My CNC Router Build - After some delay, great progress!

Jason Beam

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1,364
Location
Sacramento, CA
Ok so I was in Darren's thread about his CNC router and mentioned that I'm in the midst of building one myself. I'm on day 21 and have a rolling gantry going at this point. I'm waiting for my lead screws to come in before I can continue at this point.

So I'm not 100% sure how to structure this post - so I'm just gonna do one post for each day of progress so you all can kinda follow along. I have been designing it for the last year and started on the thing about 3 months ago. Just getting nights and weekends and a few gaps in the progress just because life gets in the way, yanno.

So here are some overview shots of the design. It was inspired by a Joe's 2006 design using a torsion box for the main table. I picked up some really cool linear bearings that I decided to use and made some pretty significant changes to Joe's original design. It's also mostly out of aluminum from that point on. This is because I have a really great place in town that I can buy aluminum stock by the pound and it's pretty cheap - for $3/lb I'm pretty happy to get just about all the plate, angle and shapes I want. They recently had a load of salvage channel that I snatched up and decided to design my gantry around. That's why all this design stuff for a year...

Anywho ... pics!

base - with bracing.jpgnearly done!.jpgTable Design - aft.jpg

The green rectangle is the total machinable area. I designed it with a 3" overhang past the end of the machine so I can fasten work vertically to it and machine the ends. Fancy dovetails, mortises, etc. I don't know how useful I'll find it, but it wasn't terribly tough to do and I had the extra rail length anyway.

In case any of you are interested in more design stuff, I took a few videos from sketchup and posted them on youtube:

http://www.youtube.com/playlist?action_edit=1&list=PLDA5F6DB18E65F718

They're kinda random without context, but it does show some more detail of certain parts of the machine. Not everything in the videos made it to the final design but they're not too far off.


OK! Next up - the Day 1 Fun :)


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Edit - it dawned on me that I didn't give much in the way of specifics for the machine. The total machining area ON the bed will be about 26" wide by about 56" long. There's a 3" overhang added to that end. The Z axis will have 7-1/2" of travel, with a full 6" of clearance under the gantry's lowest point. The lead screws I ordered are as follows:

Z Axis - 3/4"-6tpi Acme Screws (6 turns per inch)
X and Y Axis - 3/4"-.500" lead 4-start Acme Screws (2 turns per inch)

I haven't chosen my steppers yet because I want to get things together first to see how much torque I'm gonna need for the whole mess. At the moment, the Keling kits are looking promising.

My plan is to also use the machine to build a rotary 4th axis. Sorta like a mini lathe controlled by a stepper.

I'm building this machine to be as rigid as I can muster without breaking the bank. My hope is that I'll be able to machine brass and aluminum with it as well as wood. I plan to use it to make patterns, jigs and rough out guitar parts when it's done. I also figure it can earn a living while i'm not using it as well once I get to learning it all.
 
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Build Day 1

The first day was spent cutting and welding up the base. This base is all made of 1.5" angle iron, 3/16" thick. I wanted 1/8" but my supplier was out and so I went with 3/16 instead.

To spare you the tedium of my cutting and welding, I filmed about 7 hours of video and compressed it into a lot less time. It's kinda silly, but I'm a bit of a ham anyway ...


I really like my metal cutting bandsaw and welder, for sure! I'm very lucky to have all these cool toys. :D
 
Build Day 2

Day two saw pretty much more of the same. This was a fun weekend. Once the steel was welded up, I got to painting it... first, more silly scurrying ...


And a few pics of it in the shop after painting ...

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This ends the first weekend ... Next up, I build the torsion box for the base...
 
Build Day 3

On day 3, the weekend following, I set about cutting up the MDF for the torsion box ... i'll spare you all the massive number of pics I took and show ya the finished product (I have a massive thread on another forum if you're interested in all the gory details, btw).

No silly video this time - mostly because cutting MDF is dusty and boring. So just a couple pics for day 3:

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This was the dry fit - The next day was glue-up day...
 
Build Day 4

So this day was glue-up day. Kinda anxious with so many cross lap joints and two heavy skins to apply ... i took it methodically and did the best I could alone - got a fair mess of glue in a few spots, but nowhere critical. I held it all together with brad nails and will apply a spoil board to the surface when it's all set so I'm not concerned about fasteners...

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At this point, it weighs about 160lbs already - more to come!
 
