Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Engineering Techniques and Materials. => Topic started by: Brian60 on October 03, 2015, 08:34:15 pm

Title: Bevel gears
Post by: Brian60 on October 03, 2015, 08:34:15 pm
Planning for my next project I'm going to need some bevel gears. In total it's about 16 of them :o But they can't be any larger than 9mm diameter across the face, teeth number is not important (more the better for meshing)

Couple of other things, shaft size big as possible and must be made of brass. So has anyone a supplier they can suggest please
Title: Re: Bevel gears
Post by: derekwarner on October 03, 2015, 10:25:24 pm
Brian.......an American steam locomotive called the SHAY, uses conventional 3 cylinder vertical steam engines, but the power is transmitted to the driven wheels via pairs of bevel gears ....I have seen examples of model engines with 2:1 ratio bevel gear sets with the wheel being approx. 10 mm diameter  :o

...here is a link to a model build with plenty of detail of the gear sets .............Derek

http://www.modelenginemaker.com/index.php/topic,3778.msg69261.html#msg69261
Title: Re: Bevel gears
Post by: grasshopper on October 04, 2015, 01:47:58 am
Try looking up Davall Gears on google, they do loads of gear related things, had a catalogue once and it made interesting reading. Small orders and model size products were available.
Title: Re: Bevel gears
Post by: essex2visuvesi on October 04, 2015, 02:05:10 am
http://www.davall.co.uk/ (http://www.davall.co.uk/)


book marked for future reference.... some good stuff on there
Title: Re: Bevel gears
Post by: Klunk on October 04, 2015, 06:51:39 am
meccano gears any good?
Title: Re: Bevel gears
Post by: grendel on October 04, 2015, 09:17:38 am
even the small meccano bevel gears are about 13mm minimum, and you would be looking at a small mortgage for that quantity - lego do small bevel gears that might suit.
heres the smallest meccano one http://meccanoman.co.uk/catalog/product_info.php?cPath=1_14_17&products_id=1159&osCsid=bcd6b38b89006cfe9fe8d1ef4416ed01
at just over £5 each
heres the lego ones at just about 3p each http://www.brickowl.com/catalog/lego-tan-bevel-gear-with-12-teeth-6589. you would probably need lego axles to suit.
I too have a copy of davalls gearbook as a reference.
you might also find some bevel gears in old inkjet printers, I regularly rescue old printers and strip them down for gears shafts and small bolts.
Grendel
Title: Re: Bevel gears
Post by: BarryM on October 04, 2015, 09:21:38 am
Motionco.co.uk may be able to help.

Barry M
Title: Re: Bevel gears
Post by: david48 on October 04, 2015, 09:31:08 am
Have a look here ,if only this was in good old Blighty .
http://www.smallparts.com.au/technical/timing/.  Ahhh I see its pasted the bit I was reading ,it will get you in the right area as usual follow the links to the bit you want .
Is it really dear to get things from OZ .
David
Title: Re: Bevel gears
Post by: grendel on October 04, 2015, 10:31:49 am
One of the books / catalogs I got from Davalls was the handbook of metric drive components  by SDP SI, which has a bit of everything - gearboxes, timing belts and pulleys for them, magnetic slip clutches - a bit of everything you will be likely to need.
Title: Re: Bevel gears
Post by: Brian60 on October 04, 2015, 12:13:26 pm
Thanks everyone, as mentioned meccano ones are way too large, at 18mm diamter. The motionco ones are just about right size but in Delrin, their brass ones are not small enough.

I'll take a look at the other links this evening when we are back from afternoon lunch with our daughter and son in law. Then the journey back to Spain to think about tomorrow, we leave early on Turesday morning.
Title: Re: Bevel gears
Post by: BarryM on October 04, 2015, 12:52:22 pm
OK, nobody else has asked and so I will: just what is this project that needs so many bevel gears?
 
Remember we have ways of making you talk. Not excluding exposing you to Martin's shirt wardrobe. (Insert appropriate smileys here unless, like mine, the system won't cooperate.)

