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  #31  
Old Fri 26 October 2007, 00:11
gmessler
Just call me: Greg #15
 
Chicago IL
United States of America
Hi Gerald

oops I was afraid you'd catch that. Yes it is. I made a mistake with the width of the x channels. I assumed (ouch) that they would be the width of the cross bearers. I found the mistake after I had already assembled the entire base and attached one of the rails and compared it against the width of the gantry. Because the gantry was already built the only thing I could do without rebuilding the table (lots of steel) or gantry (lasered parts) was to push the rails further out. Since I had already drilled the rail and did not want to fill the holes with weld I just moved the holes on the channel a little further out. I'll now have about 11mm between the inside of the rack and the x channel. I hope that's not too much.

I'm sure if you caught that you are probably wondering how I had ground the rails with the bolts in the way. The bolts do get in the way so I tac welded the rails to the channel. The pic shown is after the two x rails were ground cut and attached to the base. I did put the gantry (with bearings) down on the rails. I was curious if my gantry was twisted. It was not. Sigh of relief. It's amazing how smooth (even without indexing the rails) the gantry rides on the rails. One slight push and it floats from one end to the other. I can't wait until I get it dialed in.

Thanks for your input Gerald. Your attention to detail is incredible! Send some of that my way would you?

Best

Greg
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  #32  
Old Fri 26 October 2007, 00:51
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
But then that screw in the pic should have been more to the left? Anyway, your feedback (anybody's feedback) on mistakes made is very useful so that I can add notes to the drawings and save others the headache.

In this case, the note at top right on drawing 10 10 300 W must be made much more eye-catching. If I were doing a CofC* exercise on that drawing, that note would have the highest rating (critical), second highest rating would go to the 100mm[3.9"] offset.

*CofC: Classification of Characteristics : DOD-STD-2101
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  #33  
Old Fri 26 October 2007, 01:17
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
See posts 9 -19 of Fabrica's thread
http://www.mechmate.com/forums/showthread.php?t=310

You can kick me now for not making the drawing clearer then!
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  #34  
Old Fri 26 October 2007, 09:03
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
Greg,

To run my mill and lathe, I use a VFD that has single phase power input and three phase output.

The lathe was also pretty worn and the hydraulic speed adjustment for the spindle was shot. I only paid $500 and also got lots of tooling. Prices for original parts from the factory were sky high so I fabricated some pieces in my machine shop classes at night to get it running. Now, mechanically speaking, it only has two speeds. The beauty of the VFD is that I can control the frequency of the electricity, so once again, I have a very broad range of spindle speeds available to me.
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  #35  
Old Fri 26 October 2007, 09:25
gmessler
Just call me: Greg #15
 
Chicago IL
United States of America
Hi Gerald,

After finding my error I searched the drawings. Not sure how I missed that because it took me some time to find the 3.9" offset and that's on the same page and point of assembly. I did remember your comment to Fabrica unfortunately after I made the mistake. I even remembered the picture as I sat there scratching my head. Everything's there if you just read!

As for the bolt placement, I left the bolt there because I had already drilled the hole to 1/2". The old hole in the channel would be covered by the new rail location so no extra work (other than new holes in the channel) was needed.

Now in hindsight I think I should have filled those holes and re-drilled the rails. My reason for this is because of leverage. I did sit on the gantry as my wife rolled me back and forth while I watched the rails and there didn't seem to be any problems. What about long term though?

Thanks for your help and comments Gerald.
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  #36  
Old Fri 26 October 2007, 09:29
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Greg,
I missed the 3.9" offset myself until Gerald caught it on my drawings....It was clear as day on the drawing, but somehow I was just to anxious to pay attention. I now have a highlighter and mark every page dimension that is critical! Sean
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  #37  
Old Fri 26 October 2007, 09:46
gmessler
Just call me: Greg #15
 
Chicago IL
United States of America
Hey Doug,

Machine shop classes.....hmmm. Something I should have considered before starting this project! I should still probably keep that in mind. When I began ordering the parts for my kitchen table project I thought that this project would probably run similar to my laser. But as I got further in I realized this is much more complicated. My laser is a 45w co2 with a 24x12 table. The software I use to run it is Corel. Just about any drawing program can run it. No Cad or Cam programs needed. It interfaces to the computer with a printer driver. A few changes in the config of the printer and you're all set.

I'm hoping that I'll be able to export many of my "drawings" from corel and not have to re-make them in a Cad program. There is an export to .dxf function in Corel but I haven't worked with interfacing that to a Cam program yet.

