Why Build CNC When you can buy used?

[RGeo]

I posed my question in order to capture your attention.

I too love to build projects from the ground up. I currently run a business where we design and build custom machines. It is very rewarding.

What I do not understand is how people strike out to make one of these so called; poor boy CNC mills or routers with the intent of saving money and still spending a few thousand dollars. I have found what I think is a better alternative. Purchase an old NC machining center, complete with motors and drives, ball screws, table, spindle……….. and just drip feed the control from a PC.

You could conceivably buy the old iron for a few thousand, okay so maybe the tool changer doesn’t work, or the spindle is slow. You would still have several thousand pounds of iron, capable of large cuts and likely more accurate than your dremel driven homemade job for comparable money.

I know many people don’t have the space, there are also shipping costs, you would need three phase and a host of other lesser obstacles. I just want to include my opinion, which may save somebody else the hassle. This may not be the best option for a person who is doing it purely for the glory, but if your goal is truly geared toward relatively cheep, but very functional it should at least be considered.

[Brunow]

The fun of building and customizing it?

[Glidergider]

A reason to build is cost. You can get into it on a shoestring and getout early if you don't enjoy it. If you do keep going, then you'll learn more during the process of building IMO. For me, most of the costs are in software which is unrelated to the machine. I'm still not regretting it.

Yet I would like to have metal machining center

[RGeo]

Brunou,

I do understand the fun aspect. It is fun to build custom machines.

Glidergider,

What grade of machine are you building and how much do you expect to spend?

I have known people to drop between $4,000 to $12,000 and at best end up with a machine that can make .050” cuts in steel, with slow travel speeds. If they have spent less than that they end up with something like a Shearline which can barely cut aluminum.

I think many people are to optimistic, they start out thinking they are going to spend a few hundred dollars and 40hrs. They end up more like $3500. and 400 hours and the result is usually a metal working toy. The people in the $4,000 to $12,00 range purchase a mill/drill or a knee mill and by the time they finish the mechanical and electrical portion they could have purchased a real piece of iron and a PC and still stay on the low end of this price scale.

Concerning the educational aspect. You could also decide to geek out on a real machine, learning as much as possible about the workings and design aspects and end up with more marketable experience than a what you would from a hobby project. I know that the two experiences are different. My point is, in the end you end up with more machining capability, little difference in money and more common machine experience in general.

The question is what is your real goal and what are the realities of the two approaches?

[Glidergider]

Rgeo,
I built the JGRO. Here are my costs:

$zero for my old WIN2000 computer
$75 on wood
$160 vacuum system (2hp, from Harbor Freight)
$200 lead screws, plastic, nuts, bolts, hardware
$450 on electronic/motors etc,
$800 on software

The fun of building, the fun of learning Mach3/VcarvePro
PRICELESS

I've spent thousands of hours and I wouldn't trade a minute. I do want a bigger table, and if I get one, I'll probably build that one too. MechMate has free plans, large sizes and a big support group to help too.

Brunou,

I do understand the fun aspect. It is fun to build custom machines.

Glidergider,

What grade of machine are you building and how much do you expect to spend?

The question is what is your real goal and what are the realities of the two approaches?

[zippy]

Masochism, put some crazy low cap on the amount you’ll spend and beat your head into a wall LOL. Before motors and drivers my 4’X3' should come in at roughly $400 it’s made of steel tubing and I am planning on lining that with concrete and secondary internal split tubes to combat resonance on the longer members . With the motors and drivers it looks like it will come in at about $850. Now with the amount of time I’ve got in it I could of gotten a second job at Starbucks and bought a nice new machine doh. Ok your right it’s the glory I get it from my grandfather I just have to see how far I can go with almost nothing. If I try enough times maybe I can get something when multiplying by zero. It will probably be a $850 dollar paper weight, if that is the case I will justify the whole thing with everything I’ve learned. I doubt I will be able to stop my self from trying to multiply by zero again though. Besides my wife actually encourages me

[Switcher]

I've noticed, most folks that build their own cnc machine plan on cutting wood.

