DIY grooved bearings

[LeonS]

I was looking at the parts list for your laser and noticed that the grooved bearings stood out as fairly expensive at $10 a pop. I recently read a post somewhere that there is a sliding door bearing that can be modified to have a roller skate bearing pressed into it. This could probably be done for around $2.50 a bearing.

I plan on driving both sides with steppers and using 4 bearings for each rail; 12 bearings in all. so it could save me $90 overall. It seems like the design and the light weight of the gantry would allow these lower tolerance bearings to be successful.

Do you think this is a foolish trade off of cost for quality?

Thanks,
Leon

[bdring]

I think that is a great idea. I had a few good ones left over from my big router where the strength is needed. I bought a few more, but knew at the time I was paying more than I needed. I think a lot of commercial lasers use plastic bearings.

Keep this topic going with your results, where to buy and how to rework them.

[LeonS]

I haven't had any luck finding the specific roller that can have its bearing replaced by a skate bearing. As I remember the discussion the slider roller was fine except the bearing had too much play in it. The identified roller could be easily modified by pushing out the old bearing and pressing in a skate bearing.

I haven't done any searching of stores or catalogs yet, but I do intend to.

I must say, the price you specified for your bearings seems very competitive, so it may not be worth pursuing. The search for cheap v-groove bearings was intense a year or so ago when the cost 20 some dollars each.

Regards,
Leon

[bdring]

Wonder if some 100K Garages person might make some cheaply on a lathe out of nylon to press on. It would be simple to make. You just hit it with a V cutter then cut it off.

I am sure Shapeways could do it too, but it would cost a lot.

[lasersafe1]

I've mentioned before that I have a friend with a lathe. He is also a CNC builder (not laser yet). If someone wants to send him a hunk of round nylon and a drawing, I'm sure he would be willing to do a few for free as long as he gets to keep enough material to make a complete set of rollers for himself.

[bdring]

The V-Groove Bearing are actually dual row angular contact bearings. This allows them to take a high side load without wearing out quickly. With all that, $9 each in not a bad price. We don't have much of a side load so it is probably not that much of an issue, but you need a pretty good bearing to start with.

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As long as we are trying to trim out costs, maybe the we should rethink the v-track too. If we could find some way to use the existing feature of an extrusion that would help.

Could someone with a commercial Chinese laser take some close up shots of the bearing methods for the X and Y axes and comment how on the quality of them?

[lasersafe1]

You asked for it!

looking down at X drive motor and Y stage mirror

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Y rail and X motor. This rail appears to be the beefiest of all parts and contains a real bearing.

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X mirror is held to rail with small nylon rollers. These rollers are on an offset rod that can be tightened to the "curtain rod" and locked to maintain tension

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back side of sweep mirror assembly

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X rail unbolted and lifted to show belt

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X rail twisted to reveal timing belt loop and tensioner pulley

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end view profile of rail for x sweep

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Y stage motor is dual ended to drive belts on both side rails. Notice extension rod at bottom of picture.

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[lasersafe1]

They really did the best they could to minimize cost and maximize profit. It works though and the motions are quite smooth and fast.

If I were to rebuild it though, I would use a single IKO rail with a single carriage for the X sweep. These things are incredibly smooth and strong. I believe I paid about $60 for this rail with three carriages on Ebay.

IKO rail with LWL12 B carriages

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[bdring]

Found these guys. Superb Tech

Direct link

It is probably tough to buy small quantities.

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[lasersafe1]

I went into a local hobby shop yesterday. I was there to buy the nice flexible silicone fuel line to be used for air assist on my ULS rebuild. Got it and it is really flexible.

While I was there I saw the large variety of small bearings that intended for use on RC racing cars. There was one bearing that came in a set with a rubber hub that had a negative groove. It was not a tiny V, so it probably wouldn't work on your rail, but it did look very interesting. I can't seem to find it online, but this is the company that makes it:
http://www.integy.com/st_main.html?p_catid=14

Prices aren't too bad for these nice bearings.

Here is another link to the various RC enthusiast parts manufacturers:

http://www.hobbytown.com/Manufacturers/default.aspx?MfgCat1ID=3

Who knew you would buy small brushless DC motors that draw 210 Amps??? I wouldn't think I could get 210 Amps through a copper penny from a battery.