"Cheap" Robot parts

[Andy Baker]

Originally Posted by Adam Y.

Is that good or bad? Should the lubrication stay inside it or outside it?

Once an oil impregnated bearing gets too hot, the oil sorta "boils out" of the bearing, then the bearing dries up and it does not work as well. The hole gets a bit bigger and the bearing is shot. It is definitely not a good thing... you want the oil to stay inside the bearing material.

Andy B.

[Raul]

I guess I should have elaborated a little more on my suggestion to use a bronze bushing. You may get away with not using oil for some time when a bronze bushing is used for a steel (or maybe some other hard metal) shaft. But I know from experience that you must use additional oil if used for an aluminum shaft. And if you use an aluminum shaft with a bushing, you should try to stay away from using it for high RPM applications.

Raul

[Sachiel7]

Ok, here's a quick question guys. We took our pre-season vote to go ahead with my "standard" drive design (yay!)
But it was brought up that the idle shaft's bearings could be replaced with bronze bushings, at a cheaper cost.
I'll be honest here, I've never used bushings before. What's involved with them? From what I understand you need a housing block of sorts for them.
Anyway, I have 2 idle shafts. They dont spin, they provide support for the wheels and chassis. Would it be better to replace the bearings they are on with bushings?
Also, where can you find good, cheap bushings? I checked MSC and had trouble finding some.
I need 4 (one for each support point) and they need to be for 5/8 shaft (I think it's steel) and need an outside diameter no larger than 1 inch.
If someone could help me out, that'd be great. Currently, we have several 4-bolt flange bearings we're using, and they're around $26 each. So, having some of those trimmed off for bushings should help a bit, i'd suspect.
But I don't want to deal with this thing falling apart at competition. We want it to last.

[Matt Adams]

Originally Posted by Sachiel7

Ok, here's a quick question guys. We took our pre-season vote to go ahead with my "standard" drive design (yay!)

Originally Posted by Sachiel7

But it was brought up that the idle shaft's bearings could be replaced with bronze bushings, at a cheaper cost. I'll be honest here, I've never used bushings before. What's involved with them? From what I understand you need a housing block of sorts for them. Anyway, I have 2 idle shafts. They dont spin, they provide support for the wheels and chassis. Would it be better to replace the bearings they are on with bushings?

If they're not spinning at all... sure bushings... actually, you could probably just have them rest on whatever metal they're in between. However, I'd like to see a picture or a sketch (if possible) so see how these are "supporting" the wheels and chassis. Are they just spacers?

Originally Posted by Sachiel7

Also, where can you find good, cheap bushings? I checked MSC and had trouble finding some. I need 4 (one for each support point) and they need to be for 5/8 shaft (I think it's steel) and need an outside diameter no larger than 1 inch. If someone could help me out, that'd be great. Currently, we have several 4-bolt flange bearings we're using, and they're around $26 each. So, having some of those trimmed off for bushings should help a bit, i'd suspect. But I don't want to deal with this thing falling apart at competition. We want it to last.

Well, I think that your best bet for cheap bushings are McMaster-Carr or Endco. Here's a link for the exact bushings you're looking for.

Thrust Bushings:
http://www.mcmaster.com/asp/loadpage...995&catnum=109
Flanged Bushings:
http://www.mcmaster.com/asp/loadpage...996&catnum=109

Also, sometimes companies use bushing and bearing synonymously, so searching for bronze bearings can sometimes get you what you're looking for.

Let me know if you need anything else.


Matt

[Tytus Gerrish]

heres an idea i had this morning

seing as how the globe shaft only takes rotational loads it needs a bearing with a 1/4 ID and i was like "Bearings are expensove" then i asked my brother the ID of his skate wheels. he said 1/4" so then i got an old one and took a gander TADA!! it fits

32- 1/4" ID Bearings (used) ...... FREE!


the spacer just needs to be cut in half

[Sachiel7]

Sweet!
Glad you found that one out Tytus, I've been using the globes more frequently in my designs lately.
That helps alot!

[Adam Y.]

seing as how the globe shaft only takes rotational loads it needs a bearing with a 1/4 ID and i was like "Bearings are expensove" then i asked my brother the ID of his skate wheels. he said 1/4" so then i got an old one and took a gander TADA!! it fits

That is very clever. To expand upon the idea why not try and buy just the bearings themselves. I do not know about the size though. Maybe some skater can help us.
skate bearings

[Matt Adams]

Originally Posted by Adam Y.

To expand upon the idea why not try and buy just the bearings themselves. skate bearings

I think the idea was that BUYING would cost money..

Matt

[Bill Gold]

Last year Team #258 used roller blade bearings on shafts in their crab modules. I found them really cheap at a local sports store. The only problem was that none of the roller blade bearings I know of have shoulders or flanges. So we had to glue the bearings into the plates, and try design our plates to better prevent the bearings from trying to pop out. One popped out a little less than halfway through Cal Games, but luckily we had made stainless steel plates (which we hadn’t used until that point) to prevent against this. So we popped a new bearing in, and put the cover plate over it, and it was good to go for the rest of the competition.

[Adam Y.]

I think the idea was that BUYING would cost money..

It certainly is cheaper than buying them from any other place.

The only problem was that none of the roller blade bearings I know of have shoulders or flanges.

Neither did the ones that came in the kit. You could probably fabricate your own flange to push-fit the bearings in.

[Bill Gold]

Originally Posted by Adam Y.

Neither did the ones that came in the kit. You could probably fabricate your own flange to push-fit the bearings in.

There were a few flanged bearings in past years' kits. We used them in 2002 on our drive system. I think fabricating your own flange is a little overkill. There are other easier ways of holding the nonflanged bearing into a plate.