[MaxxMan-X]

My Hobby Shop is interested in getting a CNC mill to make small parts for RC cars. The biggest thing to do would be a chassis. They measure around 18x8 at most. They also need around 6-8 inches up and down (Y-axis right?). I would say some of the parts made most are rims (can you make a rim with a CNC mill?) Rims are about 3.5 DIA and 2.5 tall. Suspension arms too. You probably have no idea what these parts look like.. LOL

I don't know what works with what. We just need a small mill and were not looking to spend a fortune. I can make stuff in Autodesk Inventor and Pathtrace's EdgeCAM can make NC code from Inventor parts. I don't know what I need to do from there. I'm guessing that seperate software that comes with the CNC and I'll have to upload the NC code into that and then run the mill. If this sounds stupid it's because I only know what about half of what I said is.
Could you give me the name of a CNC you have and like or one you have seen that might work?
Thanks

[teilhardo]

Hi Max,
I'd say that all you would need to suit your purpose is a small Taig, MaxNC, Harbor Freight or Homier mill that can be upgraded to CNC (Taig and MaxNC can be bough CNC ready from www.microproto.com and www.maxnc.com respectively). However, you will probably have to kiss your plan to make chassis away beacause the Taig has the largest x dimension but it only comes out to be 12". Once you have a mill, you could make your own gantry router (many people on CNC zone have these) that can cut the required dimensions for a chassis. If you bought CNC ready systems for either Taig or Maxnc you can expect to pay about $2100 with everything needed to support the mill. If you did it yourself (you can save about $500), you could also get some CAM software (expensive) and end up paying the same price

-Tei

-Tei

[MaxxMan-X]

Thanks, good info.
What's the difference between a closed and open loop machine?

[nervis1]

None of those small mills have 18 in of X travel. For that you will need a bigger toy. Even most mill drills don't have 18. And just FYI if you want 18 get 20, because you don't want to working right up against the limits. That makes for great fun when you trash workpieces because your measuments in set up were .05 off.

Look at a knee mill retrofit. That might do what you want and give you value as well, just pick up an older knee mill in decent shape, just about the same price as a Taig and much more capable.

In the end plan to spend about the same for a decent cnc mill as you did for inventor and edgecam together. I know you don' t want to spend a fortune....but odds are you will ;')

Closed loop means the motors feedback to the controller and self correct. The open loop system has no feedback. Most closed loop systems are servo controlled.

[mysterious]

When I was looking for a cnc setup, I did alot of researching. From what I read a taig along with Mach2 software would be a wise chose. The best price on a taig ready to go was from here . You can buy Mach2 software elseware and you are ready to go. The Taig does have it's limitations, like teilhardo said, but to do a chasis I'm sure you can play aound with the mill and make one up in two parts, first you do the front end then the back. It will just take some figuring on your part to get the programming lined up. But once you figure it out you will be in business. The only reason I didn't end up with a Taig is that I ended up having a bigger budget than I thought I would. I ended up ordering a shoptask for 3x's the money. I'm sure the Taig should suffice for your purposes.

[mysterious]

I can't beleive nobody thinks of doing a chasis in two steps. This is an old trick I picked up when I used to do vinyl stickers. My machine would only cut up to 30" if I wanted anything bigger, say a 50" tall S, I would do it in two parts. Basically two 25" c's put together if that makes any sense. This is the same concept that can be done with making a chasis in two steps, but you can continue on the same piece of material, unless I am missing something here.

[MaxxMan-X]

Even if I can't make a chassis there is still many other things for me to do. Thanks

I'll look into a Taig or MaxNC

[nervis1]

If you want to make aluminum wheel rims even R/c size, and chassis parts do not get a Taig. I had one that was stepper controlled for a year before I sold it. The motor is 1/6 hp, and the first time you spend 4 hrs cutting something aluminum at .05 DOC standing there using a spray bottle coolant, getting all wet, and cutting a part in two setups when it should go in one, you'll wish you went with a more robust machine.

Now I'm thinking about a wheel rim the size of my old inferno car...my Taig would have taken several hours to cut that...if it could. The tiny end mills you are confined to using mean little DOC...= big time. I tried running a 3/8ths cutter. I could not get any better than .05 DOC without it bogging / stalling in aluminum. Think hours. With no coolant, the extra long 1/8th EM will break at hour number 2 and now it's time to redo the offsets again. A CNC knee mill could have it done in 20 min. Not only that but with an R8 spindle you can get a quick change tool holder and now you have a REAL CNC. you can write programs to drill, bore, face, mill, countersink all in the same program.

