Mimic's Sister - Shapeshifter

[Laythe]

Mike A - Thanks!
Gilrock - Right on, that 9x20 is the step up from my little Seig 7x12.  Aluminum's totally friendly to work with.
bperkins01 - Space is tough, yeah.  I've got tiny little machine tools, and they're still a substantial infrastructure commitment.

And now, on with the show.


I finished the first cap - here's what they look like when complete:



Pictured:  The amount of shavings it takes, the end product, and the blank they start from.

One down, one to go. 

The second blank goes into the lathe, and then I spend a while tinkering with the grab in the three jaw chuck. 



I fiddled around with it until I got it indicating 0.001 on the high end and -0.0005 on the low end.  Given my hasty not-square indicator placement, I'll call that within two thou anyway.  Good enough!

Then, play on the lathe for hours.



The flange is 0.300" thick, the bearing side pin is 1" long, the length of the axle side pin is adjustable by wherever you part it off at...

Spend most of the day in the shop making shavings...  end up with this:



Two matching endcaps, and a ball of compacted shavings roughly the size of my head.   

Here's how it all assembles up:



Only the flange shows, between the axle and the bearing block. 

(Yeah, they would have been easier to make without that flange at all - but I think this is classier.)



They're a tight work-it-together slip fit on both ends.  The chamfer kind of fairs the diameters together, makes it look like this stuff belongs together.

I haven't cut the tube to length yet, so it's still 48" instead of... the really weird number it ends up being... but here's the whole axle core put together:



As it turns out, the ID and OD on the center tube aren't quite concentric, so there's a bit of runout when you spin it - but considering this thing is only ever going to make 1/4th of a turn back and forth, it's gonna be OK.

[Laythe]

Now that I've got the axle complete except for cutting the tube to exact length, it's time to build the structure that rides on it.

The axle tips up 3' and angles left 3'.  The TV needs to mount on this tipped up another 3' and rotated 3' right.  That way, in pinball mode, it's straight but angled up 6', and in driving mode, all the 3s cancel and it's straight and level.  That means I have to build a very carefully crooked mounting structure, which turns out to be quite a bit more difficult.

Here's the major parts:



I let my dad waterjet the brackets; feels a bit like cheating, but man they sure turn out nice.  Having the tool available, I designed them in a manner well suited to the waterjet but fairly impossible to fabricate most any other way.

These brackets will clamp onto the axle, by squeezing the long slots together a few thou.  If it weren't for the waterjet, that wouldn't be a captive slot... it'd have been a two-piece clamp so I could get my bandsaw in there. 

The bracket on the left is the one that runs closer to the player when in pinball mode, on the low side.  I didn't like how little metal would have been left between the axle hole and the deck, so I put a dovetail there to gain the 1/4" thickness of the front plate around the hole.

This dovetail requires a matching cut in the plate.



This is midway through me filing the plate to fit.  The dovetail is complicated by the edge of the bracket being cut at the matching 3' angle - these join up to form an 87' angle, not a 90'. 

Each of the brackets gets 5 holes drilled through it - the ones on the ends will clamp the bracket to the plate, the ones in the middle close the clamps against the axle. 



There's some fancy drilling to be done, with regards to those rectangular holes in the tall bracket.  I wanted more strength than I felt I could get from aluminum threads. Those rectangles are exactly the size of 5/16ths nuts.

So... just drill 2" deep, in from the top... and hit the center of those windows at the bottom.



Like this.   

Twice.

Result:



The clamping screws engage the nuts, the captive nuts can't turn because the rectangles are only the flat-to-flat length, not the corner-to-corner length, and the threads are all steel-on-steel.

(I did have to nudge the rectangles a little with a needle file to get it all to work, I admit.)


I have yet to drill the countersunk holes in the plate to catch the heads of the hardware, but with the parts set together to get a sense of how this subassembly will go:

From the back:



All the empty holes will have the ends of machine screws (heads countersunk in the plate side) coming out of them, with nuts on top from this view.


From the TV mounting side:



jeremymtc - now you can see what I mean, that it's somewhere halfway between stub axles off a box structure and a mount plate hanging in the middle of a freestanding axle.  With both clamps tight on the axle, the plate should be a good doubler over the axle, I think.

