Hey guys

A friend of mine who's not really on the forums has been working on making urethane diff bushings for the FD. He spent a LOT of time getting these just right, since urethane is VERY difficult to cut accurately. He finally found a way, and got a set produced.

In short, he's thinking of making more of these if there's interest, and that'll obviously depend on an unbiased third party's trial, experience, and writeup. So I'm looking for someone willing to give these bad boys a shot. I think you'll be pleasantly surprised, as I had this guy make me a few parts (that require machining etc) and his work is excellent indeed. That's just an attestment to his workmanship.

These bushings were actually a huge PIA for him to make (he kept on calling me and complaining LOL). The reason being, since urethane is so hard to cut accurately, these CANNOT be machined. They must be done by hand, so basically he's gotta do one set at a time. Oh, and these bushings are made of 90A polyurethane, which is the expensive high-grade material.

In all honesty, I'm looking for a well-known and respected member known for his experimentation to try these out (like Paul aka Rotorbrain), and report back to the forum w/ his honest impressions.

Thanks!
~Ramy

Pics of the finished product:

 

I'd be willing, but prob lookin for someone who is better known. I'll have to keep an on how it turns out though.

 

hey ramy. . . ill give em a shot w/o a doubt. david might as well. we have been looking into some poly bushings for most everything and ive been planning on changing the diff bushings out for a while now. so, yeah. . . just let me know what i need to do.

id be more than happy to check em out. . . and you can be assured that the test post will be nice and comprehensive. . . cause. . . i have a pregnant wife and shell be able to sense anything different.

paul

 

are future sets going to be hand cut also? i would think it would be kinda hard to duplicate the hand cut each and every time.

 

Good Point, but I'm sure he has some kind of tool for fitmint...just a guess though.

 

pearlyellow, thanks for the offer, but my man Paul is up for it

Paul congrats on the baby He's a future RX7 tester already!

What you need to do...umm...PM me your mailing address? hehe It's that simple. They're free of charge.

Alberto, they're not cut by hand physically. What I meant was, he can't just program a machine to cut it, so that it's automated/independent. In fact, it isn't being "cut" at all. He's using a grinder which must be operated by hand - the urethane simply can't be cut within such precise tolerances. The grinder has tolerances of 1/1000th of an inch (.001), so it's very accurate.

I hope I didn't explain anything wrong, since I'm not a machining guru. I'll see if I can get him to post a little blurb about how he's "cutting" them and how they can be replicated within very narrow tolerances.

 

Just a little advice about cutting plastics\urethane on a lathe or mill , you cant inch up to your final dim. you need to take of a pretty large amount (for example .062 of an inch or more). The right kind of cutter will make a big difference ofcorse. In other words I would do a precut that you can assume to be about .062 from your finnal dim. then measure, then take your final cut after that. plastics and urethanse will flex away from your cutter and seem to be more accurate with larger cuts (as long as you measure correctly). exactly the opposite of steel\aluminum.

just .02$

P.S I am not the one machining them.

 

Ramy thanks for posting this for me.

As Ramy explained above. I've tried differentways to cut urethane but I couldn't find nothing to work, except grinding it. It's a huge PIA. I can hold +- .001 with the grinder but I think +-.005 is good enough for bushing.

I am going to send rotorbrain a set with .005 different from each other. We'll see how it turn out.

Thanks