90 degree joint in rotating shafts

[Brian Rupnow]

Good wife and I just returned from the Princess Alexandra theater in Toronto. Seen a musical called 'Come from away', about the 7000 people who's planes were diverted to Gander air base in Newfoundland, Canada, during the 9/11 crisis. Sounds like a strange premise for a live play, particularly a musical. However, it was good. It was really, really good!! Made me laugh, made me cry, touched all the buttons that a good live musical will do. That was my dash of culture for this year.---Now---As for the strange 90 degree shaft joint-----when I first assembled everything, I coated all of the sliding and rotating members with grease. This worked, and did the job for the initial running, as you seen in the video. The longer it ran, though, the harder the drill had to work. It was stiffening up, not loosening up. My next amazing stunt was to reach for the can of spray on WD40 that I use when cutting aluminum in the mill or lathe. I gave everything that moved a liberal shot of WD40, which immediately washed out the grease and made the joint even stiffer. At this point I was wondering what I should do next, so I grabbed my squirt can of #40 automotive lubricating oil and gave everything a good squirt. This immediately fixed things and loosened everything up again.--My forensics on this, are that although the grease provided initial lubrication, it very soon loaded up with microscopic metal particles, as all of the rotating and sliding parts "wore in". All of the metallic particles were then held in suspension in the grease, and instead of a lubricant, the grease itself became a fluid abrasive and was jamming instead of lubricating. the WD 40 then washed out any of the remaining grease, and left basically a metal on metal situation. Then the #40 lubricating oil washed out the remaining metal particles and saved the day. I have sussed this out based on the greasy, gritty residue that has dripped onto the aluminum baseplate from the rotating joints.

[crueby]

Are the sliding tubes also made from steel? Would it be better if they had a sleeve of bronze maybe? Hard to tell on the pics of the antique R&T one,  looks like it may have a sleeve of some sort. Or maybe that is just grease.

[philjoe5]

how do they do that ball in a casting thing anyhoo?

Someone told me a while back that the ball is cast in the sleeve, then the connection is cut and the flash or whatever its called is ground off.  Since I know little about casting I don't know if they were "selling me a left handed screwdriver" or not.

Cheers,
Phil

[Brian Rupnow]

Are the sliding tubes also made from steel? Would it be better if they had a sleeve of bronze maybe? Hard to tell on the pics of the antique R&T one,  looks like it may have a sleeve of some sort. Or maybe that is just grease.

It should have a bushing in there on a real working full size unit. I didn't sleeve mine, because it was just a "what if" model.

[Brian Rupnow]

After a half hour of running in, with the big red beast (My 1/2 HP 1750 rpm bale elevator motor) the wonky joint has loosened up remarkably. The "hard spots" it encounters are right at the point where the sliding sleeve on the main-post is at it's very highest and very lowest points. I think this mechanism would benefit greatly from a decent sized flywheel on either the input or the output shaft. You can see in the picture the almost mirror like finish on the main post where the slider travels. I think a linear ball bushing riding on a hardened, ground, and polished shaft would make this thing almost perfect. I'm not going to do that. For what I want to do with it, it will be just fine the way it is. Since I have yet to make a pulley for it, I may incorporate a flywheel into the pulley.

[crueby]

On the antique one from the R&T museum, it looks like the cranks they used are heavy enough to act like flywheels, maybe they saw the same action you did. Neat stuff!

[Brian Rupnow]

I believe I may have found my flywheel---maybe even my pulley as well. A gentleman from western Canada was in Barrie last summer, visiting relatives. He has been following my build posts for several years now, and wanted to do something to show his appreciation. He brought me an assortment of cast iron valve handles that he thought I might be able to use on one of my "creations". The offset between the center hub and the rim has kept me from using them on one of my engines, but for this project I think they could be perfect.

[Brian Rupnow]

So, as I promised, here is the 90 degree shaft transfer being driven by one of my steam engines. It has been a fun and fast little project, and the transfer mechanism is quite intriguing to see working.---Brian
<a href="https://www.youtube.com/watch?v=c57Hh9E-ovg" target="_blank">http://www.youtube.com/watch?v=c57Hh9E-ovg</a>

[philjoe5]

Nicely done Brian.  I do remember your build log of that twin cylinder steam engine.

Cheers,
Phil

[PStechPaul]

Very interesting and well done! If you think about it, this converts linear oscillatory motion to rotary, then back to linear, and finally once again to rotary. The linear motion of the right-angle drive could be used for other purposes, such as a valve, or maybe something like a trip hammer. But cool enough as it is!

[gerritv]

An interesting puzzler to mesmerize people.

[Art K]

Brian,
You just keep finding cool things to build, love it. Cant wait to see whats next.
Art

[Brian Rupnow]

Thanks guys. The action on that mechanism was still a bit "herky-jerky" when I made that video with the steam engine, so I set the mechanism up with the old bale elevator motor again, covered it all with oil, and let it run for an hour. It is as smooth as silk now.

[b.lindsey]

Brian, the pulley/flywheel thingy's add a lot to the visual of watching it run. Should play well at shows and generate lots of interest for sure. Very neat mechanism and well executed also!!

Bill

[Brian Rupnow]

Something neat that I hadn't noticed before---there is a tight spot in the mechanism, just as the sliding sleeve on the main-post reaches the top and starts down again. Watch the way the flyball governor reacts to that tight spot. You can see the balls flying in and out, allowing more air flow into the cylinders as the torque demand increases at that tight spot. It isn't in exact synchronization because of the elasticity of the o-ring drive belt, but it is definitely there. The flyball governor is trying it's best to keep a constant rpm at the engine. Ya got to love that old time motion control action!!!