There will be 4 holes drilled near the center of the plate to take the VESA mount layout of the main playfield panel.  That pattern of holes, of course, will be rotated 3' clockwise off of square on the plate, to cancel for the unwanted half of the axle tilt in each game mode.

This compound angle business is complicated.   

The semicircular ears you can see sticking off the top of the plate with small holes in them will be drilled out to pick up a .250" spring steel rod 24" long, to form the bellcrank arm, the center of which will be grabbed by the linear actuator that rotates the table.  That should give it a little bit of shock absorption for the abrupt start and stop - if that proves to be too much spring, I figure I'll just bring more additional mounts in closer toward the centerline to shorten the effective spring length.


Still a bit more fab work to go to get the plate attached to the brackets.  I'm looking forward to testing the bearing carrier blocks mounted on the axle with the axle mounted to the TV, to check if my excitingly close clearance when the corner of the block swings past the TV on the low side turns out to be positive or negative. 

[Malenko]

This is some amazing engineering. The nut cut out is genius.  When I start Ginger 3.0 I'm going to hire you for a custom lock down bar.   

[jeremymtc]

Laythe, that looks fantastic! You weren't joking when you mentioned that the center carriage was going to be beefy. That thing is going to be rigid as hell. I'll bet that you could just about cut out the center portion of the axle between the clamp flanges out and still be just fine - what you've basically built is an IMSA-style adjustable racing sway bar, just made from aluminum instead of spring steel and without any design tendency to twist.

 

[Laythe]

This is some amazing engineering. The nut cut out is genius.  When I start Ginger 3.0 I'm going to hire you for a custom lock down bar.   

Thanks!

I'd try it, in aluminum, if you like - but I say that while pointing out, I bought a factory Williams lock down bar and designed around that because I wasn't confident I could form one out of sheet stainless for my own build.

I think my best odds of success to make a nice looking lockdown bar would be to grind the corners down on one big solid piece.  I'd start with something like a 1.5"x3.5" or so of aluminum bar stock, length equal to the width of your cab.  I'd grind whatever angle taper you want across the bottom of it, and then grind the corners out to that nice generous radius that feels good under the hands.  Unless you absolutely need the volume inside, you could build your cabinetry with a L-shaped missing corner notch that that solid bar fit along and filled out.

(If you really need the volume inside, I'd still do it solid and then try to mill the inside of it out, I guess.  That'd be a long battle.  The solid bar's actually WAY easier.)

Some coachbuilder with an english wheel and a innate visceral grasp of sheet metal forming might be able to hammer out a lock down bar out of sheet metal and end up with it looking good.  Slippy might know an armorer with panel beating skills like that.  I'm fairly sure the commercial bars are stamped between male and female dies.  Those draws are *deep*.

TLDR version:  Yeah, I'd be game, especially if my proposed solid version meets your design needs.  PM me.

Laythe, that looks fantastic! You weren't joking when you mentioned that the center carriage was going to be beefy. That thing is going to be rigid as hell. I'll bet that you could just about cut out the center portion of the axle between the clamp flanges out and still be just fine - what you've basically built is an IMSA-style adjustable racing sway bar, just made from aluminum instead of spring steel and without any design tendency to twist.

 

Ha, you're right!  Would never occurred to me, but there is a resemblance there.  That's funny.   

It's true, the center of the axle is probably redundant, but it does clear everything in the design, there's just enough space for it to run through like this.  Belt-and-suspenders logic - the extra strength can't hurt.

Thanks for the consultation.  Glad this looks like it'll work to you as well.

[javeryh]

This is so far above my skill set I'm just blown away.  Incredible.

 

[Laythe]

More work on what I've taken to calling the "TV tray", because it kind of looks like a TV tray, and in my application it is the tray the TV bolts to.

The big plate got 3' right-leaning (from this view) drilled countersunk holes for the brackets, and a 3' clockwise rotated 300mm square of M6 holes for the television to mount to.



I probably made a mistake using this 5/16ths inch hardware in the brackets - you can see the edges of the heads of the hardware touch the edges of the plate.  The webs of remaining metal on the outside edges of all the countersinks are thinner than I'd like.  It's mechanically sound - even if the webs had blown out the plate would still be pinched between the screwheads - but I think the assembly might actually have been a little stronger if I'd only gone for 1/4" hardware instead.  I didn't blow out any webs, but there was some pucker factor toward the bottom of drilling out those countersinks deep enough.

