Flexible dial indicator holder.

[kd0afk]

This will be my next build. I can't afford $200 for the real thing but I can afford to make a few. I got the balls on the mail the other day and today I'm having a cookout/metal softening session.

I'll be posting photos and videos on YouTube to document the build.

 

[kquiggle]

I look forward to seeing your progress on this. For what it's worth, I tried "softening" some ball bearings by heating them to red heat with a MAPP gas torch, and just letting them air cool. This worked pretty well, but it did leave them with a coating of black scale (although the scale was fairly easy to polish off with some abrasive cloth). I don't know if some kind of anti-scaling treatment would help or not, but it might be worth looking into.

I have read reports that some people have used borax powder for this (preheat the metal to about 600 deg. F and dip in powder to coat). There are also commercial anti-scale powder available.

Just some thoughts - good luck in your cookout!

 

[kd0afk]

The plan is to cook the food and then heat the bearings in a can filled with sand in the coals and bury the whole thing with new coals and let the whole thing burn itself out. I'll be poking the coals to make sure they are well buried in the ash as it starts to die so that they will cool as slowly as possible.

 

[purpleknif]

Seen similar ones for about $45 w/indicator.

 

[velocette]

Hi
it is possible to drill holes through ball bearings with a concrete drill bit slow!!! speed lots of pressure and lots of coolant-lubricant.
The annealing process will help to make it a bit easier keep in mind that cans are soft soldered an will melt it out before the can reaches bright red.
Be aware that some sands will leave glazed coating on very hot steel.
keep us posted on this project please

Eric

 

[kd0afk]

Seen similar ones for about $45 w/indicator.

All the materials have cost me $30 and I can make three of them

 

[kd0afk]

Here's how I did the fire. It took a whole bag of charcoal. I filled the can with red hot coals stoked them well and put the can in red got coals and stoked them for about and hour. Also used wood in the fire. The can reached a dull red just above the coal line. Even if the can desoldered it wasn't disturbed so the bearings should stay in one place. I also had a bucket of ashes that I piled on top to further insulate them so they'll cool slower.
We'll see how they are in the morning.

 

[kd0afk]

Sorry, here's the photo of the fire.

 

[kd0afk]

Success!!!
I pulled the balls out of the ashes and a file cut em like cold rolled.
Next step: drilling

 

[kd0afk]

How can I reharden them? Red hot and cool in air? The data sheet I read says 1204 c as the quenching temp.
Would I also need to temper the balls or can I just harden them?

 

[kquiggle]

Do you even need to re-harden them? Given how you are planning to use them, it doesn't seem like they are going to be exposed to much force or friction. If you don't buy that, you could just case harden them with something like Cherry Red.

 

[kd0afk]

I probably don't need to reharden them. I was just wanting to cover my bases.

 

[tornitore45]

Hard surfaces are harder to grip, if the balls need to have a friction grip they bare better off soft. For the same reason drill bit shank are left soft.

Annealing call for very slow cooling to relive stress but if all is needed is to soften to a machinable level, simply heating to cherry red and avoid quenching is sufficient. I just pull the part slowly out of the torch flame and always been able to drill afterward.

I paid money for the Brownell anti-scaling powder and is nothing but borace, probably mixed with charcoal to reduce decarburization.

 

[Jyman]

One of the best and cheapest ways to avoid scaling, is to use a heavy liquid hand soap. Just cover everything you want protected. Guys in the metal fab shops around me use the soap method

 

[chucketn]

I paid money for the Brownell anti-scaling powder and is nothing but borace, probably mixed with charcoal to reduce decarburization.

What is borace?

Chuck

 

[Swifty]

What is borace?

Chuck

It's just borax.

Paul

 

[Cogsy]

It's likely that the balls were originally only case hardened. A lot of bearings are, which is why they don't last long after you start hearing them make noise, they wear through the hard case into the soft material underneath and fail. If they're through hardened they cannot be made as hard as case hardened or they become too brittle. Less hard = less life so many manufacturers opt for case hardening.

 

[kd0afk]

I took the video down and I probably won't be filming any more till I get a proper camera and mount.

 

[kquiggle]

Nice video - appreciate the effort you are making to document this.

I wonder if you needed to heat the steel balls that long. In my quick and dirty test (with much smaller steel balls), I just heated them red hot and then let them cool, and they drilled OK. If, as was suggested, they are only case hardened then likely this would work even for larger sizes. I wonder if they could even just be "spot softened" - just heat spots on opposite sides of the ball to allow drilling.

I've got some old bearings around somewhere - maybe I'll make a few tests . . .

 

[kd0afk]

I think I read a thread somewhere that they used a dull drill bit to friction heat a spot so they could drill. You just maked me member it.