Tag Archives: steering box

Still thinking about improvements

Yep, mind still churning about the Sprint-T. This time I’m thinking about how to mount the steering box.

There are two orientations the box can take and still turn the front tires in the correct direction as commanded by the steering wheel: the kit orientation was pitman arm pointed forward controlling a steering arm pointed back, or the OE orientation of the pitman arm pointed back controlling steering arms pointed forward. The problem I’m trying to solve is making room for the engine and radiator and also sneaking the steering shaft from the steering wheel to the box around the radiator without hanging out in the breeze.

Aero is not critical but it is important for freeway fuel economy. I mean there is going to be a lot of junk hanging in the breeze simply because T-Bucket, but that’s still not an impediment to decent but not fantastic aero. For examples of decent aero and exposed wheels see https://www.google.com/search?rlz=1C1CHBF_enUS809US809&sxsrf=ALeKk02olFWp4zhsrQs1tNKIuVFdAMTU0A:1602022917053&source=univ&tbm=isch&q=images+lakester+racers&sa=X&ved=2ahUKEwiP3JG3gKHsAhUEKawKHdSNBDoQjJkEegQIChAB&biw=1517&bih=694 “lakester racers” that are required to have exposed wheels. The old belly tank racers are a good example of that.

Anyway, I have been thinking about it and there is a 1½” gap under the radiator because it sits on top of the frame that would be good to sneak the steering shaft through without hanging out in the breeze. The closest to a problem would be clearance for the U-joints to turn that close to the bellypan. And something to block the air from going under the radiator, but that would be a great place to mount the bearing that guides the steering shaft under the radiator. I really need to find out how big are those U-joints that connect to the steering shaft. I may need to make a relief bump in the pan for the U-joints to swing, but if I need one it wouldn’t be very big.

The other problem is properly bracing the top of the box to prevent it from rotating in reaction to the forces from the pitman arm hanging off the bottom of the box. Side to side is easy, just weld the mount to the top of the frame rail. Boom, you’re done! The other is a bit more tricky, because there has to be something to brace against to do the top part of the mount. On the kit the mount welds to the side of the frame rail, so the twisting moment from the force through the pitman arm is close to zero and is resisted easily by the sheer mass of the frame rail and the extremely short arm the force has to act through. It’s basically all sideways against the rail for the kit mount. Now there is another frame rail to run a brace from on the same side of the frame, plus its mirror on the other side of the frame for slightly better angle on the force. Which brings us to the actual point of the post, the reason why I mentioned the OE orientation of the steering box: I’m thinking of attaching the steering box mount to the front bulkhead with the drag link under the steering shaft and ahead of the axle.

If I move the box in front of the axle, then I could brace the top of the box against the front bulkhead at whatever place is convenient to mount the brace. The bottom of the mounting bracket still mounts to the frame extension that also acts as the mount for the panhard rod. As a point of fact, that was the original reason for the frame extension in the first place, someplace to mount the frame end of the panhard rod so the panhard rod could be the same length and parallel to the drag link for no bump steer. And now it looks like I only need to make a slight adjustment to the front of this extension to mount the steering box, because there are braces from the bulkhead in two directions to locate the front and triangulate it in two dimensions, and the vertical one can be used as the actual place to weld the mount.

So these are the pros and cons of moving the steering box in front of the axle:
Pros: simplifies the top mount of the box, lighter, gets the drag link completely away from interfering with any suspension links.
Cons: puts weight in front of the axle, increases to moment resisting changes in direction, susceptible to damage when hitting curbs while parking.

And that last one is only mentioned because it is a slight possibility, not because it’s likely to happen, and a curved skid plate in front of the box will prevent even the slight possibility from coming true. Or it might not even be a possibility because of how high the box has to be mounted for the drag link to be level, especially if I don’t drop the drag link at the steering arm on the spindle. I think mounting the drag link to the top of the pitman arm and the bottom of the steering arm will give enough offset to prevent binding. This will raise the bottom of the box to about 9-9½:” above ground with the street tires. Considering the frame is about 6″ above ground with the street tires that would be a very tall and vertical curb to hit the steering box. It would have to be a really tall and narrow parking bumper that didn’t block either front tire, a freak of parking bumpers.

And I still haven’t gotten this editor down pat, because I have no idea how to insert text to a link and not leave the URL all over the page, so I’m going to quit fighting it and publish the post.

It’s finally here!

And by “It” I mean the steering box that has been on backorder since early June because of the Stupid Virus. I’m changing the name because the existence of COVID19 seems to make people stupid, besides what it did to my employer and the GOP. Anywho, this is a picture of it below.
Steering box, remotes and bumpersticker for scale

I’m keeping it in the plastic bag for the nonce, having learned my lesson about surface corrosion from the spindles I bought a few years ago. I may be slow, but I’m not stupid. And FYI that thing is HEAVY! no, it’s HEAVY! That tiny chunk of metal has to be over 15 pounds (6.8 Kg) which brings up the question of why they still use iron in the main casting? Probably because steel or iron is cheaper than aluminum, but then the question is why it isn’t an option since this is a repop for a part that has been out of production for five decades, the Vega stopping its run in 1977, and presumably GM stopping production of replacement parts shortly after.

