CNC Joinery (woodworking)

[FelixPQ]

Hi,
I'm seriously considering building myself a CNC router but the design I've seen so far seem to be focused mostly on flat material.

As of a few days ago I was thinking buying a mortice and tenon machine and most likely a dovetail jig as well but as you know these cost quite a bit and they take up space and can't do much else. Then I saw the woodrat machine and it seem more versatile at least but still pricy and then I thought the only thing missing on this machine is step motors and then it would be something super. After thinking this through for a while and doing a bit of research I came accross this site via www.cncrouterparts.com. His link page directed me to quite impressive machines.

Now I'm thinking of building a CNC machine that could do most if not all a woodworker would need on all 6 faces of a piece of wood, all this in an accurate and repeatable fashion.

In my shop I have the advantage of having a pit that would allow me to work on vertical piece of wood of up to 12' long but I wonder if having a flexible router mount such that I could setup the router either horizontally or vertically would be a better option in the long run.

I just finish a project where I would have loved being able to do a sliding dovetail at a 22.5 degree angle on the edge of a piece of about 30" long.

This is the piece I'm talking about. From what I understang of CNC I'm sure it would have taken me less time to write the g-code manually then it took me to build the back of this piece and all this without using a single nail.

If you need more photos or drawings of what I'd like to do with a CNC router, I'll be glad to post them for you but at this time I would be satisfied to have suggestion(s) to work on both edges and ends of pieces of wood. With a standard 3 or 4 axis machine I'm sure I could figure out how to work on the faces but I'm still open to suggestions.

Thanks,
FelixPQ

[Realmseeker]

I've seen 1-2 members of these forums post about doing dovetails,

Splam set his up to do that type of work on a modified Joe 2006:
Vbearings and Ply

And I think BobF did too,
I lost a link to his build log,

I am not sure how theirs ended up working out,
but I am sure both will chime in here soon,
and give much better info and ideas then I can,

GL!! I'm a cabinetmaker by trade,
and anything that saves me having to reset tablesaws with dado sets and breaking out jigs and router tables is a big win!

Jordan

[Regnar]

If your just looking to do dovetails you could try this http://www.woodworkerswholesale.com/...s.asp?Cat=1240

no need for special setups, although not completely the real thing either

[FelixPQ]

Thanks for the post you guys,

before I build a CNC router I want to think it through and figure out what "things" I'll be able to do with it and of course is it worth it. In fact it's the other way around, now I spent most of my time moving wood over blades and bits and for each cut (almost) I need to do some setup work on one or more machine to get the pieces of wood the way I want. It would be nice to draw the piece like I want it to be, place a raw (almost) piece of wood in the machine, push the start button and watch it make the cuts to bring the piece like the drawing I made.

I consider that a CNC router as the potential to replace advantagously many if not all the tools and jigs I have now and even those that I would eventually buy to simplify my life as a woodworker.

Considering I'll need a bandsaw sooner or later, a Leigh FMT (tenon and mortice jig), a good dovetail jig most likely a Leigh as well and I'll need to replace or modify my router table and replace my tablesaw as well. I'm inclined to believe that a well designed CNC router could do most if not all the work I do with these various tools. If it is actually the case then I think it is worth the investment of both time and money.

For now I have to go but I'll be back.

Thanks,
Félix

[BobF]

Most, if not all of the machines people have built here are 3 axis machines. They have a flat table on which to clamp parts and the router can move in 3 planes. You can cut out pieces that are not too thick and can make 2.5 d cuts.
You cannot cut edge in a dovetail fashion, unless you can find a way to stand the wood on its edge.
I considered adding a way to clamp boards up to about 12 inches wide standing on end, but have never completed my idea. I would be limited to lengths the height of my table, since I have no pit in the shop to extend the end into.
With that said don't let me discourage you. There are a lot of things you can do that are easier than other methods, and some you may not consider doing otherwise. I cut out the headboard for the bed I am building. I probably could have cut it on the bandsaw, but it would have been much more difficult, and required a lot more sanding. I also cut all the mortises in the legs for the rails and the large countersink holes for the bedbolts on the opposite side, and the slots in the rails to hold the nuts. I am considering a carving in the headboard if I can find something the wife likes.
I have done some V-carving.
Its fairly easy to cut curves and large holes that would require carefull use of a handheld jigsaw. You can cut all sorts of pockets you probably wouldn't even consider otherwise. You can drill multiple holes in all manner of arrays and patterns that would drive you nuts at the drill press.
It will take your woodworking in a new direction.
Here is my build log.
Another Joe in GA
Also look at the Vectrc forum. Look at some of the galleries.
http://www.vectric.com/forum/
In the last few weeks I have been cutting pearl for a friend who makes guitars. I am using a 1/32" bit and cutting out letters not much larger than
this
They are a script font, which I cannot illustrate here.
Hope all of this is helpful. Ask more questions. Rant off.

[ger21]

There's some info on ShopBots site about building a dovetail "jig" into a Shopbot.

http://www.talkshopbot.com/forum/mes...164/28434.html

More info here. Scroll down a bit.
http://www.shopbottools.com/garysmusings.htm

[FelixPQ]

Thanks you guys, great links and ideas you've given me here.

