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  #1  
Old Thu 29 March 2007, 19:35
Loren Gameros
Just call me:
 
Capped rails using standard "BWC" V-track

This is an edited version of the original thread that is now archived:

If anyone is interested I have had a very good experience with Superior Bearing.

I have purchased (2) 12' hardend tracks and (2) 7' hardend tracks along with a 2' hardend track for the "z" axis
for $378 (no shipping).



By Gerald:

Dimension F is not from the shoulder, but I think this is a drawing error on their part. Are the 9/32" holes chamfered to allow for the fillet under the screw head, or must a washer be used between the screw head and the capping?
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  #2  
Old Thu 12 April 2007, 08:21
Gerald_D
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I have been reading the BishopWisecarver catalogue rather closely. (link - they want your particulars first)

Their standard V-cap rails are not ground - they are "formed" and polished. I would guess the forming is the standard cold-drawn process. Some of their v-cap rails are hardened before polishing.

But, the main reason for studying their catalog was to learn about how they would like us to mount them. Their application notes on page 29 are important when selecting a base rail to screw the cap onto. They emphasise "The flatness, straightness, and parallelism of the plate or bar to which the DualVee® track is attached (bolted) determine the accuracy of the system. Cold finished or extruded bar or plate is adequate for many applications."

Further:

"Greater accuracy is obtained by using a plate or bar that has been ground flat and parallel on the mounting surfaces. To achieve straightness and flatness characteristics to within N grade accuracy levels is fairly routine (± .004 inch; ± 0.10 mm). In fact, accuracies as low as ± .001 inch (± 0.03 mm) have been achieved using carefully prepared mounting surfaces in relatively short stroke applications (1-3 feet; 0.3-1 m). For designs requiring accuracy levels of ±.005 inch and better, mounting surfaces must be prepared straight and flat, and appropriate doweling or reference edge assembly techniques must be employed."

Although the above comes from the BWC catalog, I am sure that the Superiorbearing product is exactly the same, and that the same notes also apply.
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  #3  
Old Thu 12 April 2007, 09:18
Loren Gameros
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Ok, here are a few pics. I will post more if requested or I can email larger files.
Let me know.


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  #4  
Old Thu 12 April 2007, 11:09
Gerald_D
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I thought the rails were pre-drilled?

That close-up pic; from which direction is it? (I am trying to understand the "scratches")
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  #5  
Old Thu 12 April 2007, 12:58
Loren Gameros
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The drilling of the rails was offered to me as an option for an additional price.
I have chosen to drill them myself since I have a drill press, I will let you know if I have any problems.
I plan on drilling this weekend and will be using 1/4" 20 button head cap screws to fasten the angle iron to allow for clearance issues.


The close-up pic is the flat side (no notch)and the scratches are very superficial.
The scratches showed up as a reflection from the florescent light in my garage.
Those scratches are really nothing.
You can see where the top portion of the rail was heat treated by the dark witess line.

I will post more pics as I continue.
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  #6  
Old Thu 12 April 2007, 13:14
Gerald_D
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Thanks for all that info Loren. The standard holes/spacing is 9/32" holes at 3" intervals. De-burr or chamfer the hole until the cap-screw head sits down "hard".

What base rail are you planning to screw the rails to? (I want to do a fairly accurate drawing for you)
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  #7  
Old Thu 12 April 2007, 20:44
James Webster
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Your local "Industrial Metal Supply" http://imsmetals.com/ has aluminum angle uneqal in 2.5" x 2" x .25" in 25' lengths. you could rip the short leg on any tablesaw down to .75" . The leftover drop could be used inside the Y car rails?

OR

They have aluminum .5" x 2.5" flat bar stock in 12' lengths.

You might call them tomorrow morning and see how much each costs.....
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  #8  
Old Thu 12 April 2007, 22:42
Gerald_D
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Reckon the aluminum uneqal angle in 2.5" x 2" x .25", ripped in a saw, as James suggests, is a good option. Would everyone be happy to rip alu in a table saw? You won't be getting a precise top face to hook under the shoulder of the V-cap, but I don't think you will see it in the final machine performance. The angle can be drilled with clearance holes.

If you go the flat bar route, the clearance holes need to be in the V-cap rail. Tapping lots of blind holes in alu will be a long job. But the match to the shoulder would be better.
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  #9  
Old Thu 12 April 2007, 23:14
James Webster
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You could do a rough rip with any bandsaw (wood or metal bandsaw will work, set belts for fastest speed, blade with as few teeth per inch as you have on hand) then do a finish rip on the tablesaw (do this if you worry your tablesaw is grossly underpowered).

The finish cut would be very light.

Clean out all of your dust and turn your dust collector off for this job!
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  #10  
Old Fri 05 October 2007, 13:17
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Sean, here are my dressed up doodles:

The white motor shafts shown are the shorter 32mm shafts from the geared motors:

Clipboard01.gif
30mm tall angle iron rails

Clipboard02.gif
V-Cap rail attached to inside of
alu angle - it works out well.


Clipboard03.gif
The problem of attaching to the outside . . .



Clipboard04.gif
Why locate the shoulder on a sawn edge?
Let's work towards shimming at S1 . . . .
And then it dawned on me; just rest the rail on the extruded face at the
bottom and saw a small clearance at S2.
(Might have to do something about the tiny fillet in the angle . . . )

So, the result is that the rail drawing M1 10 110 M has been changed to show an overall height of 28mm [1.1"] to make the JR Skated rails interchangeable with the BWC/Superior rails resting on 6mm [1/4"] strip/extrusion.
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  #11  
Old Sat 06 October 2007, 06:25
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Dave,
I can use steel and have access to all the tools to deal with it. I was just keen to using the Architectual alum angle due to the nice crisp (and almost always) straight 90 deg flange to wall alignment. Not to mention drilling and cutting the leg down to size is easy! Gerald has been kind to quickly update the dwg files and show the pros/cons of the arrangement we have been talking about for days now. I think now Gerald has a nice "universal" change to his machine design to work with most everyone depending availability of iron, alum or JR's Skate grinder.

