Old Man Learning CNC (OMLCNC)

[OMLCNC]

Hi All

Introductions - Reminds me when we had to do it as apprentices and one bloke got up and said "My name is Steve, I like fiddling about with motor bikes and going out with girls but not necessarily in that order."

Anyway my name is Robert I am a professional woodworker, (bit posh actually self employed bloke in a shed, making a living from wood)

Previous life of engineering, MOD apprentice served metal turner, Degree in Mechanical Production Engineering, 20 years in food industry engineering and production management.
Redundancy (Best thing ever) then last 18 years in a shed.

I wish to be educated in the ways of the force (CNC) so that I can build a CNC Router of my own. (I could buy one but what’s the fun in that)

I think I have a grasp of the mechanics of CNC but the electrics/computer side is a mystery to me.

The Forum has been a great help already to me. (Not just the CNC stuff). So I thank you all in advance of helping me with my build.

I have, I think completed the first two rules required to build a cnc machine.
Rule 1 - Spend no money on the project - I'm not a Yorkshireman but apply the same principles.
Rule 2 - Learn Sketchup and produce model of machine for everyone to laugh at.

Before I head over to DIY Router Build Logs to start here are some pictures of things I want to make on my CNC Router. (Really just checking I can up load pictures)
197391974019741

[njhussey]

Hi Robert,

Welcome to the forum, could have sworn I typed a reply to you a couple of days ago but obviously not!! Anyway, have seen the model of your router design, and commented I think, good luck and I'll be following the build with interest. P.S. electrics are a mystery to me too, give me a spanner any day!

[JAZZCNC]

I have, I think completed the first two rules required to build a cnc machine.
Rule 1 - Spend no money on the project - I'm not a Yorkshireman but apply the same principles.
Rule 2 - Learn Sketchup and produce model of machine for everyone to laugh at.

Hi OMLCNC

I am full blown Yorkshire Man and let me tell you that proposed Rule one is the quickest way to waste Money and time. No way to build CNC on the cheap that will be any use. Certainly not one that will work to the standard and produce what your looking to do.

Rule #2 is spot on regards knocking up design but we won't laugh at it. We will of course pull it apart and probably take the piss out of ya at any chance given but we'll never laugh at design.

So OM Crack on get drawing and then we can set you on the road to great machine. But start saving or getting used to idea it can't be done on the cheap.

[OMLCNC]

Hi OMLCNC

But start saving or getting used to idea it can't be done on the cheap.

I'm having a stab at the budget £2.5 to £3.5K. In the right ball park?

[JAZZCNC]

I'm having a stab at the budget £2.5 to £3.5K. In the right ball park?

Spot on.:thumsup:

Posted on your Beever.!!!

[routercnc]

I took the OPs rule one as 'don't spend any money on bits until the design is ready, research done, etc (rather than do it cheaply). Otherwise money wasted on poor choices . . . And no one including Yorkshiremen like to waste it'

Either way no matter, good luck with it. Perfectly possible to build a machine to do what you want. Trick is not to let machine building become the hobby.

[OMLCNC]

I took the OPs rule one as 'don't spend any money on bits until the design is ready, research done, etc ' rather than do it cheaply. Otherwise money wasted on poor choices . . . And no one including Yorkshiremen like to waste it

Either way no matter, good luck with it. Perfectly possible to build a machine to do what you want. Trick is not to let machine building become the hobby.

Yep, that is how It was intended, but nice to have a confirmation on the budget, for "She who must be obeyed"

I'll try not to let it become the hobby, but its all work and shed related - I fully intend to make it pay for itself.

[routercnc]

I see you like to cut dovetails. Have a look through this thread posted by Gerry:

http://www.mycncuk.com/threads/7688-Is-anyone-interested-in-cutting-dovetail-joints

[OMLCNC]

I see you like to cut dovetails. Have a look through this thread posted by Gerry:

http://www.mycncuk.com/threads/7688-Is-anyone-interested-in-cutting-dovetail-joints

Thanks for that, I am way off the software side of things yet, but glad someone has already done the work for me.
On length of work, I did this credenza and nest for someone and put dovetails on the end of the top (8 feet long) by clamping the Leigh dovetail jig onto the workpiece and using the router verticaly.
If you see what I mean?
But dont think a CNC could do that, well I havent alowed for it in my design. I suppose a rotating spindle thru 90 degrees on anther axis would do it.19776

[magicniner]

But dont think a CNC could do that, well I havent alowed for it in my design.

