2mm threaded push rod Doobery things

[toto]

As the title suggests ...... I am after 2mm M2 dooberies.

 

Little push rod connectors ..... threaded both ends ..... about say 2 inches long.

 

I ordered some snakes from SLEC and rather than ordering the versions with fittings included, I just ordered the inner and outer tubes ..... I already have 2mm clevises but forgot that I did not have the doobries.

 

The SLEC spec says 2mm but I only see 3mm on line.

 

I would prefer to buy in bulk .... say packs of at least 10.

 

Any help appreciated

 

Toto

[Paul De Tourtoulon]

Can't you order a metre of 2mm threaded rod ?, don't forget that 2mm won't work with Sullivan golden rods.

[Caveman]

Toto, here you go https://www.slecuk.com/accessories/control-fittings/m2-brass-studding-25mm-1quot

 

GDB

[Geoff S]

A lot of so-called 2mm push rods (like the ones from SLEC) have rolled threads (like bike spokes) and the actual rod is smaller than 2mm. For a pushrod as short as 2" it might be better to use 2mm threaded rod - available from Modelfixings amongst others.

[Nigel R]

You only need about an inch of threaded rod at the end of the snake.

 

as suggested already, M2 studding is available from many shops, just cut it down as you need. 

 

[toto]

Thanks for the link Caveman.

 

I looked on the SLEC site when I bought the tubing which is on it's way. I couldn't see ..... what I now know is called studding. I did not realise what that actually was so ...... I know now.

 

This is for the Tiger 60 as the push rods were giving me bother so as suggested on the thread ....... snakes are substituting them.

 

Thanks again

 

Toto

[gangster]

19 hours ago, Geoff S said:

A lot of so-called 2mm push rods (like the ones from SLEC) have rolled threads (like bike spokes) and the actual rod is smaller than 2mm. For a pushrod as short as 2" it might be better to use 2mm threaded rod - available from Modelfixings amongst others.

That’s interesting, just seen this post. I posted an almost identical reply to another post a couple of hours ago but had no idea what you called that method of threading a thinner rod was called,  Many bolts are made like that, very frustrating when you need to add a few threads more. Rolled thread. I have learnt something today.

[Geoff S]

26 minutes ago, gangster said:

That’s interesting, just seen this post. I posted an almost identical reply to another post a couple of hours ago but had no idea what you called that method of threading a thinner rod was called,  Many bolts are made like that, very frustrating when you need to add a few threads more. Rolled thread. I have learnt something today.

 

Yes, I've actually got a tool for rolling spoke threads. It's well over 100 years old!  I used to build a lot of wheels for our bikes and trikes but always used stainless steel spokes and the thread rolling tool couldn't deal with it so I had to make sure I got exactly the right spoke length for each build.  Not sure what the thread is except that spoke nipples fit it 🙂

[Nigel R]

Fairly sure it's a weird thread specific to spokes. I've built a few wheels too. DT Swiss swaged spokes every time...

[Nigel R]

Incidentally. Dubro lazer rods are very good and come as a complete kit with studs and clevis etc etc. They are still fairly priced too (unlike the now absurdly priced sullivan snakes I used to buy)

[Paul De Tourtoulon]

I have used 2mm gas welding rods threaded with the usual 2mm die for years.

[Don Fry]

Funny, but off topic, nowadays I use 3 mm, 0.5mm carbon tube instead of steel for control rods. Roughen inside and epoxy glue (15 minute or longer) threaded stuff inside, as needed.  Zero failures so far. 

[Paul De Tourtoulon]

19 minutes ago, Don Fry said:

Funny, but off topic, nowadays I use 3 mm, 0.5mm carbon tube instead of steel for control rods. Roughen inside and epoxy glue (15 minute or longer) threaded stuff inside, as needed.  Zero failures so far. 

So have I,,,,🤩 but mainly with 2mm .

[Cuban8]

I've not been satisfied with the fit of 2mm threaded rods in Sullivan Snakes, they do fit, sort of, but I wouldn't rely on 'em - no real choice but to use the proper weird 2-56 thread that they're intended for. The fit of 2mm clevises and 2mm studding can also vary and be a bit slack as well.

Whether Sullivans or whatever, I use my electric drill on a very slow speed to drive them into the snake - no bodging with pliers or grips......please.

[Wookman]

I used the Sullivan snakes on a model years ago and could never get the thing trimmed correctly. Every time I took it out it would need retrimming.

After an investigation I found that the fluted inner snake was expanding and contracting under variations in temperature.

The cure was to feed a bowden cable inner wire down the inside of the Sullivan snake with a normal solder adaptor at each end.