And it turns out that it was fortunate I bought the Pitman arm for the 5/8” heim joint, because this was shipped with the arm for the Ford taper tie rod end. There is something I can use the extra Pitman arm for, by placing the two arms side by side with the ends reversed I can get an fairly accurate center-to-center distance to use in making the steering arm to mount on the spindle. I mentioned this in a post a while back, this post to be precise, that I can use the steering arm to change effective steering ratio without adding any weight. In the post I was thinking that since I was using the steering arm at the spindle instead of a steering quickener the difference between the arm and the quickener box was the amount of weight I was saving, but in reality the arm at the spindle has to be there regardless of what I do at the box, so I save the entire weight of the steering quickener when I go with the shortened steering arm on the spindle, plus the weight loss of using a shorter arm instead of the one normally used. I think what I was thinking about was there’s no need to use a steering arm at the spindle because there is an extended bolt to attach the drag link on the arms I already have, except that unless I move the steering box further behind the axle the drag link will hit the tie rod, and I don’t have that problem with the steering arm for the drag link mounted to the lower holes of the spindle and the steering arms for the tie rod mounted to the upper holes of the spindles, especially if I use the extended bolt on the drag link arm to drop the drag link even further from the suspension links.

Now I just need to figure out the load path from the steering box mount that was in the kit with the box, to the rest of the frame. For the application the kit was made for the box mount welds directly to the frame rail of a ’23-34 Ford. This is going to be a bit more complicated as the frame rails are either over a foot above the box or several inches below it, and beyond just holding the box in a certain place in space relative to the frame and axle there are significant forces that will be applied to the mount, off axis forces at that. That means either the mount will be very heavy and apply torsion to the frame tube, or the mount will have to be braced from the other side of the frame. Since there’s nothing in the way of the mount going to the other side of the frame I’m going with that unless and until something else has to be put in the space between the radiator and the front axle. The radiator will be mounted slightly to the right to make the nose symmetrical and keep everything under cover, but since the tie rod and the pitman arm are both going to have to extend beyond the side of the nose it’s actually a moot point. The steering will come out of the left side of the nose because it has to, the Pitman arm will swing to the left further than the confines of the nose at full lock anyway, even the reduced amount of lock with the shorter steering arm at the spindle. The fun part now is how do I adjust the internal stops in the box to prevent the steering linkage from getting damaged by over travel caused by the steering box? Without internal stops the drag link could be overcentered and the car be unable to return to center when the steering wheel is turned the other way. Or I could use a stop on the axle that hits something on the spindle to prevent turning far enough to the right get to that point. Turning to the left the drag link hits the back of the spindle before getting to the over center point, I could use a stop on the axle that stops the spindle at the same point of rotation in the opposite direction. Hitting those stops would generate substantial forces on the steering mount, getting back to the original topic of internal stops in the steering box and the steering box mount. There is also the point that at full lock the tires will be almost perpendicular to the axis of the car. This would be useful for moving the front of the car sideways when not running, but I don’t see any practical application for this much steering angle.

And here we see yet another example of how I think, wandering here there and everywhere as I solve a problem. I’m not sure which part of my mental problems this typifies, but I know this isn’t my PTSD or depression at work, the only mental illnesses I have that I can’t blame this thinking style on. Maybe my ADHD, yes this is undoubtedly what happens when genius meets butterflies and squirrels. And since I just noticed my word count has tripped the 1K mark for this post I think this is a good spot to put this post to bed.

I’ll check the account balance on Saturday

As I said I’m feeling lazy, and I really don’t have anything specific to buy right now except some comic books that have been put on extended hold until I can come in again. I will be going to the store that has the ATM I’m going to use on Saturday and I have money for bus fare to use until the 15th if I don’t have any in the checking account to use on my GoPass app.

I’m saving up for this to use to steer the Sprint-T. The pitman arm in the kit is longer than the steering arm on the spindle meaning I get slightly more than 90° of steering from lock to lock reducing the steering ratio to 18.8:1 without using a quickener. If I build the quickener I want (5:1) I’m looking at 3.76:1 total ratio from steering wheel to front wheels. This will definitely require power assist and the only add-on assist made right now is electric. I want to put the sensor on the steering wheel side of the quickener and the motor on the output side of the quickener so the load on the motor is reduced. The effect will be the same, but the possibility of overloading the motor is reduced by the same ratio as the quickener.

And now I feel really old because the tech on the electric power steering vendor saw my request for information and called back immediately, and he had no idea that Vegas didn’t have rack and pinion steering, and likewise did not know what a recirculating ball steering box was. Anyway, we discussed the technology and it was his professional opinion that the power assist should be fitted on the steering wheel side of the quickener to prevent lag from the motor not reacting as quickly as I could force it through the quickener especially with the high ratio in my quickener box. The motor would not overheat from trying to work against a very high resistance and was designed to be capable of extended periods of working against stall, so the only question was could my steering quickener hold up to both my muscles and the electric motor working against the stall of trying to turn past the limit locks of the Vega box. Given that the components I’m using to connect the steering wheel to the steering box can withstand 4 times my weight applied to the steering wheel, I think at this point wear is a greater concern than ultimate strength, and I have accounted for that by putting the chain and sprockets in a sealed oil bath.

And since I have things I need to do before midnight tonight, this seems like a good place to quit for today,