# CNC kits

#### BobW

##### Active Member
Lately I've been thinking of taking the plunge and buying a CNC kit. Banggood has a bunch of fairly inexpensive ones.
Has anyone here had any experience with these?

#### Mickster

##### Well-Known Member
Has anyone here had any experience with these?
With those? No, but I have had some experience with DIY CNC in the past.
Are you dipping your toe in the water, or do you have some specific project in mind, and what material do you intend to machine?
To start off with small projects in plastics and wood, taking light cuts, those machines might be ok, but the spindle motors will probably be quite noisy and runout on the cutting tools could be a problem due to the tool holders they use. A machine with a brushless spindle and ER11 collets would be my starting point.
The prices for a complete entry-level kit are quite attractive though, you'd spend a lot more buying the individual components.......ask me how I know .
I have enough rails/bearing blocks, ballscrews, steppers/drives to build 2 machines, just need to get into gear and start building.

#### Pommie

##### Well-Known Member
No experience but the laser engravers worry me. If that laser happens to fall on a shiny piece of metal it could be reflected into your eye at which point you can say goodbye to your eyesight. What are the regulations for useing a 2.5W unshielded laser?

Mike.

#### Mickster

##### Well-Known Member
Good point Mike......we would be wearing safety glasses, but the wife/kids/friend coming in the room would not.
An enclosure would be best.
Regarding the glasses, a quote from CNCzone sticks in my mind:
Buy the best pair you can afford, they may be all that is in between you and a lifetime of darkness if you make a mistake.

#### BobW

##### Active Member
I don't expect to do anything heavy duty. Mostly cutting out holes in small panels for electronic enclosures. So, aluminum and wood.

Laser etching would be handy too. Yes, I'd definitely get the goggles. Banggood sells them too, but I'd probably get a pair from a more trustworthy source, or just leave the room when it running.

#### Mickster

##### Well-Known Member
Machining aluminium on those small machines might be a push, IMO.

#### gophert

##### Well-Known Member
For IR lasers, we found the best option for safety is a metal housing with a camera inside the box to monitor progress.

Dark tinted acrylic or polycarbonate sheets are surprisingly transparent to IR. The tint only covers the visible wavelengths and allows more than 85% of IR energy to pass.

Dyes that absorb in the 800 - 1200nm range are expensive and not used unless near-IR management is required for the specific application. Expensive as in making the polycarbonate resin 10x more costly for heavy tints.

#### BobW

##### Active Member
Thanks. I'll check it out.

Machining aluminium on those small machines might be a push, IMO.
It would be fairly thin sheet aluminum, but I'll do some research and see what they're capable of before I buy anything. Hopefully, whatever I buy, it will be something that is reasonably easy to upgrade if necessary.

#### Mickster

##### Well-Known Member
Spindles/steppers/screws are reasonably easy to upgrade, but the components which provide mass and rigidity are less so.
Not saying don't buy one of the Banggood machines, I may just get one myself at some point in the future, just be aware of the potential limitations of what can be reliably machined on them.

#### Nigel Goodwin

##### Super Moderator
Thanks. I'll check it out.

It would be fairly thin sheet aluminum, but I'll do some research and see what they're capable of before I buy anything. Hopefully, whatever I buy, it will be something that is reasonably easy to upgrade if necessary.
They specifically say not to, plastic and wood are about all that's recommended - and 'fairly' thin obviously means NOT thin

I've got a Banggood type one, but other than testing it I've not had time to play with it yet - too many new toys (including three 3D printers and a vinyl cutter), too much to do!. While it would be 'nice' if it could do aluminium boxes, the intention it to use it on plastic boxes for cutting holes for displays etc.

As for the laser engravers, they all come with suitable goggles, and plenty of warnings about possible eye damage - a much larger risk appears to be laser pointers, many of which provide illegally high powers, and are freely given to children.

I've been considering buying a 'cheap' milling machine, and adding a few stepper motors to it, it could be controlled by the same Arduino board and software as the Banggood types.

We do have some machining done at a local CNC place, and it's pretty pricey, but it's often using stainless steel which doesn't help.

#### BobW

##### Active Member
I could get by without aluminum. Plastic would be okay. I'm surprised that aluminum would be a problem though. It should just be a matter of having the correct cutting bit and slow enough feed rate.

Getting a cheap milling machine is not a bad idea. I'd been considering that too. I see that a local supplier has one listed for about $1000 Cdn, but they have an annual 1/2 price sale coming up soon. #### Nigel Goodwin ##### Super Moderator Most Helpful Member I could get by without aluminum. Plastic would be okay. I'm surprised that aluminum would be a problem though. It should just be a matter of having the correct cutting bit and slow enough feed rate. The main issue is rigidity, and 'possibly' you could do something with very slow and shallow cutting. There are a few people on-line who claim to manage to cut aluminium OK. Getting a cheap milling machine is not a bad idea. I'd been considering that too. I see that a local supplier has one listed for about$1000 Cdn, but they have an annual 1/2 price sale coming up soon.
I've been thinking of it for a good while now

Must admit I've never used a milling machine, or a metal lathe - I went to a Grammar school, and we only did woodwork - the lads who went to the Secondary Modern school did metalwork as well. Basically the better school had better teachers and a better education, but the poorer school had better facilities, more funding, and poorer teachers.

I did build a cross bow in woodwork, making the trigger mechanism from a piece of 1/4 inch steel plate with a junior hacksaw, and a friend of mine took the trigger to the Secondary Modern school and case hardened it for me.

#### BobW

##### Active Member
I have one of those Chinese mini metal lathes, and have been very happy with it. It was another one of those 1/2 price sale purchases.

I used a milling machine for a brief period many years ago when I had access to a machine shop. Later, I bought a cheap machinist's vise with X&Y lead screws, and used that with a drill press as a crude milling machine. It didn't have a lot of travel, but it was okay for milling small work pieces.

I'm not a machinist by any means, but as with most things, if you use common sense, and go slowly and carefully, things generally turn out well. I still have all of my fingers.

#### Nigel Goodwin

##### Super Moderator
I still have all of my fingers.
Which is always a bonus

It's amazing how many people you see with missing fingers - I took the ends of my right fingers with an electric plane, but they grew back - not got 100% feeling in them, but far better than I expected.

#### BobW

##### Active Member
I think power woodworking tools are the most dangerous. I'm terrified of my table saw.

#### Nigel Goodwin

##### Super Moderator
I think power woodworking tools are the most dangerous. I'm terrified of my table saw.
An old friend of mine has a few missing digits from a table saw, he did working in a furniture factory in Jersey.

#### BobW

##### Active Member
Nigel, Which model CNC machine did you get?

#### shortbus=

##### Well-Known Member
As a life long retired die maker machinist, I can see no need to buy a CNC. Un less your going to make many of what you want to make. One or two or even ten of one thing can be done faster with a old time standard non CNC machine, be it mill or lathe. In my years of machine work things went from manual machines to today's state of the art CNC. The younger guys that I worked with all seemed to think CNC was needed to do something, but given the same part to make and just making one part each, I could make mine manually to the same accuracy as their CNC part, in half or less time.

If your making things is just to say you did, and you want to know or learn to do the CAD part of things that's great. But know that you still need to know what a machine is capable of doing and how to do it. And that in the end, means you need to understand manual machining first, to know what a machine is capable of doing or how to do it. And that isn't in any CAD script I ever saw them using at work. Without that knowledge it just lets you screw parts or the machine up faster.