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Gerald_D
Registered
Username: Gerald_d
Post Number: 13
Registered: 11-2005
| | Posted on Thursday, December 15, 2005 - 08:40 pm: | 
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Have been of the opinion that the BWC rollers selected for the gantry are too small in diameter. Going up to the next size is a huge jump in cost. So, set out to make own rollers.....
The basic design dimensions are so that the roller is interchangeable with the BWC size2 roller - the offset from the left face to the center of the V is identical. The bore size and OD make these close to the BWC/Hepco/Yitong size 3.
BWC on left, own design right
The "rings" or "tyres" are precision CNC turned, inside and outside without removing from from the chuck, then heat-treated hardened in a vacuum chamber to protect the smooth surface finish.
Bearings (and seals) are a pair of these ($3 ea):
But the inward facing seals are removed to reduce friction:
 
A single bearing is entered slightly into a tyre and a thin ring of LocTite is applied:
 
Quickly, the bearing is pressed in with a vice with paper towel in between
It is important to press in one bearing at a time, and to keep the tyre flat against the vice jaw (the jaws must be good and parallel).
The LocTite must not migrate to the inner diameter of the bearing, because that is where the seal rubs. The marks left on the towel show where the LocTite has migrated:
Finished job in front with some spare tyres at the back. (Made more for a later application).
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Gerald_D
Registered
Username: Gerald_d
Post Number: 14
Registered: 11-2005
| | Posted on Thursday, December 15, 2005 - 09:10 pm: |
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Roller fitted under gantry with 12mm bolt:
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Steve Minuskin
Registered
Username: Stevem
Post Number: 1
Registered: 12-2005
| | Posted on Friday, December 16, 2005 - 12:31 am: |
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Gerald, nice job. I believe that the BW bearing have dual angular contact bearings. You may have some issues with axial loads and play with the bearing you chose. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 19
Registered: 11-2005
| | Posted on Saturday, December 17, 2005 - 07:19 pm: |
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Steve, these are "deep-groove" bearings with the result that they do have a significant axial load capability. I will do some homework on the figures and post them here some time, but in practice they are performing very well so far. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 20
Registered: 11-2005
| | Posted on Saturday, December 17, 2005 - 08:45 pm: |
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From SKF pages:
On Deep Groove bearings:
"Deep raceway grooves and the close conformity between the raceway grooves and the balls enable deep groove ball bearings to accommodate axial loads in both directions, in addition to radial loads, even at high speeds."
"If deep groove ball bearings are subjected to purely axial load, this axial load should generally not exceed the value of 0,5 Co." (The Co value for a 6001RSR is 2.36kN (530lbs) The load is not purely axial, and the axial component is certainly less than 265lbs)
For a matched pair of 6001 bearings with standard internal clearance, the axial clearance (play) is 0.02mm to 0.04mm (<0.0015"). Radial clearance is .003mm to .018mm (<0.0007")
On Angular Contact bearings:
"..double row angular contact ball bearings correspond in design to two single row angular contact ball bearings but take up less axial space. They can accommodate radial loads as well as axial loads acting in both directions."
For a 10mm ID SKF dual row angular contact bearing (probably similar spec. to BWC2), the axial clearance (play) is 0.006mm to 0.023mm (<0.001"). Radial clearance is not given.)
Hepco/BWC don't publish clearance values, and they want a maximum axial load of only 36kg (80lbs) for a size 2.
Bottom line is that I may have half a thou more play, but I have a much higher load carrying capacity. |
Jay
Unregistered
| | Posted on Friday, May 26, 2006 - 05:24 am: |
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We have good economical V-wheels from China, but they don't make rails. How did you make your rails? |
Gerald_D
Registered
Username: Gerald_d
Post Number: 87
Registered: 11-2005
| | Posted on Friday, May 26, 2006 - 10:59 am: |
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Hi Jay
Our rails were rough cut on a milling machine and polished by drawfiling afterwards. If you don't mind, let's continue a "rail" discussion over here, and leave this thread for V-rollers. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 88
Registered: 11-2005
| | Posted on Friday, May 26, 2006 - 11:02 am: |
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Contact Frank Hu at:
YITONG INDUSTRY (NINGBO) CO.,LTD.
Tel:+86 574 8630 2585 Fax:+86 574 8630 3168
http://www.yi-tong.com
master@yi-tong.com
for economical V-rollers.
Can anyone vouch for Yi-Tong's quality?
http://www.yi-tong.com/yi-tong/en/guide_wheels.htm |
Domenic
Registered
Username: Domenicxx
Post Number: 1
Registered: 08-2006
| | Posted on Thursday, August 31, 2006 - 04:53 am: |
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Hi Gerald
I cant believe your site.. Any word i choice to describe wouldn't do it justice..
I have brought some roller bearing off Frank.
I have attached a pic...
