Yep...thats the joint I like to use on workshop tables and such. With metal it must be near immovable.
Cant wait to see some more pics....( hint hint..)

SJ

Perhaps the answer is obvious, but just to confirm...to make the 50"x50" we are gonna have to pick up an extra set of the 35mmx1600mm rails and associated bearings and supports, right? I just wanna plan for future expansion.

I believe the idea is to have a feed roller system that moves the stock on the table into the position of the 50x50" working area of the robot. ?

Yes, if you truly need the 4x4 bed.


CNC roller is one possibility, but I've since realized it is simply not necessary if you are willing to move the 4'x8' sheet 4 times to completion.

Manually moving the 4'x8' piece after each area is cut can do everything that a 4'x8' router can do, with a machine that is > 24" Y and > 48" X...the machine ops are simply divided into four separate regions; one for each 2' of a 4x8 sheet. After each region finishes, you can simply move and re-clamp the sheet. As long as you have a "squaring fence" you'll be fine.

So some bad news and some good news. The metal shop called and said the truck didn't bring my 3.5" square. This was ok with me since all night I kept thinking that 3.5" was just too heavy for a 2x4 machine...a 4x4 is better but it's still just huge...I always want to overbuild everything! So I figured it was serendipity that the piece was left off the shipment. Robin and I set to work calculating how we could re-engineer the frame around 2.5" and 2" bracing. It just so happens we lucked out and the guys hadn't cut up our smaller tube yet...

After a few minutes Robin figured out we can do the whole machine with the three 20' "sticks" of the 2.5" square tube we had ordered. This was great news since it cut the cost of the frame by $117, plus it showed us the "sweet spot" for performance and cost. By carefully planning the cut-order of the pieces, nearly all the waste can be eliminated. You can always tell a "sweet-spot" because all the other options right around the same size/performance cost a lot more. Only one arrangement lets all of the puzzle pieces "settle" efficiently. Anyway this is the good news...

The bad news is that all of this shuffling bumped us from the cut-queue for the day, and I can't pick up my pieces 'til tomorrow morning. I think it is for the better though...zzzzzzzz...

Cheers all, until tomorrow!

True, but sometimes it's nice to be able to put your material down and walk away. In my case, it's probably a pipe dream, but I won't be tight on space forever.

Exactly, and for those who have the luxury, you can simply expand RoBLOKS...by adding on to Y, by adding two machines side by side, by adding material carriages or rollers...it's up to your creativity and your wallet. For those on a budget, you can do the same things, but have to pay a little more attention yet not much more for sure! (Most CNC jobs I've run keep you pretty attentive, and then there is the whole "clone-drone" problem in which you become transfixed by the cutting bit, nearly to the point of drooling and wetting yourself...)

Back on topic! My goal for RoBLOKS is to modularize the parts for a "DIY: build it to your need RoBOT". I conceive of the ability for a creative person to "fab-up a bot" depending on their requirement; build the tool, then the work in record time.

Sweet! Got my 2.5" 11g steel tube today. I was able to cancel the 3.5" and I'm glad I did...it would have been way too huge. You just don't have a grasp on materials until you have them in your hand, hehe.

That said, Robin and I re-engineered the cuts based on the premise I put forth yesterday. After making the final cuts in the shop (metal shop makes "rough cuts", you finish), which we cut on the bias, I soon realized that even after all of the materials reduction, the piece was still way way overbuilt. This is all good news (if you aren't me with all my "spare pieces") because the economy of the frame keeps increasing and is actually very economical compared to the original overpriced T-Slot alum...can you believe I've been working on this forever? It is always changing, but this iteration is especially good; it just feels right. The magic combination is square steel, billet alum and Chinese bearings.