(The screw heads, and the dovetail on the left, all had to be flush because the TV will sit on all of this.)


Next, I took a big file to the end brackets and chamfered all the corners that don't touch the plate, by hand.  I like the gleam of light an eased edge can catch.  Gave the brackets the kind of polish this whole assembly will eventually get, while I was at it.

I also built the op rod that the actuator will grab; .250 steel bearing shaft, which has a nice spring to it, with domed ends, and crossways holes for what I've always called cotter pins but which I just learned are probably correctly called hitch pins?



The pins sit over stainless washers to protect the aluminum. 

This oprod will slide through a bushing in the captive eye on the end of the linear actuator, and being able to slide it out to get the actuator out will make assembly easier.

Looking at the TV tray assembly more from the side,

you can see that the oprod runs exactly parallel to the main axle.  (You can also see what I mean about that eased corner catching the light pleasantly, under the axle, now that I've knocked the sharp corner off.) 

From the other side,

you can see that the oprod very much is NOT parallel to the plate. 

This view also gives a sense of the size of this thing - it is moderately massive. 

The playfield TV will extend another 9" or so off each end of the plate, so that's how long the axle ends will also end up trimmed to.

I'm going to cut a few window holes in the plate where air vents existed on the back of the TV so I'm not covering over them, and then I'll knock the unneeded sharp corners off the plate like I did the end brackets.  I'll also polish it, just because.  This assembly will be visible in the final setup when it's in driving mode if you stand on the pinball side of it.  There's about $150 of aluminum here - might as well make it look nice.

I think the next steps from here are going to be making the brass bushing for the actuator, measuring out the exact (complex) length for the axle and trimming it, bolting the TV onto the tray, testing the axle bearing block to TV clearance to see if I have to grind one corner of one block down slightly, and then maybe testing the linear actuator rotating the TV.  I may need to build a counterweight to balance the final assembly on the shaft instead of relying on the actuator manhandling the unbalanced weight.  It's rated for 22lb, so it might be close enough without.

[yotsuya]

You one crazy mofo, my friend!

[Mike A]

That thing will survive orbital bombardment. I love it.

[Gilrock]

Gotta admit I'm totally lost on how or where this installs into the cab...lol.

[Laythe]

Gotta admit I'm totally lost on how or where this installs into the cab...lol.

Hehe.  This thing connects the front cabinet to the rear cabinet.  Mounts in bearings at both ends.  Holds the playfield monitor.

[Laythe]

I previously said that I thought the next steps from here were going to be measuring out the exact (complex) length for the axle and trimming it, bolting the TV onto the tray, testing the axle bearing block to TV clearance to see if I had to grind one corner of one block down slightly, and then maybe testing the linear actuator rotating the TV to see if it needed a counterweight.

I measured the exact axle length and boy it messed with my head.  I know I've got a bizarre 42.33" distance cabinet to cabinet to make the room the angled monitor needs to sweep on it's compound offset angle, I know the bearing blocks are metric chinese parts with a spherical bearing that isn't flush to the front or the back of the block, so I've got to allow for the height to the rotational center of each bushing plus the distance to the axle collar ends when they are inclined 3' and skewed 3'...  so I build a really high fidelity CAD model of all that to take measurements off, because I know it's going to be some bizarre number...

... and it ends up being 39.5000"

This is like when you do your taxes and get a round number to the hundreds. 
I tell you what, I triple checked my math.

I've got the axle cut to that.  I bolted the TV to the TV tray, and test fit the bearing blocks.  Turns out the clearance was negative, one corner of one bearing block will need ground back about 1/10th of an inch.

This all gets me close to being able to attach the bearing block carriers to the front and rear cabinet, so I got to thinking about the hardware for doing that.  The blocks have enormous holes, like they're expecting some kind of crazy huge 12mm bolts.  I want to set these in thread inserts in the plywood, same as the linear rails below, and I can't afford a lot of bolt head size because of the tight (already negative, in fact) clearance on that one corner.  So I decided to make up some spacers.

The eight spacers I need are all in this piece of round stock...



They just don't know it yet.

First I reduced the whole diameter to the 0.600" I figured I can fit into my final clearance, which I want for the outer flanges.

Occasionally, the lathe goes into self cleaning mode - if the curler coming off the tool interacts with the pile of curlers in the chip tray in a certain way...



