I'm almost positive this has been brought up as a subject,but I'm too lazy to look it up if it is in here.Basically,I'm asking if stainless 302,304 and/or 316 bearings are hard enough for ball/socket armetures?They are RC 25-36 and you can still machine them.The other S.S bearings I've found are too damn hard to drill or do anything with.You need an EDM machine them or a grinder to make holes in them.
302 is just the ticket. Soft enough th drill on a regular drill press with carbide bits (much better if you first file a flat area on top). Not sure about the others.
Hey Mike,thanks for putting your 2 cents in.I needed a little rienforcement to get my mind right.No,the other S.S is WAY too hard to drill.It is impossible,not even with carbide tooling.It'll just spark and dull the hell out of your drill bits and end mills.You can only EDM or grind bearings that hard.I'm looking into buying (preferibly) pre-drilled S.S bearings(a multitude of sizes/diameters-up to .250).I can't imagine using a bearing much larger than 1/4"?Well,having the bearings pre-drilled depends on how much that might rocket the price up?If the cost is minimal,it be worth having the bearing drilled for me.However,for really small bearings like .0625,.0937,.125 and maybe .1875? I'm considering "interferance/shrink fits" on the really small bearings. Trying to silver solder bearings that small will be a major pain in the butt and I don't know if I can do it?An interferance/shrink fit is a mechanical fit/bond that will hold indefinately.The shaft will break before the bearing pulls off.I wish I had a Machinery's Handbook to look at the chart for hole to shaft sizes.I have plans of making a holding fixture to hold bearings so I can drill more than one bearing at a time and also a fixture to aid pressing the shafts into small bearings which will be one at a time.I'll try it on a few to see how it goes,but I have to get back into the shop.
I have both his tutorials printed out and in a binder with allot of other puppet and armature making stuff.I like his tutoirials too,but he doens't get into smaller bearings.Granted,the concept and techniques are very much the same,but...for small .0625 bearings...I think you have to be extra careful.A regular sized torch will fry smaller bearings.I think a smaller torch would be necessary,but an interferance/shrink fit I think can and should be equally as effective on smaller bearings.The hold should be just as strong.
Ah ok - yeah, I've never messed with smaller bearings.
I have drilled balls from 3/4" down to 3/16" or 5/32". Mostly use 1/4" to 3/8". SS 302, using cobalt bits. I have a jig that makes it trivial to drill without any preparation other than putting the ball in the jig.
I have always used a basic propane torch from the hardware store and silver solder regardless of size. There's no difference I can tell other than how long it takes to heat the ball.
That does make sense - hard to imagine too big a flame being a problem, only the other way around. If your flame is too small it takes too long to heat up the metal all over.
I read an interview (I can't recall who it was) who worked on Coraline and the armtures saying that they used a dental torch to solder the 1/16 bearings and maybe some of the smaller ones too?
Would probably work fine as long as it's not too small.
Wait - hold on!! You found an article on technical details for Coraline armatures and you didn't post about it??!!
I found it randomly searching on google a couple years back and I haven't been able to find it again.I don't remember if I printed it or not?
Type 302 ball bearings is sort of the 'standard' for use by hobbyists stop motionists (even the pros use 302s). You actually don't need to use 'carbide' drills bits to drill the holes. Regular HSS drill bits can work with generous cutting/machining lube and also at speed where you're not getting it smoking hot. The better drill bit is what's call M42 Cobalt grade drill bits. Just do internet search on those kinds of drills. M42 are still affordable drills (compared to carbide). They are a little harder & longer lasting than the standard HSS drill bits. I know there are special coated drills and I don't have much experience with those. I just go the cost-effective route what has worked for me.
Wear characteristics of type 302 stainless balls is very good when used with cold roll steel plates, brass plates, or alum aircraft grade plate such as 2024, 7075 & similar types. Also can work with the aluminum you get at regular hardware stores ... those are usually 6061 type which has less tensile strength (can possibly bend with high ball joint tension) if used as sandwich plates, but 6061 still usable if armature joints not subjected to high joint tensions.
Where type 302 balls might show some wear is when it's used with the oil hardening precision steel stock (e.g., ball joint sandwich plates). Do not be confused by the term 'oil hardening'. For most armaturing work, you do not harden this metal but use in its natural state. It's very machinable and comes in more variety of stock sizes. The oil hardening stock is slightly harder & better clean machining than 'cold roll steel' stock (which does not come in as much variety of sizes), but cold roll steel is less costly than the precision steels. For the general machining metal working trade, they have option to 'harden' these kinds of precision grade steels for their specific application of whatever they are fabricating. (Cold roll steel is not really a hardenable type metal).
Cobalt - THAT'S what I meant! Hey, I got the first letter right (at least I didn't say copper! )