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  #1  
Old Tue 06 March 2007, 13:01
Gerald_D
Just call me:
 
Summary of rail & roller situation

Talking of rollers first, there is a good (USA)source of a set of rollers listed on this Forum. Beats the BishopWiseCarver (BWC) prices by far and the quality is apparently 100%. The YiTong (China) option may suit people nearer to them, but their shipping charges kills export to other continents. Some folk (like me) make our own rollers from the plans here.

Making the rails is the most daunting task facing the builders of the MechMate. Lots of guys give up on building a MechMate when they discover that the required rails cannot be purchased over the internet from the comfort of an armchair......

The main rails are defined in drawing number: M1 10 110 M which basically shows 6mm [1/4"] angle iron, with one leg shortened down and then "sharpened" with 45 degree bevels.

a. I have had 2 sets made on a bandsaw and milling machine with only a 900mm [36"] bed. link

b. Fabrica did an experiment with a drill and shaper to prove to himself that milling is viable. link. After that he had the rails milled with confidence.

c. DocTanner made his rails with sweat...and grinders. Took him a day and no shipping charges link. Some more "home" grinding ideas illustrated here and here. (See also link in later post below) This is the way to do it on a low budget, far away from "proper" facilities. It will give you a machine that is fine for 95% of paying jobs.

d. CharlieT had some precision rails made by a knife grinding company. Cost him about $130 per rail which is still cheaper than buying any of the so-called "linear bearing" rail. link.

In short, passable rails can be made with a day's worth of sweat. Fully ground rails are also possible at costs lower than mounted linear bearings. It is one of the non-armchair steps in building a MechMate, and there are a lot more of those steps.....
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  #2  
Old Sun 15 April 2007, 10:37
Gerald_D
Just call me:
 
V-Rollers:

Superior Bearings of Ohio have by far the best deal on V-roller bearings and they ship worldwide. Many reports have come in about how good their service is. Here is their special offer for a "MechMate kit" - 12 rollers (size 3) and eccentric bushings as a complete set for only $185.52, excluding shipping, from Ohio. (Note that the size 3 is substantially heavier and more robust than the size 2 used by ShopBot and stocked by IMS). The Superior Bearing product is made in the USA.


V-Rails:

Until recently, the BishopWisecarver rail was thought to be the best, but very expensive. I avoided it purely on price, particularly the price wanted by the BWC agent in this country.

In addition to rail options mentioned in the post above, two more viable options have emerged:

1. Make rails with a small angle grinder and some home-made jigs. see this thread

2. Use V-cap rails identical to BishopWisecarver, but for a much better price (70% less !!??) from Superior Bearing. see this thread.
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  #3  
Old Tue 12 June 2007, 00:14
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Newsflash: See J.R.'s "skateboard" rails in his thread.
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  #4  
Old Sun 03 February 2008, 11:00
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Just an update since June last year . . . .

The JR Skate method has become the "standard" way of producing MechMate rails. The alternative (in the set of drawings) is purchased V-rails screwed to alu, but nobody has done it that way yet.
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  #5  
Old Sun 03 February 2008, 19:41
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Gerald,
Didnt Art use the rails on his turning Mechmate? I know he used a different mounting method, but did use the bolt on rails. He said he liked them. Isnt there an option in the plans for using steel angle for bolting as well or is it just the aluminum?
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  #6  
Old Sun 03 February 2008, 23:30
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Art did use the Superior rails, but he screwed them to small brackets at 12" centers, which is only at every 3rd or 4th hole in the rail. (Bottom this thread) That is too flexible to resist forces in the sideways direction.

Quote:
Originally Posted by domino11 View Post
Isnt there an option in the plans for using steel angle for bolting as well or is it just the aluminum?
The steel angle has a radiused fillet on the inside which gets in the way. If the rail is mounted on the outside of the angle, then there is a problem with the rack position and the pinion gear too far overhung from the motor shaft/bearing (see sketches/discussion in this thread). The alu angle has a nice sharp corner on the inside - solves a lot of issues without adding any negatives. That's why the drawings only show alu for the bolt-on V-cap "rail" (I hesitate to call that stuff a rail in the fullest sense of the word - it is weak unless you have lots of screws to a strong rail)
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  #7  
Old Mon 04 February 2008, 08:10
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Gerald,
Thanks, that clears up my confusion. I guess I was thinking the superior rail would be stiff and not that flexible.
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  #8  
Old Tue 16 June 2009, 14:11
J.R. Hatcher
Just call me: J.R. #4
 
Wilmington, North Carolina
United States of America
Send a message via Skype™ to J.R. Hatcher
Gerald is 28mm the standard height of the rails?
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  #9  
Old Tue 16 June 2009, 14:37
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
The 28mm came from here. It makes the ground angle iron the same height as a "V-cap" screwed to alu, which means the same laser cut motor plates can be used on both rail systems. Why the question?
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  #10  
Old Tue 16 June 2009, 20:33
J.R. Hatcher
Just call me: J.R. #4
 