... the resulting birds nest spins with the part, scoops up all the loose shavings, and showers you with glitter and confetti.

Good times.

You can also see at the bottom of that picture a brass clamp I made a long time back.  This is an upgrade I made - it slides on the ways, and if you tighten it down, it forms a carriage stop.

Setting it carefully and locking it down lets me work confidently really really close to the chuck, like so:



which I wouldn't have the nerve to do if not for it keeping me from moving any further left.

I kept working my way down the bar, drilling a bit farther, cutting the shape I needed, and then parting off each spacer.



The result:  8x spacers that thumb-press into the bearing blocks, internally fit 1/4-20 button head machine screws, and look kind of nice.




I ground the problem corner back, re-radiused it, primed it and painted it, and here's the whole kit together:




Here's a closeup to show the new contour of the block, and why it dictated the head size of these spacers and the hardware.



This contour now clears the monitor by about 1/16" when it rotates, and the spacer and bolt don't extend at all beyond it, so this should work for the low side where things get tight.  (No mods are necessary on the other block, the high side has got a mile of room.)


I hope to mount these blocks soon, now that I've got my hardware for them all sorted out.

I've also decided I'm going to need a spring and/or counterweight to assist the linear actuator - the TV is startlingly heavy, and being even the few inches offset off the axle that it is, makes the force requirements to swing it uncomfortable as things stand.  I've got room in the design - it's just going to be more stuff to fabricate. 

[bperkins01]

Thanks for the update.. So fun to watch machine tools in action. 
Very well done.

[Laythe]

Time to mount the front bearing block to the front cabinet.

There's a decent amount of guts in a small amount of space inside the front cabinet, so I did some disassembly here just to be on the safe side. 

This is the view with the rear wall removed, looking at the back of the coin door from inside:



(There's room for future solenoids in here if I can keep them under 1 1/8" tall.)

I spun the rear wall around, and did an obsessive amount of measurement and layout to locate the footprint for the bearing block.



The margin for error on this is small.  The position of the axle is designed for a lot of things to barely clear a lot of things, all at once. 

The back of these fasteners are going to be visible through the coin door, so I drilled the small centered hole shown all the way through, then used a 3/8s forstner halfway in from the front and halfway in from the back, meeting near the center, then opened the hole out with a 25/64ths drill to smooth the join and get the fit I want on the threaded inserts.  This kept the holes on both sides pretty clean.

Installed the thread inserts, and, for the first of several moments of truth:



There it is.  All the hardware fits, bridging my spacers into the thread inserts - that's a good start. 

A long time ago - back in February - Arroyo mentioned expecting that he'd be seeing holes for the axle before the paint went on, and that he was curious how this was going to go.  3+ months later, here you go - this is how this part goes!   

I looked up the shear strength of stainless 1/4-20 bolts, out of curiosity, and I'm seeing a conservative safe working load of 200lbs each, with an ultimate yield around 2000lbs - given I've got 4 of them per end, I feel I'm OK for the weight of the TV on these anchors.

I couldn't leave well enough alone at this point, so - satisfied that, theoretically this bracket should be FINE with half of the weight of the TV assembly on it - I plugged things together for a very heavy mockup.

Gotta admit I'm totally lost on how or where this installs into the cab...lol.

This should answer the question.  Here's a mockup of driving/simpit mode, as seen from the back:



So, that's what all that TV tray chassis is for.  (Pretend I'm the back cabinet and backbox; I haven't mounted that bearing block yet.)   


It all seems to work so far - the axle tilts up, but the TV tilts down on the mount.  The axle leans toward the camera, but the TV leans away from the camera on the mount.  They cancel.  The playfield monitor is square to the front cabinet and level. 

The actuator to motorize this can be seen in a few of these shots; it's on the floor under the TV in this last picture.  It'll be perpendicular to the axle - which is 3 degrees off of parallel with the legs, mind you - grabbing the op rod at the top of the TV mount, with the other end bolting into the structure of the back wall (still to be built). 

My next steps from here are probably locating the bracket onto the backbox, VERY CAREFULLY mocking up the TV between the front and back cabinets, and then tuning the axle length and the position of the axle in the clamps until my gaps on both ends are as close as I'm comfortable getting them without the TV corners rubbing.  Then, I'll know the ground truth correct distance between the cabinets... and then from there, I can build the shelf that connects them and the T-shaped back wall to that precise length, and eventually the driving/flightsim control panel to that length minus the linear rails.

