Propshaft to flex shaft / MHZ drive

[Gerwin Brommer]

Please show us a pic of the propshaft.
If the shaft is 6mm indeed, it must be possible to fit a 4,75 flex.

btw : DRILLING that hole exact isn't possible, you HAVE to do it on a lathe.

[uncledirty]

The flexshaft show the step from 6m to 4,75 and on 4,75 section there are the ballbearings. Other ballbearings are in the other end and still inside in the "black tube".

I will show this on weekend to cnc miller, but probably the lathe he has is made to handle bigger parts. Clocksmith would be better. MHZ advised to make a 30mm long hole. (after 10mm long 4,75 section is taken out. So in a scale it would go about half way of the shaft. Hard to make. would the ballbearing lay on flexshaft?

I would say that possible to do, but its no everyday job for cnc miller used cope with bigger parts... so why they sell these together if they know that it is basicly just theory to connect these.... "buy 1674/A and 1674/F (flexshaft 4,7mm) for it... "

BTW: I also got email that MHZ will sent the missing hydraulic dummies that should have came with rudder... gradually all fit in to its place.


this is why I am concidering other options than flexshaft...

[Gerwin Brommer]

I don't get it.

There is plenty of room for a 30mm deep hole.
You should NOT shorten the shaft !!!!!!!!!!!!

Edit : hm, do I get it right ? : the first part of the shaft is thinner, and the bearings on the pic are on that part ?
The innerdia of the bearings in NOT 6mm ?

What are these 3/16th ballbearings for ???????????????????????
They seem useless to me.

[uncledirty]

Yes the first part is thinner 4,75mm and bearings are on that part. The inner part of bearings is 4,75 and the outer about 8-9mm.

There is similar set of bearings in the other end stamped to that black cover. The propshaft is also thinner in in the other end for the bearings but of course for the prop. The propshaft is suported only by these two set of bearings in both ends.

So if I enlarge the hole to 4.7mm I lose the first thinner part and bearings. So same as cutting the thinner part away. Then the propshaft wont be supported anymore from this end unless I put bearings to flexshaft. Dont know if it would work because flexshaft will shape a bit under stress.

[Gerwin Brommer]

If the 4,75 mm bearings are pulled out/off , all 4 :
what do you see inside the drives ?
Bushings 6mm ? brass-coloured ?

Edit : just noticed what you said : only supported by these 4 bearings.

Well , the only possibillity : mill the shaft to 4,75 mm for the flex and replace the bearings ( on the flex-side of the shaft ) by 6mm bearings.

[Gerwin Brommer]

Uncledirty.

I've send an email to Ernest ( in German :-) ) to ask him what
the right "procedure" is if you wanna change to 4,75 flex.

[uncledirty]

I am really grateful.

[Gerwin Brommer]

Shirley replied !

According to HER , slidebushings ( right word ??) are the STANDARD by MHZ.
Ballbearings are impossible , to small and to weak for those high revs.

I'm gonna send her your photo from the drives, shafts/ballbearings.

[Gerwin Brommer]

Another reply van Shirley :

these trimms are for 2mm wire ONLY.
You should have asked for specific 4,75 flex shaft in your order.

[uncledirty]

F**k MHZ, I trusted their opinioins 1674/A (drive) possible to fit 4,7mm flex shaft... hopefully they correct things to webshop imidiately.

I will ask for refunds and I will GET my refunds.. and missing parts along side.

Thank Youa thousend times for taking Your time to help me!

[Gerwin Brommer]

I strongly suggest you write them an email and explain the whole situation.
Tell them their site is misleading ( correct english ?? )
Maybe you can swap the trimms if you send your trimms back ?

[Gerwin Brommer]

The 2mm wiredrives are for setups to max. 700 watt, that's what Shirley wrote to me.

[Jeff Wohlt]

700 watts from a 2mm wire? I have some out there with 078 basically-- 2mm and they are way over that like (DOUBLE)without any issues running NEU motors.

[Gerwin Brommer]

I know, I think MHZ want's to stay on the safe side.

[uncledirty]

I send an email today and looked from their webshop that the other possible drive for mystic (different code) is actually just the same drive with same 2mm hole...

I asked for refund or suggestion how to solve problem. Lets see... I dont have my hopes very high because every part ordered has had problems: missing parts, not turning drives. Hull is quite ok atleast.

[uncledirty]

Got help from cnc miller and we got the other drive to work properly and got the both drives rotate with ease.

I found 3mm pianowire, that could suit. Only thing is that the end of propshaft where the 2mm hole is, is only 4mm thick!... so miling 3 mm hole would leave 0,5 mm of wall thicknes. The cnc miller said that this is basicly not possible to do. Otherway round would be the case: bore 3mm and then make the axle around it. :)

So I dont have any idea what they think in MHZ when they say that no problem.. just drill... Do they treat me as stupid or what?

Sorry about me complaining..

[Gerwin Brommer]

I think they mean : drill in the lathe.

[uncledirty]

Yes in the lathe. But I have to trust a guy who has done cnc-milling for whole of his life (age 62) and he said, it is possible only in theory to make30 mm long 4,7mm diam hole to 6mm axle. It would leave 0,5 material for sides...and that is just too little with that material.
Other way around it is easy: take 10mm axle, drill 4,7 and lathe axle to 6mm.