Wilmington, North Carolina
United States of America
Send a message via Skype™ to J.R. Hatcher
Gerald on my machine I had to lengthen the slide hole in the motor mount to allow the pinion to drop out of the rack when the spring was removed. This was because I made my rails 28.57mm high and not the standard 24mm (2006). My pinions have 20 teeth ... I think. I have redrawn the old motor mount to give an additional .10" of clearance, it may need more. I understand the affects this will have on a few other parts (it's for my use only unless you say otherwise) If you would like I can email you the DXF.
I can also send a DXF of the skate plates? Thanks J.R.
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  #11  
Old Tue 16 June 2009, 21:57
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
JR, I was thinking that sometimes the screw had to be removed from the slide hole before the pinions could be dropped clear of the rack, particularly with big pinions and 16mm metric rack. (Some people could be using small pinions and 1/2" rack). The present dxf's seem to be working out for everybody, so I am loath to change some dimensions there. Unless everybody is just keeping quiet?

PS. Also remember that you worked from early drawings - there have been changes since your machine.
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  #12  
Old Wed 17 June 2009, 11:18
J.R. Hatcher
Just call me: J.R. #4
 
Wilmington, North Carolina
United States of America
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I had to spend a few hours reviewing the drawings to see how you took care of the added rail height in parts other than the motor mounts . Now I see why the motor mounts don't need revisions .
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  #13  
Old Wed 17 June 2009, 11:29
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
This archived thread may bring back memories:
http://www.mechmate.com/forums/showthread.php?p=6244
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  #14  
Old Wed 17 June 2009, 11:53
J.R. Hatcher
Just call me: J.R. #4
 
Wilmington, North Carolina
United States of America
Send a message via Skype™ to J.R. Hatcher
That was when I was out of town .... Sept. thru Dec. 2007 and didn't get a chance to visit the forum much. Thanks
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  #15  
Old Sun 20 September 2009, 20:45
jehayes
Just call me: Joe #53
 
Whidbey Island, Washington
United States of America
Photo/Drawing of Roller Installation

Can anyone point me to a good photo or line drawing of the correct installation of the rollers for both the gantry and the Y-car. I am sure it is in the manual somewhere but darned if I can find it. Thanks
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  #16  
Old Sun 20 September 2009, 21:19
jehayes
Just call me: Joe #53
 
Whidbey Island, Washington
United States of America
Never mind, I found it (M1 20 100).
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  #17  
Old Sun 24 January 2010, 07:38
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Length of Aluminum Rail past End of C-Channel

Gerald,

I could not find a good place to put this question.

How far can I extended my Aluminum Rail past the end of the C-Channel and not have a problem with the structure when I roll the gantry on it.

I don't enough room for a indexer without making some modifications.

Thanks
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  #18  
Old Sun 24 January 2010, 10:31
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Gut feel says about 2.5" to 3". Why not extend the channel with a steel bracket?
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  #19  
Old Sun 24 January 2010, 13:45
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Gerald,

Bolt an extension on to the channel for 12" or how long I want to make it and add an Aluminum extension for the rail. Put a leg onto the extension. Is that what you are thinking?
I will draw some thing up.

Thanks
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  #20  
Old Tue 08 January 2013, 20:27
lolailando
Just call me: lolailando
 
troy ny
United States of America
Open source groove, cheaper ones in Kickstarter

Anyone has tried/looked at this for the mechmate?
http://www.openbuilds.com/OpenBuilds...egory/bearings
best
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  #21  
Old Wed 09 January 2013, 00:02
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Interesting kits available there. (have problems with the website though)
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  #22  
Old Sat 12 January 2013, 04:12
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 !
Have an ‘ignorant’ question or a need to refresh me as time as made my aging mind selecting what is not usefull :
In our case, for the MechMate, why one would go with delrin ?....if you’re not machining it !
It appears to me the price may be a motivator or simply, one is just trying to go….unjustifiably, another way to be different !
A curious mind !
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  #23  
Old Sat 12 January 2013, 06:13
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
I support Delrin simply because it opens the mind to realise that cheaper rollers also do the job.

Technically, I don't now see a big difference between a steel and plastic roller. Some people may think that the plastic roller will protect the rail, and that it is simpler to replace the wheels after a few years.....but some plastics actually cause a lot of wear to steel (HDPE for example)

Back to the mind opening.....
When I was involved with ShopBot in the first few years of this century, they preached that only the American Bishop Wisecarver roller was good enough. Had to tell them that those rollers were printed "Made in Japan" and that BW also sometimes purchased from the same factory that Rick at Superior gets them from. (ShopBot even had a couple of wheels that broke) People were really making too much noise about the "quality" of the v-roller bearing.
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