Long way left to go.

[Vigo]

Looks great!

[Arroyo]

Any thought I had of copying this one day went out the window once I saw that metal work with the lathe.  This is incredible work. 

I’m still trying to wrap my head around the axel and tilt.  In the picture it looks like your physically tilting the axel up at the back, but I would assume that it would be a problem on the bearing (unless you mounted them at an angle which it didn’t appear from the picture.  If not tilting the axel (which I thought you weren’t because it looked like your TV Mount was supplying the tilt), then wouldn’t the right side of your monitor be tilted in towards you when in sim mode?(which wouldn’t be a big deal).  Also can’t figure out why the TV tray is rotated slightly. 

[javeryh]

Any thought I had of copying this one day went out the window once I saw that metal work with the lathe.  This is incredible work. 

I don't even know what I'm looking at with this project but it is seriously awesome.   

[bperkins01]

This image explains the offset



As a pinball machine - the screen is angled - as a driver - the screen is level.

The tilt corrects for the transition.

Does that help?  (pretty slick)

[Mike A]

Yeah. It is great and all, but does it cook waffles?

[Laythe]

Looks great!

Thanks Vigo!

Any thought I had of copying this one day went out the window once I saw that metal work with the lathe.  This is incredible work. 

I’m still trying to wrap my head around the axel and tilt.  In the picture it looks like your physically tilting the axel up at the back, but I would assume that it would be a problem on the bearing (unless you mounted them at an angle which it didn’t appear from the picture.  If not tilting the axel (which I thought you weren’t because it looked like your TV Mount was supplying the tilt), then wouldn’t the right side of your monitor be tilted in towards you when in sim mode?(which wouldn’t be a big deal).  Also can’t figure out why the TV tray is rotated lightly. 

bperkins01 is correct, he gets a gold star.   

I am tilting the axle up at the back.  The bearings are spherical in the carriers - they'll spin like a ball joint inside the block and conform up to about 20' of angle if you ask them to, in any direction.

The TV mount provides some tilt, absolutely. 

The TV being tilted in in driving mode would bug the crap out of me, that'd be a dealbreaker for me. 

All of these things are related, and it took me a while to wrap my head around it too.  So, try to follow:

Put it in pinball mode.  Stand where a pinball player would.
From this perspective, the axle is tilted up 3' in back.  That's that lift you see me doing, lifting it up extra in the pic.  The axle is skewed LEFT 3' too. 
The TV tray is tilted up 3' in back because the mount is a wedge, like you noticed.  The TV is mounted skewed right 3' on the tray.

Result:  The tilts add, so the table is tilted up 6'.  The skews cancel, so the TV is straight along the length of the machine.

Now, transform it to driving mode by rotating the axle 90'. 
The axle spins along it's axis, but doesn't move the endpoints.  It's still tilted up 3' in back, and skewed left 3'.

The 3' wedge tilt of the tray is now cancelling the 3' left skew of the axle.
The 3' TV rotation skew on the mount is now cancelling the 3' up tilt of the back of the axle.
Result:  Everything canceled, so the TV is level and perpendicular in the machine. 

(Basically, half the pinball lift is provided by the axle being not straight, and half the pinball lift is provided by the mount.  All those 3's above are one half the 6' of playfield incline I wanted.)

Yeah. It is great and all, but does it cook waffles?

If it cooks anything, I screwed up. 

I'm not ruling that out.   

[Mike A]

Cooking waffles is never a screw up.

That is some smart design work. I was wondering how you were going to angle the pinball playfield and then have a horizontal driving screen.

[bperkins01]

I'm thinking ejection seat for people who really need to be removed.. 
even just dumping them backward on their head will do   

[Arroyo]

The bearings are spherical in the carriers - they'll spin like a ball joint inside the block and conform up to about 20' of angle if you ask them to, in any direction.

Ah the missing link.

Very good explanation, I remember you mentioning spherical bearings, but didn't really understand what that meant.  Didn't know that those existed but now I totally get how you are doing it.  Very creative, I imagine the research on this project must have been a bear.  Nice work

[wp34]

I don't mean to pile on but wow!  What a cool and fascinating project.

