Need 1/8" Straight Shaft

[dethow]

Hey guys,

I've got a 10th scale shovel nose which needs a shaft. The seller of the boat told me it needs a straight 1/8" shaft made of stainless steel or titanium. Also need a shimmed 3/16" Octura drive dog (the smaller version). He said the drive dog can be found on OSE.

I've done some searching but just not sure what I'm looking for and where to find. Wondering if anyone can direct me with some links to website(s) where I can get what I need.

Needed:
1.) Motor coupler from 5mm motor shaft to 1/8" shaft.
2.) Straight 1/8" shaft made of stainless steel or titanium 15”+ long.
3.) Drive dog, shim and anything else I need to use a 3/16” prop.

Thanks in advance for any help,
Dave H

[longballlumber]

Dave,

For simplicity why not make the change to a flex shaft? Just because it's a flex doesn't mean it needs to have a bend in the stuffing tube.

Otherwise, McMaster has a selection of SS rods https://www.mcmaster.com/#standard-stainless-steel-rods

Just thought of it, what about a wire drive?

[dethow]

Hey Mike,
Thanks... but a question:
Are you talking about changing out the stuffing tube or using a 0.130 flex cable with a 3/16" end for a 3/16" prop?

I don't know these setups and have never seen one. So I am admitting complete ignorance on this...
This boat doesn't have a strut... just a straight stuffing tube. And there is a lot of space (3") between the tube and motor mount. So I'd defiantly figure I'd have to change the stuffing tube to use a flex cable.

Given those issues I assume that going with the 1/8" straight shaft would be the way to go for simplicity.
You’ve filled in the shaft part with your link, thank you. Now I’m just not sure what else I need exactly as far as coupler, drive dog, shim, and whatever is going to hold the prop on?
And then... how far should the shaft be sticking out or how far back should the prop be? Should everything be as tight as possible coming out the back end?

[longballlumber]

YES and YES,

if it were me; I would replace the entire drive line so that it uses components that are readily available. Your idea of simple must be slightly different than mine. You will need to do some creative custom work to get a driveline for this boat.

Sticking with the 1/8” hard shaft;

It doesn’t look like OSE has one that fits you sizes, but I am sure there is someone that can make or modify one for you. Depending how large the OD is on these, you might be able to get the 4mm - .098” version and modify it. I would only make the modifications on a lathe to maintain concentricity between the new holes. https://www.offshoreelectrics.com/pr...?prod=ose-1345

You could try a normal octura flex hex, but I am not sure if there is enough clamping force to “hold” a 1/8” solid SS rod. Maybe if you roughed up the end a little bit; it’s a gamble. https://www.offshoreelectrics.com/pr...oct-ocfhe5mm13

Since you will be using 3/16” props you will need to build up the OD of your 1/8” SS rod with some brass tubing to get your shaft OD up to 3/16”. If you get some 5/32” and 3/16” tubing that should get the job done. It seems many have had great success using Loctite retaining compound for applications like this. Steven has some pictures showing how the K&S tubing will telescope over each other. https://www.offshoreelectrics.com/pr...dh-ks-brass-tb
Retaining Compound - https://www.offshoreelectrics.com/pr...prod=mc-loc638


Now that you have fabricated this shaft you can use a normal 3/16” drive dog https://www.offshoreelectrics.com/pr...rod=oct-oc6dmm

For holding the prop on you can get fancy and cut some threads in the brass or just use a wheel collar similar to this https://www.offshoreelectrics.com/pr...od=dh-GPMQ4308

[longballlumber]

And then... how far should the shaft be sticking out or how far back should the prop be? Should everything be as tight as possible coming out the back end?

Out of the NAMBA rule book...

Drive Train
i)Any shaft may be used provided it maintains a straight line from hull
exit through the strut.
ii)No gearbox of any configuration is allowed.
iii)Any single propeller may be used, and a portion of the propeller must
be under the transom. The drive dog is defined as not a part of the
propeller

[dethow]

Thanks Mike.

In regards to the coupler... Do you think this option would work in size: 5mm - .130"?
I understand 1/8" is 0.125" and this coupler is 0.130", but that seems like a very small difference.
https://www.offshoreelectrics.com/pr...?prod=ose-1340

In regards to getting a 3/16 prop on the 1/8" shaft... I assume these would work and I would need to use the retaining compound?
https://www.offshoreelectrics.com/pr...?prod=ose-1035

Then I have the drive dog you linked to and then I just need to figure out a way to hold the prop on. Either thread the 1/8 to 3/16 adapter or use the wheel collars.

I do hear your point about changing the entire drive line so that I can use a readily available flex shaft... For right now (at least) I'd just like to run the boat with minimal overhaul. And if I can get the parts figured out, I will buy some extra spares so that I don't have to worry about availability in the near future.

[longballlumber]

Thanks Mike.

In regards to the coupler... Do you think this option would work in size: 5mm - .130"?
I understand 1/8" is 0.125" and this coupler is 0.130", but that seems like a very small difference.
https://www.offshoreelectrics.com/pr...?prod=ose-1340

Maybe??? However, it is possible that it will cause enough miss alignment to induce vibration in the system. This is another reason for my original comment. non-flexible solid shafts don't like miss alignment at all. However, if your objective is to get into the water quick give it a try. It's only six bucks.