Pretty steel:

Click to view attachment

A pic showing the 3.5" 1/2" bolts. Big hardware rules:

Click to view attachment

A 3.5" screw against the 2.5" square:

Click to view attachment

Bias cuts on a Chinese bandsaw. Harbor Freight's blows Northern away...this week at least:

Click to view attachment

A Y-way brace-piece with finished cuts:

Click to view attachment

I took a shot of my hand for a size reference:

Click to view attachment

A cheap DIY "gerbil feeder" oiler on the Shanghai bandsaw (a screw in the tube end):

Click to view attachment

The pieces are stacking up. Each cut took about 10 minutes, enough for Robin and I to pack a couple boxes:

Click to view attachment

An hour later the pieces were drilled for the 1/2" screws. A 9/16 bit was used in my crappy Chinese drill press. If you guys bought more stuff....

Click to view attachment

It pays to take good care when center-punching and drilling the screws. I had a lot of fighting on my hands trying to keep my drill press on center, only because it is cheap cheap cheap. An irony, if this RoGR were done, it'd cut these holes perfectly, faster, without layout, ...... you see the value here.

Click to view attachment

Last zzzzzz:

What do you get when you mix alum shavings, iron oxide and naptha? Robin insists you won't blow up....I disagree:

Click to view attachment

I've said it before but I gotta say it again -

This whole thread is

1) so far over my head its unbelievable

2) Incredibly freakin' cool!!!!!eleventyone!!!!

I love seeeing this progress it makes me feel like I am in some way making progress even though I won't be starting this project for a looong time. Thanks brain!

Cheers!

Cheers!

So how far down do you think we can go? 1.5" tube? Not looking forward to making those corner cuts without a band saw on 2.5" tube.

How else would you cut them?

Without a bandsaw, I'd cut them very poorly I'd imagine.

a hacksaw wouldnt be to bad

Let me try again: I don't know. I have argued against every "size-down". A guess is that you shouldn't go any less that 2" on this span, with 2.5" being perfect. 2.5 seems perfect for all but the bracing, which should go down to 2"; yet the project evolves! Notions of "perfection" are silly retrospectively.

I'm just looking to avoid any unnecessary hacksawing is all.

Aren't we all...good luck!

RoBLOKS will serve this issue. It is cheaper for us to cut/punch than it is for you to buy way-the-hell-up-North-metal. Can you even buy this material there (ON)? I have it figured that I can send you a kit for less than you can source the metal alone. Though I fully support any DIY that you can bring.

There does happen to be a metal SuperMarket here in the city. It looks like I can get the 6061 from them. I have to call them and ask about the square tube (what's the wall thickness on that tube you bought, anyhow?). I'm just waiting until the further along in the design so things get closer to final.

Are you factoring in the shipping cost?

Looking good!

Can't wait to see the next steps... keep on rolllllin...

Question on the new design, why 2' x 4'? You mentioned being able to feed an 4' x 8' sheet through in 2' chunks. This would mean you'd need 6' front and back, plus 2' for the machine, giving 14'. A 4' x 4' machine would only need 12', and a 4' x 8' would obviously only need 8'. What advantages for making it this size? An 8' axis may be too long to make effectively, but if you have one 4' axis, why not make it two and save a couple of feet in work space? Two feet saving might not be a big enough advantage I guess. Just thinking out loud.

I'm liking the new approach though. When I'm ready to build, (if I'm lucky!), maybe you'll have settled on a design.

Brain...motor drivers were NOT part of your intended offerings, correct? I just realized that the driver board I have is only for unipolar motors, so I would have to shop for something that can handle your bipolar motors.

Edit: NM...I see you do plan to offer drivers.

I wouldn't cut that steel by hand with a hack saw for ANYTHING! Any machine shop will have a horizontal band saw (maybe even auto repair shops that do exhaust stuff would have one).

In my opinion: the time spent finding someone that'll cut that metal for $20 will be time well spent. Your arms will thank you.

Baring that, an abrasive saw from harbor freight would probably be worth buying, of course the cut will be rough.



^^ I think driver boards are on the list for the LL store, but I don't think we've got any details yet.

