Mimic's Sister - Shapeshifter

[yotsuya]

Someone should come to ZapCon and wow us with his Hard Driving skills again!

[opt2not]

Someone should come to ZapCon and wow us with his Hard Driving skills again!

That was so awesome to witness. I was stuck watching Laythe for quite a while, in awe...

[yotsuya]

Someone should come to ZapCon and wow us with his Hard Driving skills again!

That was so awesome to witness. I was stuck watching Laythe for quite a while, in awe...

Me too. It was like watching Randy Johnson pitch a perfect game or De Niro in “The Godfather, Part II”. Mastery in action.

[Laythe]

Hehehe, thanks, guys.

Hard Drivin' was one of my big teenage passions.  I can usually beat a quarter mill, I think I posted a 251k while you guys were watching. 
I think the Twin Galaxies score for it is just shy of a million.  It was a pleasure to get to demo that the machine really is entertaining, once you figure it out.
It kinda got a bad rap I think, and Xiaou2 championing it in his usual strident style here didn't do it many favors, either.

Shapeshifter will do a very good job at Hard Drivin' - I have the gas, brake and clutch pedals, the 4-position shifter, the 900' wheel, stereo sound, and a fast enough machine to emulate it at full speed.  I haven't gotten the FFB for the wheel working and don't know if I'll be able to, but easily half of the Hard/Race Drivin cabs I've played in the wild have busted FF too and I do still get motor centering, so that's only a mild downer for me.

I'm about two thirds through the whole paint process I think.  I've test-assembled the back cabinet together to check that it fits once painted (it didn't, had to fix that).



The playfield table, in pinball mode, will be flush with the top of the lower fat red stripe.  In driving mode, the top of the main screen will be about halfway up the backbox, and the bottom edge will be just above the bottom of this cabinet.

I really like the way the black neck separating the pinball table from the backbox is turning out.  When you get the angle right, that it starts reflecting the red paint on the edge -



This neck under the backbox is not exactly an accurate pinball reproduction feature, but I think it's cool in lieu of the backbox being hinged.  It's my sci-fi futurist take on a pinball machine, anyway.


I've got the front cabinet ready to populate, and work is currently underway on that. 

Testing that the coin door fit after paint (it didn't, I had to do some sanding):




I've got a lot more sanding and polishing paint to do, but hopefully I'll be able to finish up the front cabinet and start populating the back cabinet soon.

When both of those are done, then I get to build all the stuff that connects them - the axles, shelf, cockpit dashboard arm, computer doghouse, etc.  This is good progress and I'm chuffed, but I also honestly think I'm less than half done with this thing.


(Now you see why I kept my trap shut while building Mimic until it was done - my projects take something approaching geologic time.)

[javeryh]

Looking good - don't worry about the time it takes.  You are moving at light speed compared to one of my projects.   

[Laythe]

Front cabinet is now populated and rewired.

I'm getting very close to being able to populate the rear cabinet, this much of the paint and bodywork is at least 90% done now.

Here's the two cabinets, as painted and on their legs, next to each other.



As seen from the front, this is kind of close to how it'll look as a pinball machine.



These are of course hilariously too close to each other, but this does a good job of showing how the legs fit into the design and all the shapes involved.



Here they are set the correct distance apart, and you can see how the inward-facing driving mode speakers line up.  This is at least the beginnings of how it will look in driving mode.

There will of course be a lot of structure to connect them, but I figured I'd start at the ends and work in.

[Laythe]

I'm beginning to populate the back cabinet and backbox.  This area will probably have to come apart at least once more for axle mounting and a few other tasks, but I want to build it and do some verification.

With the main rear hatch removed, the back box looks like this.



Nothing's wired up yet, but you can see the relationship of the backglass panel, the DMD panel, and the speakers.  I specifically wanted all this stuff to remain mounted and fixed in space when the hatch is off.

I should be able to route all the wiring this way, then bolt the rear access hatch up over all of it at the end.  You can see the big cord via, to the left of the DMD panel, down into the neck - that's where most of the cable runs will go.

