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Need Some Help With my Steering

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Old 03-27-2014, 10:37 AM
  #1
Stargate-SG1
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Default Need Some Help With my Steering

Well I've started this build, and really I have no clue what I'm doing. I'm just sort of running around trying to make this work. Anyways I don't want to re-explain everything I'm doing since I have documented most of it here : http://traxxas.com/forums/showthread...Y-RC-Car-Truck .

Basically I'm trying to build a large electric rc on the cheap, but I'm worried about my steering. I know it's not the best set up but its what I came up with, but there is a lot of drag. I was wondering if you guys had any tips for me, I'm fine re-working the whole system, but I'd like to keep it on the cheap side.

ps. you can just skip to page 2 post #51. Thats where the first pictures of my steering are.


Thanks
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Old 03-27-2014, 12:34 PM
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Are there bearings inside the steering knuckle?
If not, you will need to have some in there.
If there are, I'm wondering if the steering knuckle itself is rubbing against the chassis where it's mounted?
Washers between the centre part of the bearing and the chassis will help.


Also, the axle is really quite long.
The distance between the knuckle and the center of the front wheel could be shortened.
Try to make the front crossbar wider and get the knuckle closer to the wheel.


Hew flexible is that angle steel you're using?

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Old 03-27-2014, 01:27 PM
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Maybe this pic will explain it a bit better









Bearings inside the knuckle, preferably a press fit.
Part A against the knuckle and part B has to move freely.
Note the washer between car and bearing.
Same size as part B.
A tube between the two bearings, the same size as part B will help stop the bearings "pinching" when you tighten the bolt holding it all in place.










Also, look at making the frame narrower to allow for the wheels to be mounted closer to the knuckle.
This way the front wheels will turn tighter, rather than moving in such a big arc.













Or take it in like I've done here:










Hope this helps

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Old 03-28-2014, 09:31 AM
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Thanks a lot,
Yeah I don't have any bearings in there, but I haven't been able to find any that might fit in there. Do you any good site where I might be able to find some?

I'm not quite sure what you meant about shortening the distance between the knuckle and the center of the wheel though. As far as narrowing the frame goes, I probably could do that, but right now it actually doesn't rub the control arm. The hub of my wheel rubs the axle housing.

When I started building the angle steel seemed pretty rigid, but I can tell it flexes a little underneath the weigh motor and everything else.

Where did you get those tires? They look pretty cool.

Thanks.
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Old 03-28-2014, 09:50 AM
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Sorry double post.
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Old 03-28-2014, 01:21 PM
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Most of my bearings are from things I pull apart like old drills, angle grinders etc.
I've got a good scrapyard just down the road.
I also buy some from a local bearing shop when I need bigger stuff.




What I mean is shorten the axle the front wheel sits on.
See how close to the knuckle my front wheels sit in the pics compared to yours?












The wheels in the first pic I bought online.
They're some kind of 1/5th scale monster truck wheel.
Not very good, the glue lets go and they are hard to mount securely.


The ones on the big rusty one are from a pocketquad.
As is the rear axle.
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Old 03-30-2014, 12:20 AM
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Hey Stargate,

Ive never got any bearings from these guys before but they got heaps, and good deals for 10 pce bearing sets.
http://www.vxb.com/

Im in NZ so Ive used this guy. He says free shipping for orders over $50 (have to check if thats for international tho)
http://www.nzminiaturebearings.com/shipping

Cheers
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Old 03-30-2014, 12:33 PM
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Thanks guys, that helps a lot.

As far as getting my wheel close the knuckle its actually about as close as it can get to it. The pictures i have of it are without the nuts holding them in place, so they kept sliding out. But with he nuts on there the hub of the wheel is within about 1/2 inch of the knuckle.

Thanks leeber for those sites I think I found some that will work on the miniature bearings site, but i'll need to double check the measurements.