Leave a gap so that the fluted inner can "float" along the bowden cable inner.

This gives the temperature/length stabillity of the steel wound cable and the free running of the fluted Sullivan snake.

The adaptors can be installed outside the model as they can be threaded through the Sullivan Outer tubes.

[Paul De Tourtoulon]

28 minutes ago, Wookman said:

used the Sullivan snakes on a model years ago and could never get the thing trimmed correctly.

Sullivans need a piano wire down the middle of them as they are 'elastic' I tried one in a helicopter fuselage years ago for the tail rotor, a complete waste of time,

on bends controlling ailerons they wear out quickly and even new they have a lot of play in them.

[leccyflyer]

19 hours ago, Cuban8 said:

I've not been satisfied with the fit of 2mm threaded rods in Sullivan Snakes, they do fit, sort of, but I wouldn't rely on 'em - no real choice but to use the proper weird 2-56 thread that they're intended for. The fit of 2mm clevises and 2mm studding can also vary and be a bit slack as well.

Whether Sullivans or whatever, I use my electric drill on a very slow speed to drive them into the snake - no bodging with pliers or grips......please.

I find that the dedicated Sullivan tool - a knurled cylinder of aluminium with threaded holes in both ends - works very well for inserting the short lengths of threaded stud used for Sullivan snakes. It's important to use the correctly sized studs that fit the Sullivan clevises, rather than metric ones.

[Trevor]

13 minutes ago, leccyflyer said:

It's important to use the correctly sized studs that fit the Sullivan clevises, rather than metric ones.

And, just to confuse the issue further, Sullivan also supply 2mm snakes as well as their usual 2-56. So, unless you're using the whole kit in one go, when you tear off the card to get into the package, slide that card back inside rather than binning it and keep any spare clevises etc in separate labelled poly bags!

[Nigel R]

4 hours ago, Wookman said:

I used the Sullivan snakes on a model years ago and could never get the thing trimmed correctly. Every time I took it out it would need retrimming.

After an investigation I found that the fluted inner snake was expanding and contracting under variations in temperature.

 

The topic has come up on the forum a few times, I believe.

 

The outer and inner are made from the same stuff and expand/contract at the same rate. If you fix the very ends of the outer, and only the very ends, and leave the middle "free to expand", then any change is matched by any change of the inner rod.  Done this way, the only expansion that affects trim is the very small piece of inner that protrudes from the outer, that very last inch at each end. The expansion on 2" of nylon rod is small. in order of a few thou per 10 deg C, if my sums are right.

 

I appreciate this is not possible as a retrofit for an existing install.

 

[Cuban8]

Must admit I didn't know Sullivan did their products in metric sizes - far more convenient. The expansion 'problem' is interesting - I think I experienced a slight change in a snake equipped model's elevator trim on a very hot day this summer, but only a matter of a click or two to adjust out. Not an issue for sport flying.

Edited November 13, 2023 by Cuban8

[Paul De Tourtoulon]

So have you memorised this saying Cuban8, elevated temperatures = trim elevator.

I have never seen a metric Sullivan golden rods, red outer yellow inner and the Blue ones I have seen but never used.

[Nigel R]

https://www.nexusmodels.co.uk/sullivan-2mm-gold-n-rod-nylon-type-semiflex-48-inches-1219mm-f-sln576.html

 

£23!

 

Safe to say I'm finding that quite a lump to swallow for four clevis, four bits of studding, and two nylon inners and outers.

 

That said, they have changed the colour, maybe that's what you're paying for.

 

Either way 2-56 hardware is not hard to come by.

 

2 hours ago, Cuban8 said:

The expansion 'problem' is interesting - I think I experienced a slight change in a snake equipped model's elevator trim on a very hot day this summer, but only a matter of a click or two to adjust out.

 

Matches my experience, perhaps a click on or two on a hot summer day.

[Cuban8]

Silly money. Good job I've got a few in stock.

[Martin Harris - Moderator]

I’ve used many Sullivan snakes over the years and I can’t say I’ve ever noticed a problem - but then I’ve always epoxied the outers at their end points. 
 

I do like the positive locking system - maybe slightly fiddly but long nosed pliers always do the trick - far better than a ring of fuel tube which WILL fail to retain a standard clevis under mild flutter conditions. 

[leccyflyer]

Likewise - have never had an issue with Sullivan Gold 'n Rods over many years. They have become pretty expensive these days though and I've developed a preference for old fashioned dowel pushrods with Z-bends and threaded rod terminations. A shame really, as I'm running low on those wee offcuts to make doobers for protection and charge state indication on my 4mm connectors.