Next installment... Unlike most R/C models, R/C tanks get really really dirty. Here's one of the suspension arm bearings after eight years of use. It still sorta worked in that it turns somewhat in the limited arc that the suspension allows but is a bit "crunchy". These wheelbarrow bearings, and I've since learned their better known as "Freeway type" bearings (after the original manufacturer), have an almost 1/16" gap between the shield which allows crap to get in. Since I wanted to use these bearings in the wheels themselves, I wanted to see if I could harden them against the elements so to speak.
<https://lh4.googleusercontent.com/-A7xSKbJiXB0/UqXa2OaSChI/AAAAAAAAAX0/2tPPlU8B8BM/s1600/2013-12-08+10.23.53-B.jpg> My first experiment in bearing sealing was to coat the inner race with oil and then apply a bead of R6000 adhesive around the face. The thinking was that the adhesive would not adhere to the inner race and form a flexible seal once dry. I was wrong. The glue grabbed the inner race very nicely as this pick shows. <https://lh3.googleusercontent.com/-1EFPwq7AUqc/UqXdTtJXMWI/AAAAAAAAAYA/K1WDqZ_TwiQ/s1600/2013-12-08+10.23.22-B.jpg> My next thought was using felt washers cut to fit the bearings and I'd actually found some from a wheelchair parts company that would fit, but the pricing was more than what I paid for the bearings themselves. I was almost resigned to buying the felt when one day waiting in the grocery store express checkout, I spied bags full of colorful tiny rubber bands meant for kid craft projects in the bargain bin. They looked about the right size so I threw a bag onto the conveyor (still keeping under the 15 item limit of course ;-). The bands turned out to be the perfect size. Two of them stacked quite nicely onto the inner race, covering the shield gap and reaching to just below the top of the bearing. <https://lh4.googleusercontent.com/-aWaKZZ4QDzo/UqXeP5xXrtI/AAAAAAAAAYI/ZcBUtI4wXyM/s1600/2013-12-08+10.15.53-B.jpg> A bead of R6000 is run around the face. <https://lh5.googleusercontent.com/-dz611_kGr40/UqXgMcl-SuI/AAAAAAAAAYU/fDq7ayhZILo/s1600/2013-12-08+10.16.01-B.jpg> And once dried, we have a sealed bearing! <https://lh6.googleusercontent.com/-Km04IoF93A0/UqXgXPYwZjI/AAAAAAAAAYc/1-PV7_r6Zkc/s1600/2013-12-08+10.15.02-B.jpg> Something I never built into the original Cromwell suspension was a top stop on the arm travel. With no top stops, the springs themselves acted as the stop when they fully compressed. After a couple of years I started having problems with springs getting all "bent all of shape" so to speak (especially the front ones that see the most impact). To address the problem at the time, I had cut short lengths of fiberglass rod and inserted them inside the springs to keep them from fully compressing. This worked OK but for the rebuild I wanted to do something a bit beefier, so came up with this. 1/4" bolts with nuts on them are installed at the right spots to stop the arms (leaving the springs just short of full compression). I also figured that a fender washer with a slight bend in it would work well as a spring retainer (i'd had a couple of springs slip out over the years). <https://lh5.googleusercontent.com/-0YxOVi2BdvA/UqXgy4vQtZI/AAAAAAAAAYk/09n1JQr34Iw/s1600/2013-12-08+13.06.04-B.jpg> Here's a better shot of the updated suspension setup with a wheel in place. You can see how the stop limits the arm travel and how the bent washer keeps the spring in place. That blue thing at the end of the spring is a small rubber faucet washer that acts as a cushion between the spring and wood. <https://lh5.googleusercontent.com/-5iSg9uAiPQg/UqXjT9y066I/AAAAAAAAAYw/QOh3-227uGo/s1600/2013-12-08+15.54.29-B.jpg> I mentioned earlier that I wanted to cap the outside wheel bearings to keep the gunk out. I found these plastic caps meant for the end of table legs at the hardware store that looked about the right size. Cut to length, they fit snugly in the bearing hole and hopefully a bead of R6000 will keep them in place. <https://lh6.googleusercontent.com/-A8ICAYr3GXA/UqXkVehbRbI/AAAAAAAAAY4/XjqaGYgMY2Y/s1600/2013-12-08+14.11.19-B.jpg> I'm not sure if the suspension bottom retaining bar was ever highlighted in the original build photo's so here it is. This keeps the suspension at the correct height. <https://lh5.googleusercontent.com/-ujC-esgWrUk/UqXneYtuC0I/AAAAAAAAAZE/IbsKU2YR7NY/s1600/2013-12-08+15.56.10-B.jpg> That's it for now. Steve Tyng -- -- You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to [email protected] To unsubscribe, send email to [email protected] Visit the group at http://groups.google.com/group/rctankcombat --- You received this message because you are subscribed to the Google Groups "R/C Tank Combat" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
