Hello:

I am interested in buying a mini mill from harbor freight, which is a pretty cheap mill. There is a lot of posts on this website about.

I read this PCB milling forum, I do not see any post talking about the harbor freight mini mill, actually people on this forum talk about some milling machine which I am not familiar with.

I want my mil can do CNC PCB milling, is HF mini mill OK to do that? Also, what is the popular approach on this forum to obtain a PCB milling machine, DIY or buy? If buy, what brands to choose?

thank you for your help.

How fine of traces do you want to accomplish?

I plan to work with only limited SMD devices, I think trace width of 10mil (0.3mm) or so will be enough.

I don't believe you can get 10 mils out ofthe box with a mini mill, too much slop in the mechanics.

ahhh! that is good to know.

What is your recommendation for things like 10mil or 20mil? and what is the popular choice on this forum(I read almost all posts, but I do not reach a definite conclusion :( )

I am completely new to CNC milling, any help is very appreciated!

I really don't know what to recommend that isn't real expensive. Possibly a Sherline mill as I believe they are a little more precise, but the spindle isn't well suited for pcb's.

what kind of spindle good for pcb?

On drewtronics, I see some pcb milling machine kit which looks nice. But that kind of milling machine may not be good for general milling of metal parts :(

Milling metal and milling pcbs are two different requirements if you want to do 10 mil traces consistently. 16 to 20 mil reliably gets more realistic.

so seems 10mil is an unrealistic thing to pursue.

As a hobbist, i have no difficulty to give up on that and use large device and wide trace, I do not expect to work on high frequency circuit, so this should not be a big deal.

ok, the question is: what is a choice(if DIY or economical kits) of mill to do 20mil wide trace?

Again, I am sorry that I gave 10mil at first, I just start to probe this field :) and thank you for the patience and time to answer my questions, I really appreciate it

How big of a work area do you need?
What is the biggest circuit board you need to accommodate?
How much money do you want to spend?
How will you control it?
How big can the machine be given any room of space constraints?

Jay

well, at most 6x10 inch board

budget is limited, under 1500, including machine itself, motors, software, is this realistic?

plan to use a retired desktop to control it

I can build a bench(about 30" x 60" top) for the machine, should have no space conatraint.

You might look at CNCing the Sherline mill or the Micro-Mark mills knowing that you will have slow feed rates on milling pcb's. Or you could modify to add a Paul Jones or Wolfgang spindle

As a Sherline owner, I would not advise doing CNC on one. There is just too much flex in them. Although PCB work would be easier on them, the next battle you face is the limited work envelope. The boards would have to be very small. A std Sherline mill has only about 2.5" of Y-axis travel.
If you look on this site at the 'eBay ads thread', there is a guy selling a mini-mill that is all tricked out with a CNC conversion. He wants $2k for it and it's about ready to go.
Even a cnc conversion on a Taig mill would be better than the Sherline.
I love Sherline's, but you have to consider your application when choosing a machine tool.

Also, I tried milling PCBs on the X2. It works (I added a Wolfgang spindle) but too much slop for SMD. Bought a router instead (www.widgitmaster.com). The Fireball (http://www.probotix.com/FireBall_v90_cnc_router_kit/) (www.probotix.com) looks to be a capable cnc router. Might want to join the Yahoo group for it and see what others have done. Phil's is a earlier model of the Fireball that he has tweaked. On the other end of the sectrum is the Romaxx (http://romaxxcnc.com).

For me, I don't miss the X2 with it's 3x9" work area and sloppy axis (even with a ball screw conversion). You need to evaluate and be honest on how much metal you would cut. What i learned is that cutting metal is slow, noisy, and very messy (coolant, metal shards) and not worth it. Knowing what I do now, I'd be looking at the Fireball or Romaxx. Widgitmasters are handmade and not always available. The use 10tpi ACME so they are "slow" compared to the other routers that use multistart threaded ACME.

Some examples from my widgitmaster (http://picasaweb.google.com/jay.couture/WidgitmasterWideRouter#).

FWIW,
Jay

I didn't think about widgitmasters, but that is an excellent recommendation!

thanks guys, very good info I gathered, I very appreciate it :)