When I had a single u-joint I used one from a Kia. It seemed to have the right number of splines. They are hard to count. At the end of the shaft I used a piece cut from the thing that connects to the rubber disk.
In your case, Michael, I would get another double U-joint. I'd cut a slit in the end that goes on the rack, and open it up just a little. Then weld some extra material and drill a through-bolt clamp that will line up exactly with the flat.
I'm not sure your set-screw arrangement is good enough, unless you drilled a deep countersink for the grub screw in the rack shaft.
@Gordon Nichols It isn't that crucial for the rack to be absolutely perfectly centered, if it's within an 1/8(+/- 1/16th from center) turn from center the wheel can be turned and the rest can be done with the tie-rods.
Maybe I can fasten two of the Kia u-joints together.
On Sat, Aug 14, 2021, 10:39 PM SpeedsterOwners.com <alerts@crowdstack.com>
wrote:
On Sat, Aug 14, 2021, 10:39 PM SpeedsterOwners.com <alerts@crowdstack.com>
wrote:
I am going to try fastening two Kia u-joints together. I hate to remove my current double u-joint. It is beautifully made. The Kia u-joint seems a bit crude.
I ordered two of the things that connect to the standard rubber disc. I will cut off the splined shaft from each. I will use one to connect the two Kia u-joints together and use the other to replace the 36 spline thing in the end of my steering shaft.
Why not buy one of these and get it welded to one of your Kia U-joints?
https://www.mooreparts.com/ste...spline-x-5-8-smooth/
Or just use this U-joint:
The splined shaft in your first link is what I now have on the end of my steering shaft.
My double u-joint is 5/8 36 spline.
The Kia u-joints are 16mm 60 spline and match the rack.
Exactly. Have another one of those short splined shafts welded into the end of a Kia joint. It will be rack-Kia joint-welded to 5/8 36spline to Empi U-joint to welded spline shaft to steering shaft.
You'll end up using one Kia and one Empi, and it will be a solid and safe splined connection.
I don't know what model of Kia fits the correct spline, but if this spline is common to all Kia, this is how I would accomplish the conversion.
Pictured is a 2006-2010 Kia Optima shaft. I would cut off the side with the 2" stub on it right at the weld. I would then weld an Empi 5/8"-36 stub axle into it. This might take a little lathe work to fit, but no big deal. Then use your really nice double u-joint and it will bolt right up like it was made for it.
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The difference between 5/8" and 16mm is almost inconsequential.
5/8 is 0.625". 16mm is 0.6299". 0.0049", or just a hair under 5 thousandths. It's not a big deal.
Literally splitting hairs, here.
I've no idea what size/spline this is, but from a 1997 Toyota Camry. Looks like a VW rubber steering coupler AND a u-joint!
This looks like what we need, to adapt the VW rubber coupler to the rack, the rack is at a slight angle to the steering shaft.
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@DannyP posted:The difference between 5/8" and 16mm is almost inconsequential.
5/8 is 0.625". 16mm is 0.6299". 0.0049", or just a hair under 5 thousandths. It's not a big deal.
Literally splitting hairs, here.
Danny, the reason I suggested this to Mike, is he already has the really nice double u-joint. Why use a Kia on one end, an Empi on the other, when he already has the joint, just needs to make an adapter for the 60 spline to the 5/8”-36 spline?
The rag joint connector looks interesting.
As an aside, a bunch years ago I remember seeing a car that had a slight misalignment in the shaft, much like we are seeing here. The guy used 2 VW rag joints separated by about 2”. He said it worked great.
I guess. There is more misalignment than a rag joint alone can handle though. I think like Curtissb did, simply extending the shaft and one u-joint is the best solution.
Like I said above, I'll know more when I get my rack. And even though a Speedster and Spyder are the same parts, I have a feeling the misalignment will be a bit more in a Spyder. For you and I that matters.
@LI-Rick, thank you for your suggestion. Because I have drilled out the splines on one side of my nice double u-joint, it wouldn't grip the 5/8"-36 spline shaft. Also, I think the whole assembly would be too long.
When I first built my car I wanted the steering wheel farther from the dash so I did the spacer and two rag joints. It was a bit sloppy. So I replaced one of the rag disks with a Delrin disk. I have the spacer and Delrin disk available if anyone wants to move their steering wheel. It may be necessary to also lengthen the steering tube.
