Seek Outside U-Turn Mods

[TomJoad]

Got it @Marbles thx for the explanation and the drawing! Good idea regardless. I may shim the Alum feet with steel nuts if I need to since the short top rods are already threaded.

So some progress tonight. Mcmaster package showed up, god I love those guys, insanely overpriced but encyclopedic, high quality and as fast as Amazon. The fabrication took about 45min mostly because I’m anal and like things clean and consistent. You could hack it out in less time if you were just getting it done. These parts are going to get beat to piss and possibly melt into a pile so not real sure why I took the effort but old habits die hard. The weight is almost no different at all. I ended up upping the thickness on the tubing a lot for a little more heat sink and that brought it up, but the system is GREAT! Super clean and easy to assemble and nothing to loose anymore. Even if I end up replacing the front threaded rods with steel it’ll be worth it for simplicity. Here’s a quick photo journal:

 

[TomJoad]

Here’s the finished product... for now.

This weekend I’m gonna fire it up and see if I can’t make a big mess for all you guys who are rooting for me. I’ll make sure to document regardless. I also brought home a laser thermometer to get surface readings off the aluminum and Ti in critical contact spots and inside the stove leg area. That way if I’m flirting with failure in areas I can replace with steel or Ti or shim with steel nuts per other recommendations. I’m feeling even better about the back legs looking at the clearance to the back wall. The inside front legs... we’ll just have to wait and see!

 

[Marbles]

The recommendation on using steel nuts as shims made me think of this, ceramic fiber cloth (or some other such insulating material) could be used as shims instead and would reduce conduction to the lower legs if they get too hot.

It looks really nice and clean. A Seek Outside stove is on my list and I may copy you once I get it.

 

[JoshC]

So I just came into a SO U-turn stove for my floorless... I'm less than impressed with the legs:

- cheap steel threaded rod
- hardware store fasteners: wing nuts... really?
- all heavy and janky

My biggest issue is having not having fixed stops on the threaded rod based on the stove height which doesn't change. This seems like a no-brainer. I get that this will allow for crazy deep adjustment to foot height for leveling but I have several stoves with no adjustment and I make them work fine with shimming in the field. This set-up also seems overly heavy.

Here's what I'm trying:
- Change to 3/16 OD x 8.5" ti rod, threaded 10-24 on both ends: faster install, lighter weight
- Make 5" Aluminum tube feet threaded for 10-24 to tension bottom: lighter weight, faster install
- install low profile rivet nuts (10-24) to stove top: Enables totally flat top for cooking, less parts to lose

So with this new set-up, the threaded rod would still tension the stove bottom to top but would be fastened to rivet nuts in the top (vs. wing nuts) and threaded tube feet on the bottom for ground clearance.

Questions:
- Aluminum has a much lower melt temp than steel or Ti but it also has excellent conduction. I think it should be able to shed heat fine for the feet but we will see! Ti- tube is way too expensive in this application for me.

Here's the part list:
Ti Rods: https://www.mcmaster.com/89145K12/
Alum feet: https://www.mcmaster.com/1658T32/
Rivet nuts: https://www.mcmaster.com/98560A551/

I'll post up pics once I do this but meanwhile any ideas you all have for doing this differently I'm all ears!

View attachment 215639
Here’s where it stands today: 16 loose parts and 5.7 oz (161 grams).

Cool idea

 

[CoffeeGoat]

Turned out really nice! After seeing it, I wonder if you could just swap the aluminum legs out for titanium tubes and use rivnuts to thread one end.

At that point just grab some titanium cable and a couple titanium bolts and you could replace the part inside the stove with a cable and drop the weight to just a couple ounces.

 

[TomJoad]

Turned out really nice! After seeing it, I wonder if you could just swap the aluminum legs out for titanium tubes and use rivnuts to thread one end.

At that point just grab some titanium cable and a couple titanium bolts and you could replace the part inside the stove with a cable and drop the weight to just a couple ounces.

Good questions and and ideas. Technically rivet nuts require clinching something of thickness but you may be able to get enough friction to make it work. Sticking with the 10-24 system you’d need to find tubing that has 1/4” ID for the nuts I have linked above. That would be $80-90 worth of Ti from Mcmaster. I think there’s a good possibility that they’d loosen and rotate out however. This is however coming from the guy who intentionally installed his rivet nuts backwards to maintain a flat stove top, so certainly take it with a grain of salt.

What I love about the wire idea is being able to leave the wires attached to the top plate. Threading single fasteners attached to them through the bottom plate may be a bit fussy but should be workable. Not the cheapest route but not insane at $5 a bolt, 8 total needed for $40. Wire in Ti from mcmaster is spendy, like $70 for an 1/8lb spool for a reasonably small gauge. No reason you couldn’t use steel for all parts however and have a much easier time pushing a tiny number drill through those bolt heads.

I’d probably still opt for permanent threads rather than a rivet nut however. If you want to go the all Ti route you could just weld nuts into the tubes, assuming you have access to a TIG and a whole lot of shielding gas to burn. Alternatively per the ideas above Aluminum tube plus a heat shielding washer if needed.