I didn't realise you can use a VFD to drive other equipment besides a spindle. That's pretty cool. My original plan was to install a spindle. After Gerald's recommendation ..... I'll just use a router until I learn the machine.
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  #38  
Old Fri 26 October 2007, 09:55
gmessler
Just call me: Greg #15
 
Chicago IL
United States of America
Sean,

It's not too hard to get anxious working on a project like this.

Like they say measure twice cut once!
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  #39  
Old Fri 26 October 2007, 10:20
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Let's modify that saying: Read thrice, measure twice, cut once.

A hint: Putting dimensions on a CAD drawing is darn easy. Putting words next to the dimensions is a lot of work. If you see words near the dimensions, wonder why I spent the trouble to put them there . . . . .
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  #40  
Old Fri 26 October 2007, 10:41
gmessler
Just call me: Greg #15
 
Chicago IL
United States of America
grinding video

Well said Gerald!!!

I've posted a video on youtube showing me grinding one of the rails.

I'm a little nervous showing this to Gerald as his keen eye is capable of spotting fly sh*& out of spilled pepper. Attention to detail is something we could all benefit from.

Search Mechmate, there are only 7 videos. It's the rail grinding one.
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  #41  
Old Fri 26 October 2007, 10:51
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
http://www.youtube.com/watch?v=j0RN_C-iosU

What dance music should one play for this?

Great video!

(Gloves recommended)
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  #42  
Old Fri 26 October 2007, 11:20
Marc Shlaes
Just call me: Marc
 
Cleveland, OH
United States of America
Send a message via Skype™ to Marc Shlaes
Thanks Greg. Keep up the good work!
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  #43  
Old Fri 26 October 2007, 16:06
Bill McGuire
Just call me: Bill
 
Weiser, Idaho
United States of America
Looks kinda like a ballet movement in double speed...

Greg... you make it look easy... thanks for the inspiration...
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  #44  
Old Sat 27 October 2007, 06:44
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Greg,

Thanks for video and nice work.

I'm finishing up the spring loaded wheels for my new gantry crane today and then on to the skate.

I just have to sand blast and re-assemble the skate. Cut down my angles and grind rails tomorrow.
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  #45  
Old Sat 27 October 2007, 09:23
gmessler
Just call me: Greg #15
 
Chicago IL
United States of America
Thanks everybody

Still have to figure out what music for my "it's finished" dance.
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  #46  
Old Fri 09 November 2007, 21:22
gmessler
Just call me: Greg #15
 
Chicago IL
United States of America
Hello Gerald,

Just got back to work on the machine today. I'm working on the y rails and their attachment to the gantry. I marked my rails at 1.81" per the drawing however when I place that line along the centerline of the gantry tube it seems as though the rail hangs way to far out. I thought I'd check out J.R's machine to see what it looked like. To me it looks like his holes in his gantry tubes are closer to the inside.

What amount of clearance should there be between the back side of the rack and the gantry tube?

By the way I welded up my Y car and it turned out just fine. I used a couple of pieces of aluminum, clamped them to the sides to cover the gap, then welded into the hole just like all the others. when I removed the aluminum the weld took on the same shape as the original tab only longer. Afterward I put a slight filet weld on the inside no longer than the tab as you instructed. I'll probably use the caulk to fill the gap so it should look fine when painted.
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  #47  
Old Fri 09 November 2007, 23:20
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Quote:
Originally Posted by gmessler View Post
What amount of clearance should there be between the back side of the rack and the gantry tube?
More than what you might think!

Seriously. I left quite a big gap for the guys who can't weld their tables straight, or for people with odd sized tubes, etc. But, I don't want to advertise it - it lets me sleep at night

Don't try to reduce the gap. If you do this you will pull the pinion gear off the shaft of the stepper motor. Remember that the width across the pair of motors is rigidly fixed.

I will look for a full-size cross-section for you later today.
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  #48  
Old Sat 10 November 2007, 10:17
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
When you print the attached, make sure that your printer is not applying any "scaling" to try and fill the paper page - it should print you a pic with the rect. tube 50 x 100 mm [1.97" x 3.94"] the rack in that pic is 16 x 16mm which is the max metric size.
Attached Files
File Type: pdf Section.pdf (11.3 KB, 155 views)
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  #49  
Old Sat 10 November 2007, 10:32
gmessler
Just call me: Greg #15
 
Chicago IL
United States of America
Thanks Gerald !!

That is what it looked like. It just looked strange at first. Now I understand the thought process and it makes sense now. I'll drive on. Off to start tapping those holes.

Hope you feel better.

