Virginia Motor Sport Club Discussion Forums

General => Open Forum => Topic started by: KasbeKZ on July 14, 2013, 10:28:51 AM



Title: Is anyone in the club set up to make suspension bushings?
Post by: KasbeKZ on July 14, 2013, 10:28:51 AM
I need a couple offset bushings and the vendors want rediculous $$ for them. If anyone has some delrin scraps or anything around and has ever done it before or even just give me some advice, i'd appreciate it


Title: Re: Is anyone in the club set up to make suspension bushings?
Post by: Paul Inskeep on July 15, 2013, 01:49:01 PM
I've done it a few times for the XR. Mainly because stuff is hard to find and I'm cheap.

(https://lh3.googleusercontent.com/-a_hY6QxnEgY/UKDoZrlqvzI/AAAAAAAADUg/jFYHNiPKx4g/s903/2012-11-09_16-07-23_558.jpg)

(https://lh6.googleusercontent.com/-oXE5LQXZANY/UKDoZmM5QyI/AAAAAAAADUg/s99scWlKPkc/s903/2012-11-09_16-09-49_875.jpg)

(https://lh5.googleusercontent.com/-nF1UKLOs6Ks/UdCIiyvFjUI/AAAAAAAAKJA/9GuMA7LXpjA/w825-h619-no/20130629_084754.jpg)

(https://lh6.googleusercontent.com/-QhNCTGBHzUk/UdCIi8Qfr8I/AAAAAAAAKJA/k-fp2nhnGVE/w464-h619-no/20130629_094951.jpg)

Its pretty quick depending on how complicated. LMK if you need help figuring it out.

Material wise: Delrin works ok there are a few others that work was well and may be cheaper. I can offer advice in this area too if need be. McMaster Carr is your friend here.

-Paul


Title: Re: Is anyone in the club set up to make suspension bushings?
Post by: KasbeKZ on July 15, 2013, 04:56:14 PM
thanks for the response. the problem i'm having now is finding appropriately length inner sleeves. i need them to be 1 9/16 long with a 3/8 I.D. can't find those. i may have to find a material that i can cut. i'm decently outfitted but i'm no machine shop.


Title: Re: Is anyone in the club set up to make suspension bushings?
Post by: Paul Inskeep on July 16, 2013, 04:52:36 AM
What you need is.

4130 Cold Rolled tubing. Comes in .375 (3/8") ID and .75 (3/4") OD = .1875" wall

I think that is what you see if the picture below, I'm having a hard time remembering.

onlinemetals.com should have it. If 3/4" is too big you can always turn it down a little. Or you may have to open up the inside a hair if the bolt you are using has a 3/8" shoulder. What car is this going on? Does it have SAE or Metric bolts? You may have to turn something a little special but shouldn't be a big deal if you get it close from the get go.

If the bushings are not concentric (like you trying to get camber or caster out of them by offsetting the hole) then take a hard look at what you want to accomplish. This could be the reason the other vendor is so expensive. Press Fits and other techniques come into play a little more.

Hope this helps


Title: Re: Is anyone in the club set up to make suspension bushings?
Post by: KasbeKZ on July 17, 2013, 09:42:16 AM
nice. thank you. i am actually doing off set bushings for the outer link of the rear LCA's in my NA miata. i can't get less than 2* of camber now that i've got the ride height down to a reasonable level.

the bolts will be metric, but i measured the one to be just about exactly 3/8" around o the threads. if it didn't fit i wouldn't have trouble getting it honed or drilled out i don't believe. i'll see what i can do.

question though: is it really necessary to turn those shoulders on the outside edges of the bushings, or could i just make a washer out of a bigger piece of delrin to serve the purpose of keeping the sleeve centered?


Title: Re: Is anyone in the club set up to make suspension bushings?
Post by: Paul Inskeep on July 17, 2013, 10:15:14 AM
Without really studying it I'd say you are fine with washer like substitution. Especially if you can find something that is the correct diameter to start with for the inner part of the bushing. If you are doing offset bushings I'd seriously look into good solid press fits that are designed correctly or other means of mechanical attachment. You don't want your bushing rotating in the control arm and throwing your alignment all to hell.


Title: Re: Is anyone in the club set up to make suspension bushings?
Post by: KasbeKZ on July 17, 2013, 06:21:59 PM
yeah for sure. my plan so far is to drill through the control arms a few times and put some type of screw i there to hold them fixed. the parts sold (for $120!) come with zerk fittings for that, so i figure it may work.

but you're saying that i might be able to find bushings made to the diameter i need with no center hole drilled? that would be a nice find


Title: Re: Is anyone in the club set up to make suspension bushings?
Post by: KasbeKZ on July 17, 2013, 07:46:26 PM
when milling them, how tight do you make them? exactly the same O.D. as the I.D. of the hole you're putting them in? or you add 0.05" or something?


Title: Re: Is anyone in the club set up to make suspension bushings?
Post by: Paul Inskeep on July 18, 2013, 06:32:06 PM
My engineer side says this. Press fit/slide fits all have a range. That range is based on several factors. For example overall diameter of the bushing, material of each (bushing and control arm), type and class of press fit you want and wide range of others. The engineering handbook has pages on the subject.

However my pratical side says for most plastics you will use add .010-.015 (10 to 15 thousands) and call it a day. If you have ever machined plastic you will know this. It moves A LOT under machining making it hard to lock down a finial diameter. Trick here is to keep it cool, turn it fast and don't take too much off at once when you start getting close to finial pass..

You'll figure it out.


Title: Re: Is anyone in the club set up to make suspension bushings?
Post by: KasbeKZ on July 18, 2013, 07:38:03 PM
well fitting tight would be nice, so i'll shoot for around .013 over and see what happens. thanks for the advice.

now the trick is getting a measurement that good of the hole it's going in...