Another freshman - Statesboro, Georgia
 

Gerald & friends, Thank you for the forum. I am at step one of building a MechMate. My name is Rob and I'm in Statesboro Georgia by the way, so HI!
I have fairly good carpentry skills: I just designed my house on Autocad and built it with my own two stick-figure arms. (And a lot of help from Randall: he's out looking for a job so if you need a good carpenter let me know)
So I'm reading the forum. That's step one. I downloaded the plans and printed them out on quality paper (8 1/2"x11" is not A4 but I did not read the post about 11x17 until after I printed it). That's step two. READ the plans: that's step three. Make a cutlist/bill of materials. That's where I've bogged down.
So I'm back in the forum.......my wife is wondering what I've been sitting around all day for. Third day or more just reading! Let's see.. if I had a good first question what would it be? I know, As of this date (May 26th 08) who has a source for steel and laser cut parts? Did any of the buying clubs work out?

She'd better get used to it! There is a lot of studying... :D (At least for me)

So I've been reading
 

And after reading some more I find answers to questions I've asked... or not.
I'll put my head down and study some more. You guys have all covered this ground quite well: it's just scatttered around the forums.

Hi Rob,welcome to the Group.
I’m one of those who has yet built one but been ready (and tweaken to almost perfection) my approach to built it since… well, say over 12mo !:o
In my opinion & most of other here, read, read ...& read again the plans and then, when you’ll have that feeling knowing them as if you drew them, not to many questions should/will remain unanswered !
Only then, take some notes on your printed plans from various threads and next thing you’ll realize, you’ll be readier then ever to tackle the “making of the beast” with not only any hesitation but huge knowledge !
Best of luck & post some pics of your gradual built as this is a big source for others whom are hopping to learn from those !
Amicalement, Robert ;)

Hey Rob,

Just wanted to welcome you and say hello from Social Circle.

Jay W

Rob,
Welcome, you have a really great source for laser cut parts in Alabama. Go to the "laser parts" of the forum and list you needs. I think another run of parts is getting close!

I can't remember the forum members name, but there was a time that 2 other atlanta folks were building machines, i don't know how far they got, but they may be a good local resource if their machines are close to being done.

Good luck....it's fun!

Forum member JBMCLAIN is the source for laser cutting parts in Alabama. The quality is fantastic. That is where mine came from.

Thanks Marc,
It's hard to search the forum when you typing in a 240 x 240 window on your blackberry! Yep...I even keep in touch on the go.
Sean

Sean,
Sounds like you should try upgrading to an EEE PC. A little larger screen and a lot more usable for people on the go. Can run linux or Win XP. Set one up for my dad who is a contractor, he loves it. :)

Yes, that would be great, except it only works as a wifi device. The phone is always connected!
The EEE pc is a great device. I have an associate running windows xp on theirs with great success. The perfect Starbucks machine!.

I will purchase one when the 9" screen model is readily available and my wife approves the purchase!

Steel 300MPa, mild, 25 Rockwell C ...
 

Hi all,
Many many thanks to you all for the info, especially Gerald. I'm not a fan of forums, only this one really strikes me as a great one. you usually have to go through piles of words before you get anywhere, not here:)!

Having said my freshmen foreword, to the business: can I ignore the steel type specification and have it all cut for me from what we call here 'black steel'? They told me some name with '37' and said it was like Rockwell C 25, is it good enough? (they = the laser cutting and bending guys).

Please respond asap, I need to confirm the cutting tomorrow.

Thanks a lot you all!!!

Omri.

That is also what you would call mild steel. st.37 i believe is the technical name for it. st.37 is the most commonly used type of steel, the higher the number the harder the material gets...

Hi kim,

thanks for the clarification. This boils down to the following question:
What if all the parts for the MechMate will be cut and shaped from mild steel??

Surely it take some of the strength off, but will it be ok? should I up the steel thickness by 20%? what should I do? getting to the 300 MPa steel proves to be difficult here. Most cutters don't even bother giving me a quote (they hear 1 set and say 'yeah, well I give you a quote tomorrow' only they didn't specify the tomorrow of which day :P).

What say you guys? all mild steel, what changes are required to thicknesses, if any???

Cheers.

All mild steel is as good as all high-tensile steel. I know it sounds hard to believe, but I will try and explain . . . . . . .

I put 300MPa on the drawings because that is about the lowest strength that laser cutting companies keep in stock. The point is that one does not need a higher strength. What we really want is a high stiffness.

Strength: Our concern is not that the machine will collapse or break - the point at which steel collapses/breaks is its strength. This is measured in MPa. That ST37 steel is rated 370MPa.

Stiffness: This is our big concern! We want the parts to have minimum deformation/flex under loads. The stiffness of steel (Young's Modulus) is 210 Gpa. That is true for nearly all types of steel (and iron). Yes, all steels are equally stiff, even though some of them may be harder and stronger than others.

Remember that most heavy CNC machines are built of cast iron - a weak metal, but as stiff as steel.

So, you can happily build with any old steel you find lying around! :)

Thanks so much Gerald. I was afraid you'll send me on a goose chase for some unknown steel, some holy grail :D.
everyday you learn something new.

Cheers.