Regards,
Sean
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  #12  
Old Sat 06 October 2007, 07:01
driller
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Seems that there is a path for everyone. Those who want to grind their own, and those who want to use pre-fabricated.

I can see that Gerald covered the two main points he was worried about. the big one was getting the motor shaft directly under the full gear rack.

the second (minor one) was that the rack was on only one piece.

Dave
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  #13  
Old Sat 06 October 2007, 07:32
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
. . . . there is a third one . . . .

That the rail locates to extruded, and not sawn surfaces.

. . . . a very important third one that has been eluding me until waiting in the car for wife to get the Thai takeaway meal last night.
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  #14  
Old Sat 06 October 2007, 07:59
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Gerald....so TRUE. Keep it to machined / extruded face and I have 1/2 a chance of getting something right on my first build.
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  #15  
Old Tue 30 October 2007, 13:03
GregW
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I just received an email from Rick and as long as the rails are not over 8' he has no problems. When they go over 8' shipping goes up by as much as $140.00. Shorter lengths can be butt jointed but then you have a seam, would this make a difference?
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  #16  
Old Tue 30 October 2007, 14:19
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Forum,
My experience is that a butt joint on a linear machine should be fine, but you should stagger the seam to alternate ends of the table so only 1 bearing (out of 4 on the gantry) will touch the area. With proper alignment, you may never know the seam exists! I use multiple segments on angle track rail on my large Turntable designs and I haven't notice a problem - ever. Good luck with your choices! Sean
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  #17  
Old Tue 30 October 2007, 16:02
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
My point about the cap rail is you can install it like a scarf joint on crown molding. Just cut it at a 45 and marry the two together to form a rolling joint. Very easy to do out of NON-hardened rail like superior sells.
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  #18  
Old Wed 31 October 2007, 10:44
Art
Just call me: Art #2
 
Lancaster,Texas
United States of America
Just got a quote from from Superior Bearing on 8' non hardened T3S rails without pre drilled holes of $51.12 each. At least for us in the USA this eliminates doing your own.
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  #19  
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?

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  #20  
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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  #21  
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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  #22  
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
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  #23  
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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  #24  
Old Mon 04 February 2008, 12:45
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Looking at my drawing above, 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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  #25  
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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  #26  
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, 5126 views)
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  #27  
Old Tue 05 February 2008, 19:51
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
caprail vs. MM steel rail ? Pro's and Con's

Robert,
I for one, actually made a mock-up of the cap rail and alum angle prior to deciding to use the MM rail system. I like both options for the right reasons. The next machine I build, and it will be soon, will be of the alum rail section for proof-of-concept. Plus, I like a challenge

Caprail:
Pro's
- easy to buy - but cost's more than just steel
- easy to drill
- alum ARCHITECTURAL angle easy to cut down to right height - but is an upcharge for alum
- alum ARCHITECTURAL angle has nice geometric shoulder for cap rail to register to with minimum inside fillet to deal with.
- saves oodles of time grinding and cutting down steel.
Con's
- assembled rail is still flexible in x and y direction like steel and requires you to mount it to the main C channel frame for rigidity.

Steel MM option:
Pro's
- steel angle iron easily and readily available
- fairly easy to cut down to required height, but takes time.
- fairly easy to grind profile, but takes time
- skate method is VERY EASY to use and is now included in the laser cut steel package. A luxury I didn't have, but love knowing it's available now. *thanks to JR, Greg, Gerald for helping me work out the kinks*
- many machines on this great planet use it and is a tried and proven method.
Con's
- assembled rail is still flexible in x and y direction like steel and requires you to mount it to the main C channel frame for rigidity.

If you notice, both rail sections require the machine frame to dictate the rigidity of the rail profile....not it's metallurgy. Good design, many choices.

Good luck - choose wisely.
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  #28  
Old Tue 05 February 2008, 23:38
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
I don't think there are major advantages of one system over the other. Both options offered in the drawings are sound. Substituting steel for the alu angle is also okay, but you need to figure out for yourself how to find a reference surface for the V-track to rest on. The finished height is a factor to keep your eye on - it affects the motor mountings and the stop blocks.

The height is not super-critical, you could go up a little if you have 1/2" high rack (the design also allows for the metric guys with 5/8" high rack). If you screw the V-track to steel instead of alu, you can use thinner steel, even down to 1/8" thick.

Lots of options to fiddle with. But I think I've done my share of giving options on rails and I don't want to get buried in little details of what radius can be purchased where, and what should be ground to fit what. Sorry if I sound disinterested on this one, but the rail discussion has ground me down.
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  #29  
Old Thu 07 February 2008, 06:00
Robert M
Just call me: Robert
 
Lac-Brome, Qc
Canada
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Gerald, Even if
Quote:
Sorry if I sound disinterested on this one, but the rail discussion has ground me down.
I’m certain that not only I but others will appreciate you comment & views on this option.
Thanks
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  #30  
Old Thu 07 February 2008, 06:23
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Which option? To replace the alu with steel? If that's the case then there is not much I can add to the discussion. I am sure everyone can figure out what will personally suit them better. The Alu will be easy. The steel will be cheap. Both will work.
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