Benchtop CNC Mills ($2.5 to 3.5K)

[Hannibal]

I am in the market for a benchtop CNC mill in the $2500 to $3500 range. Anybody have any experience with particular brands or features to look out for? I am somewhat new to machining, although I am knowledgable in drafting and I have an MS in Mech. Eng. Any thoughts/help would be appreciated.

[lsloth]

I have looked at them and have to wonder how much a cut they can make on each pass. Not that they can not make the part, but it will take alot longer than a larger more rigid machine. Most of things I see on the machinist boards online are people that own them only use them to cut aluminum or plastic.

[Hannibal]

[Moderators please delete my duplicate post, my apologies. For some reason I am not able to delete it??? I thought it did not go through at first.]

I am not so concerned with speed as it will be for personal use and possibly smalltime production (assuming my business plans go through), but you do raise a very good point.

[Reflexx]

AVOID THEM! They are too weak for anything other than engraving and plastics work. The frustration will drive you nuts and many broken tools.

I have a real knee mill (Bridgeport) and a full size CNC. THEY sometimes have trouble with decent cuts in steel and alum.

You're better off with a used knee mill with CNC controller, ala PROTOTRAK. Do a search for CNC KNEE MILLS and see what you can find. You'll probably spend a little more now, or a lot more later.

AND take a night school class in basic machining. I've been doing this since I'm 14 (36 now) and still learning tricks. Flying, broken cutters can put you in the hospital, I've come close when learning.

take care,

Reflexx

[fj40guy]

Given enough time you can mill out some nice parts on the Sherline sized
machines.

Matronics did their housings on the Sherline Machine. Details are here

Yep, I have a full size Machine. Not CNC, old hand wheels. I realize everyone doesn't have the space for such a machine, but if you understand your limitations on the small machine, might be just what you need.

Tom

[PAToyota]

My father has used a Sherline mill and lathe for a number of years. Bought it when he retired. He has made some nice pieces with it and it does a really nice job. However, he mainly works in aluminum and brass and is working on small pieces. It is not something that I'd see myself making truck parts on nor would I see doing a lot of steel work with it.

[Hannibal]

Thanks for all the replies. This is what I am looking for. I plan to cut steel and aluminum (mainly small brackets and such, mostly automotive applications). What can I reasonably expect to pay for a machine that could CNC a high steer arm for example?

[randii]

Get some experience before you buy! ...perhaps through a local community college. You'll get a good basic understanding of the mechanics involved, learn basic safety, and get a few tricks, but most of all, you'll get experience on different machines, each with different tolerances.

I can crank out pretty nice work on this machine in the shop at work:
http://www.grizzly.com/products/item...mnumber=G1007&
... but it comes at the cost of taking more time and operating within the cpacity of the equipment. It'll take a pretty fair slice of material off in a single pass, but it won't hold tight tolerances for the trip. It will hold pretty tight tolerances for light cuts, at obvious sacrifice to speed.

A full-size machine would be better in almost every case except storage space and cost -- and you'd be hard-pressed to really know what you need until you have experience with different machines and tooling. Buying tools before getting experience will likely cost you more money in the end...

Randii

[fj40guy]

Originally Posted by Hannibal

What can I reasonably expect to pay for a machine that could CNC a high steer arm for example?

The biggest expense is tooling! Machines are not that expensive, but start adding features and tooling... and the price goes up.

Intro CNC machines can be found for around $12K or so. Basic full size mill with a retrofit.

"turnkey" CNC Machines with Fanuc controls, etc... starting around $30K.

Biggest problem in finding a "used, good CNC machine" is knowing what to look for and how to test it out before you buy it. You do not want to spend $5K on that bargin machine to find out later the controls/servo's are all trashed. Lots of bargins on eBay, but I would not buy one without personally inspecting it under power.

If you look on that link I posted, it has a link to Ahha (something like that). There specility is retrofitting older machines. So find a nice CNC mill for $3,000 (i.e. dead electronics, no one wants to mess with it) and spend $4,000 on the retrofit and you have a decent starting point. Reasonable for PBB occasional use. For someone running a business, get the $30K machine and get to work!

Tom

[Urban Wheeler]

I've been looking at one of these. Mostly for aluminum, but I may do a steel part now and then.

[PTSchram]

Why does everybody complain about the cost of tooling? I buy lots of cutters mainly from Enco and have never been overly upset about the cost. Yes, there is more expensive stuff out there, but all we're trying to do is make chips.

[fj40guy]

Originally Posted by PTSchram

Why does everybody complain about the cost of tooling? I buy lots of cutters mainly from Enco and have never been overly upset about the cost. Yes, there is more expensive stuff out there, but all we're trying to do is make chips.

Not complaining, just trying to let folks know "the mill is just the beginning"

Tom

[Black Sabbath]

I think alot of people include things like vices, rotary tables, ect in tooling and that can add up fast.

[JeepinDoug]

Why are you set on CNC?
You can make hi-steer arms with a standard Bridgeport, rotary table and some imagination.
If your set on a CNC check out a Bridgeport with Boss controls. You can find them for the same price as those tiny little plastic mills. You'll be banging your head trying to figure out circular interpolation but the Boss controls will do it. Figuring "I" and "J" cordinates will be fun.
Hint; "I" and "J" are incremental arc dimensions from arc center.

[Hannibal]

Why am I set on CNC? Mainly because I have Solidworks at home and can draw anything I can dream up. Plus, CNC is the wave of the future and I figure if I start small at least I can get some practice for the day I am rich and can afford a $50K machine. Plus there are just some things that would be very hard to machine accurately by hand (continuous contouring) that the computer can do easily. I threw out the high steer arm just as an example of the size of the parts I am interested in making. Plus, you just can't beat the repeatability of a CNC (every part is the same); I just can't see doing small production work manually. I guess part of it is my age (26), I am real comfortable with computer technology. I started drafting in high school right as they were tearing out the old drafting tables (I have never done any drafting by hand, but have a lot of CAD experience), so CNC seems like a natural extension of my computer skills. Anybody else have any thoughts on the subject? Thanks for all the replies.

[JeepinDoug]

A CNC is only as reliable as the programmer, operator and inspector, not to mention the tools and fixturing.
Learning manual machining is a valuable asset.

[MC]

You may have a hard time drilling a .5" hole on a benchtop cnc and even with a 1/4" endmill making .200 passes might be overloading the spindle bearings. It would be fun to have one that was really stout.....but then again it wouldnt be a benchtop.