Greg
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  #50  
Old Sun 18 November 2007, 18:29
gmessler
Just call me: Greg #15
 
Chicago IL
United States of America
Hi everyone,

I've made some progress on my machine. Not as much as Fabio, Doug, or Sean (great job guys!). I took a few photos before I left town for the weekend. Unfortunately I was in a hurry and didn't get quality shots. I'll try to take more this week. Gerald, as you predicted the y rails turned out just fine.
In looking for a good vendor for the teflon washers I ended up at a vendor someone suggested on this forum, www.Fastenal.com. Great service / selection / price and they had a store about 15 min from my house. They also had the 12mm jam nuts and shim washers I needed.

I still have to order up the items needed to make my z assembly.



Glad to hear you're still around Greg J.
Attached Images
File Type: jpg CIMG5993 (Small).JPG (65.2 KB, 1075 views)
File Type: jpg CIMG5994 (Small).JPG (51.0 KB, 1072 views)
File Type: jpg CIMG5997 (Small).JPG (66.3 KB, 1072 views)
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  #51  
Old Sun 18 November 2007, 18:56
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
Looking great Greg. Feels good doesn't it?
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  #52  
Old Sun 18 November 2007, 19:20
gmessler
Just call me: Greg #15
 
Chicago IL
United States of America
Thanks Doug, Yes it does feel good....but the anticipation of completing the project is killing me!!

Gerald,

I can see your concern now regarding the placement of the bolts on the x rails. The car stoppers will just barely miss the bolts. I still need to attach my stop blocks on both axis' though

Something for everyone to keep in mind. An unintentional change or mistake in one dimension can alter the geometries of many other parts. "The butterfly effect".
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  #53  
Old Sun 18 November 2007, 20:23
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Greg,
Nice to see your boat in the basement project getting done! Nice work. It looks like your almost ready to start cutting soon. I like the look of you rack on the gantry. Is that rack from McMaster or another supplier?
Sean
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  #54  
Old Sun 18 November 2007, 21:11
gmessler
Just call me: Greg #15
 
Chicago IL
United States of America
Hi Sean,

Late night Mechmate surfin?

I'm getting close...but the thing that worries me is grinding the z plate. I still have to order it. I had considered doing the table saw thing. I'm just a little concerned about the whole grinding dust/bearing issue but I can't think of a better low cost option.

I got my racks from http://www.stdsteel.com/gr_stock.htm
they were $28.8 each and only $24 for shipping. I made the mistake of ordering 6 racks and only needed 5 so that probably inflated my shipping. McMasters price for the same rack was $40.60. I still have to figure out what to do with the last rack. Maybe ebay....maybe offer it up on the forum...(offer it to Gerald for free if he tells me who in the states to send it to for his 3rd machine!!). When I ordered my din rail I also ended up ordering up about 12' too much. I thought about offering it to the Mechmate builders for free and only ask for shipping costs. I'm not sure if that will work or not. Postage for sending out an 18-36" piece of din rail might be more than the cost that people can get their din rail for.

Happy Mechmating!!
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  #55  
Old Sun 18 November 2007, 23:02
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
A nice chunk of steel! This makes me itch to get started with No. 3

Thanks for the rack offer Greg, but you probably use that nasty inch stuff - I can get the metric stuff here quite economically.
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  #56  
Old Mon 19 November 2007, 06:20
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Looking Good and thanks for the pic's Greg,

Hopefully I can have some rails in a couple of weeks, then I can post some pictures.

One of the interesting aspects of this project is the local interest in my MechMate. People are amazed that this is not a hobby machine. My favorite saying when someone sees it in the shop for the first time is "ooh, that is quite large" or "very substantial".

This machine is designed for work! (not that you can't have fun with it also)
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  #57  
Old Mon 19 November 2007, 06:49
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Greg,
Nice work on your machine. Keep the pics coming. They inspire the rest of us.

Gerald,
How many machines are you planning on building? Do you have a link to your machine for sale?
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  #58  
Old Mon 19 November 2007, 10:36
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Heath, I am only going to build one MM. The machine for sale is the original ShopBot, but I think that Sean actually did sell it today.
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  #59  
Old Mon 19 November 2007, 11:00
gmessler
Just call me: Greg #15
 
Chicago IL
United States of America
Darn inch people
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  #60  
Old Mon 19 November 2007, 11:17
hflwaterski
Just call me: Herb #126
 
Genesee, WI
United States of America
Building a MechMate Mamba

Greg,

I north of you near Milwaukee. I would be interested in your spare rack. I'm building the table this spring and I'm accumulating parts for now.

Thanks,
Herb
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