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View Full Version : Necessary equipment for CNC mini-mill?



Vrogy
03-24-2003, 07:16 PM
I'm looking into the cost of getting a CNC mini-mill up and running, and I'm wondering what accesories I should get with it instead of finding out after I order it that I need additional parts...

Here's what I've got on my list of stuff to buy so far:

a Harbor Freight mini-mill-----------------------------------549.99
Harbor Freight Mini Milling Machine (http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=36739)

the mini-mill starter kit at littlemachineshop.com------74.95
Starter Kit, Mini-mill (http://littlemachineshop.com/products/product_view.php?ProductID=1262)

the starter kit includes a clamping kit, parallels, 1-2-3 blocks, a edge and center finder, and a t-slot cleaner.

I also think I'll need a dial caliper, a dial indicator, a magnetic dial caliper holder, and one of those little steel rulers...

I'm wondering what other stuff I'll need, especially the CNC equipment. Can anyone point me in the right direction?:confused:

cncadmin
03-24-2003, 07:51 PM
1)-Well, you will need 3 stepper or servo motor's.
2)-Steel or aluminum plates to mount the steppers on.
3)-3 qty servo or stepper drivers
4)-3 qty belts
5)- 3 qty pulleys
6) NC software
7) CAM software

cncadmin
03-24-2003, 08:20 PM
Here is some of what you need. That is a 25v power supply to run 3-7A stepper drivers.

cncadmin
03-24-2003, 08:23 PM
Here is how what is going to hold the x stepper motor. I will post more pic as assemble this machine.

Vrogy
03-25-2003, 12:51 AM
servo motor...could large size RC servos be used, or is there a need for lots of torque? Also, has anyone ever put together a how-to site of sorts?

cncadmin
03-25-2003, 12:56 AM
NO r/c servo's will not work, you need NEMA 23- 34 stepper motor's 100-300 in oz.

cncadmin
03-25-2003, 12:57 AM
Originally posted by Vrogy
Also, has anyone ever put together a how-to site of sorts?

That is one of the reasons, I started this site, that is site is for LOL :):D

HomeCNC
03-25-2003, 02:06 PM
Vrogy, Check out my web site. I have my entire learning about Homecnc documented there. Start at the top and read each link.

CNCnUtZ
03-25-2003, 09:35 PM
well I would definately get a quick change collet set like this.......
http://www.grizzly.com/products/item.cfm?itemnumber=H2689&site=grizzly
To keep from having to wail so much on the drawbar of the spindle to release whatever you are using in the spindle at any given time.

And I would suggest you get a rotary table to do arcs and circular cuts....littlemachineshop has a decent selection and competeitive prices

You should also check out http://www.wttool.com as they have alot of good prices and just about anything youd need in accessories.

Also http://www.reidtool.com for a large selection of things from springs to ballscrew assemblies in case you want to convert you milling machine to ballscrews for extra precision when you convert it to CNC.
I suggest that you look for a 2 inch dial indicator /magbase holder kit at wttool.com as it really makes it easier to use considering you have 2 inches of travel at a time to use in measurement.I think they have a decent set for around $30 -35.

When you purchase drives for the steppers/servos, go with geckos, as they are the best you can buy for the money, hands down! And the guy who owns it, Mariss, gives A+ customer service for his products and is a very, very nice guy to deal with.

Shop ebay for a power supply in the range of your requiremnts, as they are quite expensive if you buy them commercially.
I purchased nearly everything to convert my sons mini mill to CNC.......including the preloaded ,O backlash ballscrews that I fitted it with.
I think I spent in the range of $1200 including the Grizzly mini mill to get a very precise, small hobby CNC milling machine that can cut nearly as fast and precise as my +$4000 converted RongFu mill.
Good luck

Vrogy
03-26-2003, 01:58 AM
ok...I think I'm looking at outfitting a mini-mill for CNC before I do a lathe, and I've seen a difference pop up sometimes--3MT vs. R8 tapers. Which is best, and why?

CNCnUtZ
03-26-2003, 10:33 PM
R-8 sized accessories are more commonly found everywhere they sell milling accessories.
MT3 are a little harder to find.

The only place that sellls an R-8 spindle mini mill is Harbor Frieght and Ive heard quite a few less than desirable things from various people about the quality of the machine, and mostly the poor customer service.
BUT.............You can buy a MT3 mini mill and convert it to R-8 if you so choose, by purchasing a spindle convertion kit from http://www.littlemachineshop.com for roughly about $40-45 dollars, including the toolkit required to make the removal of the original spindle and insertion of the new one, as simple and painless as possible.

