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dneisler
Registered
Username: Dneisler
Post Number: 58
Registered: 12-2006
| | Posted on Wednesday, April 18, 2007 - 05:24 am: | 
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Gerald,
Been reading the plans alot lately since I am about to get a little time, to MAYBE start a build. I am not seeing or understanding the placment or use of this item. Probably right under my nose and just not seeing it. Can you shed some light on it? |
Gerald_D
Registered
Username: Gerald_d
Post Number: 1274
Registered: 11-2005
| | Posted on Wednesday, April 18, 2007 - 06:20 am: |
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When having problems like this, look at the top left corner of the title block of a drawing. In this case it says: Higher drawings: 10 20 200 A (1x assembly per gantry).
On drawing 10 20 200 A you will see 10 20 235 mentioned.
It goes down the inside of the gantry tubes, and it acts as a row of nuts for the screws that hold the y-rail down. |
dneisler
Registered
Username: Dneisler
Post Number: 59
Registered: 12-2006
| | Posted on Wednesday, April 18, 2007 - 03:22 pm: |
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That is what I was thinking, just never could confirm it.
Thanks |
Gerald_D
Registered
Username: Gerald_d
Post Number: 1277
Registered: 11-2005
| | Posted on Wednesday, April 18, 2007 - 05:32 pm: |
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Here is something I wrote for the ShopBotters - not all applies to MechMate:
The huge bolts to the Unistrut are an overkill and too far apart. One needs to be able to shim/push/pull/tilt the rail at about every 8 to 12" when getting them perfectly set up. 5/16" bolts/screws at those intervals are perfectly adequate. The "drill" (pun intended) is as follows: (after welding the gantry)......
1. Take a 2 lengths of .75x.25 flat bar, nearly as long as the rect. tube. Mark a good screw spacing off onto one of the flat bars, making sure to miss the redundant huge holes in the rails. Center punch the one strip only.
2. Clamp the second strip to the back of the first strip (vice grips) and drill 1/4" holes right through. Unclamp, reverse/flip the strips and see if all holes still line up. If they don't, you need to mark the strips for the position in which they will finally be used - top & bottom and end for end.
3. Using the strips as templates, clamp them to the rails and tubes. Measure from side to side for parallel rails, etc. - there isn't much room for error on a 5/16" screw through a 1/2" hole. First drill 1/4" holes in all of them. Lots of holes I know, but 1/4" is easy.
4. Enlarge the holes in the rails to 1/2" and enlarge the holes in the tubes to only 3/8" (keep the tube as strong as possible.
5. Enlarge the holes in the strips for the right tapping drill size (I havn't tapped a non-metric thread in 30 years, I can't remember the size) and tap 5/16UNC threads in the strips.
6. De-burr all holes. Maybe use a big flat bar to push/scrape through the rect tube? Degrease. Paint.
For installation:
7. Push flat bar into end of gantry tube (a slot must be left there for the motor wire connectors anyway). Let the flat bar lie on the bottom. Appease your gods now...
8. At each end of the gantry, drop a short (6") length of slightly sharpened 5/16UNC "full thread rod" (Allthread/readybar) through the top of the tube and "find" the corresponding threaded hole in the flat bar. Do at both ends, leavin rods standing proud on top.
9. Lower the rail over the rods and then lift the rods to bring the flat bar up to the top surface. Add more screws. Etc. Give thanks where thanks is due..... |
DocTanner
Registered
Username: Doctanner
Post Number: 50
Registered: 11-2006
| | Posted on Thursday, April 19, 2007 - 01:10 am: |
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For those of us that dislike using a tap, weld nuts attached to the 3/4" x 1/4" flat stock are a cheap answer.
www.fastenal.com
DocTanner |
Gerald_D
Registered
Username: Gerald_d
Post Number: 1279
Registered: 11-2005
| | Posted on Thursday, April 19, 2007 - 07:14 am: |
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Dislike taps??
Okay, maybe I did too, but then cordless drills came along. Granted, it took a few broken taps to get the right feel about 10 years ago, but it has become oh_so_easy to tap holes! 
I still hate tapping blind holes, because that needs 3 taps. But, for through-tapping, we only use HSS spiral point machine taps - the ones used by industry in their automated tapping machines. |
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20. Gantry