You don't have to -

http://www.tailmaker.net/

- Nick

[Ger21]

You don't have to -

http://www.tailmaker.net/

- Nick

But those aren't "real" dovetails. :friendly_wink:

[OMLCNC]

You don't have to -

http://www.tailmaker.net/

- Nick

Thanks Nick, Looks great I have earmarked the web site and will look at it when I'm getting near completion of the build.
Long way to go before then.

Robert.

[magicniner]

But those aren't "real" dovetails. :friendly_wink:

In the strictest sense possibly not, but you don't need special software for conventional dovetails with a dovetail cutter, just decent CAM ;-)

- Nick

[Neale]

Horses for courses, I guess. Fusion 360 has a very powerful CAM package that knows about dovetail tools, and lets you define your own if there isn't something in the library to match what you have. So F360 could do the job. I might do it that way (my machine is built to take vertical panels at the end of the machine, although couldn't quite manage 8' panels...) if I were just doing a one-off, but I could understand why someone might want a better package optimised for this specific job if they were doing it at all often. I could do V engraving CAM with F360, but it's a whole lot easier with vCarve. At a price, of course. I have tried to use F360 for some relatively complex slot-together tab-and-slot panels but it was hard work, even with a special plug-in, to add dog-bone fillets in the internal corners. I ended up designing the tab-and-slot panels in F360, then writing out the DXF designs, importing into vCarve, and using that for the fillets.

Powerful-but-complex, specialised-but-straightforward? I think you have to try the options and see what works for you. Especially if this is going to be part of a money-making process. A friend who runs a small sign-making business cheerfully bought vCarve; the £400 or so it cost will pay for itself in saved time in just a few jobs compared to "free" software. Gerry's software looks quite good against that. Ho hum - we all have to choose our own ways forward.

The Leigh jig has templates for some really strange-looking "dovetail" interlocking joints. Not sure how many of them are possible with CNC...

[magicniner]

If you have basic CAM and a clue you can generate the required paths for dovetail cutters to cut dovetails, at it's simplest you can tell your CAM that the cutter is the largest OD of the dovetail cutter, use the geometry at the base of the cutouts and fudge it a little to ensure that the Z moves take place off the part.

Taper cuts with taper cutters don't always need 3D CAM that can use the cutter shapes, just someone making intelligent use of the tools available to him,

- Nick

[Ger21]

In the strictest sense possibly not,

In any sense. Real dovetails create a mechanical joint. You can put a dovetail box together without glue.
The joints made with Tailmaker are totally reliant on the glue joint.

The whole purpose of software is to save time. Yes, you can model and CAM any type of joint in any CAD and CAM program.
But if you want to create an infinite variety of joints, then specialized software has huge advantages.

With JointCAM, enter a few numbers and click a button to see what it will look like. In less than ten minutes, you could look at 20 or more different variations. Once you're ready to cut, you click one button.

Also note that the Tailmaker joints are done using 3D carving, with a small ballnose tool, and take a long time. If you have a good, rigid machine, a dovetail joint done in JointCAM takes less than a minute.



The Leigh jig has templates for some really strange-looking "dovetail" interlocking joints. Not sure how many of them are possible with CNC...

All of them, if you want to spend the time to program them.

[magicniner]

Real dovetails create a mechanical joint.

But only in one direction, and you can knock them apart fairly easily, understanding the geometry of the "Half blind Dovetail Joint" would show that this joint is as mechanical in one direction as a conventional dovetail joint ;-)



Also note that the Tailmaker joints are done using 3D carving, with a small ballnose tool.

Erm, that is not correct,
And I quote - "All G-Code is to be executed with a 30-degree engraving or V-bit." ;-)

- Nick

[OMLCNC]

The Leigh jig has templates for some really strange-looking "dovetail" interlocking joints. Not sure how many of them are possible with CNC...

This is true, but they are expensive £564.96, I think (But they were made on a "Precision CNC Machine" in aluminium alloy according to the catalogue), so what could I do with my machine when its built? (Naughty)

No I won't do that I will be designing and programming my own or using someone else programme, its this infinite possibility idea of CNC that I like.

[Ger21]

Erm, that is not correct,
And I quote - "All G-Code is to be executed with a 30-degree engraving or V-bit." ;-)

My mistake, I was thinking of Fingermaker.
But the principle is the same. Lots of passes with a small bit, and no other option.

Bottom line, as with any CAM software, use whatever you like best.

[magicniner]

Lots of passes with a small bit, and no other option.

You can use as big a cutter as you like as it's the angle that matters, watching the video it's not particularly slow or limited to tiny cuts either.
The main feature is all the things it cuts only require the material to be mounted at 15 degrees from horizontal meaning ordinary routers can cut joints on the end of long boards.