From the front:



I haven't yet built a fascia to cover all this - I'm thinking about a thin waterjet cut acrylic gloss black bezel type panel, with holes for the screens and speakers, to tie the back box contents all together visually.


I'm planning to do the wiring next, with a goal of getting back to a working mockup with the playfield temporarily on a table between these two end cabinets.

Making it live again at that next level of incremental approximation should be encouraging.

[Arroyo]

I’m very curious to see how you handle the motor and rotating function.  I would have expected to see holes for that in both sides before painting, so I’m looking forward to seeing your solution.  This build is entertaining, a lot of innovation here.

[Malenko]

This build is entertaining, a lot of innovation here.

I'm more excited about this build than I am my own.

[Ond]

My fav build too.  I like the approach to the complexity of the design, Laythe's way of making various components and the pics of his workshop with stuff everywhere!  I have to be braver and take a pic of my workshop at the end of a day’s hobbying because it's always totally trashed.

[opt2not]

Coming along nicely, Laythe!  You think you'll be done before Zapcon?

[Laythe]

I’m very curious to see how you handle the motor and rotating function.  I would have expected to see holes for that in both sides before painting, so I’m looking forward to seeing your solution.  This build is entertaining, a lot of innovation here.

Thanks!  Glad you're enjoying it. 

The axle can't actually penetrate into the backbox - it would run directly into the DMD LCD screen right behind the wood.  It's going to run inside a compound 3 degree angled machined flange attached to the outside face - there's plenty of height room back there under the screen, because that's the tall end of the playfield panel's taper.   It will end up piercing into the front cabinet though, because that's the tight end of the taper where the TV is right against the axle.  The rotation will be done via a linear actuator on a bell crank, but there's lots of fabrication between me and there yet.

I'm more excited about this build than I am my own.

Thanks.  I'll try not to let ya down. 

I figure I owe you one - I like GB2.0 a lot, and none of this would have happened at all if you hadn't sent GB1.0 to Zapcon.  That was really the turning point on me deciding to commit.  I've played with a few other commercial vpins since then and they kind of sucked, so if I hadn't had time on yours I would probably just think that they all did.  I'm pretty sure the end result I'm chasing here is not going to be a better vpin than Gingerballs is - just bigger, weirder, and maybe better at running racing games.

My fav build too.  I like the approach to the complexity of the design, Laythe's way of making various components and the pics of his workshop with stuff everywhere!  I have to be braver and take a pic of my workshop at the end of a day’s hobbying because it's always totally trashed.

Yes, that's it - my messy shop is a virtue!   I'm just that brave.  Yeah.  I'm going with that!

In all seriousness, thanks. 

And yeah, you should - the carnage and chaos is part of the project, in my opinion.  Many shop rags died to bring us this finish.

Coming along nicely, Laythe!  You think you'll be done before Zapcon?

Thanks! 

Done before Zapcon?  No way.  None at all.  Nope.  Zero percent.

I'm thinking I'm about seven months into a twelve month project here - I'm not even 100% certain I'm going to be finished before the following Zapcon. 

This is gonna be a long ride. 

I won't quit unless I run into irreparable disaster - but this is just going to go on and on, until it has half as many pages as Chance's Flynn thread.

[Laythe]

More progress.

I've started populating the back cabinet.  I'm not 100% sure that this isn't premature, but I -think- the rest of the work that Arroyo mentioned doesn't require me tearing this stuff back out, and I want to make sure it'll work.

The backbox exhaust fans are now properly installed with quick disconnect connectors and grills.



I turned out to have 23 of the 24 screws I'd need to mount all these fan covers on hand, so there's one missing screw in the bottom for now.



(The bundle of cables that have to come out of the bottom of the backbox is amusingly large... and that's maybe not quite all of them.)

I installed six standoffs and mounted the ultimarc U/IO encoder board in the lower left corner of the rear cabinet.



That lower left most standoff was pretty tricky to install, being right near the corner and blind behind the corner brace that the rear access hatch bolts into.  I had to get creative there and make myself a very long simple burr drill bit out of piano wire that I could fish through the mounting hole in the brace and flex into position... and then it took another hour or so to battle that screw into the standoff in a space too short for even my stubby screwdrivers.  It's in now, though!