In regards to getting a 3/16 prop on the 1/8" shaft... I assume these would work and I would need to use the retaining compound?
[url]https://www.offshoreelectrics.com/proddetail.php?prod=ose-1035[/url

If you sleeve the end of the shaft up to 3/16 from the face of the drive dog to the end of the shaft you don't that sleeve.

[dethow]

Thanks a lot for all your input and time here Mike.
You are truly one of the good guys in this hobby willing to give your time to help others.

And that McMaster website is amazing. Has all kinds of useful stuff. Very cool.

I've made my orders from McMaster and OSE. Time to get this boat ready to race next season

[longballlumber]

Thanks a lot for all your input and time here Mike.
You are truly one of the good guys in this hobby willing to give your time to help others.

No Worries, I try and help where I can. Lots of ways to "skin the cat" so others my have different opinions.

And that McMaster website is amazing. Has all kinds of useful stuff. Very cool.

While McMaster Carr isn't the cheapest, they have lots of great stuff. Most importantly; they have a warehouse in Toledo. That means if you order today you will have it by tomorrow (at least for me).

[bozo586]

i believe Qc/Carr has a warehouse on grosbeck highway betteen 10 and 11 mile rd. Roseville mi. wait Graingers might be the place i am thinking about! they sell the same stuff.

[ray schrauwen]

Die ejector pins. Very hard, very true.

[oscarel]

What about using one off Jeff Wohlts .093 wire drives? It would be a lot easier and he also makes collets to fit.

[dethow]

What about using one off Jeff Wohlts .093 wire drives? It would be a lot easier and he also makes collets to fit.

I checked out his site and it looks like a thought to consider. Thanks
http://rcraceboat.com/StorePAGE.html

[Coug90]

Mr. dethow, you got this. Here's what you need. Get yourself some 1/8" SS or Titanium. You'll need about 12.5" to make a shaft that you can trim off when you're done. You can shim it to fit your prop and drive dog length using a piece of K&S #87113 SS tubing 3/16" OD. It has an ID that fits 1/8" pretty well. Cut your shim to the length you need so that it will be flush with the front of your drive dog and just short of where your prop hub will extend to so it allows maybe 1/4" of the 1/8" shaft to extend behind the prop. Red lock tite is great for permanently securing that shim in place, but mark the shaft where you want the shim because the stuff sets up fast and it's stuck once you put them together. That's why you want to cut the shaft long and trim both ends later. Once you've placed the shim on the shaft, You can put a little flat spot on the shim for your drive dog set screw and secure the drive dog. You may even prefer to secure the drive dog to the tubing and then cut off the tubing, file it flush to the drive dog and then cut the tubing off to the desired length. You can then secure them to the shaft in one piece. I don't trust the set screw, so I secure the drive dog to the tubing with red lock tite too.

Your motor should be mounted in the boat and use a Flex Hex Coupler (5mm to .130 Cable) type. They clamp down great on the 1/8" shaft. Never had a problem with that. It's the Octura oct-ocfhe5mm13. The drive dog is the Octura OC6DMM 3/16 ID with 5/16 OD. You can put a long piece of 1/8 shaft in the coupler to get your shaft length estimated and start there. I estimate you'll need about 13" so you'll have some extra to play and trim to fit after the shaft is made. Make a few shaft and you'll figure out your own assembly preferences. A Dremel tool with a reinforced cut off wheel is a must and will make it very easy for you. Remember that some prop hubs are longer than others, so you may have to make different lengths of shims and have a few different shafts or make the shim to just accomodate the shortest one an leave more shaft hanging out the back. You can secure props using a flat notch in your 1/8" shaft and a 1/8" Dura-collar. That has worked great for me. This system isn't super fancy, but it has few failures and is at least a good place to start. You'll come up with some idea along the way, but this is the best I've come up with so far for building and running straight shafts in 1:10 Scale.

I recognize the photos. I built that boat you have and it served me very well for six year, four CT championships and some great NAMBA rules racing wins too. The 1955 Gale V is a rocket when set up properly. She needs some work and TLC, but still has some good racing in her. I'm glad someone is going to have some more fun with it. Let me know if I can be of any help and I hope this rough tutorial makes some kind of sense.

[dethow]

Thanks Mitch...
Got all my parts in yesterday and everything looks like they will fit together nicely.
I did end up going with this coupler: https://www.offshoreelectrics.com/pr...?prod=ose-1340
Much like the flex hex coupler you mention, the shaft side is 0.130". I think it will work fine as there isn't much play at all. I think there is actually more play in the bushings that are at both ends of the stuffing tube. Once I have everything set and shaft length is finalized I'll put a small flat spot on the 1/8" shaft for the coupler set screw. That will hold the shaft from ever spinning or moving in either direction off the coupler.

Have a great weekend.

[Coug90]

That coupler should work fine and is a bit less expensive. I have never been a big fan of set screws for motor couplers. I used to use them but they would get off center somehow if you really cranked them down over time. I do like that the set screws are bigger than the ones we used do use back in the day. I would get some spare bushings to keep on hand because they do loosen up over time and get bigger. I use thicker wall tubing for the stuffing tubes so they are wedged in there pretty tight. The rear bushings especially. I replace them periodically if they get too loose. You can drill them out pretty easily. Use a bit that gets progressively bigger in size. The bushing will spin out of there usually on the second size bit. You can then tap in a new one with some taps of a hammer. Happy racing!