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  #1  
Old Tue 08 January 2008, 18:03
cobra427mnsi
Just call me: Paul
 
Leamington, Ontario
Canada
Welding commenced - Leamington, Ontario, CA

I guess it's time to start a personal page. First, I would like to introduce myself. My name is Paul and I live in the southern most part of Canada ( same parallel as Northern California). In fact, this is one of a very few places in Canada where you have to go north to get to the USA. As of June 2007, I am a retire high school wood shop teacher.
I have posted several times already in other threads. There are so many very helpful people on the sight. I'm getting excited about reading of others who are just beginning their build. So far, I have taken the DXF files to 4 laser cutters and one water-jet cutter for prices. At this point, I have only received one estimate back. I will post all the price quotes after I get them all back.

I hope this post won't be too long but, in it, I would like to include the results of the research that I have gleaned from reading :

Bill of Materials Dec26, 2007 (not confirmed yet)

-Stepper Motor - Oriental - PK296A2A-SG7.2 geared motor (other options PK299-01 AA 7.2:1, MotionKing 34HS980))

-G203V Gecko Driver (resistor needed for for 203v two right most terminals- see pic "resistor placement on geko"- (for a PK296A2A-SG7.2 motor, the resistor to use is 19k ohms 1/4 watt)

-Breakout Board - PMDX-122 (other option ncPod) (ask pmdx which solid state relay "SSR" does the 122 drive directly) the "bob" gets its ground from the parallel port from computer. Do not connect "bob" ground (also the home and limitswitch) to power supply ground which includes metal enclosure, AC source, frame, gantry, etc.

-Power Supply - Antek PS-6N56R5R12 (600W, 56 VDC, 5VDC, 12VDC) - according to "Richards" the motors must be wired "bipolar series" with this power supply ( this gives more low end torque and less high end speed

-Power "Box” - FactoryMation - NEMA 4Enviroline Junction Box # SCE-20168ELJ $113.00 Sub Panel SCE-20P16J $23.00 " other suppliers: McMaster Carr, Standard Electric, Hoffman,Weigman,Saginaw: see below "gas springs" additional info - nema 4/12 enclosure w/ full hinge & back plate.

-contactor ??? Teco cn16 (resistance between A1 and A2 is 139 0hms) (not sure what this does yet !!) (edit Jan 06/08) I think a "contactor" is the South African for relay (need SSR to turn router off and on: some other brands of SSRs are Opto-22 and Potter-Brumfield)

-shielded cable by Helukabel

-V bearings and eccentrics -from Rick @ superior bearing in Ohio ( mention mechmate when ordering) The Vee rollers are size 3. (Haven't decided wether to buy or grind rails)

-connectors for wires to motors etc called NEMA Hubbell twist locks (McMaster has Leviton and Eagle brands)another connector is called Amphenol modular backshell and crimp pin, NEMA l series twist locks,Amp crimp pin, XLR, Molex twist connectio type, Phoenix 4 and 5 pin, Nuetrik, (do not buy Wegman connectors)

-"For Gears & Racks in the USA, look to Boston Gear 0.5" square rack, (0.5" gear face width), 20 pitch, about 20 (edit Dec 2007-30 tooth for geared motors) tooth pinion, 20 degree pressure angle <-- the three 20's are coincidental, they mean different things- Canadian distributor (

"-pinion (spur) gear pitch=20 pressure angle=20 (Gerald D. recommends -Mech builders with 7.2 geared motors-a 30 tooth gear )- McMaster-Carr part no. 5172T14 page 1013

"-rack from WWW.STDSTEEL.com #BF200011 (talk to Tim)Best place I've found rack in the US. About a third the cost of others http://www.stdsteel.com/gear.htm"

-gas lifts for Z slide (new drawings based on the 9416K2) at www.Mcmaster.com (using a router order the 15lb option)(with a spindle use the 20lb option)



I guess this post is long enough for now.




Paul

Last edited by cobra427mnsi; Tue 08 January 2008 at 18:07..
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  #2  
Old Tue 08 January 2008, 18:14
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Excellent post and good luck with your build.
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  #3  
Old Tue 08 January 2008, 23:48
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Gee Paul, for a teacher, you sure did a lot of homework! Good job!

Suggest you add quantities to your list.

Where is the fan for the box? (not discussed much, to my slight surprise)

I think "contactor" is also common in America - it is a rugged form of relay that has longer life, mounts direct to a DIN-rail, and has integrated screw terminals for all the connections.
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  #4  
Old Tue 08 January 2008, 23:52
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Oh, talking of teachers, why don't school metal shops tackle the MM as a school/parent project? I think the expertise needed is within a school metal shop's capability. It would give me immense satisfaction to find a bunch of kids building a MM......heck, I would even give them the plans for free!
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  #5  
Old Thu 10 January 2008, 07:48
GregA
Just call me: Greg
 
Dundee MI
United States of America
I think the time/experience requirements for a MechMate might limit the possibilities in a typical shop class. On the other hand at a Vocational school, where they will have a welding department, electrician's department, and an IT department it would be a great fit for a class project.