Above that, is the amplifier, and above that I installed a power button - it will get attached to the computer motherboard where the case power switch currently connects. 



I like the look of this behind the rear leg - the amp face showing gives you volume control and a headphone jack, and it and the power button kind of go visually with the aluminum legs I think.

All up, here's the filled cabinet so far:



Ignore the one VGA cable off to the left, that's a temporary extension cable to make up for the PC being too far away from the backbox - it isn't correctly routed, but the rest of the wiring more or less is.  I'm trying to keep all the airflow up the center that I can.

Above the amplifier, you can see a chunk of DIN rail that contains the 12v power supply for the fans, and the audio switching relay that handles flipping the speakers from pinball mode (both in the backbox) to driving mode (left speaker in the front cabinet, right speaker just behind the amp). 

The fans work, the relay works, the amp and speakers work;  I'm real close to being able to fire this thing up as a mockup in pinball mode and playing some games with the playfield on a table between the two end cabinets.


As Arroyo has correctly noticed, I'm not close to having the transformer half of the thing fabricated.  Yet.   

(I'd post a Yotsuya style SOON graphic here, but, it'd be a lie.  It's not exactly going to be SOON, and there's no good image macro for IN A WHILE.)

[Laythe]

So, paintwork on the front and rear cabinet are close to done. 

I drug them together and lashed up Mockup v2.0 to work on some system integration and give it a good test.

The distance between cabinets should be about 42".  I fouind I've got a 48" long folding table, and I built a setup on and around it, which means there's an extra 3" of dead space in the following photos that won't really exist when it's all done.



I built a temporary plywood frame to hold flipper buttons in roughly the right spot; it clips in under the lockdown bar assembly for now, but the real carrier for them will be part of the rotating playfield frame.

The entire front cabinet comes out on a 25-conductor cable to a DB25 plug, which attaches to the rear cabinet - this is designed to stay modular so that I can move it in pieces.

The rear cabinet is now mostly wired up, and I've got the painted access hatch properly fitting as a plug-in fit. 

It fits well enough the bolts are kind of optional, though having the big 3/4" thick plywood hatch bolted in forming a back spine should further reinforce the backbox.



It takes some lifting and levering to get the hatch out, especially after the bolts have all pulled it in tight.  I also don't want anyone to ever back this machine up tight against a wall so tight the exhaust fans can't work.  To serve both ends, I found some industrial looking rack server handles and installed those on the hatch.  Slippyblade may appreciate that it's a strap away from being an adequate kite shield now.

I am stunned at how good the airflow is, with it buttoned up - it makes a wind tunnel in there.  Tried leaving the monitors both on for increasing durations with the fans running, and after a 6 hour test they weren't particularly warm - tiny bit of warmth coming off the glass in front, cold cases in back.  Not loud, but it's moving a ton of air up the slot.  Overkill, I'm sure, but it's hard to find replacement 2709WFPs these days.

I've also acquired the linear bearings and rail that are going to support the sliding driving panel assembly.



These are 25mm hardened steel shaft rails, and ball bearing trucks for them.  They weigh about 5lb apiece, but the play and flex on them is minimal.  These are going to mount in this orientation along the bottom edges of the cabinets, and the still-to-be-built driving shelf on the blocks side then rises up about 6" from there and bridges across the center.  I'll need an actuator to move it, and locking pins to keep the drawer from moving along the rail or rotating on the plane of the rails when deployed - but these rails should do a very beefy job of keeping the wheel and sticks solid versus the other 4 degrees of freedom.

The main purpose of this lashup, though, was to further develop the software stack, tinker with table settinggs, and build and test the wiring of the modular assemblies so far.



HAHA, IT'S ALIVE.

Well, this half of it is alive.  Mostly. 

