How to make movable lift arms that stay put.

[bower315]

Hello All,
I’ve been “lurking” on your site for several months now and am reading almost every thread through to the end. You have some highly skilled people!
I like making toys but I get discouraged when the loader I made from a plan in book “A” is able to carry the truck I made for it to from a plan in book “B” in its bucket, I’ve decided to try to convert everything to “G” scale (1 : 22.5) since that seem to be a reasonable size. Smaller scales require much closer tolerances. Even at G a 1/16” equals almost 1 ½” on the real item.
I’ve found some sources of drawings with dimensions for popular equipment at:
http://www.ritchiespecs.com/ (http://www.ritchiespecs.com/)
http://www.kellytractor.com/ (http://www.kellytractor.com/)
Also, anyone interested in farm tractors may be able to find some very basic sizes (wheelbase, OA length, wheel width) at :
http://tractortestlab.unl.edu/ (http://tractortestlab.unl.edu/)
Now for my question.
I would like to make the lift arms on a front end loader stiff enough to stay in position and not fall to the floor when the “operator” removes the “lifting force”. Plans found in wood magazine use threaded rod and acorn (cap?) nuts. These may work but the cost and appearance are issues. Any suggestions?

[crowie]

G'Day & Welcome "down under" to a top forum in the western pacific "bower315",
You'll find a heap of helpful & knowledgeable blokes & ladies on the fourm and for the most very willing to assist.
The toymakers & modellers are a top mob and you'll get a good few replies and from all over the world..
Make sure you show off your handiwork as everyone loves a photo, especially WIP photos & build notes;
PLUS it helps with questions & "how to" things.
As to this question, I saw some months back were a bloke used a number of plastic hospital syringes & tube with coloured dye to push & pull a crane boom.
Maybe that would work here for you too.
Enjoy the forum.
Enjoy your woodwork.
Cheers from "on top down under", crowie

[bj383ss]

Hello Bower,

Welcome to the forum. You have found a great place to share your passion for wood scale models. Thanks for the links they are much appreciated. As far as you question goes can you post of a pic of exactly what you are talking about.

I am picturing the threaded rod going horizontaly across the boom with the acorns on the outside of the boom arm. Have you thought about building real cylinders with a large dowel and a small dowel inside of it that goes in and out. It could be made to fit tighlty in the hole. I have attached a picture of a scale backhoe plan that is made this way.
221626
Hope this helps.



Bret

[bower315]

I knew I could count on this site to offer help!

Calling my "projects" scale models is a big reach. They simply are toys built close to scale. I'd love to make the backhoe with operable cylinders but my main objective is having a toy that will survive being dropped from a table or being thrown. My "clients" are still too young to appreciate the detail work.

I'm looking to do something to stiffen the pivoting points so they will stay put. "Wood Magazine" has a series of trucks, excavators, and crawler tractors. They use threaded rod inserted through holes drilled in the pivoting arms and body of the tractor (usually horizontal). They are capped with acorn nuts. Usually they use #10 threaded rod. I've tried using screws and washers but the wood quickly wears away as the joint pivots move.

My work at this time is not near the quality I've seen on this site. I've been busy with mass produced projects for my wife's club. A small group of ladies have taken on several social agencies as projects. One fund raiser they have is a Christmas craft show. I recently completed 25 wine glass holders (square piece of wood with holes in the corners to hold 4 wine glasses and one hole in the center to go over the bottle. I also have a herd of 27 dinosaur puzzles roaming my garage.

[Pogo02]

I used rubber bushings on the ladder of my firetruck and that worked fine.

[bower315]

I've studied your fire truck Pogo02 and it’s a great job. That's exactly the concept I'm looking for! Can you give me some more info on the bushings you used and how they are installed? Is the material "repurposed " rubber tubing? How did you apply it? I assume you used it for both the ladder hinge (up and down) as well as the pivot (left and right). Thanks for the idea!

[crowie]

For what it's worth, I too have used rubber bands to hold the tension on my "Big Rig Tow/Recovery Truck", works well.
http://www.woodworkforums.com/f174/tow-truck-norm-marshall-style-156932/index2.html
It's drying in the sun at present but I'll take a few extra photos of the mechanism for you later.
Cheers, crowie

[Pogo02]

I've studied your fire truck Pogo02 and it’s a great job. That's exactly the concept I'm looking for! Can you give me some more info on the bushings you used and how they are installed? Is the material "repurposed " rubber tubing? How did you apply it? I assume you used it for both the ladder hinge (up and down) as well as the pivot (left and right). Thanks for the idea!

Bower,

I used rubber washers like the ones in the attachment. I bought a set in a box of different sizes in what you can call a dollar shop. I only used it on the up and down movement.

You have the base (which turns left and right) with a hole in it. Then you have the ladder, which has holes in it that align with the hole in the base. That alignment is your pivotpoint.
Form both sides you insert a dowel with a bigger end, that way you secure the whole lot. The only thing you have to do is apply the washers between the base and the ladder (both sides of the base), and put a clamp on both sides of the dowels. Put enough pressure on it so that it moves up and down, but does not fall down on itself. When you are happy with the settings, let the glue dry.

When I read this back it does not sound logical, if you do not understand, please say so, I will make a drawing of example. My technical english is not good enough to explain clearly I think.

[bower315]

Your suggestion makes perfect sense! I was picturing (i my mind's eye) a flat washer made of rubber but didn't know where to look. Seeing your photo, it came perfectly clear. "O" rings are available here and are cheap. I made some "crawling bugs" with wooden wheels but they refused to craw on a smooth wood or vinyl floor. I bought some 3" O rings, converted my drill press to a "verticle lathe" and "turned a small groove on the tread portion and achored them with CA glue. Worked great!

I was experimenting most of the afternoon and just about resinded myself to have each moveable joint cost about 2 bucks. Thanks for the idea. Will pick up some faucet repair kits at our dollar store. Sounds like the answer to my problem. Thank you!