Sure it's easy to find a huge mill, compared to a router table on places like ebay etc... , can you afford the shipping, shop space?

I'm sure most diy folks don't plop down $5-10 grand all at once, on the routers they build, If they spend that much at all, I'ts drawn out over a long period of time, so it won't hurt the wallet as bad.

It's all about what you plan on doing, with the machine, routers are plentiful, low cost replacement (Home Depot) & the tables are easy to build!


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[wcarrothers1]

Well I believe I did all I could on the cheep side.

Got my round pole gear head mill from Harbor freight for 600, made the conversion plates and such from Home cnc to make it CNC then used it to build my 4x8"

Since I re-used the controll (gecko's) to power both machines now I saved there. also for the money spent on the router table I'm pretty sure I could not have found a used machine that would preform as well (not as many CNC wood sign milling buisnesses going to auction as machine shops..hehe)

That said..

I only just picked up a series 1 v2r3 which hopefully would qualify as "old iron". seems like it's fully functional and cost 1000 at auction. a bargan considering it seems to all work but still have to learn how to use it vs mach which I think is easy (how ever even with mach I wish I knew more as I'm sure I could tune my other machines to work even better)

for 1000 + moving costs I could not have built or converted a standard bridge port and has as nice a machin (I hope)...hehe

Only down side maybe is it's 20+ years old. State of the art in it's day..hehe

b.

[thkoutsidthebox]

If you take your time and build to exacting spec's ( Unlike me! ) then for that $10k at the end you have a new machine, instead of a 20yr old hunk of steel that needs a lot of maintenance and possibly repair. At least thats my story and Im sticking to it!

[RGeo]

I agree with all that you say; Glidergider and Zippy building machines is likely the most rewarding experience I can think of (I don’t have offspring).
Sometimes I get our company in trouble by giving a customer a reasonable quote for a machine, well with in the confines of what a quality, well made machine would cost. Then I go into psyco-mode and pimp the thing out so it looks like a show piece, has to many bells and whistles and we end up making it for cost. My partners freak out and the customer expects this level of workmanship the next time.

I understand industrial strength masochism. My gig is, lets get real. Think of how many more psyco projects you can perform with a beastie piece of iron on your floor, hogging of material, the wind in your hair, the roar of the spindle, chicks falling at you feet because you reek of flood coolant and being covered in the industrial glitter of metal chips. Now were talking.

Not to mention the fact that people are sometimes selling these old NC machines for scrap metal, that is until you ask to take it off their hands, then they want $3000. Think of it like this; viable awesome pieces of industrial antiquity are being melted down and sent to the far east. Let us who would like to have a metal working machine and who are willing and obviously able to deal with the technical problems unite, separately of coarse. And capitalize on the tragedy that is occurring all around us.

Free---dom!!!! (Gratuitous Braveheart reference)

[ger21]

In your original post, you mentioned both mills and routers. It's relatively easy to build a router for much cheaper than you can buy one for. A mill, otoh, is a whole different story. I'll agree with you there that you're much better off buying an old one.

[wcarrothers1]

Yep I agree.. I'd much rather see some one local keep the thing, move it to their basement and do things on the side rather then letting the next guy bid who's job it is to cart that tool to chille or some where in south america to have some one run it for a buck an hour..hehe

That way when we have to start buiding tanks again we will not have to go to south america to do it..hehe

I think a lot of the dificulty is in the tool moving area. Moving heavy objects is both hard to do (for an individual) and expencive to pay for. Assuming you are not moving it to chille where you will make up the moving expence in the first hours pay difference..hehe

Lot of great opertunity for tooling and stuff at auctions, With my machine I got some 20+ ericson chucks, and also ended up with a cabinet full of end mills and taps for ~100 bucks. Not sure what I'm going to do with the taps but pretty sure I will never have to buy another tap for the better half of my life.

b.

b.