Anyway as you posted that Shirley had said this drive to suit only 2mm. For me she stated that 4,7... we aint equal.

so wire drive it will be as I got the drives "tuned".

[uncledirty]

I could replace the drives to ones that has 4,7mm boring. I would have to pay all the cost which would be about half of the price if I would order totally new ones (freights t and from and so on).

Customer has to rely on what states on webshop. It doesnt help if MHZ send an email later on saying you should have known better... better than they write on webshop....

....and when they send me the missing parts from the rudder they added freight to it.... that s more than quite rude... but I need the parts...

I am very unsatisfied with MHZ. I dont know why they just wont say that "sorry we made a mistake, lets find a way to correct things".

[Gerwin Brommer]

You have to pay for the shipping for missing parts ??????????????

[Jeff Wohlt]

I have made many metric stubs and lathed them down to 3/16" for the prop ends and threaded.

I even have done some of the big 8mm down to 3/16" for the stub end.

Also, you can drill larger holes with a drill...it will follow the path of least reistance...should not be a problem.

[uncledirty]

^ it is possible to make a hole for 4,7 mm and lathe axle down to 6mm. But opposite would leave so little margin. With these drives (eventually admitted by MHZ) it is not even possible because the axle is only 4mm where the 2mm hole is and where the bearings lay.

I would use 3mm pianowire, but yet again 4mm axle and 3mm hole... I will try to find 2,5mm pianowire just in order to get a bit more streght because I am planning to use 1950/7 lehners with 5s or 6s lipos.


Anyway. Thanx for listening my problems and helping me out. I will provide pictures of the boat when I get things started.

[ernesto]

Dear Mr. Rautesalo,

I´ve been following you online conversation for a while and I think its time to mention the truth now. Your ordered the drives at MHZ and like it says in the online shop there are 2 different versions of it. The standart version is 2,0mm and this is the version you will get (standart) if you dont order different.
About the cost for shippment. Shirley told you that she will send the spare parts for free but you said that we should wait since you want to order some more parts anyways.
The parts you ordered had to be send with a parcel. The spare parts could get sended with a letter. Shirley took the price for the spare part sending off from the cost for shippment of your new order. Therefore you only had to pay the difference.
Shirley also said that we would take the standart drives back and give you the other ones for it. Of you course you would have to pay for the shippment cost since you ordered the wrong article and not that we sended the wrong ones.
Therefore we ask you to stay with the truth for your own interest.
Best regards
Ernest Zavarsky
MHZ

[Gerwin Brommer]

Welcome Ernest !

Nice to see things are cleared up now !
I hope you will stay on this board and help people if they have questions.

I've had some issues in the past with Ernest, but I hope it's all good now.
I really like my own MHZ-hull, and the more than 20 mhz-hulls I've build in the past.

But : to be honoust with you :
If I look at your online shop : where do I find the "other" propshaft, suited for 4,75 flex ??
The only thing I can find : that it is possible to enlarge the hole to 4,75 flex.

Uncledirty has a point if he has that the shop isn't 100% clear. maybe you should add an art.nr with description that says : propshaft for 4,75 flex only.

[Gerwin Brommer]

BTW : Uncledirty :

Don't be afraid for the thickness of the wall if you want 4,75 flex in that shaft.
It's more than enough !
I've build a lot of Lizards, with Trimax. They come with a 3,2mm bore.
I ordered new shafts for 4,75mm flex, and I've never seen one snapped/broken.
They can handle Plettenbergs 220/50 and Lehners 2250 easily.

[uncledirty]

I will post only one post to clear my side of things. This post can be deleted by moderator if not suitable.

For my point of view (customer) it looks like in this case you dont know yourself what you sell (strong comment but let me explain).
At first you intructed me to drill 2mm hole to 4.7. Then now you say, that you have two different items. I see that you have added a comment of this in your webshop. Really good you did that of course, shame it wasnt there before. So the customer wasnt totally wrong?

About the cost: It looks from my point of view that I was charged of missing parts. Atleast You should have mentioned it. Missunderstanding.

Changing the drives: in Finland (the law) customer can change item ordered in 14 days or later if found seller mistake - and freight is paid by the vendor: sending back the item and sending proper item to customer. So of course I am angry that you wanted me to pay for changing the drives!

On my order there was 4,7mm flexshafts. So of course you could have asked whether I need 2mm boring or 4,7mm? You know these things better than me, you are the manufacturer.

I have tried to be most polite in email excange with you (Shirley) and I have nothing against you. It is just the transaction: buying proper drives and poor info on your webshop.

For the final: these things happen, it is just how you handle reclamations. If not handled properly help might be asked from internet forums.

[uncledirty]

Sorry to take this thread back to top of list, but I just wanted to give credit to MHZ as they decided to split the costs with me of changing the drives. So I am pleased. I have read from other forums that other people have also changed these drives so one can trust that one can change products ordered from mhz - good.

I express my apologies to mhz and forum readers. I reacted strongly, but hobby is more on to do with emotions and expectations than worklife, which is based 99% on rational behaviour, euros, pieces, markets and very little on emotions exept customer emotions.

I will order from mhz in future (if not blacklisted :) ).