Also, with some of this stuff, it is easy to forget how much mastry has been developed over the years. My machinist for example looks at me in awe over making the computer and electrical bits work, and I feel about the same way with his ability to start with some scrap wood and end up with a working model-t engine. At the same time, the welder does these stunt welds without thinking about it, and he never has little holes to fill(but he is a pressure tank and boiler welder, so little holes are out of the question in his profession)... At the same time, put that guy in front of a computer and he gets excited when e-mail works.

Also, in Michigan at least, all the kids are college bound now days, and they don't do things like shop class anymore. For that you go to community college...
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  #6  
Old Mon 28 January 2008, 21:27
cobra427mnsi
Just call me: Paul
 
Leamington, Ontario
Canada
Gerald, I know that you recommend the "kitchen project" to be the first step in the built. I will get to it shortly, however, the electronic part of it is a little intimidating and I still have to wrap my mind around it. The building of stuff (getting my hands dirty)is the part that I enjoy the most, so I have started the table. I picked up the steel for a 50" X 100" square tube table the other day (cost $1198.00 including taxes). I have opted to build a bolted together table. I would like to be able to disassemble it, if it needs to be moved. Moving a 850 lb table in one piece would be difficult.
I am using a mig flux core welder. I haven't welded much in 30 years so I am a little rusty. The welds aren't pretty but I am sure that they are sound. Any welds I didn't like I ground off and did over. I found a mini grinder with a twisted wire wheel will take off most of the splatter then a chisel gets the rest. I will try to post several pics of what I have done so far. More pics to follow as I progress.

Paul
Attached Images
File Type: jpg table1.jpg (50.3 KB, 648 views)
File Type: jpg table2.jpg (51.8 KB, 649 views)
File Type: jpg table3.jpg (36.1 KB, 647 views)
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  #7  
Old Mon 28 January 2008, 23:00
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Paul,

Looking good !! Your welding looks much better than mine.

I like the rectangular tubing construction. Hmmmm, where have I seen that before.

Don't be intimidated with the "kitchen project". There is so much help here, that even I did it.

Have fun guy !
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  #8  
Old Tue 29 January 2008, 00:13
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
You could use half that number of welds and it will still be strong enough. But half the distortion.
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  #9  
Old Tue 29 January 2008, 08:00
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Gerald,
How much of the joint for the table parts should be welded for max strength vs too much distortion? I remember seeing diagrams on where and how much to weld on the y car and z assembly but not on the table parts. I probably would have welded the seams fully on all the table joints to make it stronger. Also should we space the timing of the welds to minimize heat distortion like you would have to do for thinner applications?

Last edited by domino11; Tue 29 January 2008 at 08:02..
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  #10  
Old Tue 29 January 2008, 09:23
cobra427mnsi
Just call me: Paul
 
Leamington, Ontario
Canada
Greg, thanks for the encouragement. I'm sure with the help and info from this forum the kitchen project is within my capabilities. I just need to make that plunge by ordering the motors etc.

Gerald, thanks for the advice. I had forgotten about heat distortion. I promise when welding the y axis car I will weld only those spots recommended. I think I went overboard on the table steel. All square tubing is 1/4" wall thickness including the 2x2 braces. This thing is going to be heavy. Will there be as much distortion on the thick walled tubing as opposed to say 1/8" thick walls ? If I weld just the sides if the joint between the legs and the longitudinals, will it look complete? How would you weld a joint like that ? I would like to learn as much as I can. I am having a great time building this machine. Thanks, Gerald for the plans and inspiration. I'm glad I found this sight.

Paul
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  #11  
Old Tue 29 January 2008, 09:50
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Distortion was not an issue when I welded my base table. My tubing was .188 wall. I did tack everything first, then a good welding sequence like the Y car. One 4 inch weld at one cornor, then welded the opposite cornor, etc. Very easy for beginners.
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  #12  
Old Tue 29 January 2008, 10:00
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
If you take one of those huge main beams for the x-rails, and under it you weld 4 sq. tubes (2 legs + 2 uprights), each square tube with 4 welds, there will be 16 welds under that beam. My gut feel says that beam will bow by 5mm [3/16"] if those welds are made by a good penetrating stick welder.

It is only necessary to run 2 welds (parallel and opposite each other) at the top of each tube - that will bring us down to 2.5mm [3/32"] distortion with a stick welder. Change that to a MIG welder and we will get around 1.6mm [1/16"] bow on that beam.

