Ideas to make Beetle IRS arms? Done and thanks!

[Foxer]

I need to build the diagonal arms for the rear IRS suspension for a '69 Beetle I'm working on. I think a buildup of styrene strips can do the arms with some tubes at the ends. I'd like to model the ribbed boot covers at the axle end similar to the ones already on the kit. Here's a photo of the kit mocked up .. And, here's some photos of the Beetle IRS added in 1969. The diagonal are is the only piece I really have to add to make it look right. The diagonal are is at the upper right of this composite photo. I'd appreciate any comments and ideas about how to make this part you may have. There's always more than one way to turn a wheel

Edited June 15, 2013 by Foxer

[pandamonium2112]

First question you have to ask is: Is this in my skill level?

If you can do it. Go for it.

I think styrene is going to be your best option because of the thickness variable, it gets wider, the further back you go.

I think I would start with 2 strips (one for each side) as wide as the skinniest point (where it bolts to the engine) Heat and bend will be the tricky part but once you get them to length and bend, layer strips to them and sand them down to get that gradual widening affect.

It's do-able and it would add so much to the build if you can pull it off.

[VW Dave]

I'd say the conversion is well within your skills, Mike; the inner and outer CV joints on an IRS axle are the same, so I'd either use 4 of the Tamiya kit parts or cast copies of just one...those kit boots are incorrect anyway, as the OE swingaxle boots were smooth rather than ribbed. To do the conversion with 100% accuracy you'd have to modify the kit's transaxle as well, because the swingaxle and IRS units are physically different in more than a couple ways.

*VW geek moment for me: while 1969 was the first full production run for it, the IRS trans was actually introduced to the Type 1 part way through the 1968 model year, but that was only for the autostick-equipped cars

[Foxer]

Some good thoughts to ponder from you all ....

I'm sure I can do Steve's method of building the arms up, even starting with a center piece that would end up as the seam that is so noticeable.

I have a Tamiya Karmann Ghia that would have the boots for casting, but all my casting needs are too small and in between to get new resin to do it. I might try turning some plastic rod on my Dremel "lathe"

And Dave, I do know the IRS was on the '68 Autoshift. My wife had one and I saw it on the lift after I bent the main shaft of the transmission! . I better fess up ... I added a two barrel carb to it and at least I knew I also needed a centrifugal advance distributor also thinking I'd lose the vacuum line. What I didn't realize was the autostick also had a vacuum line that seemed to control the shifts. So I just connected the new carb's vacuum to the transmission line. Obviously, the vacuum levels were different. When the transmission shifted it did it with a bang and a jolt! I drove it like that for a month or two ... until the main shaft bent! It was back to stock after that.

[VW Dave]

I think the center piece seam idea is a good one, and you could maybe use styrene tubing to get the outer shape started too.

Lemmee check my spares boxes...I might have a spare axle assembly from one of the Tamiya VWs that I wouldn't miss

I'm sure I can do Steve's method of building the arms up, even starting with a center piece that would end up as the seam that is so noticeable.

I have a Tamiya Karmann Ghia that would have the boots for casting, but all my casting needs are too small and in between to get new resin to do it. I might try turning some plastic rod on my Dremel "lathe"

[Foxer]

I've taken all the suggestions to heart and have been working on the arms. I have been determined to not change any geometry and left the stops at the ends of the axle. I was going to do the hubs in two halves but this may just be making it more difficult. So I'm going to file the axle smooth so the diagonal (and the boots when I do them) will just slip over the end. I'm going to get the ends done before I add material to the diagonal arms to shape and thicken them. The shocks are mounted to the diagonal arms but I'm gonna just leave them as in the kit and take some artistic liberty.

[Foxer]

The arms are done so here's a shot. I put 3 strips together and a tube on a pin on the inside with a square at the outside. The boots are just three punched out circles.