Yeah, I SOOO don't want to have to cut steel with a hacksaw. I don't think I'd do a very good job with my reciprocating saw. I might try and rent a cutoff saw from Home Depot or something if I really must do the cuts myself.

This tool should work " the nuts" as my grandpa used to say. Will cut that metal like butter and leave the metal cool to the touch.

STEELMAX 2802 PORTABLE METAL CUTTING CIRCULAR SAW

Yep. The frame weighs under 150lbs making it comparable to the bearings.


Good observation, but here's why it's not important:

#1: In your scenario above you assume the sheet has to be fed entirely through, but the sheet can be turned around for the last two 2' chunks. It's easy to flip the "job" in software. This makes the footprint for cutting an 8' sheet 10', not 14'. This of course assumes that the cuts (or whatever) need to traverse the long dimension entirely (worst case scenario). If you are cutting cabinet doors, guitar bodies etc, you can simply "part" the sheet as you go.

#2: 2'x4' is a good size for a small shop or home shop. Most materials can be purchased in these sizes readily (RoGR has a 26" x 50" cutting area BTW, since MDF comes in these oddball sizes (50" width) I was sure to leave room). Many many people would never use more than this 2x4 capacity, so it makes sense to offer them a smaller machine. If they did need more though, they have the ability to "feedthrough".

#3: Most important, RoGR is designed modularly. If you need 4x4, just bolt on the same parts used for the X ways. Supported ways are possible for 4x8, plus a few other options which will play out when in invariably get there,

I suppose the bigger size would be for the production guy like BC says a machine that is 2x4 will be very versatile. For most applications. The supported ways for the type of Linear bearings used in this machine become spendy .

The biggest problem I see with moving the work piece is registering it properly.
For instance if you were line boring an eight foot bookshelf for shelf pins. If things get kittywumpass the shelves tilt and kids can have their little fingers smushed when they try and get Daddy's engineering books off the shelves.

This machine has Plenty of room to mill custom guitar hero bodies and what not.,
and because it is flexible you can upgrade later.. Right BC?

If I'm brutally honest with myself, 26"x50" is actually plenty for the majority of jobs I intend to do. It's just fun to think of having a 4'x8' cutting area.

If I had the space, I'd feel pretty much covered with a 4'x4' area tho.

I could see a couple of things that I'd like to do making use of 4' by 4', but for those, the extra space to feed the sheet through shouldn't be a problem

Actually when I was in the shower this morning, (my best thinking time ), I realised that it wasn't a good observation. All designs that would take an 8' sheet in through one 'end' would require 16', (assuming you're feeding the whole thing in and not flipping it, or parting it). You'd need a clear 8' just to get the sheet in, and then feed it until it was all the way in would be another 8', regardless of machine size, (give or take a bit for clearance etc.) I had also considered the parting as you go and the like, I was just trying to think of 'maximum capability, minimum work handling' boundaries.

It was in no way a criticism of your design, I was simply thinking out loud. Clearly the intended use would dictate what size would be most effective, and then any constraints that a particular user might have would make for minor compromises as to what extra effort, if any, would be require to flip the work or part off, etc.

#2 and #3 are most definitely the beauty of your design. You're absolutely right in saying that there's no need to build an 8' machine when most people would only need a 2' machine, especially when that 2' machine can be scaled up if necessary.

I can't wait to see more as you continue to develop this!


This. Exactly.

Hi Dave, I'd appreciate your feedback anytime....I've been wrong as much as right, and I'm not ashamed to say it. I'd rather be "caught" than "wrong" nearly any day! It is work after all, be a shame to waste it!

Alright, I had a big day. Took Kellie-mama to the baby place, they said our little girl Oli (due 5/03/08!!) was in sweet shape. This birth is so much easier for me mentally than Ixa's was; I guess you get better at these things, or at least know what battles are worth fighting.