I've got a few bugs to fix here and there, I think I'm going to have to write a couple AHK scripts to slap VPX into working the way I want it to - the playfield doesn't always get the focus, and you have to alt-tab into it about half the time.  But my custom front-end is coming along well.  As of last night's work, you can now push the button above the amp to power it all up and end up in a game selection menu.  You can also do a graceful shutdown using the same button, or pick "power off" from the game menu, and that all now works.

[Arroyo]

That.... looks....dope.

[meltman]

Wow looking superb!

Can't wait to get to the same state with my project.

[Mike A]

25mm supported linear rail?

Nice.

[Malenko]

AMAZING! 

[javeryh]

Holy crap.   

[Nephasth]

Lookin' good!

[opt2not]

The money shot! This is coming together nicely. Can’t wait for the transformer pics when that part is done. 

[barrymossel]

I am so looking forward to the end result!

[Ond]

Looking mighty tasty my man!  I hope I haven't missed it, but what are you planning on using to turn the monitor through 90 degrees?  I'm a big fan of stepper motors and the code to drive them, but they are pricey.  I've seen simple linear actuator based mechanisms used but I question their strength (and speed) for heavy work like this. Steppers are great for the precision and sheer torque strength, especially with some gear ratios in between to leverage them.  Edit  I re-read this project from the begining and you do mention a linear actuator for rotation.  I'll be keen to see how this pans out.

[Laythe]

I've seen simple linear actuator based mechanisms used but I question their strength (and speed) for heavy work like this...
...you do mention a linear actuator for rotation.  I'll be keen to see how this pans out.

I admit, I am also anxious to see how that particular part pans out.   
(It's entirely possible it may not work, in which case I'll have to drive the axle differently.)

[bperkins01]

Looks amazing - if you are anywhere in driving distance for me..  well.. you know.. 

[Laythe]

Meltman, Mike A, Malenko, javeryh, Neph, opt2not and barrymossel - thank you.  I enjoy the hours in the shop working on this, but knowing that I'm not the only one who cares how it all turns out, helps.
bperkins01 - I'm pacific northwest, and I think you're new england based on things you've said on your boat projects.  Might meet you at Zapcon sometime though!

This weekend I mostly spent hacking on the software.  But one thing kept nagging at me. 

From the back, the cabinet looked - exactly as designed - like this:



In my head, that was gonna look really cool, with the bracket-shaped red edges of the front showing around the solid black fill of the rear hatch.

It didn't look that cool.

So I kept staring at it, and screwed around a bit in an image editor trying things out, and decided to paint three 3/4" wide red stripes on the hatch.

On it's own, it looks pretty stupid:



But, when you install it, they line up and complete the shape like so:



And now I'm happy with this part - now I think it looks cool.

(The stripes don't line up perfectly in this picture because the paint was still wet and so I didn't want to leave the panel vertical for long, so it's not pushed all the way in - it's just leaned in long enough for the photo.  There will be 10x silver washer-and-bolt combos like you can see at the upper corners in all the holes, which will crank it down nice and tight, and the stripes should then push in flush when it's actually together for reals.)

[bperkins01]

That's my kind of OCD!
Well done 

[javeryh]

So I kept staring at it, and screwed around a bit in an image editor trying things out, and decided to paint three 3/4" wide red stripes on the hatch.

This is some next level attention to detail.  I love it and you are right - it looks WAY better.

[Laythe]

So, back when I made the wooden piece that accepts a normal 25" Williams widebody lockdown bar, I figured I'd just slice in from the ends to cut out some of the clearance holes on my bandsaw.

Unfortunately, over time, these fingers released some pent-up stresses and warped a bit, and the bottom ceased to be flat across the gap.  Additionally, I found that the lockdown would look better if it was just a touch wider - if you flush it on the back edge of the front cabinet, you can see a step under the lockdown bar on the front, and if you flush it to where the lockdown bar looks nice in front, there's a step in the back.  Some adjustments were called for.

I drilled and pinned it on both sides.  I could have used a dowel, but I had some 1/4" stainless round stock handy, and nothing says "STAY" quite like a steel pin.

Drilled 1/4 holes in from the back wall, while tweaking the floor level with my other hand, then tapped the pins in with a pin punch.

