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-   -   Make your own V-Rollers if too expensive in your country (http://www.mechmate.com/forums/showthread.php?t=20)

Gerald_D Thu 15 December 2005 11:40

Make your own V-Rollers if too expensive in your country
 
Have been of the opinion that the BWC rollers selected by ShopBot 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.....

Also, see this later thread and notice that Superior Bearing sells at a much better price than BWC

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.


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).


Gerald_D Thu 15 December 2005 12:10

Roller fitted under gantry with 12mm bolt:


Steve Minuskin Thu 15 December 2005 15:31

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 Sat 17 December 2005 10:19

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 Sat 17 December 2005 11:45

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.


Gerald_D Fri 26 May 2006 03:02

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 Wed 30 August 2006 20:53

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)http://www.mechmate.com/Forum/messages/11/1181.jpg

Gerald_D Wed 30 August 2006 23:13

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.

Gerald D Tue 24 July 2007 01:01

Reported this morning that the Loctite had come loose on the Dec 2005 rollers. Should have used genuine Loctite 638 instead of this "copy".

Alan_c Sat 08 September 2007 00:48

Gerald

What is the spec for the hardening of the wheel rims re final hardness & reccommended steel.

I can get mine vacuum hardened, will that eliminate the need for grinding of the flange faces after hardening?

I have just been reading the other thread re hardening of these tyres and would like to know if you have indeed tested the four "soft" tyres and the final result - is hardening really necessary if we are using angle iron rails?

Gerald D Sat 08 September 2007 01:25

I have forgotten about that test already, and I should go and have a good look at the machine again. (For those that don't know it, my day job is no longer located near the machines, so I seldom get to see them these days)

The vacuum hardening guys are very fussy that your steel is bought from them. Then they "guarantee" that they will hold the before & after surface finish, but not the colour. Ours were hardened by Sanderson in Parow and they were not ground afterwards.

I am convinced that I won't bother to go the hardening route again. Plain steel wheels are much cheaper to make and they will make the rails last longer. Much easier to replace a wheel rather than a rail. (Not that our rails are showing signs of wear after 2+ years either)

ldorta Mon 17 September 2007 10:34

Hi friends. I'm starting my mechmate here in brazil, but for me is a little bit difficult to find the "V" tires. does anybody knows where I can find this and ir could be shipped to Brazil?
Thanks

ldorta Fri 21 September 2007 19:56

Hi Gerald.
This V tires are done by you? They are terrific.... Do you sell them? Here in Brazil I could find only some v tires to be used in some home gates, and they are not as good as yours...
Another question, do you treat the V rails (make it harder)? What´s the iron alloy of the rails?
Thanks
Leandro

Gerald D Fri 21 September 2007 22:27

Leandro, read the drawings, all the information is there.

DMS Sat 29 December 2007 05:30

My V-rollers and Eccentric Bush are made at local lathe workshop. Ecc. Bush are made from M12 High Tensile bolts as per drg no. M1 20 210. I found that Ecc. Bush are loose fit in Bearings and has little play. Does this have any effect on roller movements.
As I see Bearing support Base and Ecc. Bush head grips Bearing sleeve firmly and there should be no effect of this play. Please suggest.

Doug_Ford Sat 29 December 2007 16:26

I don't think it will be a problem but I'd be interested in Gerald's opinion. Or maybe Greg J's opinion. He's a mechanical engineer too.

Have you measured the V-rollers and eccentrics with a micrometer or a caliper? What specs did you give the machinist? If they aren't within the specs you specified, could you go back and ask them the make another set?

Greg J Sun 30 December 2007 19:24

Sharma / Doug

I haven't gotten to the assembly of the V-rollers yet. So, not sure what the consequences might be. I can tell you that my eccentric bushings fit perfect into the V-rollers. No play what so ever. Very nice fit. Mine are from Superior Bearing.

Today I was cutting the cross members for the Y gantry. Actually, I cut them 1.00 inch [25.4 mm] too short :o so I was welding on extensions and re-cutting. Not an easy task with that 1 mm tolerance. I know: measure twice, cut once.

Anyways, tomorrow I'll drill holes and hopefully weld up the Y-gantry. I've ordered the M12 bolts for the V-rollers, so maybe next week, I'll have a better response.

Greg J Sun 30 December 2007 19:32

Had one more thought.

You could put a "light" knurl on the bushings so that there is a snug fit between the bushings and the V-rollers.

Bill McGuire Sun 30 December 2007 21:30

Quote:
Originally Posted by Greg J View Post
Sharma / Doug

Today I was cutting the cross members for the Y gantry. Actually, I cut them 1.00 inch [25.4 mm] too short :o so I was welding on extensions and re-cutting. Not an easy task with that 1 mm tolerance. I know: measure twice, cut once.
Greg... if that's the first mistake you've made all year, you get an "A". :D

Hope you and everyone else on the forum has a good New Year...
Bill McGuire

Greg J Mon 31 December 2007 06:25

Bill,

I wish that was the first and only mistake. I've made plenty :)

That's the cool part about making this beast from the ground up. It's only metal and can be corrected. It's OK to make mistakes , ONCE.