One more questiondo you guys know of any good servos? I found these the price and specs look pretty good but im but they seem really cheap compared to some of these hi-techs I'm seeing. http://www.hobbyking.com/hobbyking/s...3kg_21sec.html



But this is more what i would expect to pay for a servo of this size. But if I can get away with the cheaper one i would MUCH rather do that.

http://www.servocity.com/html/spg805..._rotation.html


Thanks guys!
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Old 03-30-2014, 03:56 PM
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Quote:
The pictures i have of it are without the nuts holding them in place, so they kept sliding out.
Ah yes I see what you mean now.
I got hung up on the pic where it's sitting on an angle and the wheel has slid off.


As for steering servo, I've been using a Hitec HS805BB for all my homebuilds, including the very big and heavy rusty one I posted a pic of above and it handles it no problems.
As long as you get rid of the drag in the steering it should be fine.
I usually have mine connected about halfway up the servo horn for better torque.
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Old 03-30-2014, 03:59 PM
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I've made an aluminium backing for the plastic servo horn to strengthen it a bit as well.

This steering setup is about as simple as it can get, but very effective.
Note the adjustment points at the rod ends and also on the linkage between servo and steering rod.


here's the project thread on that build by the way FERAL (Just a bit of fun)


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Old 03-31-2014, 05:03 AM
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Thank you, I had almost convinced myself that I would actually need something closer to this http://www.servocity.com/html/heavy_...l#.Uzlkw863PMI But at $300 this build would have gotten really expensive really fast.

I noticed that it had nylon gears, but there was a metal gear version too. Have you ever stripped any gears? Or is the extra $20 for the metal gears not worth it?

Also the steering rod looks a lot like a gas shock or something, is that what your using as a servo saver?

Thanks for posting the link to your thread, I was actually about to ask you if you did a build thread on it.


Sorry one more question, What size BEC are you using, I was lookin on the spec sheet, and it said it pulled like 800ma with no load, would a 10amp BEC be able to handle it?

Thanks for all your help.
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Old 03-31-2014, 12:37 PM
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Amazingly enough I've never stripped any gears which is strange considering the amount of abuse the servo has taken.
Never had a servo saver on any of my builds either.
I did strip the spline that the servo horn sits on however.




The steering rod on that build is an aluminium tube which I threaded on the inside to be able to adjust the length.

Have a look here as well : Alloy Monster MKIII
i think the specs of those batteries are listed in that thread somewhere.
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Old 03-31-2014, 02:02 PM
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Anyway, keep us posted and show some pics of your progress
I'm keen to see more of this project.


Any more questions, just ask.
I dunno what happened to all the other homebuilders here on the forum.
Thought a few more would have chimed in by now...
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Old 04-10-2014, 02:40 PM
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Any progress here?
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Old 04-14-2014, 01:48 PM
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Sorry, no progress. School is finishing up so i have been super busy with papers, projects, tests, and prepping for finals. After school's out I will be able to work on it though.
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Old 04-15-2014, 04:10 PM
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That's ok, I was just checking that you didn't disappear back to that other forum without keeping us updated
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Old 05-19-2014, 06:38 PM
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OK a slight update, I ordered some bearings that I thought would fit, but they don't fit as well as I would like in the spindles, and I could probably bore them out and maybe find a bearing that fits right. But that is a lot of work to try and save a system that wasn't very good in the first place. So I ordered a whole steering system for a go kart. I think this should work out all right, it says it comes with bushings, which isn't as good as bearings, but hopefully that will work out alright, if not I'll try to find some bearings for those.

I am waiting for some stuff in the mail as far as power train goes, and I have started work on the body. I plan to make the body out of fiberglass and the mold out of card board. I went with a 1985 Toyota HiLux because it is already pretty boxy so when I make it and it's boxy it won't look quite as bad. Plus it has a bed, so I can put stuff and maybe even my 6 year old sister in the back and give her rides around the neighborhood.

Here's what It looks like so far. It isn't great, but it looks better than nothing.




Anyways that's all I have so far, but after I work out this steering stuff it is just about ready to drive.
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Old 05-22-2014, 10:52 PM
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Haha, first thing I thought when I saw the pic was HILUX.
Looks good!
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