Welding up a CNC machine, can it be done?

[Tommy B]

I am about to build a home-brew CNC machine, and I want to weld it together from various sized steel tubing.

I'd like to hear from the board what kind of experience you've had in this. Since hole spacing, alignment, parallelism is critical to a well functioning machine, and welding on a part has a way of warping it, is this a bad choice?

Let's say the Y-axis is going to be welded upright to a lower horizontal square tube, if there is some twisting due to the welding, will the axis be out of whack?

Any advice would be appreciated. If I have to, I'll resort to tapping and using threaded fasteners to hold everything together.

[DareBee]

Weld it up, stress relieve it, then machine it.
Make it really heavy and in some cases you need to allow for adjustment, then ream and pin during final set-up.

[jalessi]

Tommy B,

There are some builds here on the Zone that are partially welded (IE the table) and then leveled by either precision machining or some sort of epoxy filler.

Welding the columns or uprights without the ability to tram would be a nightmare.

Jeff...

[Tommy B]

Weld it up, stress relieve it, then machine it.
Make it really heavy and in some cases you need to allow for adjustment, then ream and pin during final set-up.

Well, machining it is out of the question, first because I only have Home Depot type tools, and secondly I don't want to pay all the $$$ for machine work.

I guess the answer is "no" then.

[Tommy B]

Tommy B,

There are some builds here on the Zone that are partially welded (IE the table) and then leveled by either precision machining or some sort of epoxy filler.

Welding the columns or uprights without the ability to tram would be a nightmare.

Jeff...

I'm talking about welding the uprights, and clamping everything real tight so that it stays aligned. Precision machining isn't in the cards. All I have (actually will soon buy) is a surface plate, a height gauge and some internal micrometers.

Is this enough? Perhaps by making some strategically placed tack welds proper alignment will be OK.

BTW, can you point me to that epoxy thread?

Also, has anyone done this by using babbit metal?

Any help would be graciously appreciated.

[jalessi]

Tommy,

See the links below for several of the router builds.

My First Router, Built in Steel - CNCzone.com-The Largest Machinist Community on the net!

MadVac CNC - home made 4'x8' cnc precision gantry router

Hope this gives you a little better insight,

Jeff...

[Tommy B]

Tommy,

See the links below for several of the router builds.

My First Router, Built in Steel - CNCzone.com-The Largest Machinist Community on the net!

MadVac CNC - home made 4'x8' cnc precision gantry router

Hope this gives you a little better insight,

Jeff...

Excellent thread and website. This Moglice stuff sounds like it may be for me. So, it's like almost as strong as steel and is pourable? I can see the possibility of oversizing holes for the bearings and then sliding in my ways (only a hardened rod) and letting the rod determine it's correct position.

Anyone have any experience with this metallized epoxy stuff? I see he used it to get nice contact between pieces of hot rolled. Interesting that there is only 15% contact between two pieces of hot rolled.

[lgalla]

Tommy,similar thread here.
http://www.cnczone.com/forums/cnc_wo...uld_use-9.html
Larry