My paddle wheels/drive system.

[2late]

A couple of photo's of paddles I made using my home made CNC machine. They are from 0.75 mm brass and are 145 mm in diameter, they took about 20 minutes per side to cut, the blades are notched to fit over the outer ring and then there was a small amount of filing to clean them up. They are held on the shaft by grub screws. The motors have adjustment either up or down to stop the O rings from jumping off the pulleys and a 20 minute dry run and occasional jambing of the paddle saw the O rings stay where it was intended that they stay. There is a small neat fitting O ring in the aluminum block that acts as a water seal to stop the ball bearings from getting wet. The paddles spin at about 160 RPM and have speed controllers for each motor. At this stage everything is working

Graham

[Eddy Matthews]

A nice job Graham, well done. What is the boat you are building?

Regards
Eddy

[amdaylight]

After admiring your wonderful work I have a quick question, on the wheels themselves, why does everyone make the bars that go between the radial arm's curved so they look like a wheel. I can understand this on a wheel where the framework is iron and the bars can be forged but with a wood wheel it would make no sense to spend all that time and effort to cut the wood stock to a curve with no gain in strength. If you look at the photo from the Steamboat Natchez you will see that they are straight and not curved. A straight piece would also be easy to fabricate in the field when emergency repairs were being made. I am getting ready to build one or another side wheel ocean steamer and want to get it right.

Andre
Puzzled over yonder in Portland Oregon

[derekwarner_decoy]

Hi PD's......Andre...if you have time...spend a few hours viewing our WEB pages on wheels....the attachment here is from one our founding members [Mick  ] and discusses an alternate construction of a wheel rim being made with a series of flats...or similar construction as you have displayed with Natchez

http://www.btinternet.com/~mjt60a/models/paddlewheel01.html

....However with more ....[about strength] it becomes apparent that the outer wheel rim members when entering the water are in compression & so if radius-ed element as commonly depicted ......has lower compression strength than a similar straight grained wooden element

With respect to your build.......your call but it is generally thought best to stick with the proto typical example - which ever way....please post some snaps of your build.....they will be appreciated by many.......Derek 

[2late]

Eddy

The boat started out as the Emmy Lou but what it ends up as will be a wait and see. I will keep building and do some sea trials (in the dam) if it gets too top heavy then I will have to make other plans, it may end up a Heinz variety and be called "Bugg*r It" and just put a flat deck and wheel house on it. Can always take the electrics out and just have it sit on the shelf and use the bits for another boat.

Graham

[kno3]

Nice looking paddlewheels. But why are the paddles soldered? A few small hex screws would look pretty good.

May I suggest mounting the two engines transversally? That way you wouldn't have to use the awkward belt set-up.

[rpbidgood]

Nice work, Graham. The trouble that I have with brass is that I never want to cover it up with paint.
Keith.

[2late]

kno3. The thought of trying to (a) find any brass or other screws small enough and (b) trying to hold it all together while it was drilled did not really have any great appeal and as some 60% of the paddle is covered and they are going to be painted anyway. As for the mounting of the motors it only took one motor mount to be made with all the adjustments and the O rings are capable of handling what I have asked of them and are no more difficult to fit than if they were across the boat and if they do give major problems in the future I will look at other methods then.

Keith they might just end up on a shelf if the boat turns over too quick and then I can give them a shine

Graham

[mjt60a]

.... why does everyone make the bars that go between the radial arm's curved so they look like a wheel.....

I would imagine it's because on 'real' ships (british coastal paddlers, at least) they usually are built with a circular outer rim, maybe that's better if the wheel hits a floating log or something.
If you look at Waverley's 'rimless' wheels, the pieces that make up the 'inner ring' inside the floats form an octagonal, not circular shape...

[rpbidgood]

Hi,
    Andre makes an interesting point about the ease of fabrication of the straight "spacers?", but a quick Google image search for sternwheelers seems to suggest that most had circular spacers. Unfortunately, older images are generally indistinct, but the first attached picture is clearly the remains of an old ship. The construction in the second photo is quite unusual, but definitely circular.
 Andre's post initially had me running back to the drawing board, (or whatever it's called these days), but paradoxically, although it might be easier to build a wheel with straight spacers, it is a lot more difficult to draw the wheel in this way on a CAD program. at least for me anyway. I might draw one up as a design exercise, keeping the outer ring circular.
 Keith.

[Barrie]

I was stuck for a long time with my plans to build Lulonga because I couldn't find a way to make the circular rims to my satisfaction, then I saw one with straight sections, and so I built it that way. On Lulonga not much of the wheels are visible when its on the water, so I'm happy, and as its not a model of anything in particular, no-one can say its wrong

Barrie

[mjt60a]

....I couldn't find a way to make the circular rims to my satisfaction....

I've used a 'compass cutter' to make them, works well enough on styrene sheet 2mm thick or ply(wood) up to 1.6mm, haven't tried on anything thicker - http://buy.maplin.co.uk/Free_UK_Delivery/Compass_Cutter_30607/Compass_Cutter_30607.htm

[Talisman]

Hi 2late,

Nice looking wheels


A couple of questions for you.


any tips for cutting brass on a cnc machine? what cutting tool do you use? do you use any cooling system?

My reason for asking is i'm new to cnc but cutting brass and plastic is costing me a fortune in pcb end mills as they keep breaking


Many thanks in advance

[steamboatmodel]

Hi mjt60a,
When you say "pcb end mills" what do you mean? what size end mills are you using and at what speed and feed? Also what type of CNC equipment, a industrial unit or a hobby conversion? It has been many years since I have done CNC work, but the usual cause for end mill breakage is too low a cutting speed, and too high a feed rate. If you are using a hobby CNC conversion remember the speeds and feeds in the books and charts are for rigid high HP commercial equipment. You need to keep the speed up but cut the feed rate down. I have cut brass shim stock on CNC equipment, using 2 flute end mills down to 1/16" dia., held the stock on an aluminium plate with double sided tape, and was able to do cuts both through the material and half way through, used flood coolant.
Regards,
Gerald

[Talisman]

Hi mjt60a,
When you say "pcb end mills" what do you mean?
I'm using printed circuit board end mills


what size end mills are you using and at what speed and feed?

0.8mm > 1.5mm speed not sure its a freiser router with no speed reading.

 Also what type of CNC equipment

a step four 1000 basic

It has been many years since I have done CNC work, but the usual cause for end mill breakage is too low a cutting speed, and too high a feed rate.

i usually get a ragged cut could this be that im not cutting deep enough in each pass?

used flood coolant.

whats that ?


many thanks

Kim