Princess Elizabeth Sea Trials - Latest progress

[ihughes]

Well its been a while since I visited the forum or posted any news. I've been distracted by sailing my 1/24 scale Thames Sailing Barge (but that's another story!).

I've continued to struggle with the Princess Elizabeth Minesweeper throughout the summer. We have got the electrics sorted and I have to say that the motors and gearboxes I used (from Squires in the UK) are just right from a gearing perspective. However, I've had real problems with the gears slipping both on the paddle drive shafts and within the gearboxes. In both cases they are very tight friction fit (no grub screws or any other type of real locking mechanism) and I have found that with very little use, the gears are sliding on the shafts, so much so that they disengage themselves. I've tried various ways of getting a permanent fix but with no real success.

Next mod will be to change the paddle shaft drive gears to a similar size but 'grub screw' fixing. However, gearboxes will be impossible to modify, so looks like they would need to be replaced (plus motors).

Not highly motivated to do this at the moment so I guess it will be next season before I try any further mods to the boat. Shame really, as it does look good on the water and attracts a lot of positive comments when show in public.

Have posted some new pictures of PE in the gallery.

[Eddy Matthews]

have you tried some Loctite studlock on the gears that are slipping Ian?

I've used it to great effect in the past - The downside is that it can take up to 48 hours to cure, and the only way to get things apart after using it is to either apply quite a bit of heat (not practical if it's plastic gears!) or to cut them off.

[derekwarner_decoy]

Hi PD's - Ian - plastic [gears] can be very unforgiving when trying to secure them onto parallel [non splined] shafts

Look at snap #2 from our Photo Gallery - it is the two Cheddar steam engines for PS Reliant/Old Trafford & the builder [David] mentioned say 4 years ago that they were slipping & he ended up pinning the plastic [SPDSI] chain pinions to the engine output shafts - the pins are visible in the snap & similarly, the paddle shaft chain pinions are also pinned to the paddle shaft

The other alternative is the SPDSI WEB site & use a metal gear set... but these people are expensive  :rant - after reading of Davids  experience, I  spent $350 AUD for my 1' of 0.1475" pitch S/S of roller chain & two chain pinions for Decoy

I considered an open gears set, but naturally the alignment is far more critical   than a chain drive - Derek

[Bill Hudson]

Hi PD's - Ian - plastic [gears] can be very unforgiving when trying to secure them onto parallel [non splined] shafts
-------------- Derek

A hint for affixing plastic gears to smooth shafts.  Knerling or splining the shaft works well before pressing on the plaastic gear.  
before I had a lathe where I could knerl a shaft I used files in a vise.   It  is best to have two alike files.  I like the small 6" mill files which are about a half inch wide.  Open the vise about two or three inches to give your self room to work.  

Lay a piece of waxed paper between a file and the back jaw with the file tang sticking well beyond the right side of the jaw. Wrap a light wrap of masking around the file and one end of the vise jaw. Do the same  to the other end of the same jaw just enough to hold the file against the jaw.  Do the same with the second file to the front jaw only with the tang pointing the opposite dierection. If you look at the files the teeth of each file should be  running in the opposite direction or crossing each other.  

Now place you shaft end (the area you wantot emboss) in the vise and close the jaws until the file teeth bite into the shaft. Tap the tang of the back file. It should start rotating the shaft as you tap it. It may be necessary to  stop and tap the file up or down (do not losen  up the vise jaw) to keep it in alignment. Then tap the tang of the other file. Keep repeating this process until the shaft ha s completely turned 360 degrees. When you remove the shaft it should have little diamonds embossed in it.  
Play with doing this untill you can trust what you are doing.  When you are confident then do the real thing.

This process will expand the shaft  diameter slightly and give a rough surface to bite into the plastic gear.  As an additional grip I paint the inside of the gear hole with enamal paint. While it is still wet I press the gear on. The paint acts as a lube while pressing the gear  on and when it drys acts as a glue.  
Again  I stress that you practice on old shaft and gears first.