[Laythe]

That is some smart design work. I was wondering how you were going to angle the pinball playfield and then have a horizontal driving screen.

Thanks!  The conceptually simpler but mechanically more complex way would have been another actuator - something like a jackscrew that either kicks the back end of the monitor up 6' for pinball, or pulls it flat to the axle for driving.  Given the TV rotate is an actuator, and the control panel retract/extend is an actuator, and the chair retract/extend is another motor of some kind, I didn't really want to add a FOURTH one.  I'll just deal with the crazy angles.

I'm thinking ejection seat for people who really need to be removed.. 
even just dumping them backward on their head will do   

Hahaha!  Yeah, when we get to the motorized chair, we'll see... I've had nightmares about misprogramming the stow sequence, and somehow crashing somebody sitting in it up into the TV. 
(Talk about force feedback.  Most realistic video game crash physics ever - once.  Though I doubt the actuating motor will actually be strong enough to do that, even if I were to screw that up.)

Very creative, I imagine the research on this project must have been a bear.  Nice work

Thanks!  Yeah, the research and the CAD model have both been pretty hefty. 

The whole thing is too complex for me to keep in my mind at once.  Portions of the floor and chair track are not yet even final designed, I'm just leaving myself a lot of space to work it out as I get closer.  I knew that if I waited until it was 100% Design Complete before I started working, I'd never even start.  As a result, this thing has a fairly terrifying gradient in it - from parts like the front cabinet that are basically finished, through parts like the TV assembly that are designed but not finished, through parts like the shelf and back web and control panel that are designed but not yet even begun, through parts like the floor and the chair actuator that are not even completely designed.  It's good in that it leaves me many kinds of work to vary between to keep the project interesting - but it's downright scary to not be certain I haven't painted myself into some impossible corner that I just haven't realized yet.

It's an open wager, whether future-me is smart enough to solve everything that present-me is leaving him to figure out.  I guess we'll all find out.  Some problems are easier solved with the thing physically in front of you, and some can become impossible short of starting over.  I just gotta ask myself, do I feel lucky?  Well?  Do I?   (Wait, no, that's what yamatetsu had to ask himself, my mistake.)

I don't mean to pile on but wow!  What a cool and fascinating project.

Thanks! 

Pile on!  This thread is a party, and everybody's invited.

You can even post just to tell me I'm a crazy mofo - Yots is not wrong.      

I encourage all commentary.  If you're reading and thinking about whether or not to say something, pull up a chair.

[Gilrock]

Ok I get how the axle will spin the TV now but does that mean you play pinball from the front and then when you flip the TV vertical you gotta move over to the side of the cab for a driving game?

[PL1]

does that mean you play pinball from the front and then when you flip the TV vertical you gotta move over to the side of the cab for a driving game?

Yes.  In pinball mode, the seat, steering wheel, and pedals are stored underneath the playfield.

When you switch to driving mode, the seat, steering wheel and pedals slide out on tracks and the playfield monitor rotates.




Scott

[Gilrock]

I'm sure that reply means more if I could see whatever photo you posted....lol.  All of Laythe photos show up just fine but whatever you posted is blocked from my location.  So if I have design suggestion do I come back to you or Laythe?  Just seems weird you answering for him.

[Laythe]

Gilrock -

PL1 is correct. 

Walking around to the side is how I solved the portrait vs landscape thing - vpins are portrait, sim cockpits are landscape.

I'm the one for design suggestions.  bperkins01 and PL1 have both figured out how the thing works, and I'm glad for their help explaining it. 
The photo PL1 posted is an animated GIF render from page 1 that shows everything rotating and moving.

[Gilrock]

So is it too late to suggest 2 different cabinets?

[Laythe]

This IS the second cabinet - it's for all the stuff I couldn't make Mimic do!   

[Gilrock]

You're doing great mechanical work and it will be a design masterpiece.  But I think it's missing what can make a vpin cab awesome.  Are you going to have any vpin "toys"?  Contactors, gear motor, shaker, leds?  Mine feels really close to playing a real pinball with the contactors providing physical knocks when flippers and bumpers are hit.  When I hit the alien ship in Attack From Mars the shaker vibrates the entire machine.  When I nudge the cabinet the ball reacts.

