CRP2448 build plan: is it rigid enough or is it just plain overkill?

[kinghong1970]

So i'm putting together plans and sketches of the 2x4 router... and the word "rigid" must have been in my mind throughout.. as now, when i look at it.. .i worry if this is overkill...



so, the color chart is as follows:

Axis Beams
X-Axis Base: 1545 extrusions (d.blue)
Y-Axis Base: 1530 extrusions (l.blue)

Gantry
typical CNCRP gantry (not illustrated... yet)

Cross Members & Legs
y-length cross members: 1530 extrusions (l.blue)
x-length cross members: 1530 extrusions (pink)
4 legs: 1530 extrusions (l.blue)

SUPPORTS
"http://www.amazon.com/80-20-Inc-Series-Support/dp/B006YVZ42S/ref=sr_1_1?s=industrial&ie=UTF8&qid=1331859288&sr=1-1"]#2535 15 series 45 deg 12" support (lime)

BRACKETS
"http://www.amazon.com/80-20-Series-8-HOLE-INSIDE/dp/B001IA4PP2/ref=sr_1_1?s=industrial&ie=UTF8&qid=1331858991&sr=1-1"]#4338 15 series 8 hole inside gusset corner bracket x8 (at each corner only)
"http://www.amazon.com/80-20-8-HOLE-INSIDE-BRACKET/dp/B001IA2MD4"]#4304 15 series 8 hole inside corner bracket (at each mid area cross member)

now, the 4304 red brackets, i did find a very good deal for some mis-drilled lot... so it's done... but wondering, can i actually get by with just 1515 instead of 1530 on the lower horizontal cross members of the build?

do you see anywhere else that needs supporting?

i was also considering using 4301 under the legs to hold them in place... overkill?

thanks in advance

Al

[lgalla]

Al there is no such word as "overkill"when designing a CNC machine.
Larry

[kinghong1970]

Al there is no such word as "overkill"when designing a CNC machine.
Larry

Larry... i like your style

/opens 80/20 catalog...

[louieatienza]

I don't think you could build a machine 'ridgid' enough! The only limiting factors are you budget, means, and needs.

[kinghong1970]

ok, so let me ask the better question...

where can i trim the fat?

i would like to put some plates on the outer corners of the x-axis with the legs and seems i'm too dense in the inner brackets...

thoughts?

if it were you, what would you add?

[CarveOne]

Mounting your rails to a large chunk of tombstone granite is just about rigid enough for the frame, but the rails and gantry can, and will, flex.

CarveOne

[kinghong1970]

should i add another vertical support mid way along the X-Axis? between the blue and pink?
and from pink to the floor?

i think putting granite slab is out of the question for me.. lol?

[lgalla]

Al here is an example of overkill...One of the zone members did beam deflection calcs for me with Beam boy.Picture a 4"x12" 1/4" beam,gantry 100lbs centre load
The deflection was .0001.If a fly landed on the centre of the beam the deflection would be....0000000000000000000004563 Over kill?possibly
I did a trade show for a Japan company and they were showing their mini mill,the smallest they produce.50HP spindle.40,000lbs 5" ballscrews,,30 tool changes.The base to floor had hundreds of brackets and bolts to fine tune the mount.Overkill?Yes

[kinghong1970]

thanks Larry... i think i saw a mill similar to that you mention when i was at Tokyo... a nifty lil store called Tokyu Hans... love it... had the smallest mill and lathe i've seen.

i guess i can get the parts, build it up and then make a decision.

[louieatienza]

Al here is an example of overkill...One of the zone members did beam deflection calcs for me with Beam boy.Picture a 4"x12" 1/4" beam,gantry 100lbs centre load
The deflection was .0001.If a fly landed on the centre of the beam the deflection would be....0000000000000000000004563 Over kill?possibly
I did a trade show for a Japan company and they were showing their mini mill,the smallest they produce.50HP spindle.40,000lbs 5" ballscrews,,30 tool changes.The base to floor had hundreds of brackets and bolts to fine tune the mount.Overkill?Yes

I want one!

[harryn]

I am not sure if it makes sense or not, but my own plan is to more or less take a box like that, and build the router inside of it, rather than on top. That way you get:
- An enclosure
- solid bracing
- close to the floor for minimum shake

And - the top can be a work bench.

[louieatienza]

thanks Larry... i think i saw a mill similar to that you mention when i was at Tokyo... a nifty lil store called Tokyu Hans... love it... had the smallest mill and lathe i've seen.

i guess i can get the parts, build it up and then make a decision.

I guess the real question before you ask if it's overkill, is what are you cutting? If it's balsa and foam, the answer may be yes. It may be no. If you were cutting stainless steel, probably not. I guess overkill is relative.

On my latest build, I'm using 5050 for the table rails, 50100 for the table ends and gantry uprights, and 100200 for the gantry beam, with a 3/4" cast aluminum plate for the table. For cutting balsa, maybe overkill. For aluminum, it's probably adequate. For steel, I'm not too sure. And this is a 2x2 cutting area...