MikTip

I'm afraid to install'm! They looks so good! ;O)

They are by far "thee best" bushings I've ever bough & installed on my Audi! I've had every type available too!

Just waiting for my RS2 front anti-sway bar! ;O)

VAP

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between turning centers. Then the CNC lathe makes 4 identical passes, each one a little deeper to achieve the desired depth of cut within the stainless steel OD to hold sufficient lubricant. Once its done each piece has to be removed from the live centers by hand and a new one installed between the live centers. Then the process repeats itself.

I only made 30 sets of these for the B4 as each "set" represents 4 stainless bushings (120 total) and 8 Acetron GP bushings (240 total).

Pic is of about 1/2 of total run after grinding/boring but prior to helix grooving or final length finishing and during one of 6 "wash" stages required during manufacture to keep them absolutely "clean" at "every" stage of machining.

Jretal

I'm curious if I could get away with doing a helix on the inside of the bushing (softer material that I could do it one pass) by hand without a CNC pull. Obviously it wouldn't be as accurate or clean, but it'd probably do the trick. whaddaya think? You're more experienced with this stuff than I, so you'll have a better idea of whether it's feasible or not.

VAP

First it reduces surface area that the stainless bushing will wear on which will cause accelerated wear to the "softer" material tho by how much I cannot say. Far far better to have the helix in the harder/longer wearing part. Second, its difficult to find a small enough tool to fit inside the bore and have sufficient "relief area" so the CNC can move the tool in to make a cut in the bore wall then move away from the cut while making the helix. Thirdly, the Acetron is so slippery that its hard to hold in lathe jaws without it slipping/spinning within the chuck unless gripped HARD! Hard enough that it makes deep indentations where its being held. Thats why these are best made on "self-feeding" CNC lathes using material that is "at least" +/-.250" larger diameter O.D. then the 2.09" OD finish-size so that as each Bushing is made it is cut and falls off the longer piece where it was clamped "deeply" but those clamp indentations were machined off as each one was turned/profiled to its final shape then parted from its original length. Once its shaped and parted from the long (8 foot) self-feeding rod it can no longer be chucked up in the lathe as the chuck jaws would leave deep indentations in the finished part if re-gripped by the chuck jaws. Those indentations would be on the precision-fit smaller diameter "finished" parts that go into the control arm bushing.

But no matter where you locate the helix you still can only achieve it via CNC programming as no one can do a nice, even or "planned" helix spiral by hand. Especially one with a "blind" end that stops before reaching the outside end of the part its being machined into. And if its not a blind-end helix all grease/lubricant is free to escape out the outer ends of the bushing which defeats 100% of the reason for using a helix in the first place, ie; "lubrication retention."

odelay12v

wow

Jretal

which was, could the helix go off the edge... I was figuring it could, but you basically gave a very good reason why it shouldn't... easy path for the grease to escape and dirt to enter!

I'm gonna start asking some sources I have in the area and see if there's a machine shop that someone knows someone that would like to either a) let me use their machine or b) work for some beer haha. If nothing materializes from it, no harm no foul for sure.

Thanks for all the explainations, Mance. I've learned a lot of this stuff in the manufacturing stuff I did in school (and did some hands on with the lathes) but I never went as indepth with the CNC lathes, only the CNC mills.

CrazyCab

and it is one of the more difficult toolpaths to generate in the G-Code / CL Data world. To create this type of toolpath on a software basis alone would require you to have about a couple thousand dollars worth of CNC programs around (unless you are using some of the older more cruder technologies). But more importantly, the software and hardware is one thing, but the education and ability to program such a toolpath is another, and this is the where it all begins, if the toolpath created is crap then the finished part will be too.

Note: G Code is a standard language that CNC machines understand, CL Data is what all those CAD/CAM packages output so that it may be converted to CL Data.

Jretal

I've designed things (most extensive was a matchbox mold for injection molding) on a 3d design program (IDEAS), did the tooling paths, then uploaded it onto the CNC machine... so I've never "written" the code myself... I had the computer do it for me basically.

Word on the street though is that we have a functioning machinist lathe in our factory, so I might be able to work with this... we'll see.

Another idea for the helix though, tell me if this is feasible. Make a series of rings that are parallel with the ends, and then cut a groove on several sides to join them together, basicalyl making a grid... would that also work? Just curious.

A side view would look like this: |-|-|-| where "|" is the parallel and "-" would be the connecting runner...

Jretal

Make a series of rings that are parallel with the ends, and then cut a groove on several sides to join them together, basicalyl making a grid... would that also work? Just curious.

A side view would look like this: |-|-|-| where "|" is the parallel and "-" would be the connecting runner...

VAP

you can but it, by design, will tend to be abrasive and try to gaul into the softer plastic