If you clamp the pair of beams head to head (lying flat on the floor), and weld the legs out to either side, the 2 bowing beams will counteract each other and there will be minimal distortion.

Heath, we are not looking for "maximum strength" in the welds. We are looking for a stiff table with as little welding as possible. The stiffness of the table comes from the diagonal braces. Look at an old steel windmill or electricity pylon - they have "weak" bolted joints, but overall a stiff structure.
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  #13  
Old Tue 29 January 2008, 10:06
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Gerald,

I do not plan to weld any of the parts because I last welded when I was a kid and I do not think that I will every need to weld again. So I will pay some one to do it.

The information you provided is very useful for me to know what to tell the person that is going to do the welding.

Thanks
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  #14  
Old Tue 29 January 2008, 11:19
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Paul,
Are you going to weld the entire table or are you having some of it as bolt together?
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  #15  
Old Tue 29 January 2008, 17:16
cobra427mnsi
Just call me: Paul
 
Leamington, Ontario
Canada
Gerald, thanks for the info, I will try to keep the welds to a minimum eg weld opposite sides not all 4 sides.

Heath, I am making the two long sides with beams attached. The ends will be separate. I will try to attach a drawing of the table end view later. I have to go for now.

Paul
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  #16  
Old Tue 29 January 2008, 23:10
cobra427mnsi
Just call me: Paul
 
Leamington, Ontario
Canada
Hi Heath
Attached is a drawing that lost a lot in the conversion from Mastercam to CorelDraw to JPG. However, it shows how I am building the table. The upper and lower longitudinals will bolt the front and back beam sections together. I removed the angle braces from the ends as per the original drawings and replaced them with the triangular shaped brackets for two reasons. First being, I didn't want a complete end piece this way, when unbolted, the two longitudinals will be separate pieces (4 pcs with both ends). The second was so that I could store sheet goods under the table. I don't know how convenient that will be but, if it doesn't work out, no loss. I hope my explanation isn't too confusing. I hope this change will make the table rigid enough. I really hate to redesign Gerald's table but I need it to unbolt so it will be easier to move around.
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File Type: jpg table end.jpg (44.3 KB, 605 views)
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  #17  
Old Wed 30 January 2008, 08:24
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Paul,
Thanks for the update. This is sorta what I was thinking for the table as well. I take it you will be welding up the table sides that support the x axis right? Are you using 2x3 square tubing for all of the spoil board supports? If so are you going to just drill all the way through to bolt the spoil board to it?

Gerald,
Any comments on using the underside of the table to store sheet goods waiting to be consumed by the beast? Any problems using tubing instead of c channel other than the spoil board mounting? Would tubing be stronger than c channel?

Last edited by domino11; Wed 30 January 2008 at 08:29..
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  #18  
Old Wed 30 January 2008, 08:53
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Quote:
Originally Posted by domino11 View Post
Any comments on using the underside of the table to store sheet goods waiting to be consumed by the beast?
Murphy says: The thickness and type of sheet you want to use will never be on top. Sheets are much more accessible if stored on edge. Also don't like the small gussets compared to large diagonal braces.

Quote:
Originally Posted by domino11 View Post
Any problems using tubing instead of c channel other than the spoil board mounting?
The design has lots of tubing in it - albeit round instead of square. Square tubing is similar in strength and flexibility, but it does collect more sawdust on top compared to round tube.


Quote:
Originally Posted by domino11 View Post
Would tubing be stronger than c channel?
That's a loaded question. All I can say is that you won't notice any difference in the final machine's performance.
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  #19  
Old Wed 30 January 2008, 09:35
cobra427mnsi
Just call me: Paul
 
Leamington, Ontario
Canada
I attached a drawing of the front view but the conversion from MasterCam to a JPG thru CorelDraw is a little faint.

Heath
The spoil board supports are going to be 1 1/2"X 3" channel. They will be bolted to the main beams using 7/16" bolts and wedge shaped washers. I am also going to weld some of those triangular gusset to the channel (not all of them just the last 2 on each end) to help prevent the table from racking out of square.

Gerald
I agree. I like the diagonal braces better as per your design. I used an upper and lower longitudinal with the triangular gussets rather than just the lower one to try to increase the lateral strength. I hope it will be strong enough.

Paul
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File Type: jpg Copy of CNC TABLE FRONT.jpg (21.7 KB, 584 views)
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  #20  
Old Wed 30 January 2008, 13:06
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Those gussets near the bottom of the legs will make no significant difference to the stiffness.
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  #21  
Old Wed 30 January 2008, 14:28
cobra427mnsi
Just call me: Paul
 
Leamington, Ontario
Canada
Gerald, you are probably right but they can't hurt anything. It may be overkill but I'll feel better with them than without them. Thanks for the input.

