View Full Version : First steps, advice needed

01-11-2012, 10:22 PM
So, after years of wanting to build a CNC machine but not actually doing it for one reason or another the wife has convinced me I should get on and actually do it.

My plan is to try and avoid as many of the new builders mistakes as possible so please point out anything that looks like it won't work - I promise to listen and not take offence (I've read enough to know that I know almost nothing).

In the spirit of trying to avoid mistakes how does this sound as a target for my first build:

Budget: 1500 (possible to go a little higher if really necessary)
Size: X=1000 to 1500mm, Y=700mm, Z=100mm
Use: mainly hardwood (oak) but ideally also aluminium if possible. I see myself mostly working on flat items hence only 100mm travel in Z, if necessary that could probably be reduced slightly.
Base Frame: steel box section, bolted together.
Basic Design: gantry style
Runners: fully supported rails - I think

My current building skills lie mainly in woodwork although I have a little experience with metal work and electronics and I'm always ready to learn. My day job is software engineering so I'm happy I can wrap my head around the computer side of things. I can't currently weld but I plan on learning, the frame will currently be bolted together as I'll need to move it in the future (it's complicated). My tooling is, for the most part, woodwork based. I'm planning on buying a bench drill in the near future so I'll be looking to get one that is good enough for light metal work.

Does this sounds like a reasonable target?

Given that I will do all that I reasonably can to produce a quality machine what sort of accuracy could I expect to achieve?

Finally, for now, can anyone recommend components and suppliers for this sort of budget? I've seen linearmotionbearings2008 on eBay and I'm tempted with one of the kits for my first foray into CNC to keep things simple. I'm a bit wary of this option though given the quality of a lot of the stuff that comes from that area of the world.

Thanks in advance for any help.

01-11-2012, 11:35 PM
Welcome to the forum, OK so I.m new to all this myself so any advice will be limited but there are a few things I may be able to help with. Firstly the ebay supplier you mentioned has been recommended by a lot of the members on here, I am wary myself but from what I have read he is one of the better suppliers & well priced as well.
I wouldn't start to order anything yet though as you need to get the design sorted first. Don't worry about missing a certain item on the dreaded auction site as apparently this guy will put together a package to suit your needs at a good price.
First thing I did was to have a read through some of the build logs, you will find you will pick up a lot of infomation & get some good ideas about design.
Best of luck with it, your in the right place if you are happy to learn.

02-11-2012, 11:31 AM
A few thoughts from a fellow newcomer that may help...

Although I have yet to buy most components, there have been that many positive posts about Chai at linearmotionbearings2008 that I will feel more than comfortable dealing with him. As Martin54 mentioned, he will put together a package to suit your needs at a good price, but you need to be clear on your design first... And email him and buy outside of eBay at a better price.

Similarly, Gary at Zapp Automation seems to be the favoured go-to UK supplier, offering great local support, and I will be using him particularly for many of the electronics components.

As a woodworker too, I have chosen to size my machine to have a working area that can handle a quarter sized sheet 1220x610, that could potentially in the future be resized to 1220x1220 or 1220x2440 vertically.

One of the forum gurus recommended to me that the Z-axis have a minimum travel of about 200mm purely to limit the potential for being stymied by longer tool lengths.

There are peeps on the forum who are willing to assist in the machining of bespoke aluminium parts at a reasonable price.

Btw, I wish I had a missus offering to fund my build ;-)

02-11-2012, 11:48 AM
Design First, otherwise you will spend money you don't need to. A very good place to start is go through the build journals here on the forum. Best of luck and ask all the question you want and will help as able.


02-11-2012, 11:56 AM
Thanks for the heads up on Zapp, I've been compiling a list of suppliers and somehow they hadn't found their way on to it.

I was thinking about sizes last night and I realized that my target size was basically a 1/4 sheet (X-axis would probably be closer to 1500 than 1000mm). I'd like to try building a full sheet machine but I don't have that much space, perhaps one day we'll actually build the workshop we've got plans for!

A Z-axis travel of 200mm would be preferable. I dropped the Z-axis travel right down in order to maintain stiffness so that aluminium machining remains an option. Does this make sense?

Edit: I seem to have given the impression that I was just going to rush out and buy stuff. That isn't me at all :-). Everything will be designed in SketchUp first down to the last nut and bolt. I was looking for some supplier advice before getting started with the design so that I know what pieces to draw. With some ringing endorsements of LMB2008 I think I'll probably base my design around pieces I can get from there. I'm planning on going through the build logs again tonight to get some ideas, I've read a few builds so I have a bit of an idea of what I'm looking to build.

Out of interest how long does stuff from LMB2008 normally take to get here? I've got a lot of time off over Christmas and I'd like to get started on this if possible.

Cheers :joyous:

02-11-2012, 12:46 PM
Some people think it's a good idea to start collecting parts as & when they can afford them having a good idea in their head how the machine will be built. If you read through the build logs you will see designs change sometimes quite a lot from the original design which is why people on the forum tell you not to start buying parts until the design is pretty much sorted. It's just something people mention to try & save the poster money on parts that may change so no reflection on yourself.
From what I have read Chai will pretty much supply what you need so don't think you are limited to just what you see on the auction site. If you decide you want a machine 1500mm x 1500mm but can't see a package with the right components at that size he will put it together for you.
If size is important to you but you are limited by floor space then read this thread.

02-11-2012, 01:30 PM
A Z-axis travel of 200mm would be preferable. I dropped the Z-axis travel right down in order to maintain stiffness so that aluminium machining remains an option.

Your thinking is spot on in that having the cutting tool as close as possible to the bottom bearing on the Z-axis gives maximum possible stiffness as would be preferable especially for cutting harder materials, but this can still be achieved in a number of ways whilst still having the potential of longer travel... This includes having an adjustable height bed, or simply using some kind of a "box" to raise the workpiece closer to the cutter. And having the bearing blocks spaced as far apart as is practical naturally improves rigidity.

From other peeps posts I have an idea that delivery from LMB2008 takes 1-2 weeks.

Btw, there are a number of CNC machine components available for Sketchup via links in the following thread - http://www.mycncuk.com/forums/cad-cam-software/3803-google-sketchup-components-3.html