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[bikerdude666]

I bought 1 of these http://www.cornwallmodelboats.co.uk/acatalog/graupner-1782.html and I need to couple it to an M4 shaft, but I'm not sure of what sort of coupling I can use, that will still allow it to turn?

Thanks, this is the final thing holding up the build.

[john s 2]

Why not ask The seller? John.

[bikerdude666]

Mainly because I didn't think of that..... and also, it didn't come up on their list of suggested items to purchase along with it.

[DickyD]

   
http://www.cornwallmodelboats.co.uk/acatalog/couplings-graupner.html

354.4 Graupner 4mm Coupling Assembly
The shaft coupling is made of top quality plastic with metal inserts. In the case of considerable vertical differences in line-up of main drive units mounted at an angle to each other, a compensating member must be installed. Maximum operating angles per joint is 10°. Exchange universal joints give still more connecting possibilities.
Shaft coupling without compensating member. For shafts diameter 4+4 mm
Bridges 36 mm
Outside diameter: 10 mm
Part No: G354.4

Price: £4.09 (Including VAT at 20%)
Euros: €4.71 (Inc VAT) / US Dollars: US$5.32 (Tax Fr

[john s 2]

Dickie. Would a bush or bearing, seal, be required for where the prop shaft goes through the boat? Or do you use a  normal inner and outer shaft? John.

[DickyD]

Normal prop shaft I believe John.

You can always ask Malcolm at Cornwall Model Boats, a very helpful man.

[bikerdude666]

Thanks for that Dicky, rather annoyingly I forgot about needing a coupling, and I've just placed an order with them, could've saved on the postage!

[john s 2]

If using a normal propshaft please remember that you will also need a coupling for the motor to propshaft.Thanks Dickie.John.

[bikerdude666]

If using a normal propshaft please remember that you will also need a coupling for the motor to propshaft.Thanks Dickie.John.

Got 1 for the motor coupling, 1 of the rubber tubing 1's, just doesn't give enough movement to allow for steering...

 Now to attach it to the 'unconventional' hull, and it'll be ready to go! pictures to follow in the next few weeks!

[irishcarguy]

Hi everyone, there has been a long discussion on here in another thread by Oldiron (John) that showed when he did a lot of testing that in fact the Huco was actually the worst. A single Huco will only give you alignment in one plane, you will actually always need two if you don't want it to bind, there is a connector available for just that fix. In johns testing the Dumas dog bone was the best of the ones he tested. This has been a bit of a mission for me for some time as I work in the auto business & am very familiar with drive lines, U/J's & C/V joints. It is obvious to me that we are sadly lacking in driveline technology when it comes to our model boat hobby. Walk into any good hobby store & have a look @ the sheer variety  of drive systems for model cars of all types, the mind boggles. Because of the restricted space we sometimes work with in our models we need a single type C/V joint in different sizes to fit into many different configurations & power settings. I have been giving it a lot of thought & am at present trying to develop such a joint, I have made three prototypes of which two worked in a half a--s ed way one I ran up to 2000 rpm but had some vibration problems. It drives @ angles of 15 to 20 degrees without any problems.To make it accurate enough to eliminate vibration I require a milling machine as I can't drill the bearing slots for the ball bearings accurate enough & also embedding the balls in the inner hub must be exactly the same distance from the centre for all the ball bearings. As you can see I have solved most of the technical problems, now it is the cost of a good milling machine that is the biggest problem. I am working on that with the boss, with very little success up to now." cant you do it on that new fangled lathe you just bought 6 months ago' is a familiar reply. I will keep you posted on progress, sorry no pictures yet, if I get it right I will probably patent it & put it into production. From once the dwawings are done it could be CNC machined in bulk @ a reasonable price I think, then I hope you will all want to buy one or two, LOL. Mick B.   

[RAAArtyGunner]

Keep us posted 

[tugs62]

the hugos blow apart if fitted to ic so we need some thing stronger mick

[irishcarguy]

Hi again, once I get the precision part sorted the C/V joint I am working on can be made in different sizes & strengths. Ball bearings from 1/8 inch to 1/4 inch can be used with an increase in diameter & from 4 ball bearings to 8 depending on how large it is made. I can't see it being easy to sheer 4, 6 or 8 1/4 inch ball bearings very easily, that would take a very powerful motor. The outside casing can be expanded to any reasonable size to increase its strength. I hope it works out as I have put a lot of time & effort into it & made some stupid mistakes along the way, but that is par for the course with any prototype work. I am now off to look for the um-teen time @ milling machines & am leaving the boss @ home, LOL. Mick B.

[Subculture]

Raboesch do the splined fitting couplings like huco, but also do a ball and cup variant, which is useful if you don't want a Hardy-Spicer type coupling.

I think what makes these couplings very popular is that it's a cinch to match different size shafts up. Most other makes of couplings come in fixed sizes which can be a problem for the modeller, especially if they don't own machinery to make reducers etc.

If you want tough metal couplings, Prop Shop offer a range that looks good for i.c. use.

A CV joint has to be the ultimate, especially for out of true running. I'd have thought a Delrin/acetal cup and cage with metal ball bearings would be strong enough for most electric users, and would be quiet and self lubricating.

[Circlip]

Once more for the people,

http://www.puffinmodels.com/product.php?prod=1706

Even 7cc Tappies were coupled with this type. The recent 15cc  Taplin on flee bay had a leather disc and pin type. Strange how plastic moldings have thrown reliability into obscurity. CV joints on toy boats???

  Regards  Ian

[RAAArtyGunner]

 

[tt1]

Hello Mick, (Irishcarguy), please keep me in mind when you've progressed to a satisfactory product  

         Good luck in your venture, regards, Tony.

[Subculture]

recent 15cc  Taplin on flee bay had a leather disc and pin type.

Thye were known as rag couplings weren't they? Very popular on cars years ago, and gradually were replaced with rubber versions as the rubber compounds were improved post war. Rzeppa type CV joints seem to have replaced all those types of coupling on fullsize vehicles.

[Circlip]

Not sure if they're still available, but there was/is a version with metal "Springs" for coupling tuning capacitor (?) drive shafts to the knobs on the old steam radios. Ex MOD equipment was littered with them. In the mid 50s andearly 60s a new coupling came out that had a couple of brass slugs that had one end tapped to screw onto the I/C engine the other end being straight knurled and the other bit likewise for the propshaft. The coupling was a piece of flexible PVC tube (   ) They were superb at breaking the propshafts if not perfectly aligned, another variation was the "RubberFlex" type, a slug of rubber bonded between the metal ends. Last two seem to have been re-invented recently?

 The best answer came when Max Coote started marketing the "RMA universal coupling", same as the one I previously posted.This was the start of sloppy instalations that allowed angular missalignement and still get a full power drive from an I/C engine. The now universally accepted renderings from Mr Huco have only made it easier to not correctly align drive trains, but one small problem with them is that there ain't no slip joint in them so thrust and end float are ignored. On the good old Hardy Spicers fitted to the prop shafts of RWD cars, not only did we have up to two HS's but also a telescopic splined drive on the shaft - wonder why that was?

    Irishcarguy s cv joint solution is going to be interesting. The use of Delrin (Acetal) iin the joint should only be used to "Cage" the bearings as shock loading from the little balls is going to fluff it and unless the ball and socket of the two drive units are spherically machined, it ain't going to be a C/V joint.

  Regards   Ian.