Barry M
Title: Re: Bevel gears
Post by: ballastanksian on October 04, 2015, 04:10:06 pm
With four bevels to a drive, I reckon Brian is building something that in real life would need very accurate drives for positioning, so perhaps an exploratory vessel or something the Oil companies use with four schottel drives?

Title: Re: Bevel gears
Post by: derekwarner on October 04, 2015, 09:25:24 pm
Think you are on the money here Ian.......a few weeks back we saw a vessel with a combination of multiple Voith drives & used for constant GPS positioning....

From memory  {-)...it had markings for twin bow tunnel thrusters, however the Chinese build only showed one single athwart ship thruster,  in subsequent images we detected a Voith schottel type drive just aft of the tunnel thruster that could be lowered for use & raised when not needed 

I wonder if a model gyro from a helicopter be used in this application?..................Derek
Title: Re: Bevel gears
Post by: Brian60 on October 04, 2015, 09:43:43 pm
OK to put you out of your lust for info. I need four of these, 2 forward, 2 aft. But having spent an hours searching for gears, they came to over a £100 I am now on a different track!

Basically I was going to fabricate the housing, have a through prop shaft with a bevel gear in the centre, then a down shaft with  a matching gear to mesh together. The top end of the shaft would have matching gears to go to the motor drive. The whole unit would be revolved around at the top by a crown gear and suitable waterproof seals.
Title: Re: Bevel gears
Post by: grasshopper on October 04, 2015, 10:38:38 pm
Can you not mount the motor vertically and eliminate one set of gears?
Not sure of the size of things but have you googled gear sets from slot cars? They use bevel gears but I'm not sure of the sizes. There are slot cars up to 1/24th so might be big enough.
Title: Re: Bevel gears
Post by: johno 52-11 on October 05, 2015, 01:27:58 pm
Hi Brian

Not sure if this is of any help but I used some nylon gears from HPC gears in my working outboards http://www.lifeboatmodels.co.uk/atlantic.htm (http://www.lifeboatmodels.co.uk/atlantic.htm)
I did try and make some brass ones they did work but slipped on the shaft after a time so I'm back to using the Nylon ones and they work well.

John
Title: Re: Bevel gears
Post by: Brian60 on October 05, 2015, 04:01:45 pm
Hi Brian

Not sure if this is of any help but I used some nylon gears from HPC gears in my working outboards http://www.lifeboatmodels.co.uk/atlantic.htm (http://www.lifeboatmodels.co.uk/atlantic.htm)
I did try and make some brass ones they did work but slipped on the shaft after a time so I'm back to using the Nylon ones and they work well.

John
This why I didn't want to use nylon/delrin, I reckoned they would slip on stainless steel shaft. I thought using brass gears I could solder to brass brass shaft.

Can you not mount the motor vertically and eliminate one set of gears?
Not sure of the size of things but have you googled gear sets from slot cars? They use bevel gears but I'm not sure of the sizes. There are slot cars up to 1/24th so might be big enough.
I checked out what I could and like above those that are bevel gears and small enough are nylon. The larger sizes use standard sprockets made of aluminium, the motor mounted transversely to allow its shaft to line up with the sprocket on the axle.
Title: Re: Bevel gears
Post by: essex2visuvesi on October 05, 2015, 04:05:04 pm
Once you get the gears on the right place why not drill through the shaft and collar and drift a pin through
Title: Re: Bevel gears
Post by: ballastanksian on October 05, 2015, 07:52:55 pm
Put the motors in the pods and surround them with fine weave fabric so that while they might get wet, the weave will keep the very worst of the silt and glop out of the workings. I am sure that a chap of your skills could make two part pods saving oodles on gears etc, probably simpler to make as well. Could you utilise technology that model submariners use to keep their motors dry?
Title: Re: Bevel gears
Post by: Brian60 on October 05, 2015, 08:10:56 pm
Ian that was my first thought. But there isn't as far as I know a small enough motor with the torque required to drive 55mm props pushing a 1metre displacement hull.
Title: Re: Bevel gears
Post by: ballastanksian on October 05, 2015, 08:19:37 pm
Even in the brushless market? Hm.

