Chief Delphi - Wheel Axle Material

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Chief Delphi (http://www.chiefdelphi.com/forums/index.php)

- Technical Discussion (http://www.chiefdelphi.com/forums/forumdisplay.php?f=22)

- - Wheel Axle Material (http://www.chiefdelphi.com/forums/showthread.php?t=98641)

Peter Matteson

06-12-2011 07:28

Re: Wheel Axle Material

Quote:

Originally Posted by Ninja_Bait (Post 1088941)

We're working on a WCD drive right now for the off-season (future t-shirt cannon, probably) and we figured that tapped ends, bolts and fender washers would be a better choice than little snap rings.

This is what we do to trap our axles and bearings in place in our drivetrains. But then we do live non-cantelievered axles making this a more logical setup.

Karibou

06-12-2011 08:35

Re: Wheel Axle Material

Quote:

Originally Posted by Ninja_Bait (Post 1088961)

I guess it's just the idea that more metal means more secure. A bolt seems less likely to be wrenched out than a snap ring.

Advice for that method: check those bolts before and after every single match to make sure they're tight. We had one that managed to come loose last year, and it took the span of several matches to fix the damage caused (this was on a normal, run-of-the-mill 6WD, not technically WCD).

On the other hand, I used snap rings for three years with no problems other than "I can't get the @&*#$^ snap ring off".

Brandon Holley

06-12-2011 08:57

Re: Wheel Axle Material

Never have had any issues with snap rings coming off in a properly machined groove.

As someone stated earlier- the grooves are stress risers though so it could be the potential failure point on the shaft if it were to fail at some point.

Tapping the ends of the shafts is also something we've done before with good success.

-Brando

Cory	07-12-2011 02:24

Re: Wheel Axle Material

Quote:

Originally Posted by craigboez (Post 1088919)

This was one of my main thoughts. For the added strength and relatively low weight penalty, why not just use 4140?

Follow up question, again as it relates to West Coast Drives: is it typical to just use snap rings or e-clips on the end of the shafts to hold everything together? It seems that there could be relatively significant side loads at times of heavy turning or impact. Has anyone ever seen a snap ring/e-clip give way?

A 1/2" external retaining ring can take a 4000 lbf thrust load. No problems whatsoever as long as you cut your groove properly.

rcmolloy

07-12-2011 03:32

Re: Wheel Axle Material

Quote:

Originally Posted by Karibou (Post 1089082)

Agreed 100%!

Snap rings, with the correct groove, should do a much better job than bolts because of the actual loosening factor that occurs every match.

ajlapp

07-12-2011 22:19

Re: Wheel Axle Material

Team RUSH has used 1/2" OD 4130 steel tube for the last 4 years with great success.

This shaft material isn't precision sized, so you'll have to do some work to adjust the OD.

I also use snap rings extensively on all 221 Robotics products. They are my weapon of choice!

joek	13-12-2011 19:50

Re: Wheel Axle Material

if the shaft is steel, a snap ring will be more than adequate for almost any FIRST robotics application, so long as the grove is properly made. I have 40 year old snowblowers that use a snap ring to hold the drive platter onto the 3/4" steel shaft. the platter runs straight off the engine, and turns a friction wheel, and i have never heard of any problems with them

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