I think I got it, at least the part for putting the work vertically. Say I build my machine with a 4' x 4' work area or whatever I could simply reserve say a foot or so for a panel that could be set at any angle downward. I even begun to think of ways to setup piece at compound angles and how to setup multiple pieces at the same time to do box joint for exemple. Since I would make this panel as large as possible, 4' for exemple in this case this would allow me to make my (angle) sliding dovetails on piece up to 4' long.

If the work table is 4' to 5' from the floor this would allow me or anyone else to do tenons, dovetails or whatever on most pieces I will need without using the pit.

When I say 4' x 4' I'm also thinking of panels and of course half sheet of mdf, plywood or whatever.

Without going through the details of howto's at this time, I think this relatively simple idea would allow me to work on all 6 sides of a piece of wood with acceptable limitation on the size of workable pieces. By the way I also thought of being able to setup the table at varying height under the router such that I can setup board(s) on there edge also.

Tell me what you think on these ideas, can it work, is it practical?

One thing one of you said got my attention, about this 2.5D thing, does this mean the moves or toolpaths I can program are limited to 2 axis at a time instead of something like goto (x,y,z), I could only say goto (x,y) at some z value setup before?

My experience tells me don't waste time and money trying to build electronics controls ourself even if you think you can, I'll follow my own advice (to myself), I'll go with professionally build stuff and it will simplify my life greatly I'm sure.

At this time, I would be happy if I could use the CNC router to make mostly joinery, panels like this,

"complicated" moldings and things like the curved part on the bottom of this piece.

I'm sure I'll find many other uses as time go by but I would be happy still if it could do only what I mentioned.

Following on the principle behind the advice I gave myself for the electronics I'd be looking for plans of a proven design I could build with the confidence it will work fine when I turn the power on. So I'd be more then happy to read your suggestion(s) on this as well. Before you ask, the reason I don't buy one already build is they cost to much for the work area I'd like. One last thing for today, I haven't ruled out a non metal construction at this time.

Many thanks again for the links and advice you already given me.

Regards,
Félix

[tajord]

At this time, I would be happy if I could use the CNC router to make mostly joinery, panels like this,

"complicated" moldings and things like the curved part on the bottom of this piece.

This is one of the major things i do with my cnc, cut the simple things by tablesaw/hand, more intricate stuff i leave these to the router, saves "alot" of time and can tackle things that would normally be difficult or impossible to do otherwise, i don't have a bandsaw, but my jigsaw has almost become obsolete.

My advice, a 2' x 4' would be great but try to shoot for a 4' x 4' machine if you can.

[BobF]

Sorry if I confused you. 2.5D is the term commonly used. I suppose you could call it 3D as all 3 axis move at the same time. You can cut 3D items like these.
http://www.vectorart3d.com/
I have cut the free fleur-di-les on my machine.
I think this is called 2.5D because you can't cut all 3D items. In the example above you can't cut the back of the piece. You would need more than a 3 axis machine to get full 3D hence the term 2.5D.

[Arquibaldo]

in post #5, BobF said:
"You cannot cut edge in a dovetail fashion, unless you can find a way to stand the wood on its edge"

This limitation has always bugged me: why can't you route the edge of a board with a standard
3-axes moving-gantry machine?

I think it might be feasible to build a contraption to overcome this limitation: Why not have
a second tool-mount which holds the router with its axis parallel to the x-y plane, and perpendicular
to the gantry axis? Assuming that the machine has the x-y plane free of obstructions (ie: the screw
that moves the gantry isn't in the middle of the machine), then the board could be mounted in a position
that enables the tools to route the edge, although still horizontal.

Of course, this second tool-mount would be used only for these operations and one would still be able
to replace it with the standard tool mount, which holds the tool perpendicular to the x-y plane.

Could you follow this argument? Do you think such a contraption is feasible?

Nelson

[CarveOne]

in post #5, BobF said:
"You cannot cut edge in a dovetail fashion, unless you can find a way to stand the wood on its edge"

This limitation has always bugged me: why can't you route the edge of a board with a standard
3-axes moving-gantry machine?

I think it might be feasible to build a contraption to overcome this limitation: Why not have
a second tool-mount which holds the router with its axis parallel to the x-y plane, and perpendicular
to the gantry axis? Assuming that the machine has the x-y plane free of obstructions (ie: the screw
that moves the gantry isn't in the middle of the machine), then the board could be mounted in a position
that enables the tools to route the edge, although still horizontal.

Of course, this second tool-mount would be used only for these operations and one would still be able
to replace it with the standard tool mount, which holds the tool perpendicular to the x-y plane.

Could you follow this argument? Do you think such a contraption is feasible?

Nelson

I think it is perfectly feasible to do this by just elevating the work piece above the table enough to reach the proper height for the cutter position. You would need the work piece support to be reliably parallel to the cutter path or the dovetail groove will not stay centered vertically on the edge of the board being cut and/or it will be deeper at one end than the other end.

If you make your removable fixture to attach to your table in a fixed position you can use your machine to plane these surfaces to match your x/y/z paths.

CarveOne

[rrdiaz30]

Take a look at this design for a little inspiration:

New machine by the new guy!

...and this:

Dovetails and box joints with CNC


Rick