[Laythe]

The machine is going to weigh something in the neighborhood of four hundred pounds maybe, and I don't really want anybody manhandling it, so I'm not going to do physical nudge. 
I'm considering possibly setting up the lockdown bar to slide left-right on the top of the front cabinet on a stiff rubber centering grommet, and making that the nudge input - I think that might be a cool way to do nudge.  That's a down-the-road version-2 type upgrade possibility though.
The design limits me from being able to do an analog plunger, I don't have the depth for it - but that and inertial nudge are the only things that I can't do and might have done if this were a conventional vpin.

I've got contactors for the flippers in hand and planned into the design, and room in the front and back cabinets for more if I decide to add more; the back cabinet may get a knocker.

[Laythe]

Got the second bearing carrier attached; now the back cabinet has one as well.



The thread inserts I'm using are slightly under 3/4" long, which is important.

Here on the inside, with all the monitors removed, you can see where the four mounting bolts ride...

(Also, Gilrock - in this next photo you can see the side cheeks under the backbox are largely empty, that's temporary wire routing stuffed in there.  These are one example of a place I might put some bumper solenoids later.)



The four mounting bolts exit right on the display face of the unused portion of the DMD monitor, so it's critical that all of that hardware be below flush. 

They are below flush; the DMD monitor slides down over it without a problem.



If any future owner puts over-length replacement screws there, they're going to have a bad time.   


I still have to cut one more large via through the front face of this cabinet, down below the DMD monitor, just above the power plugs, but beneath where the as-yet-unbuilt shelf that connects front and rear cabinets will land.  That via will carry an aluminum plate with a bunch of connectors on it; the front cabinet DB25 will attach there, as well as a few other subsystems.  Once that is done, I can repopulate the back cabinet completely, and it will be done-ish except for details like the backbox front fascia.

The next big step, though, is going to be tuning up the TV axle subassembly - now that both bearing blocks are mounted, I can hoist the TV between them.  I'll nudge the clamp placement until the clearance gap on the front cabinet is right, and then I'll measure out how much length I still need to grind off the axle to make the rear gap correct, and creep up on that dimension a bit at a time with test fittings between.

[Gilrock]

Well I wasn't even going to say anything because I don't want to be negative but you prompted us to give feedback.

I never saw you comment in my thread so if you missed it:  Hyperspace Pinball

I've also authored a table in Future Pinball and Visual Pinball so I really like the pinball stuff.

[Laythe]

No worries!  I totally appreciate the feedback - sorry if I sounded otherwise.  Tone is difficult over text.    

I hadn't seen your project thread - I'll check it out. 

[Ond]

I'm keeping my comments to only the best of the best projects.  Right now, this is it.  Wonderfully ambitious and very inspiring for its innovation and coolness.  I get what it means to be able to design and consider individual components and their functions and then integrate and add them to the whole.  Too complicated to keep all in your head, but broken down into individual functions things make more sense.  With CAD skills you can examine complex designs before any construction ever takes place.

Bah, it does nothing but rain where I am, stuff like this keeps me checking in to BYOAC and thinking of my own projects.

[Laythe]

I'm keeping my comments to only the best of the best projects.  Right now, this is it. 

Wow, thank you.  That's better than a UCA.

Bah, it does nothing but rain where I am, stuff like this keeps me checking in to BYOAC and thinking of my own projects.

I'm glad this is a comfort to you.  If my thread indirectly contributes in some small way to more Ond cabinets existing, that's extremely worthwhile.  Malenko also mentioned enjoying this detailed format, so I'm going to keep at it.

In today's episode, I learn a valuable lesson about trust from Mr. Forstner Bit. 


I'm going to have a metal plate, about 3" x 4.5", on the front face of the back cabinet, with connectors on it.  This plate will host a DB 15 that goes to the retracting control panel, a DB 25 that goes to the front cabinet, and probably a second one of each in the other polarity to account for the to-be-built limit switches, actuator signal lines, flipper buttons and vpin toys.  (The connectors are for me being able to transport the thing from my shop to the room it'll live in, which I think is going to take about five trips, so I'm building it to be a bit modular.)

I probably should have cut this before painting and polishing, but, no problem.  I'll just use a forstner bit - they make beautiful consistent holes with finished sides in my experience. 

My via is going to be taller than it is wide, I plan to use two overlapping forstner holes with a bit of cleanup to connect the sides together afterward to make a round-ended capsule shape.

