Hopefully Im posting in the correct section. Im not a sheet metal expert & this is my first RFQ here so please bear with me.

1) Material type
Im checking on this now, but Im suggest either 2024 or 7075 based on higher tensile strength vs 6061. ie its important that the shape is maintained under repeated landing loads (4.5# model). If you have some experience or recs in this regard, Im happy to here them. Material thickness = 0.080", I got that nominal (gauge thickness?) dimension from link below & it compares to a comparable gear I have on hand.

http://www.onlinemetals.com/merchant...p=2&top_cat=60


2) Is a material quote required or is material supplied.
Material to be supplied by fabricator.

3) RFQ Quantity = 50

4) Drawings should be immediately available or necessary specs.
- can email provide Rhino v4 cad file (cant seem to upload here today)
- I (attempted to) unfold the 3D bent surface into its 2D-plane pattern if that helps with cutting pattern & estimate.
- I assumed 0.100" bend radius but not sure if this is reasonable with material type, thickness, angle etc (the radius isnt critical, just getting the angles matched correctly)
- suggested tolerance on the pattern dimensions +/- 0.020" (hopefully this is reasonable without adding undue $).

5) Required time frame
about a month, negotiable to your timeframe

6) RFQ ending time = Aug-15-2008


7) Contact information
email petertha@shaw.ca


9) Make known any special treatments/finishes not necessarily related to the machining process.

- no surface treatment required at this point, however, depending on price I would like to investigate cost of top/bot equal corner rounding (bull-nosing) all edges & possibly color annodizing.

- of note, I have other similar parts in consideration, so seeking manufacturing relationship for some ongoing rc model work hopefully

Attached Files

	pc alum gear f1.pdf (8.0 KB, 55 views)
	pc alum gear p1.pdf (18.8 KB, 45 views)
	pc alum gear r1.pdf (5.0 KB, 39 views)

PM sent-let me know what you thnk.
Thanks,
Steve

After looking at your part, it would be impossible to bend aluminum while keeping its strength. Aluminum does not keep its strength when bent. Would you like us to quote cutting the shape of your part w/our waterjet?

Thanks for your reply. In all honesty I thought it would be dead easy, we have used aluminum for years. There are so many similar gears on the market, just happen to be slightly different (=unusable) dimensions. Here is an example for 13$U.

http://www3.towerhobbies.com/cgi-bin...?&I=LXBNA9&P=7

The good ones typically range around 25$ although that may well reflect a larger production volume. I dont have access to those numbers so I cant say.
I do think there must be something to either the alloy selection or possibly post-bending (heat?) treatment only because (from personal experience) it seems certain gears are spongy & deform easily, while others remain stiff & work pefectly - yet are the exact same material thickness & dimensional shape.

Maybe I will try & approach the outfits presently making these & figure out some more. Thanks for your feedback.

A few points to consider:

1.) The material specs for the parts shown on towerhobbies.com indicate the part is made of 3mm (1/8) sheet instead of .080

2.) Material will be weaker once bent, however the ultimate strength of the material before bending is far greater than what these parts will see. (note that the part for sale at towerhobbies.com is not a cast piece but a cut and bent piece)

3.) 5052 is the best suited aluminum for forming and is about 1/3 the cost of 7075 and about 1/2 the price of 2024.

I think that we could make these part for right around you $25 USD mark. If you would like a formal quotation please email me at:
jdavis@eliteweldingproducts.com

Jeff Davis
President
Elite Welding Products, Inc.

Hi Jeff. Thanks for your reply. The tower link was just intended as a pictorial example, not a replacement to the part. The gauge thickness is thinner for smaller models & larger for bigger models as one would expect. I recognize they are bent & not cast. For example, here are 2 more made from thicker material. yet.

0.141” dural
http://www3.towerhobbies.com/cgi-bin...?&I=LXAUR8&P=7

0.240” aluminum
http://www3.towerhobbies.com/cgi-bin...?&I=LXJMB7&P=7

I'm interested in your material suggestion though. I looked up 5052 & it has a tensile strength of 33 ksi. I know that similar gears were using 6061 (45 ksi) & the comment was they were a bit spongy & apparently the better gears used a stronger alloy. Does 'dural' correspond to a particular grade? I had mixed results searching it, seems like its more of a tradename? (but some reference made to similarity to 2024 ..."The name is obsolete today, and mainly used in popular science to describe the Al-Cu alloy system, or 2000 series as designated by the Aluminum Association"

http://en.wikipedia.org/wiki/Duralumin
http://www.onlinemetals.com/aluminumguide.cfm

Peter,

To the best of my knowledge duraluminum is 2024 or was a very close equivalent. 2024 has the second highest hardness and yield strength of the commonly available aluminum alloys.

If I understand correctly from your previous posting you are looking to manufacture these part for resale. If this is in fact the case I would recommend a test group of the two different materials (say 5 pcs. each) to determine suitability for your application. Both, from a manufacturing stand point as well as field tests of the product.

Please let me know how we may be of service.

Jeff Davis
President
Elite Welding Products, Inc.