Bill

[ihughes]

Thanks for your advice guys. I have tried roughing the surface of the shafts before but will have another go using Derek's file method. I'm also going to get hold of some Stud lock as suggested by Eddy.

I've been trying to post some 'on-the-water' pictures to the gallery but my files are too big. I'll try and convert the files to smaller images and have another go at posting them later.

P.S. Anyone know of some good/cheap/free software that makes re-sizing image files easy. When taking pictures, I'm always forgetting to change my camera settings from big high quality files (for printing) to small low quality for web publication!

[Eddy Matthews]

Ian, take a look at the following website and download "Image Resizer" it will do all you need....

http://www.microsoft.com/windowsxp/downloads/powertoys/xppowertoys.mspx

[ihughes]

Thanks Eddy. Have realised that I actually have Photoshop on my PC and figured out how to use it!

Have now posted some pics of Princess Elizabeth on the water earlie this year.

Have actually got it better ballasted than these pics show but she still heels over in the turns.

[derekwarner_decoy]

Hi PD's..... Ian ..... no Loctite product will mechanically or chemically fix your "plastic' gear components to a "metal" shaft .... simply, they were never designed to perform such plastic to metal bonds

In essence it is elasticity of plastics, however I do not believe we have a  :bow talanted PhD in Astro Physics Plastics Engineering type member that could answer our  :?: so again we may have to revert to other simple mechanical   means ...... Derek

[Barrie]

Ian,

I too tried the Squires motors in my Princess Elizabeth, but found them very noisy and not very good. At the moment it is without motors as I decided it wasn't going to work and would keep it for display only. However, I recently came across these motors http://www.fastcomponents.co.uk/product_info.php?products_id=70&osCsid=d2064abe5e599c4382cff6c06342429b which I plan to use in another project, and might just try them in PE as well.

Barrie

[ihughes]

Barrie

These motor/gearboxes do look interesting although rpm at max volts might be a bit low. They output shafts look like they have a good 'flat' on them as well......wonder what nominal diameter they are?

If I don't have any more success with locking my gears to the shafts I my purchase a couple of these to experiment with anyway as they are cheap enough.

However, I do agree that the Squires gearboxes are not really up to the job so would definitely advise others not to bother with these despite the fact that they have perfect output RPM.

[Barrie]

Ian

There is a range of those motors - I think the next up is 221rpm. Only possible drawback is the 4.5v max voltage. I guess you could risk a 4.8v pack. I thought I had seen the shaft diameter somewhere but couldn't see it on the web site just now.

Barrie

[David Allinson]

Hi there.
Another supplier who seems to have a wide range of solid looking geared
motors with a huge range of ratios is Conrad in Germany.
 www1.int.conrad.com
Need a few clicks to get there:-
Modelling
Model Enginering Accessories
Model Motor & Accessories
Model Geared Motors.
They seem good value. Most around €15 or so.
I think they may have an English branch.
Regards
David




 Ian,

 I too tried the Squires motors in my Princess Elizabeth, but found them
 very noisy and not very good. At the moment it is without motors as I
 decided it wasn't going to work and would keep it for display only.
 However, I recently came across these motors
 http://www.fastcomponents.co.uk/product_info.php?products_id=70&osCsid=d2064abe5e599c4382cff6c06342429b
 which I plan to use in another project, and might just try them in PE as
 well.

 Barrie>

 

[Red_Hamish]

Hello all, well I knew my engineering product knowledge might come in handy one day. Loctite bonding products are well suited to holding - not permanent  bonding - of gears / pulleys onto shafts. The principle is the microscopic filling of spaces between the faces of the shaft / fitting.

The one I would recommend as a general purpose with a fairly high bond strength is their no. 603 available most commonly in 10ml bottles and sometimes in 5ml too. This does go "off" fairly quickly, so don't buy too much if you can help it. This one also has a tolerance of areas where oil is present.
Alternatively a slightly weaker one is the no. 606 in similar sizes but not as tolerant of oil soaked areas.

I hope this helps

cheers

Jim