I’m going to learn a lot more about my heat shielding needs and stove surface temperature later today. I’m a little bummed as I figured out my laser thermometer only reads to around 750F so I’m not going to be able to use it as an accurate gauge of when things are about to blow-up. Regardless once the AL reaches melt temp it just completely let’s go so I’ll have a clear indication there!

 

[Mike Islander]

Confused, medicated or both? Current SO stoves have 16 THREADED COMPONENTS!

Hmmm, unless my counting ability is broken my large U-Turn has 18 threaded components, 14 of which are loose nuts. You can mod the current components with solder and end up with only 6 loose nuts. After running my stove yesterday I am seriously considering doing this. Leave top four wing nuts loose as well as the two that go under the top metal in back. Solder the rest in place.

 

[TomJoad]

Hmmm, unless my counting ability is broken my large U-Turn has 18 threaded components, 14 of which are loose nuts. You can mod the current components with solder and end up with only 6 loose nuts. After running my stove yesterday I am seriously considering doing this. Leave top four wing nuts loose as well as the two that go under the top metal in back. Solder the rest in place.

You are correct on that Mike. When I first assembled this stove I figured they were extra but upon actually looking at the assembly instructions I see they are recommended for supporting the weight of the stove in the back for cooking. Mine has seen stable enough with out these with the minimal 1L containers I’ve had on top. I may go back to these if needed down the road.

I’d be careful with soldering as this is a way lower melt temp than aluminum. Additionally capillary action may pull this between the stove sheets and fasteners making dis-assembly a pain. Brazing may be fine but torch welding small racks on these small parts would be best and most reliable. Of course, this is all coming from the guy whose about to melt a bunch of recently fabricated aluminum parts inside his stove today.

 

[Mike Islander]

Love your set up and can't wait to see it in action.

J-B Weld is good to 500 degrees, and they make a version good to 2400F. Definitely a lot of viable options for permanently attaching pieces. I'd like to be able to adjust mine, so solder seems to be one solution.

SOLDER - My guess is that the heat sink of the legs will always keep the temperature under the solder melting point, no matter how hot you get the stove. But I have been wrong many times. I have done extensive research, as well as machine design/development that involved lots of work analyzing solder systems in printed circuit boards. What I learned from that is that analysis is worthless without actual real world testing. A great excuse to break out the stove again.

Same heat sink action will likely keep your design from melting.

 

[CoffeeGoat]

Just for reference on the bolts - https://www.mcmaster.com/90152A326/

 

[TomJoad]

Just for reference on the bolts - https://www.mcmaster.com/90152A326/

Thx, yes have used these for motorcycle track days. I thought you were talking about making your own from Ti bolts.

 

[TomJoad]

OK the results are in!.... Nothing Exploded!! Nothing Melted!!! but not entirely a success either. I gave it 2 hours of testing with dry hardwood fuel and nothing really came close to melt temp. The heat on the aluminum threaded rod inside the stove caused some expansion in length so I needed to tighten up the legs a bit after the first 15 min. Then about 1 hr in I decided to load it up with nearly 5lbs of water to test stability... that's where the problem started. The intensity of heat inside the stove made the front rods/legs too unstable once a "cooking scenario" was introduced. They ended up deflecting a bit under the weight and getting wobbly. Nothing fell apart but the system was too loose to be workable for backcountry cooking with those front legs. The Rear legs and rods held up great they never got anywhere near 700 degrees I think 450 was about the top temp at the stove top corners where they intersected the rivet nuts. Here's a pretty boring blow by blow of this test in action:

And here's what the rods were doing inside the stove after the boil session:



So where to from here.... Initially I was thinking I'd just cut down the steel 10-24 rod that came with it to replace the front sections and leave the back aluminum. This would require some clear marking: BBQ black krylon on the bottom legs? Huffing burnt paint fumes in my Teepee? But then I was meditating on my original plan to jus thread the top and bottom 1/2" of some 3/16 Ti rod which is surprisingly affordable.... I chickened out since I only have HSS dies but... my dies are sharp... and its only 1/2" on 4 legs... I think I'm gonna go for it. More to come.

 

[CoffeeGoat]

Nice - nothing like being proved wrong. I think you hit the nail on the head that the reliability in the back country is the most important thing, 2 oz of weight savings resulting in a broken stove is unacceptable.

As far as the bolt/wire approach goes you mentioned drilling would be a challenge and I agree, but you could demo it with safety wire bolts (in stainles) for cheap. You can buy titanium safety wire bolts, but they're 10x more expensive.

I think you're right that the original solution is probably the best and if the only issue is tooling - give it a try, worse case you wreck a cheap die. I would guess if you sweet talked a local machine shop they'd thread it for you for a case of beer. I've done that before and particularly if you show up near closing time you can get it done without dealing with paperwork...

 

[Trial153]

Seems like I will leave my Uturn as is. We used it in Alaska a few weeks back and it worked excellent. Easy to put together, worked well, no issues

 

[TomJoad]

Nice - nothing like being proved wrong. I think you hit the nail on the head that the reliability in the back country is the most important thing, 2 oz of weight savings resulting in a broken stove is unacceptable.