When I get the Y gantry welded up and the Y car mounted, I'll post pictures. It's just taking allot more time than I anticipated.

Happy New Year To All !!!!
I'll be bringing in the New Year working on a MechMate :D
I hope that's not a sign of insanity.
Greg

smreish Mon 31 December 2007 11:57

- no mistakes for me today.
I finally drilled, tapped, drilled some more, and then countersunk all the fasteners on the spoil board.
I finally have a machine frame that is squared and stable.
Next step on Wed, start the rails. That's if my wife hasn't had our 2nd baby yet....then I will have to succumb to another short delay. It's always something.
Sean
Happy new Year

DMS Mon 31 December 2007 17:04

Thanks Doug and Greg,
I consider proper E.Bushes, not to take chances.
It seems that mistakes are inevitable.

Sean,
Congrats on you TWO achievements.

Happy new year to all.

Viperia Mon 07 January 2008 01:15

Hmm where do i find the drawings for these rollers? Or do i just save the image that is posted in the first post by Gerald?

Im planing to start building a MechMate Mamba in a while and are waiting for my laser cut parts to be done and delivered so why not start to collecting the rest of the parts or making them. Since my build will try to be as cheap as possible i will try to make many of the parts my self since i work some extra in a industrial shop that has quite a big arsenal of metalworking machines.

Will these V-rollers work good on a Mamba? And do you Gerald have a .dxf on these or do i just need to open the image in autocad/solidworks or what ever i got? Will do these rollers in a cnc lathe i guess.

Regards,
Viperia

Gerald D Mon 07 January 2008 02:21

Quote:
Originally Posted by DMS View Post
My V-rollers and Eccentric Bush are made at local lathe workshop. Ecc. Bush are made from M12 High Tensile bolts as per drg no. M1 20 210. I found that Ecc. Bush are loose fit in Bearings and has little play. Does this have any effect on roller movements.
As I see Bearing support Base and Ecc. Bush head grips Bearing sleeve firmly and there should be no effect of this play. Please suggest.
That play has no effect. Remember also that you have another 8mm [5/16"] bolt through the bush with with similar play - again no bad effects. It is the bush head that does the serious gripping. Realise also that the load on the bush is always from one side (does not oscillate) and the "play" will lie to the unloaded side.

Gerald D Mon 07 January 2008 02:24

Quote:
Originally Posted by Viperia View Post
Hmm where do i find the drawings for these rollers?
Drawing M1 20 121 T (Rev B)

Or you can import the rollers from www.superiorbearing.com

Viperia Mon 07 January 2008 03:45

Quote:
Originally Posted by Gerald D View Post
Drawing M1 20 121 T (Rev B)

Or you can import the rollers from www.superiorbearing.com
Ah missed that one. ;) Thanks there Gerald! Now i maybe can get these done either at school or the place i work either one i guess it will get much cheaper than buying a bunch of rollers.

Regards,
Viperia

Gerald D Mon 07 January 2008 04:11

Tom, suggest you make them of cheap steel, or bronze, and replace them if they wear out. Do not bother to harden them. My experimental set of "soft" rollers is still quite happy.

I would spend a little more trouble on getting the Loctite to bond correctly.

Viperia Mon 07 January 2008 04:37

Hmm yeah that should make them even cheaper then i guess, but cant you make them of some harder type of steel to hold against wear better? Maybe real tool steel or something?

So you have been having trouble with the bonding of the loctite? Never had that myself but did you use real loctite? Think you wrote somewhere that you had used some sort of loctite copy?

Well maybe add some kind of screws on the rollers that add pressure against the bearings?

Regards,
Viperia

Gerald D Mon 07 January 2008 05:37

Tom, which is easier to replace - the rail or the roller? Which one do you want to wear out first? :)

The "hard" rollers with integrated bearings are a marketing ploy I think. Those guys couldn't use soft metal for the integrated bearing - they had to offer a hard wheel if they wanted it cheap and easy to produce in their existing bearingmaking factories. :-)

The "Loctite" was a copy that was maybe out of date as well. I do have a lot of faith in genuine Loctite applied correctly. Don't think that screws should be necessary.

Viperia Mon 07 January 2008 06:33

Well to me honest i wouldnt want to wear anything out at all. ;) But that might not be possible in the real world i guess hehe.

The thing is since i both go in school to become a cnc-operator and do some part time work on a company 5-6 mins walk from my home i have quite good resources to make some high quality rails and rollers for not much more cost than the material itself.

So one way to go is to harden both the rollers and the rails so neither of em would wear to much, but since im not going to use my machine in a company or something wear should not be a big problem for me. But why if you can not do it extra good from the beginning? :D

But it will take a couple of weeks/months untill i have came this far with my project, since being a student like me you dont have to much money plus i have a son and girlfriend that wants my money to. :mad: ;)

But now i atleast got drawings for the rollers, now i just need to figure out a good size for my machine so i know how long the rails need to be etc. Thinking about a 2x2m machine if i can have it at my mother and fathers house since i dont have room in my appartment in the city here. :D If i cant store it there then i may need to go down in smaller size. :(

Regards,
Viperia


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