@DannyP, 16mm and 5/8" may be close but my 5/8" u-joint with 36 splines wouldn't fit over the 16mm 60 spline rack shaft. The 36 splines reduce the opening in the u-joint.
Michael, I get that the splines' depth is the problem.
What about a simple tube and another weld on extension directly off the end of the rack? This would take up space so a single u joint would fit and convert to 5/8"-36 at the same time.
I'm considering this myself.
@DannyP, on my Speedster, total length is a consideration. I am going to investigate my two Kia u-joint scheme. The two coupled Kia joints will be longer than my double u-joint so I will have to remove the splined piece from the steering shaft anyway.
With a tube off the rack, how would you fasten it? The end of my bored out double u-joint is essentially a tube
I was going to weld the extension/spline on with this plain steel tube:
https://www.lowes.com/pd/Hillm...BwE&gclsrc=aw.ds
1.5" long and 1/16" wall(0.0625") should be plenty strong.
At this point, I don't want to remove the rack to weld something to it,
Do you think you have more or less space between the rack and the end of the steering shaft than a Speedster?
It should be the same distance as a Speedster. Same column and old steering box, right?
The angle may be slightly different.
Danny, am I understanding correctly, you want to weld directly to the rack input shaft?
Maybe, it depends how it works out.
@DannyP posted:Maybe, it depends how it works out.
I’d have 2 concerns doing that. I would be worried about the shaft seal being effected by the heat. Secondly, the shaft is an unknown steel. It is possible that it is made from 12L14. 12L14 is highly machinable, has great surface finish, and can hold high tolerance. The downside is it is considered unsuitable to weld, as it has a high sulphur content, and leaves very brittle welds.
Nice Danny. You won't be disappointed
I used an empi 5/8" 36 spline u joint (3149). It is split on one end. I used the split end to attach to the 16mm 60 spline rack. It fits right over (tight) and I used a high grade bolt to go completely through the u joint, then added a lock nut. I haven't had any issues. I just welded in a 5/8" 36 spline shaft into my VW steering column (fit perfectly inside the column ID).
additionally, I did not have to extend my steering shaft, actually I had to cut it down.
This rack gives laser-like precision and runs true at high speed (I've had my car over 100 at Laguna Seca). I modified my steering to give a 10% faster steering ratio, but the out of the box ratio is perfect for normal driving.
For a while yesterday, I was feeling like keeping my current setup with the double u-joint and the connection at the rack we questioned.
Before that, I was thinking of linking two Kia u-joints. I ordered another Kia joint and other stuff to do that.
Now, I am thinking of using a Kia joint at the rack and a 5/8-36 joint at the steering shaft. I ordered the 5/8-36 u-joint.
I am accumulating a lot of parts I am not going to use.
Oooo the high cost of R&D... 
Hey, @Lane Anderson! Drive your cute little racing coupe up here to New England! You can climb Mount Washington (6,288 feet). I climbed in on my bicycle, once (once was enough, believe me) and it’s a nice, relaxing ride. Took me 1:57:33 Some other guy beat me by 12 minutes on a Unicycle. 
That last bit above the vegetation scrub line is pure torture because it gets pretty steep. They won’t let bicycle riders ride down, but up is OK. Mt. Washington also has the worst weather in the USA and holds some world records for high wind velocity. Other than that, it’s a great hill to hike (or drive).
Watch out as there are NO guard rails and the drop-off can be a bit abrupt (it is a mountain, after all). The bottom 75% is nicely shaded by the trees which turn to scrub at about 5,000 feet (the wind keeps snapping them off over 20’ tall) and it slopes up to almost an 18% uphill grade once the vegetation ends (6,000 feet)
Here is Travis Pastrana’s record-setting run from last weekend. Notice that the roads curve up here, unlike where YOU are:
I climbed Mt Washington by bike, too, 1:19:47. I finished, threw up, and then everything that could cramp did. I thought they were going to need a hacksaw to get me into the car for the trip down. Once is enough for some things. That's me in the red jersey right about where Pastrana finishes. The bike race keeps going all the way up, there's a 23% switchback just up the road, and those parts of the video that look like the road goes down over rollers? No it doesn't, that's just where the grade eases to like 9%. The video doesn't do it justice. I'd happily go back up in Lane's coupe, though!
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"I'd happily go back up in Lane's coupe, though!"
You're on - uh, the next time I get up that way. 
Actually, I'd love to do that drive in the Coupe. Early indications are that it will be a good traveling car.