Machining a stainless steering tie rod

[pyrotek]

Looking for help from people more familiar with machining than I am. I'm replacing two steering pins on a twin engine and removing engines, exhaust, transom assy, etc. The existing tie rod coupling the two outdrives steering levers together (and attaching to power steering ram) is badly corroded which I would like to replace with stainless. It's currently steel. I had to cut out the pins because the rust welded the pins to the tie rod.

The dimensions of the Mercruiser tie rod part is
Length: Approx 33" end to end
Diameter: 1.0"
Diameter Rod Ends: 0.75"
Thickness of Rod Ends: 0.4"
Hole Diameter: 0.375"

Ideally it would be adjustable within an inch or two but can't figure out how to make it. So far I figured I can get a stainless 1.0" diameter tube and 0.76" ID. Then I can get a solid round bar of 0.782" and either have a buddy mill it down to look like the ends of the old part, or even get it close enough on a bench grinder. The round part of the ends would slide inside the tube, but I don't have enough practical experience to know if the tolerances will work out, only 0.022" spacing. Then I'll have a buddy weld the ends to the tube.

If anyone has any ideas how to do the same but make it adjustable with threaded pieces like the Mercruiser part. I was looking at getting a 3/4"-10 threaded rod for the ends, but not sure how to tap inside the 1" pipe (it can't be NPT since it needs to be adjustable). Not sure if welding a single nut at the end of the tube is good enough.

Let me know if anyone has any good ideas.

 

[achris]

You tap the end of one rod with a right hand thread and the end of the other a left hand thread. Think 'turnbuckle'... Obviously the inside of the tube will have one left hand thread and one right hand thread, to match the tie-rod ends.

Chris........

 

[Scott Danforth]

You can buy right hand and left hand threaded tube ends. They are used in making suspension pieces

they make them in steel, stainless, aluminum or titanium. They also make threaded turnbuckel bodies

Use google to look for threaded tube ends

Or het heave wall tubing and thread the ends for the rod ends

 

[wingless]

Nothing wrong w/ the plan to make the part out of stainless.

Be aware that machining stainless can be a slow / expensive process.

On mine, I was not happy with the corrosion, so I cleaned up the steel and the bronze parts, then properly applied coatings to the steel parts, now they still have a glossy / new appearance, almost two decades later.

 

[wingless]

FWIW, both ends of my parts have identical threaded bronze ends, both with right hand threads.

That configuration works fine w/ my steering configuration, permitting accurate setup w/ complete adjustment flexibility.

 

[tank1949]

Looking for help from people more familiar with machining than I am. I'm replacing two steering pins on a twin engine and removing engines, exhaust, transom assy, etc. The existing tie rod coupling the two outdrives steering levers together (and attaching to power steering ram) is badly corroded which I would like to replace with stainless. It's currently steel. I had to cut out the pins because the rust welded the pins to the tie rod.

The dimensions of the Mercruiser tie rod part is
Length: Approx 33" end to end
Diameter: 1.0"
Diameter Rod Ends: 0.75"
Thickness of Rod Ends: 0.4"
Hole Diameter: 0.375"

Ideally it would be adjustable within an inch or two but can't figure out how to make it. So far I figured I can get a stainless 1.0" diameter tube and 0.76" ID. Then I can get a solid round bar of 0.782" and either have a buddy mill it down to look like the ends of the old part, or even get it close enough on a bench grinder. The round part of the ends would slide inside the tube, but I don't have enough practical experience to know if the tolerances will work out, only 0.022" spacing. Then I'll have a buddy weld the ends to the tube.

If anyone has any ideas how to do the same but make it adjustable with threaded pieces like the Mercruiser part. I was looking at getting a 3/4"-10 threaded rod for the ends, but not sure how to tap inside the 1" pipe (it can't be NPT since it needs to be adjustable). Not sure if welding a single nut at the end of the tube is good enough.

Let me know if anyone has any good ideas.

Great IDEA using ss, but finding not so easy. You might be able to order some ss all-thread but finding opposite rotation threads may be tough. I have a feeling that you can clean up what you have, re-thread, Ospho, prime and paint and go. Remember that rust is very inflated. If my memory serves me, 1 inch of steel will produce 10 inches of rust. about 1/10 of actual metal. It really expands. I just did the same to mine (1986 salt water boat). Unless something like a motor installation redesign, you should not need to adjust turnbuckles. However, good idea while all parts are out to clean up and recut threads, just in case you need to later on. You might be able to find used tiller parts on ebay or craigslist. New stuff will be very expensive. And, while out, you can put heat on it while in a vise. Good luck!