As far as the bolt/wire approach goes you mentioned drilling would be a challenge and I agree, but you could demo it with safety wire bolts (in stainles) for cheap. You can buy titanium safety wire bolts, but they're 10x more expensive.

I think you're right that the original solution is probably the best and if the only issue is tooling - give it a try, worse case you wreck a cheap die. I would guess if you sweet talked a local machine shop they'd thread it for you for a case of beer. I've done that before and particularly if you show up near closing time you can get it done without dealing with paperwork...

Yeah per above @Mike Islander posts real world testing is the most important and you are 1000% right that reliability is no 1 in the backcountry. That’s is my main issue with the SO design. Dropping small loose parts on dry ground is a PIA, dropping them in 18” of fresh powder they are likely unrecoverable. Despite the Aluminum threaded rod not working out this is a really nice system with a sub of steel or Ti. I don’t think I mentioned in the prior post but I didn’t use a bottoming Tap but instead just a taper tap on the tubing legs and subsequently locked 2 10-24 nuts onto the threaded rod to be able to drive the rod into the tube making a single part the same length as the original SO rods. This makes the system just 4 large parts and nothing to loose.

I also see a lot of potential in your wire design, it would certainly be lighter, as the components are easy off the shelf you should go for it!

 

[Southforkguy]

Here’s the finished product... for now.

This weekend I’m gonna fire it up and see if I can’t make a big mess for all you guys who are rooting for me. I’ll make sure to document regardless. I also brought home a laser thermometer to get surface readings off the aluminum and Ti in critical contact spots and inside the stove leg area. That way if I’m flirting with failure in areas I can replace with steel or Ti or shim with steel nuts per other recommendations. I’m feeling even better about the back legs looking at the clearance to the back wall. The inside front legs... we’ll just have to wait and see!

View attachment 216438
View attachment 216440
View attachment 216441
View attachment 216442
View attachment 216443

Sweet dude. Hope it works out. I hate fiddling with these stoves to get them set up

 

[TomJoad]

Project complete!

worth it? Definitely worth the alum feet and rivet nut changes... $10 takes you from 16 (or 18) parts many of which are easily to loose to 4 nice large parts. The threaded rod in retrospect is not worth the effort to change to Ti. While it’s only $20, it is a major PIA to thread and for marginal weight gains. I used a sharp Cleveland die and it was smoking with hand threading. If your going to do it make sure you don’t attemp with Irwin trash from a big box and get a bottle of Magic Tap, it’s your friend for this.




Going from 16 parts and 161 grams to 4 parts and 123 grams. Totally worth it! For those that don’t have a shop you can do this mod easily with a hacksaw, file and a drill. You need a rivet nutter ($30-$70) if your going to go for that step but otherwise simple tools will do the job

 

[mpk1996]

Sorry to bring this old post back up. Been looking at the seek u turn stoves myself. Really like the rivnut idea. Any issues with the alum rivnuts? Now that it’s been some time? Or would stainless steel be better? Also, the threaded alum tubes are cool, but do you have any issues with it sinking into the ground? Did you put any feet on it or anything? I’d be worried if we had to camp on wet or muddy ground it would sink in and maybe tip.

 

[TomJoad]

Sorry to bring this old post back up. Been looking at the seek u turn stoves myself. Really like the rivnut idea. Any issues with the alum rivnuts? Now that it’s been some time? Or would stainless steel be better? Also, the threaded alum tubes are cool, but do you have any issues with it sinking into the ground? Did you put any feet on it or anything? I’d be worried if we had to camp on wet or muddy ground it would sink in and maybe tip.

No problem, rivet nuts are steel not aluminum and they have held up with no issue at all. Only the lower sections of legs are aluminum and that works great. I haven’t had any issue with the foot diameter but you could always thread the bottoms of the feet and bolt on some fender washers. Personally, if I was forced into a dodgy shelter location I’d just use a few rocks under the feet. I’d say go for it and don’t look back.

 

[mpk1996]

No problem, rivet nuts are steel not aluminum and they have held up with no issue at all. Only the lower sections of legs are aluminum and that works great. I haven’t had any issue with the foot diameter but you could always thread the bottoms of the feet and bolt on some fender washers. Personally, if I was forced into a dodgy shelter location I’d just use a few rocks under the feet. I’d say go for it and don’t look back.

great. i must have read that wrong. They make alum rivnuts, and zinc coated steel, and SS. I use them all the time on custom car stuff and other projects. good to know. thats a good solution. I was actually thinking i might try the threaded rod, put on a nylock nut, then bend the end in a L shape. the nylock would stay in place and pin the lower. the L would act as a handle to tighten and give me a "foot". I'd have to see how the weight was on the 4 threaded rods. prob not much different from your setup overall. and more importantly, no pieces to lose in the field. I would just have to try it and see if the nylock would handle the heat ok and not melt and then be loose. thanks for the help. looking forward to getting one and trying it out before next season