(Part 2) Reddit mentions: The best ball bearings

I bought these ones from Amazon for $9.98 for a set of 10 in my latest build.

They worked fine for me, and now I've got some spares on hand.

Found some 3/8 Zirconium Oxide Ceramic Ball Bearings on Amazon and decided to go for it. I think it's lighter than SS balls which isn't a problem for me and I just really like how it looks on the turtle

Axial load ratings for these bearings can be roughly calculated using a percentage of the dynamic load rating. In these types of bearings pictured, it is around 30% of the dynamic load rating. So the greater the dynamic rating the greater the axial rating is.

I doubt that most people want bearings to be weaker & fail more often. I certainly, wouldn't want to be pulling apart my expensive motors to replace bearings if i could have a bearing with a higher duty cycle. In fact, The primary bearing we have selected may actually outlast the board. It's massively over-engineered for this use case.

In terms of replacement, The size really doesn't impact that. If we did choose the smaller bearing, the disassembly method, the motor design, the shaft, the bearing seat...etc. would still be similar (just with different diameters), you would just have a smaller bearing that fails more frequently.

And the big bearing actually isn't that expensive, I did take some time to choose one that is fairly common. https://www.amazon.com/6810-2RS-Bearing-Rubber-Premium-Shielded/dp/B012BIS1KO/ref=sr_1_6?ie=UTF8&qid=1491910607&sr=8-6&keywords=6810-2RS

Why buy 20, when you could buy 100?

I just bought an order of those for a mpcnc and they seem pretty heavily greased and smooth.

These WILL fit:

https://www.amazon.com/2x5x2-5mm-MR52-ZZ-Precision-Bearings-Chrome/dp/B00TVPSCVO/ref=sr_1_1?ie=UTF8&qid=1502528708&sr=8-1&keywords=2mm+bearing

https://www.amazon.com/Miniature-Bearings-MR63ZZ-L-630-673ZZ/dp/B00ZHSQX42/ref=sr_1_1?s=industrial&ie=UTF8&qid=1502528834&sr=1-1&keywords=3mm+bearing

Maker Beam starter kit - $112.50 - https://www.amazon.com/MakerBeam-Regular-anodized-including-brackets/dp/B00G3J6GDM

Riuxin Pro knife sharpener kit - $29.95 - https://www.amazon.com/Sharpener-Professional-Sharpening-Fix-angle-III/dp/B015XKSNS2

3" Lazy Susan bearing - $5.95 - https://www.amazon.com/Square-Inch-Susan-Turntable-Bearing/dp/B00ZSQSWTM

-optional-

empty blanks for jig (these are meant to be used as a base for stones, but I just used a glass plate and various grits to flatten them to attach my psa lapping film to) - $28.50/pack of 10 - https://www.amazon.com/Gritomatic-Empty-Blank-for-Stone/dp/B01N0ZINXE

lapping film (I bought 1 sheet of every grit this vendor offers, but I've seen better prices elsewhere) - $5/sheet - https://www.amazon.com/Micron-Lapping-Microfinishing-Aluminum-266Xx1/dp/B071R3S6GS

This is the Amazon LINK. Not sure what you can find in AUS. You can find this on eBay as well.

Slightly jerky movement is ok, as long as the final positioning is correct and increments slowly. Say I take 1 full step per photo, and a photo every 10 minutes. With .067deg/step motor+gearbox, it would go about 10 degrees per day total, which is probably fine since it's roughly 300 degrees per month, so if it happened to be a 3 month video, it would go about 2.5 full rotations.

For stiction, you are referring to the stiction of the interface between whatever is being rotated and the base? I have used a stepper before, but it moved much faster and probably had more torque as a result, and used this 'lazy susan'-type turntable device. Hopefully that would be sufficient for this project, and there wouldn't be any step 'skipping'.

(edit: oh unless you mean internal stiction of the gearbox, in which case... I don't know what to do about that.)

I could sync the shutter and movement, but the movement would take little time and the photo is quick (say 1/60 second), so it would be unlikely that the two would trigger simultaneously, although it would be a possibility.

tl;dr for your final question:
Photos every 10 or 20 minutes, rotation on the order of 1-2 rotations a month, leaving some room to fine-tune the rotation rate.

Apparently they can be obtained from here

Beyond that, could only find passing mentions of Norma bearings.

Amazon appears to have a timken brand 203pp which also had a 6203 listed as similar. Both appear to be 17x40x12mm double sealed single row bearings.

Ha! I broke mine 2 days ago. As far as I can tell, The bearing is a V623ZZ. 3mm ID x 12mm OD x 4mm Wide.

I found these on Amazon. They arrive tomorrow.

I need to replace the bearings in the wheels for my 250R, and having never done so before, I'm a little lost as to which bearings to get. I've found the ones linked to below, are they appropriate for use a motorcycle bearings? They seem to be able to take far more force than you could possibly experience on a motorcycle. I've got the right sizes as well. This is one bearing, the rest are all the same brand/kind ("ZZ", whatever that means).

http://www.amazon.com/dp/B007Z2NT7C/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=10P6D7IALP2K1&coliid=I3KRQ4WT1HVM20

I had a bearing go out and bought the same part number stamped on the bearing from Amazon 6 for $7.

a lazy susan is a flat table that can be rotated, usually used int he center of dining tables to carry commonly used condiments.

easiest way, mount this to your bench, mount a board to the top of it, mount your bottom mold (the cope) to the board.

http://www.amazon.com/Capacity-Bearing-Turntable-Bearings-VXB/dp/B002TIKEQ6

spinning the mold forces the silver to run to the outer areas, in this case deep into the ring mold forcing the silver to reach every area, the oversized sprue is acting as a reservoir so you don't end up with shrinkage porosity ruining the piece.

see also: http://www.ganoksin.com/borisat/nenam/wgc-sprues.htm

Wire straightening is normally done with rollers. If you have some V-groove bearings sitting around, and access to a 3d printer, you can make one in a jiffy. Or apply your own construction techniques...

From amazon

I don't understand how he managed to spend 40 euros on that though. 40 Euros is ~45 dollars.

6003 for $10:
https://www.amazon.com/SKF-6003-2RS1SKF-Single-Ball-Bearing/dp/B0767N6GPF

6204 for $10:
https://www.amazon.com/6204-2RS-Sealed-Bearing-20x47x14-Bearings/dp/B00IK4KX4G

OP overpaid by more than double for bearings.

Same as already said https://www.amazon.ca/Shuster-6203-2RS-Clearance-Precision/dp/B01NBWOEAB/ref=mp_s_a_1_1?keywords=6203-3%2F4&qid=1565217213&s=gateway&sr=8-1

It's on there so tight that I thought this might be the case, but there's a "6200" visible on the bearing, and the 6200 bearings I can find are all separate from a post like so

You mean a ball bearing bushing?

Stock large bearings:

[4 PCS] 6903-2RS (17x30x7 mm) Metal Rubber Sealed Ball Bearing (Black) 6903RS https://www.amazon.com/dp/B076BQ9ZB2/ref=cm_sw_r_cp_api_0m5TBbWQWFR5Y

I used this.

One Square 3" Inch Lazy Susan Turntable Bearing - 5/16" Thick & 200 LB Capacity https://www.amazon.com/dp/B00ZSQSWTM/ref=cm_sw_r_cp_apa_i_dziuDbB1ZASZ4