Well so I was at work on Friday and was looking for something to do to waste an hour or so. I then realized I had a YYF Protostar in my toolbox (in case the power goes out). I really liked the concave bearing but I didn’t like the quality(of the bearing). I looked though the drawer of bearings and found some shielded .250 x .500 x .187, Sweet! So put it in the optical CMM and got some numbers on the radius. That’sright they are not an angle it is really a radius. I liked the concept but did my own variation. I wanted a steeper angle and since you really don’t use the bit near the edge I just made the radius a bit tighter. Made a few of them and they turned out great. I had a bearing from my YYF Superstar. I made the mandrel to grind them on .2497 so it was just a light slip fit. The YYF one I had to give it some help on. After I ground it I tried to remove it. Well I couldn’t, I ended up cracking the outter race while trying to get it off. I put the race in the CMM just to shoot a photo of the cross section. Kind of neat. To give you an idea. the distance from the radius where the ball rides to the bottom surface of my concave is only .010" That’s about the thickness of three human hairs stacked. Seem small?? I normally work in tolerances of .00005" That 1/600 the thickness of a hair.
It is amazing how thin the material is between the inside and outside of the outer race, granted you’re only giving it about 60-odd grams of force in a normal sleeper. I had a handmade concave that split staight down the center before I even had a chance to use it. Their knowlegde of tolerances must have been little to none…
Work for a company called Andrew Tool. We make low production and prototype parts for aerospace, medical, and electronic markets.
This is a gear box for a new Mars rover. We built six of these, two out of aluminum, two out of titanium, and two out of a metal called Vascomax. Parts where a solid block of material when we started. http://www.andrewtool.com/images/gallery/aerospace1.jpg
And before anyone asks there will be no yo-yos made at work, at least until they let me run the new multi axis CNC lathe. ;D
The problem with homemade KK bearings is that the outer race on a standard bearing is not very thick. The KK bearings that Dif-e-yo sells start out with a much thicker outer race so he has some material to work with.
Dude, not being any time of engineer, you wouldn’t understand that this isn’t like to start a business or a compony, it’s for fun. Making things is amazing plus you feel legit after. Don’t give him sass.
Yeah I noticed that too with the bearing from the protostar It seems the outer race is pretty thick. The bearings I found at work, I’ll have to track down the MFG and find out who makes them. Those seemed pretty thick didn’t sound thin while grinding. None cracked or blued or discolored while being ground. The YYF bearing that broke on me didn’t sound like the others. I figured after making 5 good ones something was bound to go wrong.
when you concave a bearing you have to bee VERY CARFUL i cut at least 3 bearings in half
if it doesnt look deep enough then its good i concaved a bearing it didnt look very different then before and i took it off and compared it to a regular and found out how deep it was
BB
you mean for the new mars rover that is basically a portable lab? cool. that is actually what i want to do for a living when i am older. do you work with JPL in california?
They (JPL) hired a company to engineer the parts, a company called Aeroflex. They sent these parts to 10-15 different companies. We weren’t one of them all the other companies failed at producing these parts. One of the last companies to bail told them to contact us. We then completed the parts and now Aeroflex is one of our bigger customers. Yes this is for the large mars rover. The old ones where only the size of a coffee table. The new one is the size of a car. The part in my previous post is in the arm.
Considering you can fabricate almost anything you should try to make a konkave ceramic 20 ball bearing. And buy 20 ball I mean two decks of 10 smaller than normal balls. That would spin forever!