No tool changes on the Taig. You have to write a seperate program for every tool change.

Serious....if you plan to make things to sell, look into a bigger mill. The Taig is fine if you are fooling around but it is not a production machine.

You can get an older knee mill and retrofit kit for under 10 grand, thats less that what you have already spend on software. If you look hard you can get a working VMC for UNDER 10 grand. Think of the parts you could make with that.

[MaxxMan-X]

I found this one on e-bay
http://cgi.ebay.com/ws/eBayISAPI.dll...category=12584

How's that?
I'm now looking for a CNC retrofit.

[nervis1]

Check out route66 retrofits. There are a hundred others.

There are several mfg of ball screw conversions as well.

Flashcut makes a high quality servo system.

That mill, while not a Bridgeport will out shine a Taig all day at least in a production environment. With a retrofit you'll keep the manual capability as well. Don't get me wrong. In it's class the Taig is a very solid little mill. I could not design a better one to be sure, but for what you are talking about doing it just isn't enouh iron.

Think 1/2 cuts in 6061 with a 1" end mill all day long with a glass smooth finish. You can rig a coolant system with a small tank and pump from Enco or a mister. All of those knee mills have coolant troughs and threads for spouts in the table.

That mill is something you won't outgrow the first day.

And look at that ...30 X 12 travel. Now what can you make? 1/8-1/4 scale stuff? You can make small stuff on a big mill but you can't make big stuff on a small mill.

[mysterious]

nervis, you seem to know your stuff. While on the subject of coolants what is better a flood system of a mist system? Does the mist system work pretty good if you get the help of air?

[I.C.O.N.]

Mist systems are effective when flood is not an option. The particles in the air are not good for you though. And the mist gets everywhere where as flood in a small controlled stream directly on the cutter can be easily kept on the table. For alum just a good air blast(and a vacuum) usually does the trick.

[nervis1]

I'm not a machinist, just a hobby guy who has been down the same road you are starting on. I had lots of dissapointments, and lots of wasted money. I'm just trying to spare you some of that.

A mister can be a great asset, look at an ENCO, or Travers catalogue under coolant systems and you'll see what the different types are. ICON is right that misters can make a mess without an enclosure, it ends up all over the walls after a while. Lately microdrop systems have solved some of that, depends on what you use for coolant as well.

When I had my mill-drill converted I just used a single flood nozzle and small tank. I had a snaploc valve on the nozzle and just dialed it in so coolant stayed in the trough.

Another tip....take your time and look around, check out some auctions. You might find an early 90's Boss controlled Bridgeport for a song. Then you'd just have to replace the controller. (if you wanted to. ) with something a little more modern.

[nervis1]

http://www.rockfordballscrew.com/clonemil.htm

Check this link, in case whatever you buy doesn't come with ball screws.

[MaxxMan-X]

just went up yesterday and they are looking at a smithy granite something. (The good one) and the CNC package that you can get with it. I like it because it's a lathe and a mill. Are Smithys any good?

[tsutt]

if you want to do the wiring yourself I recommend Ajaxcnc.com it's really a centroid control. I put one on my miltronics partner 2 it works great. Todd

[Bloy2004]

If you are considering a 3in1 machine, also add the option of this machine....
http://www.cnczone.com/forums/forumd...s=&forumid=147
To see more threads there, remember to change "thread view" from 30 days to 100days in the box at the bottom of the forum.

..and more specifically what you may want to do to "refine" the initial purchase.
http://www.cnczone.com/forums/showth...&threadid=2139

All 3in1s have both advantages and "trade-offs", but with Shoptask's bridge/fifth support column, rigidity is maximized for this type of machine.

This was "entry level" for me and I based my decision on these factors...
I've got to add here though ...it is a hobby for me.

The main features of the Shoptask Bridgemill that finalized my decision to get it were ..
1. the quadralift ....allows great flexibility in height of the mill while still keeping the spindle operating well within the head.
2. Individual motors for lathe and mill
3. Included table/stand easily moveable with proper casters.
4. Integrated mechanisms for easier CNC setup/installation.
5. Driven tailstock(using carriage)
6. Price for what you get.

Do research...make inquiries

[MetalZilla]

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