Title: Re: Bevel gears
Post by: Brian60 on October 06, 2015, 09:25:12 pm
Even in the brushless market? Hm.

Brushless I have no idea over Ian, I've never used them. I did ask advice on another site, but so far have not had luck. If there was a small enough brushless that somebody could suggest I'd certainly give them a go.
Title: Re: Bevel gears
Post by: cos918 on October 06, 2015, 10:09:33 pm
what is the outside diameter of the pod housing ?


john
Title: Re: Bevel gears
Post by: Brian60 on October 07, 2015, 08:26:39 am
Motors could be up to 20mm diameter or a little more, certainly no more than 23mm or the outer pods will look too big for the scale.
Title: Re: Bevel gears
Post by: Time Bandit on October 07, 2015, 11:31:14 am
As far as I know you will nit find anything suitable in the RC sector.
All motors gave too much rpm/V.

You could check at Maxon and Faulhaber. They make very decent motors with 22mm diameter.
Maxon EC22 is what you are looking after. Maybe you are lucky at ebay.
Title: Re: Bevel gears
Post by: Brian60 on October 07, 2015, 12:07:14 pm
Maxon EC22HD  $1200 each :o :o no not a misprint! I need four. Seeing as I don't have the odd $5000 to spare I think these are in the NO category :embarrassed:

Thanks all the same Timebandit.
Title: Re: Bevel gears
Post by: Time Bandit on October 07, 2015, 01:49:11 pm
Regular price should be between 100-200£, not so sure what you found there.
You'll find them pretty often at ebay at leadt here in germany.
Title: Re: Bevel gears
Post by: Brian60 on October 07, 2015, 03:19:31 pm
Tobias that pricing was from the parent site in USA, the model I looked at is very high tech, way more than I ever could need. Produced for underwater work down to 17000ft.
Title: Re: Bevel gears
Post by: cos918 on October 07, 2015, 05:52:22 pm
On the motor side I think you will struggle to find a motor that can swing X2 55mm 4 blade brass props and be smaller than 23mm in diameter . I have seen it done on  a single prop pod but not a double


john
Title: Re: Bevel gears
Post by: Brian60 on October 08, 2015, 03:07:29 am
I've located a supply of either nylon or brass or aluminium gears. Made for customising slot cars (Scalextric) they come in various ratios and are secured by grub screws, they are not bevel gears but crown and pinion, so they will do the same job in a different way! Not bad pricing either-- I can afford these :}

http://www.pendleslotracing.co.uk/spares.html

thanks everyone for your suggestions and input.
Title: Re: Bevel gears
Post by: david48 on October 08, 2015, 10:23:44 am
This is a good find,it's gone into the could be useful folder.
Thanks Brian
 David .
Title: Re: Bevel gears
Post by: ballastanksian on October 08, 2015, 10:55:39 am
I am glad you have found something Brian. I read somewhere on the forum recently that Nylon expands to by a finite amount when/if submerged in water. It might have been in a thread about washers or prop shafts, I thought I would bring it to your attention so you can gauge tolerances when designing your pods.

You don't want gummed up pods now do you {:-{
Title: Re: Bevel gears
Post by: Brian60 on October 08, 2015, 11:12:40 am
I am glad you have found something Brian. I read somewhere on the forum recently that Nylon expands to by a finite amount when/if submerged in water. It might have been in a thread about washers or prop shafts, I thought I would bring it to your attention so you can gauge tolerances when designing your pods.

You don't want gummed up pods now do you {:-{
:-))

Especially when they will be sealed for good once built.
Title: Re: Bevel gears
Post by: cos918 on October 10, 2015, 09:06:11 pm
expensive but what you want


john


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