Speaking of worthy battles...the baby-farm is right down the street from Asheville's "Harbor Freight", which is pretty much Chinese-Crack to me. The old $30 puny, hacked drill press weighed on me embarrassingly..."RoGR deserves better" I told myself stoically

I went about the store with a commitment to disregard price and simply try to find ANY spindle that had no run-out, end play, slop_what_have_you. Amazingly, but like so many things at China-Crack, the biggest and best machines sucked, and the cheapest machines really really sucked. The only drill spindle in the store without play was a mid-sized not-bench-not-floor model. I figured I had found the one machine assembled by some old-school-China-tool grand-master-guru...so I confirmed that the floor sample and mine had the same non-sloppy tolerance..

...and guess what? This is a great drill press! It is a very solid, tight machine for $200: This is the incongruity that perpetuates "China-Crack Syndrome".

Alas, work went faster:

With a real drill press, holes went about 20x faster. Here we started test fitting the joints:

Click to view attachment
Click to view attachment

My world-famous motocross-racing neighbor (Sam) came in for some voluntary free-labor on the new drill press...Cheers Sam!

Click to view attachment

FINALLY...the 3-way intersection realized in giant tube:

Click to view attachment

RoGR taking shape...the pics don't scale well, check the 30' tape measure at the base of the rightmost leg.

Click to view attachment

A pic with Robin for scale...this is the small machine...

Click to view attachment

Ahhh, I feel like I'm rolling downhill now. When I snugged up the interface bolts, the frame snapped itself square and erect. This platform has many things for me; rigidity, expansiveness, open design, ubiquitous materials, ease (relatively)...you can use it for plasma cutting or ice sculpture...plotting or routing. You can unbolt it when you need to move it, or reconfigure when you have a larger need. It is getting quite close to the "vision" of modular robotics I have...I feel good. Cheers all~

Ah clever! Don't be surprised when you're making motorcycle parts gratis...

Geeze...seeing that frame assembly, it really does look overbuilt. Kinda battleship like.

This whole thing has got me seriously dribbling. I want one, but I can't figure out what I need it for! I suppose everything, but the rational part of me (thankfully?) is holding me back. I WILL (must/want) have one one day though!

A cnc robot is one of those things that will most likely generate uses once you have one. There are several simple plans out there that make dabbling in the dark cnc arts possible for just about anyone. One doesn't have to go the big and badass route to get one's feet wet.

Well, the "safety yellow" paint should help with the battleship look.

RoGR is only slightly overbuilt. For this size machine, I would now use 2" bracing with 2.5" uprights. For the 4x4 I'd stick with 2.5". Staying with larger tube is preferable for a bolted-together configuration, since there is more "face" on the tube at the intersections providing more squaring force. Also note the double washer configuration at the "flat side" intersections. This distributes the force of the bolt over the entire face-width of the tube. Bolts this size are capable of >100ft/lbs of tightness. The tighter you can make it, the more rigid the frame becomes. If you used a single small washer on 11ga tube at 100ft/lbs, the tube could distort.

Remember that the whole point of the frame is #1: RIGIDITY and #2: Something to hold up the parts. That order of priorities is required to build a good CNC machine.

Were the corner cuts meant to allow more direct pressure closer to the contact surface?

Looks fan-tastic, nice n beefy. Must say I am a bit envious of your warehouse space. Im looking now for 2000-3000sq ft shop space.
Good luck with the kid #2. I found the second one easier on the psychye. BUt it has all been down hill since I taught them how to read. with remarks like why are you mso mad at me you never had an all A+ average. Or why does Rachel get paid 150 dollars for her grades she got D's and I got all A's. Cause Rachel will work at wallmart and you got the money in your head.
Cheers

I'm aware of the benefits and its relatively easy (if intended) build (my two projectors were), but the money is my concern, and unlike many of the members here I haven't even started my higher education, less gotten a family and my own house to cover with projects. It's mainly the financial issue that stops me.. Also I'm a little bit skeptical about the software part, but figure it will solve itself when/if I build a machine.

I really want one though..