From beneath, you can see the pin bridging across the saw kerf.



The back face that I drilled through shows in driving mode - but that's okay, because I also cut a few pieces of thin hobby plywood to face over it all with.



Pinning it straightened out all the warping nonsense quite thoroughly - dig the flatness of the bottom now.



Hobby plywood over the top of it all hides and makes captive the pins, and nudges up the width of the lockdown bar assembly to where it fits the depth of the front cabinet better. 

Had to use two pieces, because my pieces came in 24"s and the lockdown bar is a 25", but I've established to myself by this point that I can do the bodywork to hide the seam later on in the next round of filling, sanding, priming, painting, and complaining.

I smeared some wood glue and floated the two pieces where they belong:



Then I looked at it and said, "Man, I better put a clamp on that!"



DONE.   NEXT.



I determined that 25mm linear rail was the biggest size that could fit under the rotated TV when this is in driving mode, so I went with that - but where it mounts will cover one of the leg mounting bolts on the front cabinet, and it'd be nicer if it didn't.

The hardened steel rail itself clears, it's the aluminum extrusion it mounts on that blocks it - and there's no major load bearing path or mounting screw in that region. 

So I roughed a notch out of the aluminum extrusion with my bandsaw.



Sanding wheel in a dremel tool, little cleanup with sandpaper and files, and:



That'll do.


Located it on the front cabinet, installed 6 brass thread inserts, and bolted the rail and the newly remodeled lockdown bar onto the front cabinet, which concludes this update:





Next week, doing the same rail mounting to the back cabinet!

[Laythe]

Okay, I lied about the "next week" part, it turns out.

But I didn't lie about the rail.



The rear cabinet now has the matching rail to go along with the front cabinet.  These will carry the sliding control panel between them.

There are six thread inserts placed in the plywood to carry the rail.  These were trickier than in the front cabinet for three reasons.  One, the structure is a lot more complicated.  Two, when you take the rear hatch off, you can see the backs of the thread inserts and screws, so I cared more about them coming out somewhat clean.  Three, there's a lot of electronics and stuff in there, so I had to take all that out before drilling.

Overall, it went pretty well.  The drill scuffed the paint on the leftmost upper one -



I'll have to touch that up with a little more black.

The middle ones are kind of funny, because the lower screw and insert goes through the web that the intake fans mount in.



But, the fan will hide the lower hole.

On the right, they go behind the power relay input box.



The hardware doesn't protrude beyond flush, though, so the relay will slide back in over the top of these.


I tried setting the front and rear cabinet together so the rail trucks touch, and they appear to track real nice - these rails are flat to each other when the legs are flat to the floor.

The rails did prompt an interesting discovery, though.  My back cabinet isn't actually flat, it's got some dish to it.  As you can kind of see in this picture:



The ends of the rail are tight to the plywood, and there's a gap of maybe 1/8" in the center between the aluminum extrusion and the plywood face.  I'm going to make a spacer to fill this space, because I trust the linear rail to be straight a lot more than I trust my carpentry to.  This shouldn't hurt anything, but it was a surprise to discover.

[Laythe]

I was originally going to machine out some compound angle 3-degree-by-3-degree bushing flanges to mount the playfield axle to the front and rear cabinet.  However, I then found some remarkably inexpensive cast iron spherical bearing carrier pillow blocks that will accommodate that angle - so, sure, I'll go with that.

Problem is, they're painted dark blue from the factory, and that's just not going to work for this.  So, I'm priming them so I can paint them.



But, if I've got to get the primer out anyway, I might as well also do the bodywork on the lockdown bar carrier.  When last we saw it, the sides looked like this:



I built up the matching shape to the bottom curve of metal in plastiwood filler, and ended up with a profile like this on both sides:



(The remainder of the slot that I cut because I was lazy while inletting should hide under the lockdown bar.)

On the back, I am pleased at how quickly I was able to blend the seam between having 24" wide craft plywood and having to use an extra piece on the right end to fill to a 25" wide lockdown bar.  Red arrow indicates where they join.