First, I predrilled the centers all the way through from the back with a small drill to make a pilot for the triangular point to follow and to transfer the location onto the front face so I could see it. 



These pilot holes are on 1 1/2" centers, so the biggest forstner I've got at 2 1/8" for a 1 1/16" radius won't clip the other hole's pilot location.

I chucked up my big forstner, and here I am ready to go.



You can see the pilot holes on the front face, to the left of the bit.

I figured I'd cut into both pilots from both sides fairly evenly, taking turns in all four locations.  I cut from inside the box first, just skimming the paint off and starting the circle, high and low, and then did the outside high and low.  Back to the inside, and the high hole did something I've never had happen before - the pilot hogged out to the left and the whole circle shifted sideways.



A forstner of this size in a hand drill is not so stable and clean as every prior experience I've had with them.  I shoved it hard to the right while cutting and managed to reestablish the hole back where it belongs, but you can see the crescent of accidentally destroyed surface there. 

That was sobering. 

Okay, these things aren't as safe and precise as I expected.  I decided at this point on a new plan:  if they're not completely predictable, I'm going to continue doing most of the cut from the inside of the box, where any damage will be less apparent.  There's going to be a metal plate covering the outside of the hole, sure, but any damage extending further than the plate overhang, would show in the end. 

I've basically crawled half inside the back cabinet, working from behind the machine, and I'm carefully drilling the two holes from the inside, cutting toward the outside... when all of a sudden the bit grabs like I've never had a forstner grab before, and I hear a mighty crack.

I pull the bit out, and I find this.



I don't even want to walk around to the front of the machine.  For a long moment, I suffered that same irrational magical thinking as happens sometimes when you injure yourself - if you don't look, it won't hurt, right? 

That's a thick, thick splinter.  That tore out a LOT of wood.  I just don't even want to look.

But no, that line of thinking doesn't actually work.  So I walked around to the front with a heavy heart to see how bad it was. 

Here's what I found, from the front.



Amazingly, that shallow cut I'd done from the front was enough to stop the crack from propagating across the edge.  How lucky is THAT.  The whole perimeter of wood I need is still sound.

I sat down and caught my breath for a bit, and decided I've learned a valuable lesson about trusting very large forstner bits in plywood.  I was disinclined at that point to even touch the hole again with the forstner - I got off lucky, I'm not pushing my luck.

The safest way to salvage this mess seemed to me to be my dremel, and a burr cutter.

So I spent a good hour excavating out to the edge that way.


 
I flipped over to a little drum sander on the dremel after getting both the cores out, and smoothed it back to the line, and removed the rest of the points between the holes.  I think this counts as a total save - the end result looks almost as good as I'd hoped in the first place:



Considering I'd planned almost half an inch of overhang of the plate on all sides beyond the edges of this hole to cover for imperfections, I'm feeling pretty good - this will do.  It could have gone so much worse, and for a minute there I thought it had. 


Zooming out a bit to put it in context with the rest of the rear cabinet, here's the big hole after cleanup, ready to get the edges painted black:



I can live with that.  It'll do, especially with a plate over it.

There will be two big structural features near here that connect the front and rear cabinets - a back wall web to the left along the left edge, and a roughly 1x8" shelf that goes below the bearing block, but above this cable via panel.

My next couple steps from here will probably be to tune the position of the TV tray on the axle to get the front gaps right, measure and trim the axle to exact length to get the rear gaps right, and then I'll know the true distance between cabinets to build those two structural features.  Once those are built, Shapeshifter will be able to free-stand and self support, and I'll be able to play with the playfield counterweight and screen rotation actuator in earnest.

[Laythe]

For the first time, Shapeshifter bears it's own playfield display weight. 

I clamped boards along the legs to box up the bottom, so the end cabinets don't tip apart or tip over.  But the weight of the TV, on the axle, is going through the bearing blocks, and if I take the temporary clipped-on pinball flipper button holders off the sides, the TV can rotate 90' and the clearances are tight-but-not-touching on both ends.



Look ma, no folding table!



And now that everything's in place, I can wire it up again and "work on the software" a bit more...



(The vertical propstick is just there to stop the TV from rotating of it's own.)

I'm going to need to make a lot of counterweights, but getting it freestanding is pretty cool.  I'm chuffed.

[Mike A]

It is starting to take shape now.