What size should i be using for the MechMate?.. the ones I brought are "W2 X"
regards
Domenic
(Sydney, Australia) |
Gerald_D
Registered
Username: Gerald_d
Post Number: 220
Registered: 11-2005
| | Posted on Thursday, August 31, 2006 - 07:13 am: |
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I would prefer the W3X (next size up) from Yitong for the MechMate, but the W2X will work as well.
The smaller bearing has a more intense contact point with the angle iron iron rails, and we see quite a bit of "smearing" on the ShopBot's rails that uses the W2 size. The Mechmate gantry is heavier, but the MechMate rail is slightly heavier as well. |
Greg Waggy
Registered
Username: Gawnca
Post Number: 5
Registered: 11-2006
| | Posted on Thursday, November 09, 2006 - 07:38 am: |
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What do you think of http://www.vxb.com/ for a source for bearings? Any particular size you would recommend? Sometimes they have some fantastic deals, like 100 for $20.00 USD. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 409
Registered: 11-2005
| | Posted on Thursday, November 09, 2006 - 09:37 am: |
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Greg, clicked on your link, no V-rollers jumped at me, closed the link again. Sorry, but I can't spend more time on it than that. The MechMate needs 12 V-rollers as per the downloaded drawing or as per BWC/Hepco/Yitong size 3. |
Greg Waggy
Registered
Username: Gawnca
Post Number: 6
Registered: 11-2006
| | Posted on Thursday, November 09, 2006 - 02:17 pm: |
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Gerald, I know there weren't any "V" rollers there, just bearings. Thanks for looking though. |
Greg Waggy
Registered
Username: Gawnca
Post Number: 7
Registered: 11-2006
| | Posted on Thursday, November 09, 2006 - 06:33 pm: |
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"The "rings" or "tyres" are precision CNC turned, inside and outside without removing from from the chuck, then heat-treated hardened in a vacuum chamber to protect the smooth surface finish."
May I ask how you do this? |
Gerald_D
Registered
Username: Gerald_d
Post Number: 411
Registered: 11-2005
| | Posted on Thursday, November 09, 2006 - 07:05 pm: |
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I don't do it personally....those are my instructions to the workshop where they do good turning work. But, what more or less happens is the following:
- They hold a short bar of suitable steel in the chuck of a lathe.
- they cut the inner bore, the right-hand face, and the outer profile.
- then remove work from chuck, turn it around, clamp it in the chuck again.
- then turn the "new" right-hand face, ie. the remaining face. Do not touch the already finshed bore and outer profile.
- then off to the heat-treating company...
If steel is very hot in the presence of oxygen, it starts oxidising (rusting) rapidly and the surface becomes rough. If you can remove the oxygen from the oven then the steel stays smooth. A vacuum oven is one of the ways to remove the oxygen. google |
Greg Waggy
Registered
Username: Gawnca
Post Number: 8
Registered: 11-2006
| | Posted on Thursday, November 09, 2006 - 07:13 pm: |
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Thanks again for the info. Maybe I would do better to oil treat any metal I need to treat since I would think a vacuum oven is quite costly. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 412
Registered: 11-2005
| | Posted on Thursday, November 09, 2006 - 07:29 pm: |
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Why do want your own oven - can't you send the small parts to someone with an oven? Vacuum hardening gives virtually zero distortion as well - plunging a part into oil often causes some distortion. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 414
Registered: 11-2005
| | Posted on Thursday, November 09, 2006 - 08:00 pm: |
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These people look good in your area: http://www.vpei.com/index.cfm |
Greg Waggy
Registered
Username: Gawnca
Post Number: 9
Registered: 11-2006
| | Posted on Thursday, November 09, 2006 - 08:46 pm: |
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Gerald, You have your hand on the pulse of the world. Thanks, I'll make a couple and take them over to see what they say. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 416
Registered: 11-2005
| | Posted on Thursday, November 09, 2006 - 09:18 pm: |
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Phone them first. They may want special materials, or a 50lb minimum order...... |
Greg Waggy
Registered
Username: Gawnca
Post Number: 10
Registered: 11-2006
| | Posted on Thursday, November 09, 2006 - 09:28 pm: |
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Thanks again, I will do that. By the way, where did you say you lived? |
Gerald_D
Registered
Username: Gerald_d
Post Number: 418
Registered: 11-2005
| | Posted on Thursday, November 09, 2006 - 09:43 pm: |
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Cape Town, South Africa. Does that spoil a stereotype image for you?  |
Greg Waggy
Registered
Username: Gawnca
Post Number: 12
Registered: 11-2006
| | Posted on Thursday, November 09, 2006 - 09:49 pm: |
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HA HA Oh heck no. It's just that you know of all the contacts it seems, all over the world. I understand you have some great surfing there but also a lot of Great Whites!! |
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