Build Day 6

On day 6, I attached the outriggers to support the rails on the overhang. The pics don't show it, but there are two steel rods in each joint to keep things pinned together in addition to the large gluing surface and rabbets. It should be plenty strong for my needs...

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Build Days 7, 8 and 9

These three days were finicky days - lots of figuring to get the rails mounted. I didn't like putting #10 bolts through 3" of MDF to try to hold the rails on and a few of the bolt holes lined up over some gusset ribs and some didn't. Shoulda planned that better. Instead, I found some 2x3 aluminum angle that was 1/4" thick without any inner fillet to get in my way. This was perfect - so I spent these three days getting the joinery and all the holes drilled for mounting it ...

Day 7 - cutting and dry fitting everything:
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Day 8 - Gluing, drilling and tapping - lots of tapping ...
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Day 9 - bolting it on for another "Dry" fit ...
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It was here that I ran into something that bothered me ... my "shelf" for the rails wasn't as flat as I would have liked. Out about .020"... not good enough for me .. the next few pics show some of that solution...
 
Build Day 10 & 11

This unevenness was bothersome to me so I glued on a strip of masonite and then flattened the shelf in reference to the top surface as that's the most critical relationship. Using an extended base and a bit of patience, I set about flattening it ...

Weirdly, my day 10 pics only have one ... a "post flattening" shot ... kinda boring ...

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Well day 11, I took the aluminum back off because I found a few more high spots - i needed a more solid fastening at the ends.
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Threaded inserts didn't hold very well at all and they were lifting up. So I turned some aluminum "barrel bolts" out of some aluminum stock - then drilled and tapped them - made some holes and set 'em in.

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That's it for day 11!
 
Build Day 12

Ok - so now things are parallel with the TOP surface .. on day 12, I pulled out a fancy tool to make sure they were parallel with each other ... my buddy's got one of these nifty devices... check it out:

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So i used that to get the sides of the aluminum angle perfectly parallel and then cinched 'em down good ...
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Repeated with the rails on ...
Stock (4).jpg

With a little tweaking and a lot of LocTite, those rails are within .004" of each other over the entire length. VERY parallel :D
 
Build Day 13

Day 13 was "get this thing off my bench so i can start the gantry" day ...

So that's what i did ... I'll spare you the hyjinx that this required to do alone - suffice to say that I didn't injure myself in any way nor did i break anything. A floor jack and a lot of strategically placed levers and rollers got the job done.

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And with my bench clear, i could finally begin the gantry parts!!!

First, the two sides - they're "cross lapped" into each other because the entire weight of the gantry rests on these two points. The angle will hold the bearing blocks and so I wanted this to be both very sturdy and VERY square.

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Build Day 14

Day 14 was some drilling and tapping for the angle ... and then bolting it together ... doesn't look like much, but tapping holes is dang tedious!!

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Day 15 was pretty good - I got the angle drilled to mount the bearing blocks ... then it was time to mount these little guys to the machine so I could measure how long I needed to cut the other cross pieces. We're back with some more video footage since this was pretty cool - sort of a rolling gantry at this point...

 
Build Day 17

On day 17, I cut the gussets for the bottom cross bar. The lead screw nut will fasten to this so it needs to be pretty sturdy, too. Lots of drilling and tapping - and I have the basic frame for the gantry done ...

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And a short video of me cutting those gussets out ... I don't have a good reason why ... just 'cuz
 
Build Day 18

On Day 18, I cut the guide rails to fit the Y axis. The rails I bought were a pair of 6' and a pair of 4' - the 6' i used whole for the X rails, the 4' i am cutting down to make enough for both my Y and Z axes. This steel rod is hardened and wouldn't cut with a hacksaw or my bandsaw so it was time to gingerly hit it with the angle grinder. I went VERY slowly - took about 40 minutes to cut the two pieces. But once they were cut, I could use the metal bandsaw to finish the aluminum stages off...

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Once that was done, I went after the Y rails to get 'em mounted .. We've almost got a Z carriage at this point:

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A little video of some cool moving pieces!

 
Build Day 19

Day 19 was finishing up the Z axis stage - getting it's rails mounted and a platform for mounting the spindle/router/etc.

Lots of aluminum, lots of drilling and tapping again...

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Another video of similar moving parts!

 
Build Day 21

AAAAAAAAAAAAND Finally (bet yer tired of this thread already, huh?) Day 21 comes ...

Finishing up the router mount ... got some more gussets cut and more drilling/tapping. Fun!

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Thanks for following along so far ... when I get the lead screws, I'll post another update :D
 
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