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  #1  
Old Sat 26 April 2008, 23:03
dmoore
Just call me:
 
Location and spacing of X rack from main beam?

Gerald -

In this photo:


it shows that there is a slight gap between the rack and the main beam on X. Is this gap normal? If so, why is it there - as opposed to moving the angle iron rail in closer? This would leave the rack flush to the rail (or with a slight gap between the rack and the beam) and moving the angle further over the top of the main beam.

Thanks,
David
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  #2  
Old Sat 26 April 2008, 23:15
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Two very big reasons:
- the guys outside of America have a wider metric rack
- tolerance space is added in the design for the guys who cannot weld a table very accurately, or for beams which are curved.

The rails are plenty strong enough to cope with the small overhang.

If a person ends up with no space, the consequences are drastic....saw the end of the gantry off and lengthen it. So, let's rather have some space.

Hey! I thought you were only making lists so far! Good progress there.
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  #3  
Old Sat 26 April 2008, 23:47
dmoore
Just call me:
 
Now that's a quick reponse!

Here's why I'm asking the question - I've tried cutting the rails down and didn't have good success. I do see that I can grind the rails ok if I have a flat surface to run the height adjusters on the skate - flat being the operative word here. So, what I need is a nice clean factory flat edge. So, what I'd really like is angle in 2.5"x1" or 2.5"x1.125" - both of which are not standard bar channel sizes here in the US. What is standard is 2"x1.25x.25".

It seems the 1.25" height isn't a major issue based on comments you've made - it does make the motor hang down a bit futher depending on the gear you've selected - but all it all it works. The other question is with the jump from the listed 2.5" flat/bottom angle that is affixed to the beam (X) or the tube (Y). It's 2.5" to allow it to hang over the edge with enough distance to support the rack + a little extra as you mention in your post above. Changing this angle of course changes lots of things from the plans - the length of the gantry, distance of holes drilled for affixing the angle, etc.

I'm a plan follower but it seems that I might be able to make this change and if I look out for the other related changes I can make this work. What do you think Gerald?

I'm still working on the list. I've pretty well finished the BOM. I'm also close to finishing the automated steel spec'ing sheet - you just put in your table dimensions and it figures out how much of each you need and what possible replacements can be made if your supplier doesn't have that specific item. It then feeds that information into the BOM. I've also started this "huge" sheet that lists each drawing and then what is required as for time (4 hours cutting, 1 hour drilling, 5 hours welding, 2 hours painting, etc) and what tools are required to accomplish the task for that drawing (welder, saw, drill, drill bits, punch, etc). I'll send you a sample copy for your feed back.

Thanks!
david
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  #4  
Old Sun 27 April 2008, 00:44
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
If the rails are taller, the motors drop down and the stop blocks inside the rails need to get taller.

The secret to cutting the rail down is a quality cutting disk. See posts #87 to #90 in this thread. The equivalent disk in the USA appears to be EDP #63157 on this page

Then another discussion started on cutting the rails down with TCT (tungsten carbide tipped) circular saws - see this thread:
http://www.mechmate.com/forums/showthread.php?t=810
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