Paul
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  #22  
Old Mon 04 February 2008, 11:07
cobra427mnsi
Just call me: Paul
 
Leamington, Ontario
Canada
Gerald, I've been reading the thread on rails. I am torn between grinding my own or buying rails from Superior Bearing. The drawback of bought rails was the aluminum angle needed because of the radius interference on the steel angle. I started to think of ways to grind off the radius using the same idea as the rail grinding skate. I went out to the garage to measure the angle radius and the attached picture is what I found. It seems that the angle that I purchased has a very small radius. I think the rail from Superior will work without any modification to the angle or the rail. The part of the Superior rail that sits on the cutoff angle is 5/8" (.875 - .250 = .625) long. After cutting the angle to 1" high (that would make the final bought rail height 1 1/4" : Is that too tall?), the inside leg has close to 3/4"(slightly less but more than 5/8") of flat area to attach the rail. The radius doesn't seem to interfere. On the pic you can see the pencil mark at 1". What's left on the inside is 3/4". I know it is hard to tell from just pictures but does the angle iron you deal with have a greater radius than the one in the picture?
Attached Images
File Type: jpg angle end.jpg (30.0 KB, 531 views)

Last edited by cobra427mnsi; Mon 04 February 2008 at 11:09..
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  #23  
Old Mon 04 February 2008, 12:15
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
What is your objection to alu extrusion as per the drawings?
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  #24  
Old Mon 04 February 2008, 12:26
cobra427mnsi
Just call me: Paul
 
Leamington, Ontario
Canada
The aluminum is quite expensive and, in one of the posts, you suggested that it was weak compared to the steel. If using the aluminum, what would be the cutoff height of the upright angle? I remember reading somewhere a height of 1.1" minus the rail cap height would be acceptable.
I just did some scale drawings in Mastercam and the shortest height that would work on my angle iron is 7/8" which would give an overall height including the #3 rail of 1.125" (7/8+1/4=1 1/8").
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  #25  
Old Mon 04 February 2008, 12:34
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Alu is weak compared to steel when used as a beam to carry weight. The alu was included in the drawings for this particular application after considering its advantages & disadvantges. The only disadvantage may be cost . . . . technically it is superior to angle iron mainly because of its geometric accuracy. There are no strength reservations in this application. What would be the cutoff height? . . . . I am sure that is on the drawing

copied from other thread:
Clipboard01.gif
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  #26  
Old Mon 04 February 2008, 12:36
cobra427mnsi
Just call me: Paul
 
Leamington, Ontario
Canada
I quickly looked on the drawings but did'nt see it. I will look a little harder.
I haven't completed a machine yet so I don't know how everything ties together, but I'm guessing the the limiting factor on the final rail height is the motor mount plate holes.

Paul
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  #27  
Old Mon 04 February 2008, 12:45
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
I copied the pic above from the other thread. The motor mount holes are based on the 28mm [1.1"]. Cut off the alu angles so that you have a slight clearance at S2 and so that the weight is carried at S1.....what could be easier than that?
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  #28  
Old Mon 04 February 2008, 12:53
cobra427mnsi
Just call me: Paul
 
Leamington, Ontario
Canada
Thanks, Gerald
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  #29  
Old Tue 05 February 2008, 15:57
Robert M
Just call me: Robert
 
Lac-Brome, Qc
Canada
Send a message via Yahoo to Robert M Send a message via Skype™ to Robert M
Gerald, another thought on this angle / rail subject.
Excuse my intervention even if I’m not in the “build team” yet , but I’ve been wondering about this one.
For the option of adding rail instead of making/grinding your own, why not trying this; Go with the steel angle iron approach, cut to acceptable height and ruff grind the inside corner of the ready made add on rail where it would interfere with the angle iron inside radius ?
Sure still grinding, but with out trying it yet, I feel it is safe to assume it is less of a messy job, less time than grinding your own rails, a no brainier tolerance approach and heck…another alternative that may attract those who rather not going with the aluminum option !!
Amicalement, Robert
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  #30  
Old Tue 05 February 2008, 19:48
cobra427mnsi
Just call me: Paul
 
Leamington, Ontario
Canada
Robert
I am going to try to use the angle iron with the one side cut down 13/16 overall. That will allow the pre-made rail to sit down on the bottom of the angle and leave plenty to bolt the rail to the upright leg of the angle.
I will have to deal with the small radius on the angle but between grinding the radius off and grinding the inside edge of the rail (as you suggested), I think the rail will clear the radius and sit flat against the upright angle and down on the flat part of the angle. According to Superior Bearing's specs, that would make a final height from the bottom of the angle to the top of the rail of 1.115". I have tried several to scale drawings in MasterCam and it seems to work. If not, then I will try the aluminum angle approach.

Paul
Attached Images
File Type: jpg rail.jpg (25.0 KB, 484 views)
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