro positions the cutter over the switch and then gently lowers down until the contact is made. At this point yor machine "knows" where the end of the cutter is. It's really a simple process. Search on "toolsetter" or "touchsetter" in places like CNCZone to find out more.

Here is a link by balsaman to get you started:

http://www.cnczone.com/forums/showthread.php?t=3836

Balsaman is "AllThumbs" on this board I think? Balsa, you there?

Anyway, as you can see, the toolsetter is cheap and cheerful too. So for probably $100-150 (depending on how fancy) you can cover all the bases in a very flexible way. Now you can go out and buy as many mill holders, collet chucks, or drill chucks as you can get your hands on cheap and life will be good.

BTW, there are a lot of interesting things you can do once you get a "probe" input like the toolsetter going on Mach 3. For example, you could build a digitizer probe. See the other discussion about that. You could convert an electronic edge finder so that it talks to Mach 3 via the same input and use it to do all kinds of interesting stuff. There are macros available that will center over a hole or other feature if you have that kind of rig--the digital equivalent of a Blake Coax. For your touchsetter you could convert one of the little boxes that lights up too.

In terms of other tooling that is CNC specific, there isn't much. You'll want to understand fixturing, because that's where a lot of the rub comes in. You want clever fixtures that let you machine as much as possible in one go. You can do things that would never occur in a manual machining situation with CNC. For example, one common fixturing trick is to use custom aluminum soft jaws in the vise. You can turn out softjaw blanks like crazy with a CNC. The idea behind custom soft jaws is you cut the "negative" of a part in the top of the jaws so that you can flip the part over and the jaws will clamp properly. With most CAD it is dead easy to create the negative image you'd need. Depending on the shape of the part, you instantly register pretty accurately because most parts only fit one way.

Lots of fun new stuff to learn with CNC!

Cheers,

BW

 

[Tin Falcon]

Tin,

Are you planning to replace the acme screws with ball screws on your mill? If so, where are you getting them?

Chuck

chuck: at this time no. I did purchase an odd sized ball srew and nut for the z axis from mcmaster carr. I needed 18 inches and bought two feet in retrospect I should have gotten 3 feet and had a spare or one to share. IIRC the hardware was a little over $100 . I will have some spare parts because some of the items were purchases in quantity bags will have to check after the build to see what is available .
Tin

 

[John S]

Tin,
We are using normal endmill holders on the new KX1 CNC machines.
Granted these are No#2 morse and you are on No#3 but the principle is the same.

So far we have had no problem on repeatability given that it's a taper as we are guessing the tightness every time but if it does become a problem you can always use a torgue wrench.

Our drawbars are captive and so they self extract the taper which means no hammering or bashing so that helps. Normal method is the set all the tools up for the job in hand first and touch off onto the work and set the tool offset into the tool table, then run the job changing tools as needed.

We also do the same with No#2 morse to ER25 chucks but as we only have two chucks we tend to save these for tooling that won't fit end mill holders like some of the 5mm shanked tooling.

These machines are always on demo so it's imperative that we are not messing about with tooling during a demo and it works for us.

.

 

[Brass_Machine]

Tin...

I am going to follow this. My X2 is going to be CNC'd as well. We talk Saturday when we meet up.

Eric

 

[Tin Falcon]

eric:
One of the reasons I wanted to cnc was for my son to get some hands on cnc experience before college . guess i better get my act together he starts college in the fall. Boy how do time fly. Will try to remember the Stirling steel book on Saterday.
tin

 

[cfellows]

chuck: at this time no. I did purchase an odd sized ball srew and nut for the z axis from mcmaster carr. I needed 18 inches and bought two feet in retrospect I should have gotten 3 feet and had a spare or one to share. IIRC the hardware was a little over $100 . I will have some spare parts because some of the items were purchases in quantity bags will have to check after the build to see what is available .
Tin

Tin, how much of a problem is backlash if you don't use ballscrews?

Chuck

 

[Tin Falcon]

guess that will be determined when i try it. my x axis has about .007 backlash but some of the programs have the ability to program it in so backlash is eliminated in the software.
tin