CNC router using kee-klamp style clamps?

[octothorp]

First post. I've been lurking here for about a year, though, basking in the obvious brilliance of others. I'm just planning my first CNC router, which I plan to use for woodworking.
When I was in at the bearing shop buying some skate bearings, I noticed they had these cool things called kee-klamps (www.keeklamp.com); great weld-free way to quickly build solid structures out of pipes. And it got into my head that this would be a great way to build the frame of the CNC router. I'm already using gas pipe for the rails, why not build the whole structure out of gas pipe? It should be very sturdy, and it would allow me to build it just with the tools that I have (basically a drill press, a router, and a few smaller tools).
However, the big problem with kee-klamps is that they're really pricey. But I found I could make my own by buying regular pipe fittings, hollowing them out with a bit sized to the pipe diameter, and then drilling small cross-holes, tapping them, and inserting set screws; keeps the price at about $1.50 per fitting rather than around $10 per kee-klamp.
Anyway, before I actually start throwing things together, I wanted to get some feedback from the much more knowledgeable people on here: if I were to try to build an all-pipe CNC router, what problems could I expect to encounter, structurally? Are there problems with using pipe that I wouldn't get in a more conventional build (say, MDF, or square pipe)?

Many thanks!

[project5k]

thats an interesting thought, but it looks to me like all that machine work that your going to do would eat up loads of time, and you'd have to be very precise... making sure that this one is at a true right angle to the others... i say if you got what it takes, then go for it, post lots of pics for us, but i douldnt have the patients that it would take....nor the precision...

[octothorp]

Originally Posted by project5k thats an interesting thought, but it looks to me like all that machine work that your going to do would eat up loads of time, and you'd have to be very precise... making sure that this one is at a true right angle to the others... i say if you got what it takes, then go for it, post lots of pics for us, but i douldnt have the patients that it would take....nor the precision...

Time (moreso than money, knowledge, common-sense) is the one thing I have right now. But I made up a jig where I can machine one T-fitting in about eight minutes, so I could probably do most of the machining that I need in a day. As far as the level of precision, you're right about that being an issue. But I like the idea that I can make little adjustments to it fairly easily.

[project5k]

ahh i see your in the same boat that im in, more time and skills than $$... well then i say go for it... i would love to see that be a new "style" of build

[andy_ck87028]

A couple of comments.

First .... skate bearings are a dime a dozen via ebay ... go Abec 7's dirt cheap.

Second ... good idea with Keeklamp but an absolute key to cnc building is rigidity. I started building with metal; tapped holes and bolts and it was not rigid. I then bought an old arc welder (after much hesitation I must confess) and bingo! I also realised that absolute precision is not essential for much of the build and so providing you can adjust the position of the rails, don't worry about rough welds in the frame.
In summary, use the keeklamp for jointing purposes and a welder to make the joint rigid.

Andy

[wcarrothers1]

Weld free??? Take a moment and thing about what you are saying..

no welding? miss all that fun?

b/

[andy_ck87028]

Too cryptic for me b/

A bit more clarity pls in your comment then I can work out what side of the fence u r on.

Andy

[octothorp]

Maybe I'll have to look at adding welding to the list of things that CNC will force me to learn, then. I can just throw it all together, and then if I'm having problems with the rigidity, weld it at that point.

[project5k]

you can pick up an inexpensive fluxcore mig welder from homedepot for like 300 or so... and mig is by far the easiest welding to learn, its pretty much point and click... ok theres more to it than that, but really thats the basic idea....

[andy_ck87028]

Originally Posted by octothorp Maybe I'll have to look at adding welding to the list of things that CNC will force me to learn, then. I can just throw it all together, and then if I'm having problems with the rigidity, weld it at that point.

Welding .... I'm a convert!!

Great fun ... really easy after a little practice.

I have bought a 30 year old copper cored arc welding jobby which cost me $85. Bomb proof ... designed to outlast me.

The new ones are not designed to last unless you pay big bucks. They are designed to be light now... mine is a heavy b****r ... 38Kg but it stays in the shed.

If u create a bad weld ... angle grinder .... make sure walls are min 3mm otherwise you'll blow holes in the material.

Very safe .... buy a cheap welding mask ... don't hesitate!!!!

I bought mine from ebay.

Andy

[wcarrothers1]

What I meant was welding I think is the method of choice for many of us. Because it's easy, quick and results in a stronger joint (I would say) then bolting and resists movement better then bolting would for most of us..

I will admit that I think at least some of my design will be bolt together. But the main legs and gantry rails on each side are all welded.. the table might end up bolt on between the rail supports just so the machine can be taken down and moved through a door if needed some day..

But then again when I get to the point where I'm building the table I might change my mind after spending time drilling the first few bolt holes...

b.

[project5k]

yea, the under table screw interface on mine will be bolt on, just incase i ever need/want to take the gantry off, but im planning on 3/8 bolts and plenty of them...

and you know its not the drilling part that bothers me, its the tapping, holding the tap straight while trying to start it allways gives me fits...

i have cheated a time or two and gotten away with it by putting a tap in a drill, but i know this is a major no no and yes i have broken a few taps this way...