Vee Bearings Dimensions?

[kanankeban]

Could some one tell me what size are the vee bearings used on the shopbot?
You can ckeck the size of them here:
https://reidecom.reidtool.com/xephr/edit/ITEM_GROUP
and the size of the angles used on the x and y rails?
Kindest Regards,
Hector

[ron brown]

Hector,

The vee-bearings are Bishop-Wisecarver "Dual-Vee" bearings. I think they are the "W2" size.

http://www.bwc.com/html/index.cfm

Ron

[kanankeban]

Thanks Ron,
About the size of the steel angle used for the x and y rails, do you have a idea of the size and gauge of it?
Regards,
Hector

[Brady Watson]

Hector,
BWC sells rails in thier catalog as well. If you want the steel angle rail, like the ShopBot uses, you have to buy it directly from ShopBot.

The angles are complimentary to the BWC bearings...you'll have to figure that part out on your own.

-Brady

[gerald_d]

Hi Hector, I am not near our SB right now, but I would guess that the SB rails are made of 2.5" x 1.5" x 0.25" L-angle. The short leg points up. None of these sizes are critical, if you want to make your own - the main strength comes from the part bolted under the rail.

[kanankeban]

Are the rails seled by Shopbot beveled or chamfered to go with the vee bearings? or are they just as they come when you bu steel angle?
Regards,
Hector

[gerald_d]

ShopBot grinds/chamfers the rails to match the Vee-Bearings.

[kanankeban]

Thanks so much for your help Gerald,
I'm asking this questions beacuse I want to implement the vee bearings on a table I plan to build and I in a doubt betwwen linear rails with pillow blocks (very expensive) or the way shopbot designed the shopbot. Do you have a guess whats the top speed of the gantry traveling over this vee bearings. I need to travel at about 600 to 800 ipm in respostioning and 250 aprox. cutting. Will the vee bearings sustain such usage?
Regards,
Hector

[ron brown]

Hector,

The BWC catalog has all the engineering data. I believe you are well within the range of their abilities.

Good luck,

Ron

[gerald_d]

Hector, the only problem that I see with the "home-made" rails (shaped angle iron) is that they are soft. If your v-roller has a heavy load, then it makes a dent in the soft rail. I assume that the rails from BWC are much harder.

Also, as far as I know, ShopBot has a special machine for grinding the angle iron. You need an accurate grinding machine if you want to get straight rails.

I would suggest that you talk to a company that does the repair of machine tools like lathes and milling machines. These repair companies have long grinding machines and experience with making long rails. This (http://www.psgrinding.com/index.html) is an example of such a company.

[gerald_d]

Over on this forum (http://cnczone.com/forums/), there is a claim (http://cnczone.com/forums/showpost.php?p=81079&postcount=5) that SB is using Chinese bearings and not BWC. I don't have a problem with that.

[dvanr]

But the BWC patent attorny might have a problem...

from BWCs site:

" Patented mounting shoulder on track allows for quick and accurate installation

Patented DualVee guide wheel design facilitates countless mounting possibilities as it can support loads on either the inside or the outside Vee surfaces "

There are "copy companies" in China who's business is to go to trade shows photograph and reverse engineer. I have seen a copy of a US Vutek wide format printer and then a copy of the copy , because it was so successful in China.

[gerald_d]

A quick look at the US Patent Office records mentions a Dual Vee brochure from 1981, therefore the patents have probably expired already. Anyway, the outer V is hardly ever used, and if this is left off the bearing it becomes a common "track-roller", still quite suitable for us running over v-rails.

[ted]

Hi Guys,

Interesting that this question should come up today. Yesterday I had lunch with Pamela Kan who was visiting from CA. She is president of BWC. She happened to mention during the conversations that she had recently checked and that, to date, ShopBot had purchased 53,940 of the BWC Dual Vee wheels.

So to clarify for the record, we have exclusively used BWC wheels on our tools. While the Vee is a convenient format for us, the real reason to use this bearing system is because of the very tight tolerances, the lateral stability of the wheels, their load carrying capacity, their tight seal, and the generally high quality of the machining. Not to mention that BWC has been a good company to work with over many years.

-Ted

[gerald_d]

That sure is a stack of bearings! Nearly 2000 ft high!

(BWC is a sales outlet of Hepco (http://www.hepco.co.uk/hep07a.htm#USA) of the UK, who source their products from all over the world.)

[gerald_d]

For the history buffs, here (http://patimg1.uspto.gov/.piw?Docid=03661431&homeurl=http%3A%2F%2Fpatft.usp to.gov%2Fnetacgi%2Fnph-Parser%3FSect2%3DPTO1%2526Sect2%3DHITOFF%2526p%3D1 %2526u%3D%25252Fnetahtml%25252Fsearch-bool.html%2526r%3D1%2526f%3DG%2526l%3D50%2526d%3DP ALL%2526S1%3D3661431.WKU.%2526OS%3DPN%2F3661431%25 26RS%3DPN%2F3661431&PageNum=&Rtype=&SectionNum=&id key=8C39A3FF47DE) is the original patent by Warren R Wisecarver in 1970.

(Our bearings are marked Bishop-Wisecarver Japan)