I would recommend getting a Grizzly as I own to of them myself. But aside from that, I hear that they are usually of a better quality than other places that sell these" Sieg "type of mini mills.
And that is the reason why I chose to spend the extra money on the Grizzly models.

You pay a little more, but IMO, its worth it in customer support that you recieve ,alone.

Id also Like to add, that these little mills, given you dont "skimp" on the parts to do the convertion to CNC, are rather accurate. Almost as accurate as my big mill and ,by far, much cheaper.

In this hobby(as a friend of mine stated once).....the more money you throw at it, the easier it becomes.
Expensive little hobby to get into indeed!

WOODKNACK
03-27-2003, 12:38 AM
Just a note. You can buy the mini mill thru Homier! its the same as HF. Called the Speedway like the lathe. It has a r-8 spindle. I have one and like it. Plus you cant beat the price $399!

cncadmin
03-31-2003, 10:30 PM
CNCnUtZ- how did you convert the nini mill to ball and screw?

CNCnUtZ
04-01-2003, 03:00 AM
I used thomson 5/8 inch ballscrews and made then preloaded using two nuts on one screw with a spacer that can be adjusted to any amount of load in between them.

y and z were a breeze, but the x axis was a bit more tricky, as I had to mill the top of the saddle out a bit to accomodate the ballnuts to provide enough clearance for them.

the z axis....I just put a ballscrew assembly on the right side of the column and attached the nuts to the side of the head assembly and counterbalanced the weight of the head with a gas spring to give it no weight at all.

Pretty fun project to do and big inprovement of the mills precision by using ballscrews.....as good as my big mill for roughly 1/4 the cost.

In the process of building a 5 axis mill right now...
Ever since I was introduced to CNC, I was hooked.

Its really going to be something to build one from scratch though..

Man I cant wait to get it finished.

cncadmin
04-02-2003, 12:28 AM
Do you have pics?

CNCnUtZ
04-06-2003, 02:59 PM
No not at the moment, but I can probably borrow a friends camera and snap a few .

edge
04-08-2003, 02:27 PM
I just joined this site and I have to say there is some great info here. Any thoughts on using and converting one of the mini-mills for a small business on a budget? I'm in the product development side of things, but it seems to me purchasing a small turnkey CNC mill would be $ 4K and up without the CAM software. I would be interested in any info material cost, labor time and info on CAM software for the convertion. Also, can this mod still retain the manual control for quick jobs?


Usage would be quick proof- of-concept models made from plastics, non-ferrous and non-hardend ferrous materials. More complex jobs would be outsourced. The CAD design output would be from would be run from either ProE or Solidworks.


Thanks and keep up the good work


Perry

rvan
04-04-2004, 12:54 PM
Originally posted by WOODKNACK
Just a note. You can buy the mini mill thru Homier! its the same as HF. Called the Speedway like the lathe. It has a r-8 spindle. I have one and like it. Plus you cant beat the price $399!

Did you disassemble the spindle head? What type of gearing is used, Plastic? From what I read here http://www.mini-lathe.com/Mini_mill/Reviews/Homier/Homier_mill_p3.htm the motor is powerful enough to strip the gears. I wonder if its feasible to replace the gears with metal ones and swap out the motor, which is only 1/2 HP with a better motor.

How about remounting the Head on a different Gantry. Is the Head connected to the Mill base using Bolts or is it mounted using something funky?

I found these sites selling Spindles, but they are all very pricey (> $1K):
http://www.dunhamtool.com/high_speed_spindles.html
http://www.setcousa.com/index.cfm?fuseaction=displayPageContent&SITECONTENTID=1519630D-7C66-11D4-AEDB0050046E9786&PATRIARCH=3
http://www.finleyspindles.com/straight-spindles_desc.htm

Here is some cheap ones:
http://www.sherlineipd.com/indflyer.pdf (only Belt drive shafts)
http://www.littlemachineshop.com/products/product_view.php?ProductID=1663 (Cheezy Plastic Gear head, Low pwr Motor)

If anyone else can recommend any spindles, please do. I am looking for something that can handle at least 1 HP, and be able to run at low RPMS for milling hard metals (Stainless).

Has anyone adapted a hand router by replacing a router motor with low rpm DC motor (ie, use the router spindle assembly)?

vcav8r
05-14-2004, 09:15 PM
Check out www.accuram.com they have just what you're looking for.