Yeah, of course any project ends up being a financial drain. But when I said simple plan, I was also considering the money side of it too. I've seen builds that were essentially made out of scrap mdf, aluminum angles for rails, skate bearings and standard threaded rod. I couldn't see something like that be very much, certainly less than $100. The HobbyCNC driver board plus some salvaged printer motors can be very effective and functional as proven by Joe's very first build. Call that another hundred or so. Assuming you have a router, rotary tool, or dremmel type tool, add another hundred for the psu and incedentals and I think you have yourself an entry into the hobby. IMHO, anyhow.

But don't mind me. I'm just trying to tempt you over to the dark side.

(Sorry to get off topic)

Astute observation. Since the cross bracing is also bolted vertically at the joint, we don't rely on the "squareness" of the mitered tube where it has been cut. In this scenario it is best to have the bolt tighter than it could/should be if it were crossing two box sections, especially with the end of the tube (risk of distortion, the end of the tube has a very weak cross-section). The nut could simply be installed inside of the tube without cutting the tube, but I like to leave access for a socket wrench. I also like to position the nuts inside of the frame since outside they would "snag" you.


Thanks, Cheers!

I'd say you've started it quite well. To be a "drone" or to live by One's wits?

"We do the things we have to do so we can do the things we want to do."
I heard Denzel Washington say this once. I'm not sure if it was from American Gangster, Man On Fire, The Great Debaters or something he said in an interview.

After a little more research, it turns out that it was Denzel Whitaker and not Denzel Washington - from The Great Debaters.
"We do what we have to do in order to do what we want to do."

Haha, that is genious! Though the dark side has overwhelmed me long ago, thankfully the little that holds me to the light manages my finances, so I'm still in the clear.

My cnc would be the HobbyCNC board and their strongest motors which would bring that to 400$ incl shipping to Norway, then I could make the rails and such myself, but as all other who're still human attracts to shiny, beautiful objects, the LL kit is just too nice, so I would have to use that one. That adds 500$ plus 200$ shipping, so we're in a total of 1100 already.. I'm boned. But my uncle is pretty handy, so perhaps I could lure him with me on it.. "Think of the endless possibilities!"

Sorry for taking this even further off topic. Can't wait to see it coming together further!

(Also visiting the US for three weeks in may, though as I've subconsciously understood LL is not in the vicinity of CA? Edit: No, definitely not.)

Good progress today, but I have no pictures. Most of the day consisted of (packing boxes ) carefully going over the RoGR design; trying to maximize performance while minimizing machine operations and costs. I spent the entire weekend poring over the design; looking for "sweet spots". In conclusion, a few small changes make a worthy difference, but nothing to scream about.

Woo, more progress!

Got the top supports installed and guess what? A Mack truck couldn't knock this thing out of square! Maybe I'm weird (ok ok), but I'm loving this frame. As usual I find things as I go that could be changed for simplicity, but I think we have a real winner here.

Click to view attachment

Click to view attachment

Who the hell is this guy??

Click to view attachment

Is it just me, or is Robin sleeping on the job?

Click to view attachment

Robin sketched out the relative placement of parts one of the 3/4" x 8" x 12" gantry blocks:

Click to view attachment

Rest assured some changes will be made, simply to economize on materials and maximize out the "wasted space". It seems most of these observations can only be made once the thing is going together; looking at drawings just isn't enough. The bed supports (not shown) have been taken down to 2" because 2.5" was too massive for the bed. It's possible the top bracing will move to the outside of the vertical supports to lend more interior room. 2" bracing all around may be possible, but I'm liking the 2.5" as shown above, with 2" for bed. Anyway, I'm looking forward to getting the shipment out today so that I can spend more time with my buddy RoGR.

I think that's the nature of DIY. One of the things I loved the most about my PJs. I seem to recall a newb or two complaining about the old PJ plans saying they weren't specific enough (wiring IIRC - "You didn't tell me exactly where to put these wires"). I always thought that was the best part. Here's the concept, now what can you make of it...

Yeah, one of those joints in each corner would certainly make it rock solid.