Hiding the seamline almost wasn't even a fight this time.   

All these will need another coat of primer, some sanding, and will then get painted to match the machine.  Lockdown bar holder will be red with a black top edge, I've still got to measure out where exactly the bearings land to know what colors they get. 

I do also know I'm going to have to empty the rear cabinet out further to mount the rear bearing block, because it sits right over the buried DMD LCD panel.

[harveybirdman]

Dude.....

I know I don't post much anymore, but I just had to say....


This is freaking fantastic!

Great work Laythe!

 

[Troy]

 

[Laythe]

Thanks, HBM and Troy! 

Sorry for the long delay, everyone - my day job ate my face.  Today was my first full day off work this month.   

So of course I used it to make some progress.


First was some paint touch up over the scars from mounting the linear rail in the back cabinet.



On the left side, where the drill had kissed the floor, here it is all sanded out and covered up. 

In the center of the rail, a bit of black in the holes make them less conspicuous.



Back on the outside front of the rear cabinet, I spent a while looking at and thinking about the gap I had in the center of the 25mm linear rail due to the cabinetry being a bit cupped.  I wondered what the relative stiffness was, between that roughly inch sized hardened steel rod and the 3/4" plywood structure.  I tried setting my camera up on a tripod, looking down at it, and recording video, then tightening all the screws down to pull the gap out.

Reviewed the video.  It didn't look like the rail flexed.  It looked like the plywood flexed.

Hmm.

I set up a ridiculous lashup to set the dial indicator I use on my lathe and mill to reference on the center of the rail, and then very carefully worked the screws back and forth, from slacked out such that the gap was as big as it gets, to totally tight with the gap pulled flush.



Conclusion:  Under full screw tension, at the center, the plywood structure pulls about 0.2" out, and the rail pulls about 0.006" in.

I think I can live with six thou of possible curve over a 24" long run.  I think that's as nothing.  So heck with building spacers to go under it - I'm just going to crank it down and let the steel bar be the truss that straightens out the wooden box here.  I'll revisit that if the control panel balks moving across it, but given the panel is going to be a wooden structure about 42" long between the rails, I think it's fine.



I got my hands on the materials I'm going to be constructing the playfield axle from. 



1.5" OD, 1" ID, 0.25" wall thickness 6061 aluminum tubing will be the spine of the axle, with lathe turned endcaps made out of 1.5" solid round stock.

I think this'll be a strong enough axle to support the big panel and the flipper buttons (they end up pointing pretty much through it's centerline) and the TV mount assembly while being motorized.  Opinions welcome!
 
I plan to make the endcaps a three-section spigot.  In my head, they'll have a 1" diameter spud that fits inside the tube, then out to a short fat 1.5" diameter flange that matches the OD of the tube, and then back in to a 0.75" diameter spigot that goes into the bearings.  The bearings have two set screws to grab the spigot, and I'll drill through the tubing to countersink some small screws, tapped into the spud side.

(Come to think of it, that whole endcap description will probably make a lot more sense if you just look at them while I make them.  When I get to the part where I make them.)


I also got the first coat of red paint on the lockdown bar assembly.  Needs another couple coats, sanding, polishing, etc - but here's roughly how it'll look on the machine.



Sorry for all the seamlines, but these three pieces disassemble for service.  Also, the top is just set on for the photo, I think I can finagle the fit a little better. 

A need for another small detail like the red stripes on the rear hatch arises here.  Looking down on the profile of the lockdown bar, you can see the red part matches the front-back depth of the front cabinet, which is slightly deeper than the lockdown bar is...



This means it sticks out the back a bit.  Looking down on it from the pinball player perspective, that red is far too conspicuous - that's going to show a lot in the necessary gap between the lockdown bar and the pinball playfield.  (Some gap has absolutely got to be there for the rotation of the playfield to clear the front cabinet.)



I plan to fix this by painting the top edge - basically, the whole part you can see red in the above picture - black.  That shouldn't look bad from the side when you are in the cockpit, and should fix the problem when looking down at it as a pinball player.