 

[pyrotek]

Turnbuckle is not necessarily required. Adjustments can easily be made by disconnecting one side, making the adjustment and then re-connecting.

I think I'm giving up, unless someone sends me direct links to parts. I've searched for hours and I can't find the parts in stainless (as tank1949 alluded to). I can't find stainless tube ends in 3/4". I can't find stainless threaded tube in 3/4".

My existing piece is most likely permanently frozen together and no longer adjustable, so making a fixed SS version is sounding no worse than what I have already. $130 in material. I think I wrote it backwards above, but will a 0.75" solid bar fit inside a 0.782" ID tube? Is 304 good enough for this application? It will be easier to grind, drill and machine if I go that route. I think I can just grind two flat spots on top and bottom to make the end.

 

[achris]

304 is not 'marine grade', that's 316L. 304 will 'corrode. I have 304 screws on a bracket in my boat and the rust stain is quite disgusting.

Chris....

 

[tank1949]

Turnbuckle is not necessarily required. Adjustments can easily be made by disconnecting one side, making the adjustment and then re-connecting.

I think I'm giving up, unless someone sends me direct links to parts. I've searched for hours and I can't find the parts in stainless (as tank1949 alluded to). I can't find stainless tube ends in 3/4". I can't find stainless threaded tube in 3/4".

My existing piece is most likely permanently frozen together and no longer adjustable, so making a fixed SS version is sounding no worse than what I have already. $130 in material. I think I wrote it backwards above, but will a 0.75" solid bar fit inside a 0.782" ID tube? Is 304 good enough for this application? It will be easier to grind, drill and machine if I go that route. I think I can just grind two flat spots on top and bottom to make the end.

Like Achris described, 316 is much better. I am surprised that putting a torch on it and using pipe wrenches didn't break it loose. You may also need a strong friend or Vise. Worse case scenario is to weld a couple of flat pieces of metal onto it that would add as a fulcrum if pipe wrenches keep slipping. Use a lot of heat and penetrating oil, over and over. Meanwhile search web for parts. Just in case.... Good luck!

 

[dingbat]

304 is not 'marine grade', that's 316L. 304 will 'corrode. I have 304 screws on a bracket in my boat and the rust stain is quite disgusting.

Chris....

While most good builders use 316 or 316L hardware or better, there is no such thing as “marine” grade stainless steel.

Agree....while stainless doesn’t “rust” per say, it does have other corrosion related failure scenarios.

All bets go out the door once you weld stainless.

 

[Scott Danforth]

the stainless tube ends are special order. most places stock hardened steel and aluminum.

you can simply order a few stainless nuts and weld them on the ends of the tubes to get the end threaded.

316 stainless rod ends will be expensive, most places only carry 304 body with 410 ball

As Chris mentioned, the 304 will rust.

however you can always hit it once every few months with boeshield.

 

[pyrotek]

Just posting a follow up in case anyone goes this route.

So I was able to talk to a local machinist/welder and he gave some good advice. To make it adjustable I need to tap it myself and use threaded rod. I found 3/4-16 stainless 316 threaded rod on Ebay, along with cheap taps ($15-20, not the $150 taps I found on McMaster). I would use a pipe 1" OD, 0.156" Wall, 0.688 ID because a 3/4-16 thread wants a 0.688 hole. I can't measure the wall thickness of the Mercruiser part, but I assume this is what they used since the pipe is taped.

But I settled on the fixed design using 1" OD, 0.109" wall, 0.782" ID. I'll just do the flats on the connecting ends on a bench grinder instead of bringing it to be milled accurately. Instead of having it welded, I'll drill a hole and insert a bolt to connect the ends to the pipe. This way I could drill up to 4 holes at different spots if the length had to be changed - which I'm sure it won't need to. The wall thickness will be slightly smaller than the original, but I think it is plenty good enough.

I haven't tried to unbolt the existing tie rod, I just shyed away from it due its looks! I'll put it on the shelf in case I ever need it.