Great Dane excavating co.

[Cooper]

Yes, you are right, the smaller rod is hollow because that's what I had on hand. The final one will not be hollow. And the piston part has two orings, only one will be there on final, I made the second one for centering purposes at the other end. (Just for initial set up and experimenting. ) the drawling was just a image I found off the net, it is not what I'm planing on final. I'm planing on using orings top and bottom which will center piston/shafts anyway. The way I'm making them is cutting/milling inner oring pistons and outter pistons (one on each end) and soldering them on. Well basically soldering on chunks of brass then machining them down to size. The hole I'm referring to is to allow oil to enter on retraction and exit on extension between cylinder stages. If not there it will lock and not move. I've been wanting to try building some of these for some time now and am finally getting around to it. Just figured I would make a trial one to see what pitfalls scale parts have. And once I get an working idea of what to do (and what not to do) I'll be able to slim down as much as possible and make them from stainless. ,,,,, I think

[Lil Giants]

Originally Posted by Cooper

Little does he know I'm digging a grave pit for him (if he pees on anymore equipment!!!!)

Atta boy!!! He must have some JD in his blood!

That pug just cracks me up with each pic you post.

[Cooper]

Joe it's a French bulldog! My wife gets mad at me when I call him a little pug pig!! Lol!!!



Some more done, I got them working without internal locking. Have a small hole right above each piston to allow oil to fill/empty chambers. After looking at truck cylinders I may have to have the smallest rod hollow as they are mounted inverted and oil pumps from bottom. Some more creative work to be done.

[Cooper]

I'm using 1/16" size orings, if I use smaller cross section orings I would be able to get cylinder wall thickness thinner. Only 1/32" oring thickness McMaster doesn't have in those sizes. Small thickness metric orings available but I don't think the cylinders this size will look too out of place on a machine such at a 777 or 773 haul truck. And they are only visible when dumping. I'm more into function than exact scale anyway. And I'm not sure how easily I can machine the inner oring grooves on stainless. You machinist guys,, would some soft steel be just as good for cylinders? Easier for me to machine and I imagine a good polishing would last on a oil filled cylinder. I just have always used stainless on hydraulic rods.

[9W Monighan]

Try some 12L14 "Leadloy" free machining steel if you want machinability.

[ihbuilder]

I have no problem on 316 . But then again you need your S&F's right . Oh your doin this manually Looks good so far .

[Cooper]

Yeah, all hand crankin!! Problem I have with my skills, tooling, small machines is trying to machine the inner dimensions and being 3" deep. That's why I was using tubing and making the tops/Pistons separate then soldering/brazing them in. Then going back and final machining to size. I have to make some small inside groove cutters. Only have one that I've made and it took me a bit of time grinding that one. Always seems like I spend way more time making the tooling than parts!!! Lol! Guess that how it always is!!

[bigford]

by the time RW is done with this piston he could have bought 2 scaleart 5 stages
LOL!!!!!!

[Cooper]

Haha ! Just remember that if I see you next weekend!!! Lol!!! I'm just happy I can finally make something! Even if it doesn't work!!!

[bigford]

ya working with a busted wing is rough!!

[JAMMER]

Hi Cooper one thing when you polish the cylinders you do not want a high polish you need something that will grab the oil so you want smooth not polished.

[ihbuilder]

ID grooving, I found them on McMaster . Oring groovers and snap ring groovers . You have to take them slow and a very good sense of touch , they break easy . Always use tube for your barrels. Manual or cnc , you should be able to do stainless . You could chrome your barrels .

[Cooper]

[Cooper]

Well I got it working,,,, problem I encountered on final polishing and installing new orings was on the outter most cylinder the groove I cut for inner seal let loose. The way I did it was to use tube and soldered onto end a piece smaller diameter that I could cut the groove inside. Problem was when I soldered it the solder did not penetrate the whole piece. The grove was cut just a bit into the tube so without the solder wicking the entire piece the small ring is now loose. Now I've got to take all apart again solder it in place, re grove without de soldering end. Ahh the wonderful work of not doing it right the first time!!! I think what I did wrong was had tolerance too tight and that did not allow addiquate wicking of solder on entire surface. Sooner or later(apparently later) I'll get this working. And I also realized I need to rig up a pump and tank to use as a test machine. Slowly getting there.

And thanks for the input on # of stainless and McMaster grooving tools, I don't know how I missed them on that site!!

[bigford]

we'll have to talk next weekend

[Cooper]

http://youtu.be/8JNPGro3SZs

Just the prototype of a telescopic cylinder. Now I know I can make them, so,e modifications in place but the simple concept works

[bigford]

3 more stages!!!

[RCP57]

Awesome stuff RW!

[Cooper]

Mark, I don't know how big a six stage cylinder would be with materials I'm using!!! 1/4" increments on tubes,,, a lot smaller cross section orings and it would work. Ones I'm using are 1/16". Need at least 1/32 for more stages.

Reg, they are actually pretty simple and easy now that I know what to do. I'll post up some pics of how I actually made it

[Cooper]

They are the three sizes of tube I used. And in the one pic I have a scribe pointing to the holes in tubes that allow oil to enter into on the downward stroke and oil to exit on the upward stroke. The smaller piston has two orings but doesn't need two. When I made it first I was using it as a guide. Well a mess up really. I just soldered bigger solid caps onto tubs, then machined the hole and inner oring grove. That way I never had to worry about messing up inner parts of tubes. Polished them before soldering/ and again after. I want to make them out of steel or stainless for project on dumper. Just don't know how easy that will be for me to work. I'm usually just brass and aluminum.