Lastly, I also got the first coat of red on the axle bearing pillow blocks. 



Needs more coats, but they are going to match nice. 

It looks like the actual position for both bearing blocks lands wholly within the red parts of the front and rear cabinets, so they don't have to get a fiddly black lower section at all, they just go solid red.

I'll need to take the monitors out of the back cabinet for drilling and mounting the bearing blocks, and I'm triple and quadruple checking my math for where they land on the surfaces to get a 3' horizontal yaw and a 3' vertical pitch and the correct rotational centerline... that part is going to be kind of scary, I gotta admit. 

[jeremymtc]

1/4" quarter-inch wall Al tube should do just fine for the playfield axle I'd think, though I am unclear if it'll be a single continuous axle running the length of the playfield or two shorter stub axles. If for stub axles, it'll be way more than strong enough. If one continuous piece, it'll probably have some pretty substantial runout in the middle but will probably work decently all the same given those beefy pillowblocks and some allowance for endplay. I'm not sure what sort of linkage you might have going near the center, and that may mitigate some deflection there if you're going for the single-axle approach.

*edit - just reviewed your graphic on page 1. Looks like it is a single continuous axle with a bellcrank/clevis in the middle. The way that I might have gone would be with a wooden box section for the whole central playfield with the bellcrank fixed to that, and just simple bearing or spherical bearing pivots and axles at the head and control areas with some latches or spring/slide bolts to secure it either mode. Take my rambling with a grain of salt though since I'm not the guy actually executing the concept!

Really cool project and great execution here Laythe!

[Laythe]

jeremymtc - I'm picturing both one continuous axle and having that axle running through some supplemental structure.  (The renderings on page 1 are somewhat out of date now.)  As currently imagined, the bellcrank is part of the TV monitor mount structure, which includes a big plate of 1/4" aluminum that picks up some big scope-ring style clamps onto the axle.  So load path wise, it's kind of halfway between just the naked axle and your box-to-stub-axles approach, which I gotta say I do like - thanks for kicking some ideas around!

I've made a bit of progress on the axle endcaps.  Well, one of the two of them. 

I started with that 10" chunk of solid 1.5" aluminum round stock and bandsawed it in half into two 5" pieces.

I set up the outside 3-jaw chuck and grabbed the 5" bar by one end.  This is about as long as I'm willing to cantilever a piece of work out on my tiny little benchtop lathe - but it's only aluminum, and I'm patient enough to only take light cuts, so it works for me.  I got the runout at the far end down to about +-0.002 and then started cutting down the bearing-side pin.



Starting diameter, 1.51" OD. 

Target diameter, 0.749" OD.



This takes a while, at 0.005" deep cuts that reduce the diameter by 0.010" per pass... 

But I'm patient.  Maybe 75 passes later, it looks like this:



(Shown at left is some of the metal that came off this part.)

I'm leaving a full diameter 1.5" flange, which is why the stock had to start so big.  You can see where I'm beginning to cut down the center - that'll become the axle end, and reduce down to a 1.0" OD aiming for a friction slip fit into the axle tube for about 3" of length.

The bearing pin is a very snug fit into the bearing in the pillow block:



From here I just need to finish reducing the axle end down, and then part off or saw off the full diameter end that is currently in the lathe chuck.


Oh, yeah - and then do all that over again, for the other cap for the other end of the axle.  Good thing I enjoy this! 

[Mike A]

sweet metal working porn.

[Gilrock]

Nice.  I have a Jet 9x20 lathe.  I love working with aluminum but parting steel always scares me.

[jeremymtc]

As currently imagined, the bellcrank is part of the TV monitor mount structure, which includes a big plate of 1/4" aluminum that picks up some big scope-ring style clamps onto the axle. 

Your description makes perfect sense and sounds like quite a good solution. That should really help to add some column stiffness to the axle, especially if you can get the clamps spaced out a ways. 

I'm really enjoying seeing your updates on this project. Keep up the great work!

[bperkins01]

I've lusted after metal working equipment for years..  If I had a place to put it..  Very nice