RFQ: Stailess Steel or Aluminium "wheels"

Cabbagecreek · Jun 29, 2016

[Sketch1 of steelpoolwheel.SLDPRT _].jpg

The "wheel" can be made of stainless steel or aluminium.

The drawings are made in SolidWorks and can be transformed to many formats. It was not possible to upload the drawing because the drawing is 122kB

The wheel is 35mm OD and 22mm ID and a grove inside and the wheel is 10mm thick.

I need 60 wheels.

Milland · Jun 29, 2016

It looks like you're sizing the wheel for a 22mm x 7mm bearing, if that's the case you really should have a more controlled spec for the bore. Instead of calling out 11mm for the radius, use something on the order of 22.01 +.02/-0 diameter for a slip fit, or 19.995 +.005/-0 for a press. You may want to control the OD more carefully too if you'll have multiple wheels working together, as otherwise you may wind up loading one while leaving others with light or no loads.

Big difference in wear life and debris generation between stainless and Al, not to mention machining cost. Give us an idea of the purpose and environment for the part so we can offer advice.

Finegrain · Jun 29, 2016

Milland said:
It looks like you're sizing the wheel for a 22mm x 7mm bearing, if that's the case you really should have a more controlled spec for the bore. Instead of calling out 11mm for the radius, use something on the order of 22.01 +.02/-0 diameter for a slip fit, or 19.995 +.005/-0 for a press. You may want to control the OD more carefully too if you'll have multiple wheels working together, as otherwise you may wind up loading one while leaving others with light or no loads.

Big difference in wear life and debris generation between stainless and Al, not to mention machining cost. Give us an idea of the purpose and environment for the part so we can offer advice.

+1 on all of that, especially the material. Huge difference in final per-part cost between Al and stainless.

Regards.

Mike

Cabbagecreek · Jun 29, 2016

Your reflection is perfectly right !!

The wheel is for a pool cover. The original was with open bearings and dirt has destroyed them.

It is designed for a cheap 22/8/7mm bearing because the original bearing was impossible to find.

The wheel will rotate with a speed of 16mm/s so I think the rubber sealed bearings will last for a lifetime ;-)

Stainless steel is prefered but is more expensive. Aluminium is a more cheaper solution.

DanielG · Jun 29, 2016

Also, you might double check the dimensions on your snap ring groove. It looks much deeper than I've seen for standard snap rings.

Milland · Jun 29, 2016

Cabbagecreek said:
Your reflection is perfectly right !!

The wheel is for a pool cover. The original was with open bearings and dirt has destroyed them.

It is designed for a cheap 22/8/7mm bearing because the original bearing was impossible to find.

The wheel will rotate with a speed of 16mm/s so I think the rubber sealed bearings will last for a lifetime ;-)

Stainless steel is prefered but is more expensive. Aluminium is a more cheaper solution.

Thanks for the extra information. If the loads are relatively light, you might also consider using black Delrin (acetal resin) for the wheel material, which would be cheaper than Al and less prone to marking up or particle generation on a smooth surface. I suggest black due to better UV resistance, if this is an outdoors application. If running on a rough surface, or under higher load, then stainless might be best.

On DanielG's mention of the snap ring groove geometry - you might also want to change your 6.9mm width to allow for the full nominal 7mm bearing width - I'd rather have the defined geometry than count on extra groove width to allow snap ring insertion.

Cabbagecreek · Jun 30, 2016

The snap ring is 1.1 mm thick and the grove is 1.3. The 6.9 + 0.1 = 7mm for the bearing and still 0.1 clearence for the snap ring. The deepth of the grove is taken from Solidworks and a standard snap ring. I will doublecheck.

I have tested PLA printed wheels. They are not strong enought. Delrin is much stronger. Black Delrin is a good suggestion.

The wheel-path is inside an aluminiom profile. Dirt will get in (but never out ;-) This is the main reason why the open bearings failed.

Milland · Jun 30, 2016

Yeah, inside an Al extrusion with an Al wheel is a tough one, as the two will try to eat away at each other. If you can use a plastic wheel I'd do so. If the loading is high enough, and you've got a flat section to the bearing point of the guide extrusion, you can increase the profile radius of the wheel to give a greater contact patch.

You might even looking into using a good sleeve bearing rather than a ball if the holding fastener is hard enough to act as the rubbing surface. A soft (presumably stainless) steel bolt may not be ideal, but a fancy alloy like A286/Alloy 660 (USA spec) might do well. Or a soft bolt with a hard stainless sleeve over it and a flat washer to retain it and the wheel.

DanielG · Jul 1, 2016

Cabbagecreek said:
The snap ring is 1.1 mm thick and the grove is 1.3. The 6.9 + 0.1 = 7mm for the bearing and still 0.1 clearence for the snap ring. The deepth of the grove is taken from Solidworks and a standard snap ring. I will doublecheck.

I usually pull the dimensions out of the Rotorclip catalog. They list tons of ring styles and is available as a free PDF download.

Cabbagecreek · Jul 6, 2016

I still need a price and a deliverytime.. I think that I expand the material to include platic(delrin)

Milland · Jul 6, 2016

Cabbagecreek said:
I still need a price and a deliverytime.. I think that I expand the material to include platic(delrin)

I'll send you a email (via PM) with my address.

Peter Colman · Jul 17, 2016

PM sent,can ship to Sweden easily.

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RFQ: Stailess Steel or Aluminium "wheels"

Cabbagecreek

Plastic

Milland

Diamond

Finegrain

Diamond

Cabbagecreek

Plastic

DanielG

Stainless

Milland

Diamond

Cabbagecreek

Plastic

Milland

Diamond

DanielG

Stainless

Cabbagecreek

Plastic

Milland

Diamond

Peter Colman

Stainless

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